| Message ID | 20171103232445.B2FB241C85DF3@oldenburg.str.redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | Linux: Add memfd_create system call wrapper | expand |
This should have a NEWS entry. (I have not otherwise reviewed the patch, but support the general principle of adding bindings for non-obsolete syscalls, including as Linux-specific APIs if we don't think they are appropriate for the OS-independent GNU API with a generic ENOSYS version.)
On 11/04/2017 12:48 AM, Joseph Myers wrote: > This should have a NEWS entry. (I have not otherwise reviewed the patch, > but support the general principle of adding bindings for non-obsolete > syscalls, including as Linux-specific APIs if we don't think they are > appropriate for the OS-independent GNU API with a generic ENOSYS version.) Thanks. I added this to my local copy: * glibc now provides the <sys/memfd.h> header file and the memfd_create system call. Florian
On 03/11/2017 21:24, Florian Weimer wrote: > The system call is somewhat obscure because it is closely related > to file descriptor sealing. However, it is also the recommended > way to create alias mappings, which is why it has more general use. > > No emulation is provided. Except for the name of the > /proc/self/fd links, it would be possible to implement an > approximation using O_TMPFILE and tmpfs, but this does not appear > to be worth the added complexity. I agree an emulation is not worth the trouble. > > 2017-11-03 Florian Weimer <fweimer@redhat.com> > > Linux: Add memfd_create system call wrapper > * sysdeps/unix/sysv/linux/Makefile [misc] (sysdep_headers): Add > sys/memfd.h. > (tests): Add tst-memfd_create. > * sysdeps/unix/sysv/linux/Versions (GLIBC_2.27): Add memfd_create. > * sysdeps/unix/sysv/linux/syscalls.list (memfd_create): Add. > * sysdeps/unix/sysv/linux/sys/memfd.h: New file. > * sysdeps/unix/sysv/linux/**.abilist: Update. > * manual/llio.texi (Memory-mapped I/O): Document memfd_create. > * support/Makefile (libsupport-routines): Add xreadlink, xstrndup, > xunlink. > (tests): Add tst-xreadlink. > * support/support.h (xstrndup): Declare. > * support/xunistd.h (xunlink, xreadlink): Declare. > * support/temp_file.h (support_create_temp_directory): Declare. > * support/temp_file.c (support_create_temp_directory): New function. > * support/support_chroot.c (support_chroot_create): Use it. > * support/xreadlink.c: New file. > * support/xstrndup.c: Likewise. > * support/xunlink.c: Likewise. > * support/tst-xreadlink.c: Likewise. > Missing sysdeps/unix/sysv/linux/tst-memfd_create.c entry. > diff --git a/manual/llio.texi b/manual/llio.texi > index e72c53c785..5ab68e1511 100644 > --- a/manual/llio.texi > +++ b/manual/llio.texi > @@ -1775,6 +1775,40 @@ the given @var{name} previously created by @code{shm_open}. > On failure @code{errno} is set. > @end deftypefn > > +@deftypefn Function int memfd_create (const char *@var{name}, unsigned int flags) > +@standards{Linux, sys/memfd.h} > + > +The @code{memfd_create} function returns a file descriptor which can be > +used to create memory mappings using the @code{mmap} function. It is > +similar to the @code{shm_open} function in the sense that these mappings > +are not backed by actual files. However, the descriptor return by > +@code{memfd_create} does not correspond to a named object; the > +@var{name} argument is used for informative purposes only. The > +descriptor can be passed between processes (for example, over local > +domain sockets), and mappings at the same offset refer to the same > +memory, or the descriptor can be used to create alias mappings within > +the same process. > + > +The descriptor initially refers to a zero-length file. Before mappings > +can be created which are backed by memory, the file size needs to be > +increased with the @code{ftruncate} function. @xref{File Size}. > + > +The @var{flags} argument can be a combination of the following flags: > + > +@table @code > +@item MFD_CLOEXEC > +The descriptor is created with the @code{O_CLOEXEC} flag. > + > +@item MFD_ALLOW_SEALING > +The descriptor supports the addition of seals using the @code{fcntl} > +function. > +@end table > + > +The @code{memfd_create} function is specific to Linux. > + > +@end deftypefn > + > + > @node Waiting for I/O > @section Waiting for Input or Output > @cindex waiting for input or output Ok. > diff --git a/support/Makefile b/support/Makefile > index 027a663000..dafb1737a4 100644 > --- a/support/Makefile > +++ b/support/Makefile > @@ -109,19 +109,22 @@ libsupport-routines = \ > xpthread_once \ > xpthread_rwlock_init \ > xpthread_rwlock_rdlock \ > - xpthread_rwlock_wrlock \ > xpthread_rwlock_unlock \ > + xpthread_rwlock_wrlock \ > xpthread_rwlockattr_init \ > xpthread_rwlockattr_setkind_np \ > xpthread_sigmask \ > xpthread_spin_lock \ > xpthread_spin_unlock \ > + xreadlink \ > xrealloc \ > xrecvfrom \ > xsendto \ > xsetsockopt \ > xsocket \ > xstrdup \ > + xstrndup \ > + xunlink \ > xwaitpid \ > xwrite \ > > @@ -138,6 +141,7 @@ tests = \ > tst-support_capture_subprocess \ > tst-support_format_dns_packet \ > tst-support_record_failure \ > + tst-xreadlink \ > > ifeq ($(run-built-tests),yes) > tests-special = \ > diff --git a/support/support.h b/support/support.h > index 4b5f04c2cc..bbba803ba1 100644 > --- a/support/support.h > +++ b/support/support.h > @@ -68,6 +68,7 @@ void *xrealloc (void *p, size_t n); > char *xasprintf (const char *format, ...) > __attribute__ ((format (printf, 1, 2), malloc)); > char *xstrdup (const char *); > +char *xstrndup (const char *, size_t); > > __END_DECLS > Ok. > diff --git a/support/support_chroot.c b/support/support_chroot.c > index f3ef551b05..f6fad18f33 100644 > --- a/support/support_chroot.c > +++ b/support/support_chroot.c > @@ -46,10 +46,11 @@ support_chroot_create (struct support_chroot_configuration conf) > { > struct support_chroot *chroot = xmalloc (sizeof (*chroot)); > > - chroot->path_chroot = xasprintf ("%s/tst-resolv-res_init-XXXXXX", test_dir); > - if (mkdtemp (chroot->path_chroot) == NULL) > - FAIL_EXIT1 ("mkdtemp (\"%s\"): %m", chroot->path_chroot); > - add_temp_file (chroot->path_chroot); > + { > + char *template = xasprintf ("%s/tst-resolv-res_init-XXXXXX", test_dir); > + chroot->path_chroot = support_create_temp_directory (template); > + free (template); > + } > > /* Create the /etc directory in the chroot environment. */ > char *path_etc = xasprintf ("%s/etc", chroot->path_chroot); Ok. > diff --git a/support/temp_file.c b/support/temp_file.c > index fdb2477ab9..cbd54e2e17 100644 > --- a/support/temp_file.c > +++ b/support/temp_file.c > @@ -86,6 +86,19 @@ create_temp_file (const char *base, char **filename) > return fd; > } > > +char * > +support_create_temp_directory (const char *base) > +{ > + char *base_copy = xstrdup (base); > + if (mkdtemp (base_copy) == NULL) > + { > + printf ("error: mkdtemp (\"%s\"): %m", base); > + exit (1); > + } > + add_temp_file (base_copy); > + return base_copy; > +} > + > /* Helper functions called by the test skeleton follow. */ > > void Ok. > diff --git a/support/temp_file.h b/support/temp_file.h > index 6fed8df1ea..dfefe585de 100644 > --- a/support/temp_file.h > +++ b/support/temp_file.h > @@ -32,6 +32,11 @@ void add_temp_file (const char *name); > *FILENAME. */ > int create_temp_file (const char *base, char **filename); > > +/* Create a temporary directory and schedule it for deletion. BASE > + must end with the six characters "XXXXXX". Return the name of the > + temporary directory. The caller should free the string. */ > +char *support_create_temp_directory (const char *base); > + > __END_DECLS > > #endif /* SUPPORT_TEMP_FILE_H */ Ok. > diff --git a/support/tst-xreadlink.c b/support/tst-xreadlink.c > new file mode 100644 > index 0000000000..cb2c12a888 > --- /dev/null > +++ b/support/tst-xreadlink.c > @@ -0,0 +1,72 @@ > +/* Test the xreadlink function. > + Copyright (C) 2017 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + <http://www.gnu.org/licenses/>. */ > + > +#include <errno.h> > +#include <fcntl.h> > +#include <stdio.h> > +#include <stdlib.h> > +#include <string.h> > +#include <support/check.h> > +#include <support/support.h> > +#include <support/temp_file.h> > +#include <support/xunistd.h> > + > +static int > +do_test (void) > +{ > + char *dir = support_create_temp_directory ("/tmp/tst-xreadlink-XXXXXX"); > + char *symlink_name = xasprintf ("%s/symlink", dir); > + add_temp_file (symlink_name); > + > + /* The limit 10000 is arbitrary and simply there to prevent an > + attempt to exhaust all available disk space. */ > + for (int size = 1; size < 10000; ++size) > + { > + char *contents = xmalloc (size + 1); > + for (int i = 0; i < size; ++i) > + contents[i] = 'a' + (rand () % 26); > + contents[size] = '\0'; > + if (symlink (contents, symlink_name) != 0) > + { > + if (errno == ENAMETOOLONG) > + { > + printf ("info: ENAMETOOLONG failure at %d bytes\n", size); > + free (contents); > + break; > + } > + FAIL_EXIT1 ("symlink (%d bytes): %m", size); > + } > + > + char *readlink_result = xreadlink (symlink_name); > + TEST_VERIFY (strcmp (readlink_result, contents) == 0); > + free (readlink_result); > + xunlink (symlink_name); > + free (contents); > + } > + > + /* Create an empty file to suppress the temporary file deletion > + warning. */ > + xclose (xopen (symlink_name, O_WRONLY | O_CREAT, 0)); > + > + free (symlink_name); > + free (dir); > + > + return 0; > +} > + > +#include <support/test-driver.c> I think it is better to split this test and the xreadlink addition on another patch. > diff --git a/support/xreadlink.c b/support/xreadlink.c > new file mode 100644 > index 0000000000..aec58a2aa6 > --- /dev/null > +++ b/support/xreadlink.c > @@ -0,0 +1,44 @@ > +/* Error-checking, allocating wrapper for readlink. > + Copyright (C) 2017 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + <http://www.gnu.org/licenses/>. */ > + > +#include <scratch_buffer.h> > +#include <support/check.h> > +#include <support/support.h> > +#include <xunistd.h> > + > +char * > +xreadlink (const char *path) > +{ > + struct scratch_buffer buf; > + scratch_buffer_init (&buf); > + > + while (true) > + { > + ssize_t count = readlink (path, buf.data, buf.length); > + if (count < 0) > + FAIL_EXIT1 ("readlink (\"%s\"): %m", path); > + if (count < buf.length) > + { > + char *result = xstrndup (buf.data, count); > + scratch_buffer_free (&buf); > + return result; > + } > + if (!scratch_buffer_grow (&buf)) > + FAIL_EXIT1 ("scratch_buffer_grow in xreadlink"); > + } > +} I am not very found this way to handle unknown buffer size requirements, but the other possible option I can think of (lstat plus realloc) is not really different. Ok. > diff --git a/support/xstrndup.c b/support/xstrndup.c > new file mode 100644 > index 0000000000..d59a283d25 > --- /dev/null > +++ b/support/xstrndup.c > @@ -0,0 +1,30 @@ > +/* strndup with error checking. > + Copyright (C) 2016-2017 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + <http://www.gnu.org/licenses/>. */ > + > +#include <support/support.h> > + > +#include <string.h> > + > +char * > +xstrndup (const char *s, size_t length) > +{ > + char *p = strndup (s, length); > + if (p == NULL) > + oom_error ("strndup", length); > + return p; > +} Ok. > diff --git a/support/xunistd.h b/support/xunistd.h > index c947bfd8fb..05c2626a7b 100644 > --- a/support/xunistd.h > +++ b/support/xunistd.h > @@ -38,6 +38,11 @@ int xopen (const char *path, int flags, mode_t); > void xstat (const char *path, struct stat64 *); > void xmkdir (const char *path, mode_t); > void xchroot (const char *path); > +void xunlink (const char *path); > + > +/* Read the link at PATH. The caller should free the returned string > + with free. */ > +char *xreadlink (const char *path); > > /* Close the file descriptor. Ignore EINTR errors, but terminate the > process on other errors. */ Ok. > diff --git a/support/xunlink.c b/support/xunlink.c > new file mode 100644 > index 0000000000..f94ee118cf > --- /dev/null > +++ b/support/xunlink.c > @@ -0,0 +1,27 @@ > +/* Error-checking wrapper for unlink. > + Copyright (C) 2017 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + <http://www.gnu.org/licenses/>. */ > + > +#include <support/check.h> > +#include <support/xunistd.h> > + > +void > +xunlink (const char *path) > +{ > + if (unlink (path) != 0) > + FAIL_EXIT1 ("unlink (\"%s\"): %m", path); > +} Ok. > diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile > index 0c8a009b5e..3a5515d092 100644 > --- a/sysdeps/unix/sysv/linux/Makefile > +++ b/sysdeps/unix/sysv/linux/Makefile > @@ -39,7 +39,7 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \ > sys/klog.h \ > sys/user.h sys/prctl.h \ > sys/kd.h sys/soundcard.h sys/vt.h \ > - sys/quota.h sys/fsuid.h \ > + sys/quota.h sys/fsuid.h sys/memfd.h \ > scsi/sg.h scsi/scsi.h scsi/scsi_ioctl.h sys/pci.h \ > sys/raw.h sys/personality.h sys/epoll.h \ > bits/a.out.h sys/inotify.h sys/signalfd.h sys/eventfd.h \ > @@ -50,7 +50,8 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \ > bits/siginfo-arch.h bits/siginfo-consts-arch.h > > tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \ > - tst-quota tst-sync_file_range test-errno-linux tst-sysconf-iov_max > + tst-quota tst-sync_file_range test-errno-linux tst-sysconf-iov_max \ > + tst-memfd_create > > # Generate the list of SYS_* macros for the system calls (__NR_* > # macros). The file syscall-names.list contains all possible system Ok. > diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions > index 6c9e06f4f9..992c19729f 100644 > --- a/sysdeps/unix/sysv/linux/Versions > +++ b/sysdeps/unix/sysv/linux/Versions > @@ -166,6 +166,9 @@ libc { > GLIBC_2.15 { > process_vm_readv; process_vm_writev; > } > + GLIBC_2.27 { > + memfd_create; > + } > GLIBC_PRIVATE { > # functions used in other libraries > __syscall_rt_sigqueueinfo; Ok. > diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist > index ed598aedac..140ca28abc 100644 > --- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist > @@ -2106,6 +2106,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist > index 4e57f36bcf..f698e1b2f4 100644 > --- a/sysdeps/unix/sysv/linux/alpha/libc.abilist > +++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist > @@ -2017,6 +2017,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/arm/libc.abilist b/sysdeps/unix/sysv/linux/arm/libc.abilist > index 5b70e1bfc9..8a8af3e3e4 100644 > --- a/sysdeps/unix/sysv/linux/arm/libc.abilist > +++ b/sysdeps/unix/sysv/linux/arm/libc.abilist > @@ -107,6 +107,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.4 GLIBC_2.4 A > GLIBC_2.4 _Exit F > GLIBC_2.4 _IO_2_1_stderr_ D 0xa0 > diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist > index 6a2500a8b3..5b81a6cd7d 100644 > --- a/sysdeps/unix/sysv/linux/hppa/libc.abilist > +++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist > @@ -1871,6 +1871,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist > index 9ab4e3642a..51ead9e867 100644 > --- a/sysdeps/unix/sysv/linux/i386/libc.abilist > +++ b/sysdeps/unix/sysv/linux/i386/libc.abilist > @@ -2036,6 +2036,7 @@ GLIBC_2.26 wcstof128_l F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist > index 81bb623fe8..78b4ee8d40 100644 > --- a/sysdeps/unix/sysv/linux/ia64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist > @@ -1900,6 +1900,7 @@ GLIBC_2.26 wcstof128_l F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist > index 5a33b57390..d9c97779e4 100644 > --- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist > +++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist > @@ -108,6 +108,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.4 GLIBC_2.4 A > GLIBC_2.4 _Exit F > GLIBC_2.4 _IO_2_1_stderr_ D 0x98 > diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist > index 50a86e74fa..4acbf7eeed 100644 > --- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist > +++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist > @@ -1985,6 +1985,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/microblaze/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/libc.abilist > index 250ef305c3..93f02f08ce 100644 > --- a/sysdeps/unix/sysv/linux/microblaze/libc.abilist > +++ b/sysdeps/unix/sysv/linux/microblaze/libc.abilist > @@ -2106,3 +2106,4 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist > index 87a1dc4ad7..795e85de70 100644 > --- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist > +++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist > @@ -1960,6 +1960,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist > index f2b35f250e..dc714057b7 100644 > --- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist > +++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist > @@ -1958,6 +1958,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist > index ade654dbea..ce7bc9b175 100644 > --- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist > +++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist > @@ -1956,6 +1956,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist > index 56032c3f82..3fdd85eace 100644 > --- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist > @@ -1951,6 +1951,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/nios2/libc.abilist b/sysdeps/unix/sysv/linux/nios2/libc.abilist > index c599dd9212..3e0bcb2a5c 100644 > --- a/sysdeps/unix/sysv/linux/nios2/libc.abilist > +++ b/sysdeps/unix/sysv/linux/nios2/libc.abilist > @@ -2147,3 +2147,4 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist > index 385409aa6e..375c69d9d1 100644 > --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist > +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist > @@ -1989,6 +1989,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist > index e99cb454b5..a88172a906 100644 > --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist > +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist > @@ -1994,6 +1994,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist > index 173672ab5e..fa026a332c 100644 > --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist > +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist > @@ -2201,3 +2201,4 @@ GLIBC_2.26 wcstof128_l F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist > index 8a654436ab..838f395d78 100644 > --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist > @@ -108,6 +108,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 _Exit F > GLIBC_2.3 _IO_2_1_stderr_ D 0xe0 > diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist > index dbd411ceb1..41b79c496a 100644 > --- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist > +++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist > @@ -1989,6 +1989,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist > index 5617784ca0..68251a0e69 100644 > --- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist > @@ -1890,6 +1890,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/sh/libc.abilist b/sysdeps/unix/sysv/linux/sh/libc.abilist > index 0f840e6e88..bc1aae275e 100644 > --- a/sysdeps/unix/sysv/linux/sh/libc.abilist > +++ b/sysdeps/unix/sysv/linux/sh/libc.abilist > @@ -1875,6 +1875,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist > index bb7e1042c7..93e6d092ac 100644 > --- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist > +++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist > @@ -1982,6 +1982,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist > index 4053b0a51c..b11d6764d4 100644 > --- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist > @@ -1919,6 +1919,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/sys/memfd.h b/sysdeps/unix/sysv/linux/sys/memfd.h > new file mode 100644 > index 0000000000..8255ecd7a4 > --- /dev/null > +++ b/sysdeps/unix/sysv/linux/sys/memfd.h > @@ -0,0 +1,28 @@ > +/* memfd_create system call and constants. > + Copyright (C) 2017 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + <http://www.gnu.org/licenses/>. */ > + > +#ifndef _SYS_MEMFD_H > +#define _SYS_MEMFD_H > + > +#include <linux/memfd.h> How do we handle the case of installed kernels version being lower than 3.16 (the one that provides this header)? > + > +/* Create a new memory file descriptor. NAME is a name for debugging. > + FLAGS is a combination of the MFD_* constants. */ > +int memfd_create (const char *__name, unsigned int __flags); > + > +#endif /* _SYS_MEMFD_H */ > diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list > index 8bfb080d80..40c4fbb9ea 100644 > --- a/sysdeps/unix/sysv/linux/syscalls.list > +++ b/sysdeps/unix/sysv/linux/syscalls.list > @@ -109,3 +109,4 @@ setns EXTRA setns i:ii setns > > process_vm_readv EXTRA process_vm_readv i:ipipii process_vm_readv > process_vm_writev EXTRA process_vm_writev i:ipipii process_vm_writev > +memfd_create EXTRA memfd_create i:si memfd_create Ok. > diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist > index 38a96d3a02..e9eb4ff7bd 100644 > --- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist > +++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist > @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist > index 572b917d7d..8f08e909cd 100644 > --- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist > @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > diff --git a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist > index 38a96d3a02..e9eb4ff7bd 100644 > --- a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist > +++ b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist > @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > diff --git a/sysdeps/unix/sysv/linux/tst-memfd_create.c b/sysdeps/unix/sysv/linux/tst-memfd_create.c > new file mode 100644 > index 0000000000..709cf46791 > --- /dev/null > +++ b/sysdeps/unix/sysv/linux/tst-memfd_create.c > @@ -0,0 +1,134 @@ > +/* Test for the memfd_create system call. > + Copyright (C) 2017 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + <http://www.gnu.org/licenses/>. */ > + > +#include <errno.h> > +#include <fcntl.h> > +#include <stdbool.h> > +#include <stdio.h> > +#include <stdlib.h> > +#include <string.h> > +#include <support/check.h> > +#include <support/support.h> > +#include <support/test-driver.h> > +#include <support/xunistd.h> > +#include <sys/syscall.h> > + > +#ifndef SYS_memfd_create > +static int > +do_test (void) > +{ > + puts ("warning: kernel headers do not support memfd_create"); > + return EXIT_UNSUPPORTED; > +} > + > +#else /* SYS_memfd_create */ > + > +#include <sys/memfd.h> > + > +/* Return true if the descriptor has the FD_CLOEXEC flag set. */ > +static bool > +is_cloexec (int fd) > +{ > + int flags = fcntl (fd, F_GETFD); > + TEST_VERIFY (flags >= 0); > + return flags & FD_CLOEXEC; > +} > + > +/* Return the seals set on FD. */ > +static int > +get_seals (int fd) > +{ > + int flags = fcntl (fd, F_GET_SEALS); > + TEST_VERIFY (flags >= 0); > + return flags; > +} > + > +/* Return true if the F_SEAL_SEAL flag is set on the descriptor. */ > +static bool > +is_sealed (int fd) > +{ > + return get_seals (fd) & F_SEAL_SEAL; > +} > + > +static int > +do_test (void) > +{ > + /* Initialized by the first call to memfd_create to 0 (memfd_create > + unsupported) or 1 (memfd_create is implemented in the kernel). > + Subsequent iterations check that the success/failure state is > + consistent. */ > + int supported = -1; I am not following why adding this extra logic and the one which checks SYS_memfd_create. If __NR_memfd_create is not defined by kernel headers a stub which returns ENOSYS will be created. Why not just bail out with EXIT_UNSUPPORTED if errno is ENOSYS on first call? Is there any expectation that memfd_create won't return ENOSYS with different flags? > + > + for (int do_cloexec = 0; do_cloexec < 2; ++do_cloexec) > + for (int do_sealing = 0; do_sealing < 2; ++do_sealing) > + { > + int flags = 0; > + if (do_cloexec) > + flags |= MFD_CLOEXEC; > + if (do_sealing) > + flags |= MFD_ALLOW_SEALING; > + if (test_verbose > 0) > + printf ("info: memfd_create with flags=0x%x\n", flags); > + int fd = memfd_create ("tst-memfd_create", flags); > + if (fd < 0) > + { > + if (errno == ENOSYS) > + { > + if (supported < 0) > + { > + supported = 0; > + continue; > + } > + TEST_VERIFY (supported == 0); > + continue; > + } > + else > + FAIL_EXIT1 ("memfd_create: %m"); > + } > + if (supported < 0) > + supported = 1; > + TEST_VERIFY (supported > 0); > + > + char *fd_path = xasprintf ("/proc/self/fd/%d", fd); > + char *link = xreadlink (fd_path); > + if (test_verbose > 0) > + printf ("info: memfd link: %s\n", link); > + TEST_VERIFY (strcmp (link, "memfd:tst-memfd_create (deleted)")); > + TEST_VERIFY (is_cloexec (fd) == do_cloexec); > + TEST_VERIFY (is_sealed (fd) == !do_sealing); > + if (do_sealing) > + { > + TEST_VERIFY (fcntl (fd, F_ADD_SEALS, F_SEAL_WRITE) == 0); > + TEST_VERIFY (!is_sealed (fd)); > + TEST_VERIFY (get_seals (fd) & F_SEAL_WRITE); > + TEST_VERIFY (fcntl (fd, F_ADD_SEALS, F_SEAL_SEAL) == 0); > + TEST_VERIFY (is_sealed (fd)); > + } > + xclose (fd); > + free (fd_path); > + free (link); > + } > + > + if (supported == 0) > + return EXIT_UNSUPPORTED; > + return 0; > +} > + > +#endif /* SYS_memfd_create */ > + > +#include <support/test-driver.c> > diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist > index b83d25c2e3..0a4f7797ac 100644 > --- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist > @@ -1877,6 +1877,7 @@ GLIBC_2.26 wcstof128_l F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist > index cba1d59057..23f6a91429 100644 > --- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist > +++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist > @@ -2120,3 +2120,4 @@ GLIBC_2.26 wcstof128_l F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F >
* Adhemerval Zanella: >> 2017-11-03 Florian Weimer <fweimer@redhat.com> >> >> Linux: Add memfd_create system call wrapper >> * sysdeps/unix/sysv/linux/Makefile [misc] (sysdep_headers): Add >> sys/memfd.h. >> (tests): Add tst-memfd_create. >> * sysdeps/unix/sysv/linux/Versions (GLIBC_2.27): Add memfd_create. >> * sysdeps/unix/sysv/linux/syscalls.list (memfd_create): Add. >> * sysdeps/unix/sysv/linux/sys/memfd.h: New file. >> * sysdeps/unix/sysv/linux/**.abilist: Update. >> * manual/llio.texi (Memory-mapped I/O): Document memfd_create. >> * support/Makefile (libsupport-routines): Add xreadlink, xstrndup, >> xunlink. >> (tests): Add tst-xreadlink. >> * support/support.h (xstrndup): Declare. >> * support/xunistd.h (xunlink, xreadlink): Declare. >> * support/temp_file.h (support_create_temp_directory): Declare. >> * support/temp_file.c (support_create_temp_directory): New function. >> * support/support_chroot.c (support_chroot_create): Use it. >> * support/xreadlink.c: New file. >> * support/xstrndup.c: Likewise. >> * support/xunlink.c: Likewise. >> * support/tst-xreadlink.c: Likewise. >> > > Missing sysdeps/unix/sysv/linux/tst-memfd_create.c entry. Fixed locally. >> diff --git a/support/tst-xreadlink.c b/support/tst-xreadlink.c >> new file mode 100644 >> index 0000000000..cb2c12a888 >> --- /dev/null >> +++ b/support/tst-xreadlink.c > I think it is better to split this test and the xreadlink > addition on another patch. Okay, I will commit this separately soon. >> +#ifndef _SYS_MEMFD_H >> +#define _SYS_MEMFD_H >> + >> +#include <linux/memfd.h> > > How do we handle the case of installed kernels version being lower > than 3.16 (the one that provides this header)? Then applications will not be able to use this header. If that's not acceptable, we should probably not add <sys/memfd.h> at all, but replicate the UAPI constants in <sys/mman.h>. I see that this also affects the test. So we probably should go the <sys/mman.h> route. >> +static int >> +do_test (void) >> +{ >> + /* Initialized by the first call to memfd_create to 0 (memfd_create >> + unsupported) or 1 (memfd_create is implemented in the kernel). >> + Subsequent iterations check that the success/failure state is >> + consistent. */ >> + int supported = -1; > > I am not following why adding this extra logic and the one which > checks SYS_memfd_create. If __NR_memfd_create is not defined by > kernel headers a stub which returns ENOSYS will be created. Why > not just bail out with EXIT_UNSUPPORTED if errno is ENOSYS on > first call? Is there any expectation that memfd_create won't > return ENOSYS with different flags? I wanted to test that the results are consistent independent of the flags. Doesn't this make sense?
On 11/12/2017 10:04 AM, Florian Weimer wrote: > If that's not acceptable, we should probably not add <sys/memfd.h> at > all, but replicate the UAPI constants in <sys/mman.h>. > > I see that this also affects the test. So we probably should go the > <sys/mman.h> route. I had already taken care of that, I forgot. Anyway, the attached patch has the <sys/mman.h> variant of the system call wrapper. Thanks, Florian The system call is somewhat obscure because it is closely related to file descriptor sealing. However, it is also the recommended way to create alias mappings, which is why it has more general use. No emulation is provided. Except for the name of the /proc/self/fd links, it would be possible to implement an approximation using O_TMPFILE and tmpfs, but this does not appear to be worth the added complexity. 2017-11-12 Florian Weimer <fweimer@redhat.com> Linux: Add memfd_create system call wrapper * sysdeps/unix/sysv/linux/Makefile [misc] (tests): Add tst-memfd_create. * sysdeps/unix/sysv/linux/bits/mman-linux.h [__USE_GNU] (MFD_CLOEXEC, MFD_ALLOW_SEALING): Define. [__USE_GNU] (memfd_create): Declare. * sysdeps/unix/sysv/linux/Versions (GLIBC_2.27): Add memfd_create. * sysdeps/unix/sysv/linux/syscalls.list (memfd_create): Add. * sysdeps/unix/sysv/linux/tst-memfd_create.c: New file. * sysdeps/unix/sysv/linux/**.abilist: Update. * manual/llio.texi (Memory-mapped I/O): Document memfd_create. diff --git a/NEWS b/NEWS index b7281621f4..eca0c00a9b 100644 --- a/NEWS +++ b/NEWS @@ -35,6 +35,9 @@ Major new features: are the same interfaces added in version 2.26 for some platforms where this format is supported but is not the format of long double. +* glibc now provides the <sys/memfd.h> header file and the memfd_create + system call. + Deprecated and removed features, and other changes affecting compatibility: * On GNU/Linux, the obsolete Linux constant PTRACE_SEIZE_DEVEL is no longer diff --git a/manual/llio.texi b/manual/llio.texi index 10ad546723..59eb3af711 100644 --- a/manual/llio.texi +++ b/manual/llio.texi @@ -1775,6 +1775,40 @@ the given @var{name} previously created by @code{shm_open}. On failure @code{errno} is set. @end deftypefn +@deftypefn Function int memfd_create (const char *@var{name}, unsigned int flags) +@standards{Linux, sys/mman.h} +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{@acsfd{}}} +The @code{memfd_create} function returns a file descriptor which can be +used to create memory mappings using the @code{mmap} function. It is +similar to the @code{shm_open} function in the sense that these mappings +are not backed by actual files. However, the descriptor return by +@code{memfd_create} does not correspond to a named object; the +@var{name} argument is used for informative purposes only. The +descriptor can be passed between processes (for example, over local +domain sockets), and mappings at the same offset refer to the same +memory, or the descriptor can be used to create alias mappings within +the same process. + +The descriptor initially refers to a zero-length file. Before mappings +can be created which are backed by memory, the file size needs to be +increased with the @code{ftruncate} function. @xref{File Size}. + +The @var{flags} argument can be a combination of the following flags: + +@table @code +@item MFD_CLOEXEC +The descriptor is created with the @code{O_CLOEXEC} flag. + +@item MFD_ALLOW_SEALING +The descriptor supports the addition of seals using the @code{fcntl} +function. +@end table + +The @code{memfd_create} function is specific to Linux. + +@end deftypefn + + @node Waiting for I/O @section Waiting for Input or Output @cindex waiting for input or output diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile index bf76b8773d..f974ac446b 100644 --- a/sysdeps/unix/sysv/linux/Makefile +++ b/sysdeps/unix/sysv/linux/Makefile @@ -43,7 +43,8 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \ bits/siginfo-arch.h bits/siginfo-consts-arch.h tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \ - tst-quota tst-sync_file_range test-errno-linux tst-sysconf-iov_max + tst-quota tst-sync_file_range test-errno-linux tst-sysconf-iov_max \ + tst-memfd_create # Generate the list of SYS_* macros for the system calls (__NR_* # macros). The file syscall-names.list contains all possible system diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions index d3dbcde8c9..6f2fe516d7 100644 --- a/sysdeps/unix/sysv/linux/Versions +++ b/sysdeps/unix/sysv/linux/Versions @@ -166,6 +166,9 @@ libc { GLIBC_2.15 { process_vm_readv; process_vm_writev; } + GLIBC_2.27 { + memfd_create; + } GLIBC_PRIVATE { # functions used in other libraries __syscall_rt_sigqueueinfo; diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist index ed598aedac..140ca28abc 100644 --- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist +++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist @@ -2106,6 +2106,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist index 4e57f36bcf..f698e1b2f4 100644 --- a/sysdeps/unix/sysv/linux/alpha/libc.abilist +++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist @@ -2017,6 +2017,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/arm/libc.abilist b/sysdeps/unix/sysv/linux/arm/libc.abilist index 5b70e1bfc9..8a8af3e3e4 100644 --- a/sysdeps/unix/sysv/linux/arm/libc.abilist +++ b/sysdeps/unix/sysv/linux/arm/libc.abilist @@ -107,6 +107,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.4 GLIBC_2.4 A GLIBC_2.4 _Exit F GLIBC_2.4 _IO_2_1_stderr_ D 0xa0 diff --git a/sysdeps/unix/sysv/linux/bits/mman-linux.h b/sysdeps/unix/sysv/linux/bits/mman-linux.h index b091181960..396829482a 100644 --- a/sysdeps/unix/sysv/linux/bits/mman-linux.h +++ b/sysdeps/unix/sysv/linux/bits/mman-linux.h @@ -109,3 +109,18 @@ # define MCL_ONFAULT 4 /* Lock all pages that are faulted in. */ #endif + +#ifdef __USE_GNU +/* Flags for memfd_create. */ +# define MFD_CLOEXEC 1U +# define MFD_ALLOW_SEALING 2U + +__BEGIN_DECLS + +/* Create a new memory file descriptor. NAME is a name for debugging. + FLAGS is a combination of the MFD_* constants. */ +int memfd_create (const char *__name, unsigned int __flags) __THROW; + +__END_DECLS + +#endif /* __USE_GNU */ diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist index 6a2500a8b3..5b81a6cd7d 100644 --- a/sysdeps/unix/sysv/linux/hppa/libc.abilist +++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist @@ -1871,6 +1871,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist index 9ab4e3642a..51ead9e867 100644 --- a/sysdeps/unix/sysv/linux/i386/libc.abilist +++ b/sysdeps/unix/sysv/linux/i386/libc.abilist @@ -2036,6 +2036,7 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist index 81bb623fe8..78b4ee8d40 100644 --- a/sysdeps/unix/sysv/linux/ia64/libc.abilist +++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist @@ -1900,6 +1900,7 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist index 5a33b57390..d9c97779e4 100644 --- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist +++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist @@ -108,6 +108,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.4 GLIBC_2.4 A GLIBC_2.4 _Exit F GLIBC_2.4 _IO_2_1_stderr_ D 0x98 diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist index 50a86e74fa..4acbf7eeed 100644 --- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist +++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist @@ -1985,6 +1985,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/microblaze/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/libc.abilist index 250ef305c3..93f02f08ce 100644 --- a/sysdeps/unix/sysv/linux/microblaze/libc.abilist +++ b/sysdeps/unix/sysv/linux/microblaze/libc.abilist @@ -2106,3 +2106,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist index 87a1dc4ad7..795e85de70 100644 --- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist @@ -1960,6 +1960,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist index f2b35f250e..dc714057b7 100644 --- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist @@ -1958,6 +1958,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist index ade654dbea..ce7bc9b175 100644 --- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist @@ -1956,6 +1956,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist index 56032c3f82..3fdd85eace 100644 --- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist @@ -1951,6 +1951,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/nios2/libc.abilist b/sysdeps/unix/sysv/linux/nios2/libc.abilist index c599dd9212..3e0bcb2a5c 100644 --- a/sysdeps/unix/sysv/linux/nios2/libc.abilist +++ b/sysdeps/unix/sysv/linux/nios2/libc.abilist @@ -2147,3 +2147,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist index 385409aa6e..375c69d9d1 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist @@ -1989,6 +1989,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist index e99cb454b5..a88172a906 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist @@ -1994,6 +1994,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist index 173672ab5e..fa026a332c 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist @@ -2201,3 +2201,4 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist index 8a654436ab..838f395d78 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist @@ -108,6 +108,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 _Exit F GLIBC_2.3 _IO_2_1_stderr_ D 0xe0 diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist index dbd411ceb1..41b79c496a 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist +++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist @@ -1989,6 +1989,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist index 5617784ca0..68251a0e69 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist +++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist @@ -1890,6 +1890,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/sh/libc.abilist b/sysdeps/unix/sysv/linux/sh/libc.abilist index 0f840e6e88..bc1aae275e 100644 --- a/sysdeps/unix/sysv/linux/sh/libc.abilist +++ b/sysdeps/unix/sysv/linux/sh/libc.abilist @@ -1875,6 +1875,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist index bb7e1042c7..93e6d092ac 100644 --- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist +++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist @@ -1982,6 +1982,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist index 4053b0a51c..b11d6764d4 100644 --- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist +++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist @@ -1919,6 +1919,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list index 8bfb080d80..40c4fbb9ea 100644 --- a/sysdeps/unix/sysv/linux/syscalls.list +++ b/sysdeps/unix/sysv/linux/syscalls.list @@ -109,3 +109,4 @@ setns EXTRA setns i:ii setns process_vm_readv EXTRA process_vm_readv i:ipipii process_vm_readv process_vm_writev EXTRA process_vm_writev i:ipipii process_vm_writev +memfd_create EXTRA memfd_create i:si memfd_create diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist index 38a96d3a02..e9eb4ff7bd 100644 --- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist +++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist index 572b917d7d..8f08e909cd 100644 --- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist +++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist index 38a96d3a02..e9eb4ff7bd 100644 --- a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist +++ b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/tst-memfd_create.c b/sysdeps/unix/sysv/linux/tst-memfd_create.c new file mode 100644 index 0000000000..fd173ff71d --- /dev/null +++ b/sysdeps/unix/sysv/linux/tst-memfd_create.c @@ -0,0 +1,121 @@ +/* Test for the memfd_create system call. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <errno.h> +#include <fcntl.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <support/check.h> +#include <support/support.h> +#include <support/test-driver.h> +#include <support/xunistd.h> +#include <sys/mman.h> + +/* Return true if the descriptor has the FD_CLOEXEC flag set. */ +static bool +is_cloexec (int fd) +{ + int flags = fcntl (fd, F_GETFD); + TEST_VERIFY (flags >= 0); + return flags & FD_CLOEXEC; +} + +/* Return the seals set on FD. */ +static int +get_seals (int fd) +{ + int flags = fcntl (fd, F_GET_SEALS); + TEST_VERIFY (flags >= 0); + return flags; +} + +/* Return true if the F_SEAL_SEAL flag is set on the descriptor. */ +static bool +is_sealed (int fd) +{ + return get_seals (fd) & F_SEAL_SEAL; +} + +static int +do_test (void) +{ + /* Initialized by the first call to memfd_create to 0 (memfd_create + unsupported) or 1 (memfd_create is implemented in the kernel). + Subsequent iterations check that the success/failure state is + consistent. */ + int supported = -1; + + for (int do_cloexec = 0; do_cloexec < 2; ++do_cloexec) + for (int do_sealing = 0; do_sealing < 2; ++do_sealing) + { + int flags = 0; + if (do_cloexec) + flags |= MFD_CLOEXEC; + if (do_sealing) + flags |= MFD_ALLOW_SEALING; + if (test_verbose > 0) + printf ("info: memfd_create with flags=0x%x\n", flags); + int fd = memfd_create ("tst-memfd_create", flags); + if (fd < 0) + { + if (errno == ENOSYS) + { + if (supported < 0) + { + printf ("warning: memfd_create is unsupported\n"); + supported = 0; + continue; + } + TEST_VERIFY (supported == 0); + continue; + } + else + FAIL_EXIT1 ("memfd_create: %m"); + } + if (supported < 0) + supported = 1; + TEST_VERIFY (supported > 0); + + char *fd_path = xasprintf ("/proc/self/fd/%d", fd); + char *link = xreadlink (fd_path); + if (test_verbose > 0) + printf ("info: memfd link: %s\n", link); + TEST_VERIFY (strcmp (link, "memfd:tst-memfd_create (deleted)")); + TEST_VERIFY (is_cloexec (fd) == do_cloexec); + TEST_VERIFY (is_sealed (fd) == !do_sealing); + if (do_sealing) + { + TEST_VERIFY (fcntl (fd, F_ADD_SEALS, F_SEAL_WRITE) == 0); + TEST_VERIFY (!is_sealed (fd)); + TEST_VERIFY (get_seals (fd) & F_SEAL_WRITE); + TEST_VERIFY (fcntl (fd, F_ADD_SEALS, F_SEAL_SEAL) == 0); + TEST_VERIFY (is_sealed (fd)); + } + xclose (fd); + free (fd_path); + free (link); + } + + if (supported == 0) + return EXIT_UNSUPPORTED; + return 0; +} + +#include <support/test-driver.c> diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist index b83d25c2e3..0a4f7797ac 100644 --- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist +++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist @@ -1877,6 +1877,7 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist index cba1d59057..23f6a91429 100644 --- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist +++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist @@ -2120,3 +2120,4 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F
On 12/11/2017 12:51, Florian Weimer wrote: > On 11/12/2017 10:04 AM, Florian Weimer wrote: >> If that's not acceptable, we should probably not add <sys/memfd.h> at >> all, but replicate the UAPI constants in <sys/mman.h>. >> >> I see that this also affects the test. So we probably should go the >> <sys/mman.h> route. > > I had already taken care of that, I forgot. Anyway, the attached patch has the <sys/mman.h> variant of the system call wrapper. > > Thanks, > Florian > > memfd.patch > > > The system call is somewhat obscure because it is closely related > to file descriptor sealing. However, it is also the recommended > way to create alias mappings, which is why it has more general use. > > No emulation is provided. Except for the name of the > /proc/self/fd links, it would be possible to implement an > approximation using O_TMPFILE and tmpfs, but this does not appear > to be worth the added complexity. > > 2017-11-12 Florian Weimer <fweimer@redhat.com> > > Linux: Add memfd_create system call wrapper > * sysdeps/unix/sysv/linux/Makefile [misc] (tests): Add > tst-memfd_create. > * sysdeps/unix/sysv/linux/bits/mman-linux.h [__USE_GNU] > (MFD_CLOEXEC, MFD_ALLOW_SEALING): Define. > [__USE_GNU] (memfd_create): Declare. > * sysdeps/unix/sysv/linux/Versions (GLIBC_2.27): Add memfd_create. > * sysdeps/unix/sysv/linux/syscalls.list (memfd_create): Add. > * sysdeps/unix/sysv/linux/tst-memfd_create.c: New file. > * sysdeps/unix/sysv/linux/**.abilist: Update. > * manual/llio.texi (Memory-mapped I/O): Document memfd_create. LGTM with just an update below. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > > diff --git a/NEWS b/NEWS > index b7281621f4..eca0c00a9b 100644 > --- a/NEWS > +++ b/NEWS > @@ -35,6 +35,9 @@ Major new features: > are the same interfaces added in version 2.26 for some platforms where > this format is supported but is not the format of long double. > > +* glibc now provides the <sys/memfd.h> header file and the memfd_create > + system call. > + > Deprecated and removed features, and other changes affecting compatibility: > > * On GNU/Linux, the obsolete Linux constant PTRACE_SEIZE_DEVEL is no longer Ok. > diff --git a/manual/llio.texi b/manual/llio.texi > index 10ad546723..59eb3af711 100644 > --- a/manual/llio.texi > +++ b/manual/llio.texi > @@ -1775,6 +1775,40 @@ the given @var{name} previously created by @code{shm_open}. > On failure @code{errno} is set. > @end deftypefn > > +@deftypefn Function int memfd_create (const char *@var{name}, unsigned int flags) > +@standards{Linux, sys/mman.h} > +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{@acsfd{}}} > +The @code{memfd_create} function returns a file descriptor which can be > +used to create memory mappings using the @code{mmap} function. It is > +similar to the @code{shm_open} function in the sense that these mappings > +are not backed by actual files. However, the descriptor return by > +@code{memfd_create} does not correspond to a named object; the > +@var{name} argument is used for informative purposes only. The > +descriptor can be passed between processes (for example, over local > +domain sockets), and mappings at the same offset refer to the same > +memory, or the descriptor can be used to create alias mappings within > +the same process. > + > +The descriptor initially refers to a zero-length file. Before mappings > +can be created which are backed by memory, the file size needs to be > +increased with the @code{ftruncate} function. @xref{File Size}. > + > +The @var{flags} argument can be a combination of the following flags: > + > +@table @code > +@item MFD_CLOEXEC > +The descriptor is created with the @code{O_CLOEXEC} flag. > + > +@item MFD_ALLOW_SEALING > +The descriptor supports the addition of seals using the @code{fcntl} > +function. > +@end table > + > +The @code{memfd_create} function is specific to Linux. > + > +@end deftypefn > + > + > @node Waiting for I/O > @section Waiting for Input or Output > @cindex waiting for input or output Linux 4.14 (749df87bd7be) added a new flag MFD_HUGETLB. I think ww should add and document it. > diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile > index bf76b8773d..f974ac446b 100644 > --- a/sysdeps/unix/sysv/linux/Makefile > +++ b/sysdeps/unix/sysv/linux/Makefile > @@ -43,7 +43,8 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \ > bits/siginfo-arch.h bits/siginfo-consts-arch.h > > tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \ > - tst-quota tst-sync_file_range test-errno-linux tst-sysconf-iov_max > + tst-quota tst-sync_file_range test-errno-linux tst-sysconf-iov_max \ > + tst-memfd_create > > # Generate the list of SYS_* macros for the system calls (__NR_* > # macros). The file syscall-names.list contains all possible system Ok. > diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions > index d3dbcde8c9..6f2fe516d7 100644 > --- a/sysdeps/unix/sysv/linux/Versions > +++ b/sysdeps/unix/sysv/linux/Versions > @@ -166,6 +166,9 @@ libc { > GLIBC_2.15 { > process_vm_readv; process_vm_writev; > } > + GLIBC_2.27 { > + memfd_create; > + } > GLIBC_PRIVATE { > # functions used in other libraries > __syscall_rt_sigqueueinfo; Ok. > diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist > index ed598aedac..140ca28abc 100644 > --- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist > @@ -2106,6 +2106,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist > index 4e57f36bcf..f698e1b2f4 100644 > --- a/sysdeps/unix/sysv/linux/alpha/libc.abilist > +++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist > @@ -2017,6 +2017,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/arm/libc.abilist b/sysdeps/unix/sysv/linux/arm/libc.abilist > index 5b70e1bfc9..8a8af3e3e4 100644 > --- a/sysdeps/unix/sysv/linux/arm/libc.abilist > +++ b/sysdeps/unix/sysv/linux/arm/libc.abilist > @@ -107,6 +107,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.4 GLIBC_2.4 A > GLIBC_2.4 _Exit F > GLIBC_2.4 _IO_2_1_stderr_ D 0xa0 > diff --git a/sysdeps/unix/sysv/linux/bits/mman-linux.h b/sysdeps/unix/sysv/linux/bits/mman-linux.h > index b091181960..396829482a 100644 > --- a/sysdeps/unix/sysv/linux/bits/mman-linux.h > +++ b/sysdeps/unix/sysv/linux/bits/mman-linux.h > @@ -109,3 +109,18 @@ > # define MCL_ONFAULT 4 /* Lock all pages that are > faulted in. */ > #endif > + > +#ifdef __USE_GNU > +/* Flags for memfd_create. */ > +# define MFD_CLOEXEC 1U > +# define MFD_ALLOW_SEALING 2U > + > +__BEGIN_DECLS > + > +/* Create a new memory file descriptor. NAME is a name for debugging. > + FLAGS is a combination of the MFD_* constants. */ > +int memfd_create (const char *__name, unsigned int __flags) __THROW; > + > +__END_DECLS > + > +#endif /* __USE_GNU */ As before I think we should include MFD_HUGETLB. > diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist > index 6a2500a8b3..5b81a6cd7d 100644 > --- a/sysdeps/unix/sysv/linux/hppa/libc.abilist > +++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist > @@ -1871,6 +1871,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist > index 9ab4e3642a..51ead9e867 100644 > --- a/sysdeps/unix/sysv/linux/i386/libc.abilist > +++ b/sysdeps/unix/sysv/linux/i386/libc.abilist > @@ -2036,6 +2036,7 @@ GLIBC_2.26 wcstof128_l F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist > index 81bb623fe8..78b4ee8d40 100644 > --- a/sysdeps/unix/sysv/linux/ia64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist > @@ -1900,6 +1900,7 @@ GLIBC_2.26 wcstof128_l F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist > index 5a33b57390..d9c97779e4 100644 > --- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist > +++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist > @@ -108,6 +108,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.4 GLIBC_2.4 A > GLIBC_2.4 _Exit F > GLIBC_2.4 _IO_2_1_stderr_ D 0x98 > diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist > index 50a86e74fa..4acbf7eeed 100644 > --- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist > +++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist > @@ -1985,6 +1985,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/microblaze/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/libc.abilist > index 250ef305c3..93f02f08ce 100644 > --- a/sysdeps/unix/sysv/linux/microblaze/libc.abilist > +++ b/sysdeps/unix/sysv/linux/microblaze/libc.abilist > @@ -2106,3 +2106,4 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist > index 87a1dc4ad7..795e85de70 100644 > --- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist > +++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist > @@ -1960,6 +1960,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist > index f2b35f250e..dc714057b7 100644 > --- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist > +++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist > @@ -1958,6 +1958,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist > index ade654dbea..ce7bc9b175 100644 > --- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist > +++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist > @@ -1956,6 +1956,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist > index 56032c3f82..3fdd85eace 100644 > --- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist > @@ -1951,6 +1951,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/nios2/libc.abilist b/sysdeps/unix/sysv/linux/nios2/libc.abilist > index c599dd9212..3e0bcb2a5c 100644 > --- a/sysdeps/unix/sysv/linux/nios2/libc.abilist > +++ b/sysdeps/unix/sysv/linux/nios2/libc.abilist > @@ -2147,3 +2147,4 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist > index 385409aa6e..375c69d9d1 100644 > --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist > +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist > @@ -1989,6 +1989,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist > index e99cb454b5..a88172a906 100644 > --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist > +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist > @@ -1994,6 +1994,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist > index 173672ab5e..fa026a332c 100644 > --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist > +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist > @@ -2201,3 +2201,4 @@ GLIBC_2.26 wcstof128_l F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist > index 8a654436ab..838f395d78 100644 > --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist > @@ -108,6 +108,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 _Exit F > GLIBC_2.3 _IO_2_1_stderr_ D 0xe0 > diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist > index dbd411ceb1..41b79c496a 100644 > --- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist > +++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist > @@ -1989,6 +1989,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist > index 5617784ca0..68251a0e69 100644 > --- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist > @@ -1890,6 +1890,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/sh/libc.abilist b/sysdeps/unix/sysv/linux/sh/libc.abilist > index 0f840e6e88..bc1aae275e 100644 > --- a/sysdeps/unix/sysv/linux/sh/libc.abilist > +++ b/sysdeps/unix/sysv/linux/sh/libc.abilist > @@ -1875,6 +1875,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist > index bb7e1042c7..93e6d092ac 100644 > --- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist > +++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist > @@ -1982,6 +1982,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist > index 4053b0a51c..b11d6764d4 100644 > --- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist > @@ -1919,6 +1919,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list > index 8bfb080d80..40c4fbb9ea 100644 > --- a/sysdeps/unix/sysv/linux/syscalls.list > +++ b/sysdeps/unix/sysv/linux/syscalls.list > @@ -109,3 +109,4 @@ setns EXTRA setns i:ii setns > > process_vm_readv EXTRA process_vm_readv i:ipipii process_vm_readv > process_vm_writev EXTRA process_vm_writev i:ipipii process_vm_writev > +memfd_create EXTRA memfd_create i:si memfd_create > diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist > index 38a96d3a02..e9eb4ff7bd 100644 > --- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist > +++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist > @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist > index 572b917d7d..8f08e909cd 100644 > --- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist > @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > diff --git a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist > index 38a96d3a02..e9eb4ff7bd 100644 > --- a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist > +++ b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist > @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > diff --git a/sysdeps/unix/sysv/linux/tst-memfd_create.c b/sysdeps/unix/sysv/linux/tst-memfd_create.c > new file mode 100644 > index 0000000000..fd173ff71d > --- /dev/null > +++ b/sysdeps/unix/sysv/linux/tst-memfd_create.c > @@ -0,0 +1,121 @@ > +/* Test for the memfd_create system call. > + Copyright (C) 2017 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + <http://www.gnu.org/licenses/>. */ > + > +#include <errno.h> > +#include <fcntl.h> > +#include <stdbool.h> > +#include <stdio.h> > +#include <stdlib.h> > +#include <string.h> > +#include <support/check.h> > +#include <support/support.h> > +#include <support/test-driver.h> > +#include <support/xunistd.h> > +#include <sys/mman.h> > + > +/* Return true if the descriptor has the FD_CLOEXEC flag set. */ > +static bool > +is_cloexec (int fd) > +{ > + int flags = fcntl (fd, F_GETFD); > + TEST_VERIFY (flags >= 0); > + return flags & FD_CLOEXEC; > +} > + > +/* Return the seals set on FD. */ > +static int > +get_seals (int fd) > +{ > + int flags = fcntl (fd, F_GET_SEALS); > + TEST_VERIFY (flags >= 0); > + return flags; > +} > + > +/* Return true if the F_SEAL_SEAL flag is set on the descriptor. */ > +static bool > +is_sealed (int fd) > +{ > + return get_seals (fd) & F_SEAL_SEAL; > +} > + > +static int > +do_test (void) > +{ > + /* Initialized by the first call to memfd_create to 0 (memfd_create > + unsupported) or 1 (memfd_create is implemented in the kernel). > + Subsequent iterations check that the success/failure state is > + consistent. */ > + int supported = -1; > + > + for (int do_cloexec = 0; do_cloexec < 2; ++do_cloexec) > + for (int do_sealing = 0; do_sealing < 2; ++do_sealing) > + { > + int flags = 0; > + if (do_cloexec) > + flags |= MFD_CLOEXEC; > + if (do_sealing) > + flags |= MFD_ALLOW_SEALING; > + if (test_verbose > 0) > + printf ("info: memfd_create with flags=0x%x\n", flags); > + int fd = memfd_create ("tst-memfd_create", flags); > + if (fd < 0) > + { > + if (errno == ENOSYS) > + { > + if (supported < 0) > + { > + printf ("warning: memfd_create is unsupported\n"); > + supported = 0; > + continue; > + } > + TEST_VERIFY (supported == 0); > + continue; > + } > + else > + FAIL_EXIT1 ("memfd_create: %m"); > + } > + if (supported < 0) > + supported = 1; > + TEST_VERIFY (supported > 0); > + > + char *fd_path = xasprintf ("/proc/self/fd/%d", fd); > + char *link = xreadlink (fd_path); > + if (test_verbose > 0) > + printf ("info: memfd link: %s\n", link); > + TEST_VERIFY (strcmp (link, "memfd:tst-memfd_create (deleted)")); > + TEST_VERIFY (is_cloexec (fd) == do_cloexec); > + TEST_VERIFY (is_sealed (fd) == !do_sealing); > + if (do_sealing) > + { > + TEST_VERIFY (fcntl (fd, F_ADD_SEALS, F_SEAL_WRITE) == 0); > + TEST_VERIFY (!is_sealed (fd)); > + TEST_VERIFY (get_seals (fd) & F_SEAL_WRITE); > + TEST_VERIFY (fcntl (fd, F_ADD_SEALS, F_SEAL_SEAL) == 0); > + TEST_VERIFY (is_sealed (fd)); > + } > + xclose (fd); > + free (fd_path); > + free (link); > + } > + > + if (supported == 0) > + return EXIT_UNSUPPORTED; > + return 0; > +} > + > +#include <support/test-driver.c> Ok. > diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist > index b83d25c2e3..0a4f7797ac 100644 > --- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist > @@ -1877,6 +1877,7 @@ GLIBC_2.26 wcstof128_l F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist > index cba1d59057..23f6a91429 100644 > --- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist > +++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist > @@ -2120,3 +2120,4 @@ GLIBC_2.26 wcstof128_l F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F >
On Thu, Nov 16, 2017 at 08:34:26AM -0200, Adhemerval Zanella wrote: > > > On 12/11/2017 12:51, Florian Weimer wrote: > > On 11/12/2017 10:04 AM, Florian Weimer wrote: > >> If that's not acceptable, we should probably not add <sys/memfd.h> at > >> all, but replicate the UAPI constants in <sys/mman.h>. +1 that sounds like a good idea. > >> > >> I see that this also affects the test. So we probably should go the > >> <sys/mman.h> route. > > > > I had already taken care of that, I forgot. Anyway, the attached patch has the <sys/mman.h> variant of the system call wrapper. > > > > Thanks, > > Florian > > > > memfd.patch > > > > > > The system call is somewhat obscure because it is closely related > > to file descriptor sealing. However, it is also the recommended Sure and the api is somewhat bogus given this nonesensical "name" argument in there but it actually has a lot more use-cases for userspace. > > way to create alias mappings, which is why it has more general use. For example, systemd and lxc both carry their own memfd_create() definitions including the appropriate syscall number and option numbers. A concrete use-case is e.g. using mmap() + memfd_create() to create an efficient (Linux specific) in-memory ringbuffer ( https://github.com/lxc/lxc/blob/master/src/lxc/ringbuf.c ). In general, both have valid use cases to only have an in-memory file that can't be covered by mmap() alone. So this is really good to finally have! > > > > No emulation is provided. Except for the name of the > > /proc/self/fd links, it would be possible to implement an > > approximation using O_TMPFILE and tmpfs, but this does not appear > > to be worth the added complexity. > > > > 2017-11-12 Florian Weimer <fweimer@redhat.com> > > > > Linux: Add memfd_create system call wrapper > > * sysdeps/unix/sysv/linux/Makefile [misc] (tests): Add > > tst-memfd_create. > > * sysdeps/unix/sysv/linux/bits/mman-linux.h [__USE_GNU] > > (MFD_CLOEXEC, MFD_ALLOW_SEALING): Define. > > [__USE_GNU] (memfd_create): Declare. > > * sysdeps/unix/sysv/linux/Versions (GLIBC_2.27): Add memfd_create. > > * sysdeps/unix/sysv/linux/syscalls.list (memfd_create): Add. > > * sysdeps/unix/sysv/linux/tst-memfd_create.c: New file. > > * sysdeps/unix/sysv/linux/**.abilist: Update. > > * manual/llio.texi (Memory-mapped I/O): Document memfd_create. > > LGTM with just an update below. > > Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com> > > > > > diff --git a/NEWS b/NEWS > > index b7281621f4..eca0c00a9b 100644 > > --- a/NEWS > > +++ b/NEWS > > @@ -35,6 +35,9 @@ Major new features: > > are the same interfaces added in version 2.26 for some platforms where > > this format is supported but is not the format of long double. > > > > +* glibc now provides the <sys/memfd.h> header file and the memfd_create > > + system call. > > + > > Deprecated and removed features, and other changes affecting compatibility: > > > > * On GNU/Linux, the obsolete Linux constant PTRACE_SEIZE_DEVEL is no longer > > Ok. > > > diff --git a/manual/llio.texi b/manual/llio.texi > > index 10ad546723..59eb3af711 100644 > > --- a/manual/llio.texi > > +++ b/manual/llio.texi > > @@ -1775,6 +1775,40 @@ the given @var{name} previously created by @code{shm_open}. > > On failure @code{errno} is set. > > @end deftypefn > > > > +@deftypefn Function int memfd_create (const char *@var{name}, unsigned int flags) > > +@standards{Linux, sys/mman.h} > > +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{@acsfd{}}} > > +The @code{memfd_create} function returns a file descriptor which can be > > +used to create memory mappings using the @code{mmap} function. It is > > +similar to the @code{shm_open} function in the sense that these mappings > > +are not backed by actual files. However, the descriptor return by > > +@code{memfd_create} does not correspond to a named object; the > > +@var{name} argument is used for informative purposes only. The > > +descriptor can be passed between processes (for example, over local > > +domain sockets), and mappings at the same offset refer to the same > > +memory, or the descriptor can be used to create alias mappings within > > +the same process. > > + > > +The descriptor initially refers to a zero-length file. Before mappings > > +can be created which are backed by memory, the file size needs to be > > +increased with the @code{ftruncate} function. @xref{File Size}. > > + > > +The @var{flags} argument can be a combination of the following flags: > > + > > +@table @code > > +@item MFD_CLOEXEC > > +The descriptor is created with the @code{O_CLOEXEC} flag. > > + > > +@item MFD_ALLOW_SEALING > > +The descriptor supports the addition of seals using the @code{fcntl} > > +function. > > +@end table > > + > > +The @code{memfd_create} function is specific to Linux. > > + > > +@end deftypefn > > + > > + > > @node Waiting for I/O > > @section Waiting for Input or Output > > @cindex waiting for input or output > > Linux 4.14 (749df87bd7be) added a new flag MFD_HUGETLB. I think ww should add > and document it. > > > diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile > > index bf76b8773d..f974ac446b 100644 > > --- a/sysdeps/unix/sysv/linux/Makefile > > +++ b/sysdeps/unix/sysv/linux/Makefile > > @@ -43,7 +43,8 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \ > > bits/siginfo-arch.h bits/siginfo-consts-arch.h > > > > tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \ > > - tst-quota tst-sync_file_range test-errno-linux tst-sysconf-iov_max > > + tst-quota tst-sync_file_range test-errno-linux tst-sysconf-iov_max \ > > + tst-memfd_create > > > > # Generate the list of SYS_* macros for the system calls (__NR_* > > # macros). The file syscall-names.list contains all possible system > > Ok. > > > diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions > > index d3dbcde8c9..6f2fe516d7 100644 > > --- a/sysdeps/unix/sysv/linux/Versions > > +++ b/sysdeps/unix/sysv/linux/Versions > > @@ -166,6 +166,9 @@ libc { > > GLIBC_2.15 { > > process_vm_readv; process_vm_writev; > > } > > + GLIBC_2.27 { > > + memfd_create; > > + } > > GLIBC_PRIVATE { > > # functions used in other libraries > > __syscall_rt_sigqueueinfo; > > Ok. > > > diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist > > index ed598aedac..140ca28abc 100644 > > --- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist > > @@ -2106,6 +2106,7 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.27 strfromf128 F > > GLIBC_2.27 strtof128 F > > GLIBC_2.27 strtof128_l F > > diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist > > index 4e57f36bcf..f698e1b2f4 100644 > > --- a/sysdeps/unix/sysv/linux/alpha/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist > > @@ -2017,6 +2017,7 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.27 strfromf128 F > > GLIBC_2.27 strtof128 F > > GLIBC_2.27 strtof128_l F > > diff --git a/sysdeps/unix/sysv/linux/arm/libc.abilist b/sysdeps/unix/sysv/linux/arm/libc.abilist > > index 5b70e1bfc9..8a8af3e3e4 100644 > > --- a/sysdeps/unix/sysv/linux/arm/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/arm/libc.abilist > > @@ -107,6 +107,7 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.4 GLIBC_2.4 A > > GLIBC_2.4 _Exit F > > GLIBC_2.4 _IO_2_1_stderr_ D 0xa0 > > diff --git a/sysdeps/unix/sysv/linux/bits/mman-linux.h b/sysdeps/unix/sysv/linux/bits/mman-linux.h > > index b091181960..396829482a 100644 > > --- a/sysdeps/unix/sysv/linux/bits/mman-linux.h > > +++ b/sysdeps/unix/sysv/linux/bits/mman-linux.h > > @@ -109,3 +109,18 @@ > > # define MCL_ONFAULT 4 /* Lock all pages that are > > faulted in. */ > > #endif > > + > > +#ifdef __USE_GNU > > +/* Flags for memfd_create. */ > > +# define MFD_CLOEXEC 1U > > +# define MFD_ALLOW_SEALING 2U > > + > > +__BEGIN_DECLS > > + > > +/* Create a new memory file descriptor. NAME is a name for debugging. > > + FLAGS is a combination of the MFD_* constants. */ > > +int memfd_create (const char *__name, unsigned int __flags) __THROW; > > + > > +__END_DECLS > > + > > +#endif /* __USE_GNU */ > > As before I think we should include MFD_HUGETLB. > > > diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist > > index 6a2500a8b3..5b81a6cd7d 100644 > > --- a/sysdeps/unix/sysv/linux/hppa/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist > > @@ -1871,6 +1871,7 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.3 GLIBC_2.3 A > > GLIBC_2.3 __ctype_b_loc F > > GLIBC_2.3 __ctype_tolower_loc F > > diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist > > index 9ab4e3642a..51ead9e867 100644 > > --- a/sysdeps/unix/sysv/linux/i386/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/i386/libc.abilist > > @@ -2036,6 +2036,7 @@ GLIBC_2.26 wcstof128_l F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.3 GLIBC_2.3 A > > GLIBC_2.3 __ctype_b_loc F > > GLIBC_2.3 __ctype_tolower_loc F > > diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist > > index 81bb623fe8..78b4ee8d40 100644 > > --- a/sysdeps/unix/sysv/linux/ia64/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist > > @@ -1900,6 +1900,7 @@ GLIBC_2.26 wcstof128_l F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.3 GLIBC_2.3 A > > GLIBC_2.3 __ctype_b_loc F > > GLIBC_2.3 __ctype_tolower_loc F > > diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist > > index 5a33b57390..d9c97779e4 100644 > > --- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist > > @@ -108,6 +108,7 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.4 GLIBC_2.4 A > > GLIBC_2.4 _Exit F > > GLIBC_2.4 _IO_2_1_stderr_ D 0x98 > > diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist > > index 50a86e74fa..4acbf7eeed 100644 > > --- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist > > @@ -1985,6 +1985,7 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.3 GLIBC_2.3 A > > GLIBC_2.3 __ctype_b_loc F > > GLIBC_2.3 __ctype_tolower_loc F > > diff --git a/sysdeps/unix/sysv/linux/microblaze/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/libc.abilist > > index 250ef305c3..93f02f08ce 100644 > > --- a/sysdeps/unix/sysv/linux/microblaze/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/microblaze/libc.abilist > > @@ -2106,3 +2106,4 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist > > index 87a1dc4ad7..795e85de70 100644 > > --- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist > > @@ -1960,6 +1960,7 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.3 GLIBC_2.3 A > > GLIBC_2.3 __ctype_b_loc F > > GLIBC_2.3 __ctype_tolower_loc F > > diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist > > index f2b35f250e..dc714057b7 100644 > > --- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist > > @@ -1958,6 +1958,7 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.3 GLIBC_2.3 A > > GLIBC_2.3 __ctype_b_loc F > > GLIBC_2.3 __ctype_tolower_loc F > > diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist > > index ade654dbea..ce7bc9b175 100644 > > --- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist > > @@ -1956,6 +1956,7 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.27 strfromf128 F > > GLIBC_2.27 strtof128 F > > GLIBC_2.27 strtof128_l F > > diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist > > index 56032c3f82..3fdd85eace 100644 > > --- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist > > @@ -1951,6 +1951,7 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.27 strfromf128 F > > GLIBC_2.27 strtof128 F > > GLIBC_2.27 strtof128_l F > > diff --git a/sysdeps/unix/sysv/linux/nios2/libc.abilist b/sysdeps/unix/sysv/linux/nios2/libc.abilist > > index c599dd9212..3e0bcb2a5c 100644 > > --- a/sysdeps/unix/sysv/linux/nios2/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/nios2/libc.abilist > > @@ -2147,3 +2147,4 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist > > index 385409aa6e..375c69d9d1 100644 > > --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist > > @@ -1989,6 +1989,7 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.3 GLIBC_2.3 A > > GLIBC_2.3 __ctype_b_loc F > > GLIBC_2.3 __ctype_tolower_loc F > > diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist > > index e99cb454b5..a88172a906 100644 > > --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist > > @@ -1994,6 +1994,7 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.3 GLIBC_2.3 A > > GLIBC_2.3 __ctype_b_loc F > > GLIBC_2.3 __ctype_tolower_loc F > > diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist > > index 173672ab5e..fa026a332c 100644 > > --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist > > +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist > > @@ -2201,3 +2201,4 @@ GLIBC_2.26 wcstof128_l F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist > > index 8a654436ab..838f395d78 100644 > > --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist > > @@ -108,6 +108,7 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.3 GLIBC_2.3 A > > GLIBC_2.3 _Exit F > > GLIBC_2.3 _IO_2_1_stderr_ D 0xe0 > > diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist > > index dbd411ceb1..41b79c496a 100644 > > --- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist > > @@ -1989,6 +1989,7 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.27 strfromf128 F > > GLIBC_2.27 strtof128 F > > GLIBC_2.27 strtof128_l F > > diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist > > index 5617784ca0..68251a0e69 100644 > > --- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist > > @@ -1890,6 +1890,7 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.27 strfromf128 F > > GLIBC_2.27 strtof128 F > > GLIBC_2.27 strtof128_l F > > diff --git a/sysdeps/unix/sysv/linux/sh/libc.abilist b/sysdeps/unix/sysv/linux/sh/libc.abilist > > index 0f840e6e88..bc1aae275e 100644 > > --- a/sysdeps/unix/sysv/linux/sh/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/sh/libc.abilist > > @@ -1875,6 +1875,7 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.3 GLIBC_2.3 A > > GLIBC_2.3 __ctype_b_loc F > > GLIBC_2.3 __ctype_tolower_loc F > > diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist > > index bb7e1042c7..93e6d092ac 100644 > > --- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist > > @@ -1982,6 +1982,7 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.27 strfromf128 F > > GLIBC_2.27 strtof128 F > > GLIBC_2.27 strtof128_l F > > diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist > > index 4053b0a51c..b11d6764d4 100644 > > --- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist > > @@ -1919,6 +1919,7 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.27 strfromf128 F > > GLIBC_2.27 strtof128 F > > GLIBC_2.27 strtof128_l F > > diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list > > index 8bfb080d80..40c4fbb9ea 100644 > > --- a/sysdeps/unix/sysv/linux/syscalls.list > > +++ b/sysdeps/unix/sysv/linux/syscalls.list > > @@ -109,3 +109,4 @@ setns EXTRA setns i:ii setns > > > > process_vm_readv EXTRA process_vm_readv i:ipipii process_vm_readv > > process_vm_writev EXTRA process_vm_writev i:ipipii process_vm_writev > > +memfd_create EXTRA memfd_create i:si memfd_create > > diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist > > index 38a96d3a02..e9eb4ff7bd 100644 > > --- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist > > @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist > > index 572b917d7d..8f08e909cd 100644 > > --- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist > > @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > diff --git a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist > > index 38a96d3a02..e9eb4ff7bd 100644 > > --- a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist > > @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > diff --git a/sysdeps/unix/sysv/linux/tst-memfd_create.c b/sysdeps/unix/sysv/linux/tst-memfd_create.c > > new file mode 100644 > > index 0000000000..fd173ff71d > > --- /dev/null > > +++ b/sysdeps/unix/sysv/linux/tst-memfd_create.c > > @@ -0,0 +1,121 @@ > > +/* Test for the memfd_create system call. > > + Copyright (C) 2017 Free Software Foundation, Inc. > > + This file is part of the GNU C Library. > > + > > + The GNU C Library is free software; you can redistribute it and/or > > + modify it under the terms of the GNU Lesser General Public > > + License as published by the Free Software Foundation; either > > + version 2.1 of the License, or (at your option) any later version. > > + > > + The GNU C Library is distributed in the hope that it will be useful, > > + but WITHOUT ANY WARRANTY; without even the implied warranty of > > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > > + Lesser General Public License for more details. > > + > > + You should have received a copy of the GNU Lesser General Public > > + License along with the GNU C Library; if not, see > > + <http://www.gnu.org/licenses/>. */ > > + > > +#include <errno.h> > > +#include <fcntl.h> > > +#include <stdbool.h> > > +#include <stdio.h> > > +#include <stdlib.h> > > +#include <string.h> > > +#include <support/check.h> > > +#include <support/support.h> > > +#include <support/test-driver.h> > > +#include <support/xunistd.h> > > +#include <sys/mman.h> > > + > > +/* Return true if the descriptor has the FD_CLOEXEC flag set. */ > > +static bool > > +is_cloexec (int fd) > > +{ > > + int flags = fcntl (fd, F_GETFD); > > + TEST_VERIFY (flags >= 0); > > + return flags & FD_CLOEXEC; > > +} > > + > > +/* Return the seals set on FD. */ > > +static int > > +get_seals (int fd) > > +{ > > + int flags = fcntl (fd, F_GET_SEALS); > > + TEST_VERIFY (flags >= 0); > > + return flags; > > +} > > + > > +/* Return true if the F_SEAL_SEAL flag is set on the descriptor. */ > > +static bool > > +is_sealed (int fd) > > +{ > > + return get_seals (fd) & F_SEAL_SEAL; > > +} > > + > > +static int > > +do_test (void) > > +{ > > + /* Initialized by the first call to memfd_create to 0 (memfd_create > > + unsupported) or 1 (memfd_create is implemented in the kernel). > > + Subsequent iterations check that the success/failure state is > > + consistent. */ > > + int supported = -1; > > + > > + for (int do_cloexec = 0; do_cloexec < 2; ++do_cloexec) > > + for (int do_sealing = 0; do_sealing < 2; ++do_sealing) > > + { > > + int flags = 0; > > + if (do_cloexec) > > + flags |= MFD_CLOEXEC; > > + if (do_sealing) > > + flags |= MFD_ALLOW_SEALING; > > + if (test_verbose > 0) > > + printf ("info: memfd_create with flags=0x%x\n", flags); > > + int fd = memfd_create ("tst-memfd_create", flags); > > + if (fd < 0) > > + { > > + if (errno == ENOSYS) > > + { > > + if (supported < 0) > > + { > > + printf ("warning: memfd_create is unsupported\n"); > > + supported = 0; > > + continue; > > + } > > + TEST_VERIFY (supported == 0); > > + continue; > > + } > > + else > > + FAIL_EXIT1 ("memfd_create: %m"); > > + } > > + if (supported < 0) > > + supported = 1; > > + TEST_VERIFY (supported > 0); > > + > > + char *fd_path = xasprintf ("/proc/self/fd/%d", fd); > > + char *link = xreadlink (fd_path); > > + if (test_verbose > 0) > > + printf ("info: memfd link: %s\n", link); > > + TEST_VERIFY (strcmp (link, "memfd:tst-memfd_create (deleted)")); > > + TEST_VERIFY (is_cloexec (fd) == do_cloexec); > > + TEST_VERIFY (is_sealed (fd) == !do_sealing); > > + if (do_sealing) > > + { > > + TEST_VERIFY (fcntl (fd, F_ADD_SEALS, F_SEAL_WRITE) == 0); > > + TEST_VERIFY (!is_sealed (fd)); > > + TEST_VERIFY (get_seals (fd) & F_SEAL_WRITE); > > + TEST_VERIFY (fcntl (fd, F_ADD_SEALS, F_SEAL_SEAL) == 0); > > + TEST_VERIFY (is_sealed (fd)); > > + } > > + xclose (fd); > > + free (fd_path); > > + free (link); > > + } > > + > > + if (supported == 0) > > + return EXIT_UNSUPPORTED; > > + return 0; > > +} > > + > > +#include <support/test-driver.c> > > Ok. > > > diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist > > index b83d25c2e3..0a4f7797ac 100644 > > --- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist > > @@ -1877,6 +1877,7 @@ GLIBC_2.26 wcstof128_l F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > > GLIBC_2.3 GLIBC_2.3 A > > GLIBC_2.3 __ctype_b_loc F > > GLIBC_2.3 __ctype_tolower_loc F > > diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist > > index cba1d59057..23f6a91429 100644 > > --- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist > > +++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist > > @@ -2120,3 +2120,4 @@ GLIBC_2.26 wcstof128_l F > > GLIBC_2.27 GLIBC_2.27 A > > GLIBC_2.27 glob F > > GLIBC_2.27 glob64 F > > +GLIBC_2.27 memfd_create F > >
On 11/16/2017 11:34 AM, Adhemerval Zanella wrote: > Linux 4.14 (749df87bd7be) added a new flag MFD_HUGETLB. I think ww should add > and document it. We currently do not document MAP_HUGETLB, which is closely related and not really simple to describe. The manual page and kernel documentation do not cover it in detail, either. The page size selection in particular is missing, and I would have to research how an application can discover supported hugepage sizes. In short, this is not exactly a trivial request, and I would kindly ask you to reconsider. Thanks, Florian
On Fri, 17 Nov 2017, Florian Weimer wrote: > On 11/16/2017 11:34 AM, Adhemerval Zanella wrote: > > Linux 4.14 (749df87bd7be) added a new flag MFD_HUGETLB. I think ww should > > add > > and document it. > > We currently do not document MAP_HUGETLB, which is closely related and not > really simple to describe. The manual page and kernel documentation do not > cover it in detail, either. The page size selection in particular is missing, > and I would have to research how an application can discover supported > hugepage sizes. > > In short, this is not exactly a trivial request, and I would kindly ask you to > reconsider. Maybe say the new flag should at least be added to the header (unless automatically visible via an include of a <linux/*.h> UAPI header), absent a reason not to do so, but given the difficulties of doing so we might for now not document it (generically, for new constants from new Linux kernel releases, as opposed to new functions, that's been the practice for a long time).
On 11/17/2017 11:41 PM, Joseph Myers wrote: > On Fri, 17 Nov 2017, Florian Weimer wrote: > >> On 11/16/2017 11:34 AM, Adhemerval Zanella wrote: >>> Linux 4.14 (749df87bd7be) added a new flag MFD_HUGETLB. I think ww should >>> add >>> and document it. >> >> We currently do not document MAP_HUGETLB, which is closely related and not >> really simple to describe. The manual page and kernel documentation do not >> cover it in detail, either. The page size selection in particular is missing, >> and I would have to research how an application can discover supported >> hugepage sizes. >> >> In short, this is not exactly a trivial request, and I would kindly ask you to >> reconsider. > > Maybe say the new flag should at least be added to the header (unless > automatically visible via an include of a <linux/*.h> UAPI header), absent > a reason not to do so, but given the difficulties of doing so we might for > now not document it (generically, for new constants from new Linux kernel > releases, as opposed to new functions, that's been the practice for a long > time). Would it be okay to pretend that the hugepage size selection mechanism doesn't exist? We haven't added that yet for SHM_HUGETLB, either. Thanks, Florian
On Fri, 17 Nov 2017, Florian Weimer wrote: > Would it be okay to pretend that the hugepage size selection mechanism doesn't > exist? Sure.
> Il giorno 17 nov 2017, alle ore 21:08, Joseph Myers <joseph@codesourcery.com> ha scritto: > >> On Fri, 17 Nov 2017, Florian Weimer wrote: >> >> Would it be okay to pretend that the hugepage size selection mechanism doesn't >> exist? > > Sure. Sounds reasonable to me as well.
On 11/16/2017 11:34 AM, Adhemerval Zanella wrote: > Linux 4.14 (749df87bd7be) added a new flag MFD_HUGETLB. I think ww should add > and document it. Here's the updated patch, referring back to the MAP_HUGETLB documentation I added. Thanks, Florian Subject: [PATCH] Linux: Add memfd_create system call wrapper To: libc-alpha@sourceware.org The system call is somewhat obscure because it is closely related to file descriptor sealing. However, it is also the recommended way to create alias mappings, which is why it has more general use. No emulation is provided. Except for the name of the /proc/self/fd links, it would be possible to implement an approximation using O_TMPFILE and tmpfs, but this does not appear to be worth the added complexity. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com> 2017-11-12 Florian Weimer <fweimer@redhat.com> Linux: Add memfd_create system call wrapper * sysdeps/unix/sysv/linux/Makefile [misc] (tests): Add tst-memfd_create. * sysdeps/unix/sysv/linux/bits/mman-linux.h [__USE_GNU] (MFD_CLOEXEC, MFD_ALLOW_SEALING): Define. [__USE_GNU] (memfd_create): Declare. * sysdeps/unix/sysv/linux/Versions (GLIBC_2.27): Add memfd_create. * sysdeps/unix/sysv/linux/syscalls.list (memfd_create): Add. * sysdeps/unix/sysv/linux/tst-memfd_create.c: New file. * sysdeps/unix/sysv/linux/**.abilist: Update. * manual/llio.texi (Memory-mapped I/O): Document memfd_create. diff --git a/NEWS b/NEWS index 1c5da21327..3d453644d9 100644 --- a/NEWS +++ b/NEWS @@ -35,6 +35,9 @@ Major new features: are the same interfaces added in version 2.26 for some platforms where this format is supported but is not the format of long double. +* glibc now provides the <sys/memfd.h> header file and the memfd_create + system call. + Deprecated and removed features, and other changes affecting compatibility: * On GNU/Linux, the obsolete Linux constant PTRACE_SEIZE_DEVEL is no longer diff --git a/manual/llio.texi b/manual/llio.texi index 8c7c58c216..625fe49ac1 100644 --- a/manual/llio.texi +++ b/manual/llio.texi @@ -1808,6 +1808,69 @@ the given @var{name} previously created by @code{shm_open}. On failure @code{errno} is set. @end deftypefn +@deftypefn Function int memfd_create (const char *@var{name}, unsigned int flags) +@standards{Linux, sys/mman.h} +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{@acsfd{}}} +The @code{memfd_create} function returns a file descriptor which can be +used to create memory mappings using the @code{mmap} function. It is +similar to the @code{shm_open} function in the sense that these mappings +are not backed by actual files. However, the descriptor return by +@code{memfd_create} does not correspond to a named object; the +@var{name} argument is used for informative purposes only. The +descriptor can be passed between processes (for example, over local +domain sockets), and mappings at the same offset refer to the same +memory, or the descriptor can be used to create alias mappings within +the same process. + +The descriptor initially refers to a zero-length file. Before mappings +can be created which are backed by memory, the file size needs to be +increased with the @code{ftruncate} function. @xref{File Size}. + +The @var{flags} argument can be a combination of the following flags: + +@vtable @code +@item MFD_CLOEXEC +@standards{Linux, sys/mman.h} +The descriptor is created with the @code{O_CLOEXEC} flag. + +@item MFD_ALLOW_SEALING +@standards{Linux, sys/mman.h} +The descriptor supports the addition of seals using the @code{fcntl} +function. + +@item MFD_HUGETLB +@standards{Linux, sys/mman.h} +This requests that mappings created using the returned file descriptor +use a larger page size. See @code{MAP_HUGETLB} above for details. + +This flag is incompatible with @code{MFD_ALLOW_SEALING}. +@end vtable + +@code{memfd_create} returns a file descriptor on success, and @math{-1} +on failure. + +The following @code{errno} error conditions are defined for this +function: + +@table @code +@item EINVAL +An invalid combination is specified in @var{flags}, or @var{name} is +too long. + +@item EFAULT +The @var{name} argument does not point to a string. + +@item EMFILE +The operation would exceed the file descriptor limit for this process. + +@item ENFILE +The operation would exceed the system-wide file descriptor limit. + +@item ENOMEM +There is not enough memory for the operation. +@end table +@end deftypefn + @node Waiting for I/O @section Waiting for Input or Output @cindex waiting for input or output diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile index c6675b3aa5..c484d2688a 100644 --- a/sysdeps/unix/sysv/linux/Makefile +++ b/sysdeps/unix/sysv/linux/Makefile @@ -44,7 +44,7 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \ tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \ tst-quota tst-sync_file_range tst-sysconf-iov_max tst-ttyname \ - test-errno-linux + test-errno-linux tst-memfd_create # Generate the list of SYS_* macros for the system calls (__NR_* # macros). The file syscall-names.list contains all possible system diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions index d3dbcde8c9..6f2fe516d7 100644 --- a/sysdeps/unix/sysv/linux/Versions +++ b/sysdeps/unix/sysv/linux/Versions @@ -166,6 +166,9 @@ libc { GLIBC_2.15 { process_vm_readv; process_vm_writev; } + GLIBC_2.27 { + memfd_create; + } GLIBC_PRIVATE { # functions used in other libraries __syscall_rt_sigqueueinfo; diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist index ed598aedac..140ca28abc 100644 --- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist +++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist @@ -2106,6 +2106,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist index 4e57f36bcf..f698e1b2f4 100644 --- a/sysdeps/unix/sysv/linux/alpha/libc.abilist +++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist @@ -2017,6 +2017,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/arm/libc.abilist b/sysdeps/unix/sysv/linux/arm/libc.abilist index 5b70e1bfc9..8a8af3e3e4 100644 --- a/sysdeps/unix/sysv/linux/arm/libc.abilist +++ b/sysdeps/unix/sysv/linux/arm/libc.abilist @@ -107,6 +107,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.4 GLIBC_2.4 A GLIBC_2.4 _Exit F GLIBC_2.4 _IO_2_1_stderr_ D 0xa0 diff --git a/sysdeps/unix/sysv/linux/bits/mman-linux.h b/sysdeps/unix/sysv/linux/bits/mman-linux.h index 78c07c890a..1ffa5490af 100644 --- a/sysdeps/unix/sysv/linux/bits/mman-linux.h +++ b/sysdeps/unix/sysv/linux/bits/mman-linux.h @@ -111,3 +111,19 @@ # define MCL_ONFAULT 4 /* Lock all pages that are faulted in. */ #endif + +#ifdef __USE_GNU +/* Flags for memfd_create. */ +# define MFD_CLOEXEC 1U +# define MFD_ALLOW_SEALING 2U +# define MFD_HUGETLB 4U + +__BEGIN_DECLS + +/* Create a new memory file descriptor. NAME is a name for debugging. + FLAGS is a combination of the MFD_* constants. */ +int memfd_create (const char *__name, unsigned int __flags) __THROW; + +__END_DECLS + +#endif /* __USE_GNU */ diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist index 6a2500a8b3..5b81a6cd7d 100644 --- a/sysdeps/unix/sysv/linux/hppa/libc.abilist +++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist @@ -1871,6 +1871,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist index 9ab4e3642a..51ead9e867 100644 --- a/sysdeps/unix/sysv/linux/i386/libc.abilist +++ b/sysdeps/unix/sysv/linux/i386/libc.abilist @@ -2036,6 +2036,7 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist index 81bb623fe8..78b4ee8d40 100644 --- a/sysdeps/unix/sysv/linux/ia64/libc.abilist +++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist @@ -1900,6 +1900,7 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist index 5a33b57390..d9c97779e4 100644 --- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist +++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist @@ -108,6 +108,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.4 GLIBC_2.4 A GLIBC_2.4 _Exit F GLIBC_2.4 _IO_2_1_stderr_ D 0x98 diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist index 50a86e74fa..4acbf7eeed 100644 --- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist +++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist @@ -1985,6 +1985,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/microblaze/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/libc.abilist index 250ef305c3..93f02f08ce 100644 --- a/sysdeps/unix/sysv/linux/microblaze/libc.abilist +++ b/sysdeps/unix/sysv/linux/microblaze/libc.abilist @@ -2106,3 +2106,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist index 87a1dc4ad7..795e85de70 100644 --- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist @@ -1960,6 +1960,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist index f2b35f250e..dc714057b7 100644 --- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist @@ -1958,6 +1958,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist index ade654dbea..ce7bc9b175 100644 --- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist @@ -1956,6 +1956,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist index 56032c3f82..3fdd85eace 100644 --- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist @@ -1951,6 +1951,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/nios2/libc.abilist b/sysdeps/unix/sysv/linux/nios2/libc.abilist index c599dd9212..3e0bcb2a5c 100644 --- a/sysdeps/unix/sysv/linux/nios2/libc.abilist +++ b/sysdeps/unix/sysv/linux/nios2/libc.abilist @@ -2147,3 +2147,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist index 385409aa6e..375c69d9d1 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist @@ -1989,6 +1989,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist index e99cb454b5..a88172a906 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist @@ -1994,6 +1994,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist index 173672ab5e..fa026a332c 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist @@ -2201,3 +2201,4 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist index 8a654436ab..838f395d78 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist @@ -108,6 +108,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 _Exit F GLIBC_2.3 _IO_2_1_stderr_ D 0xe0 diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist index dbd411ceb1..41b79c496a 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist +++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist @@ -1989,6 +1989,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist index 5617784ca0..68251a0e69 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist +++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist @@ -1890,6 +1890,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/sh/libc.abilist b/sysdeps/unix/sysv/linux/sh/libc.abilist index 0f840e6e88..bc1aae275e 100644 --- a/sysdeps/unix/sysv/linux/sh/libc.abilist +++ b/sysdeps/unix/sysv/linux/sh/libc.abilist @@ -1875,6 +1875,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist index bb7e1042c7..93e6d092ac 100644 --- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist +++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist @@ -1982,6 +1982,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist index 4053b0a51c..b11d6764d4 100644 --- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist +++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist @@ -1919,6 +1919,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list index 8bfb080d80..40c4fbb9ea 100644 --- a/sysdeps/unix/sysv/linux/syscalls.list +++ b/sysdeps/unix/sysv/linux/syscalls.list @@ -109,3 +109,4 @@ setns EXTRA setns i:ii setns process_vm_readv EXTRA process_vm_readv i:ipipii process_vm_readv process_vm_writev EXTRA process_vm_writev i:ipipii process_vm_writev +memfd_create EXTRA memfd_create i:si memfd_create diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist index 38a96d3a02..e9eb4ff7bd 100644 --- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist +++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist index 572b917d7d..8f08e909cd 100644 --- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist +++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist index 38a96d3a02..e9eb4ff7bd 100644 --- a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist +++ b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/tst-memfd_create.c b/sysdeps/unix/sysv/linux/tst-memfd_create.c new file mode 100644 index 0000000000..fd173ff71d --- /dev/null +++ b/sysdeps/unix/sysv/linux/tst-memfd_create.c @@ -0,0 +1,121 @@ +/* Test for the memfd_create system call. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <errno.h> +#include <fcntl.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <support/check.h> +#include <support/support.h> +#include <support/test-driver.h> +#include <support/xunistd.h> +#include <sys/mman.h> + +/* Return true if the descriptor has the FD_CLOEXEC flag set. */ +static bool +is_cloexec (int fd) +{ + int flags = fcntl (fd, F_GETFD); + TEST_VERIFY (flags >= 0); + return flags & FD_CLOEXEC; +} + +/* Return the seals set on FD. */ +static int +get_seals (int fd) +{ + int flags = fcntl (fd, F_GET_SEALS); + TEST_VERIFY (flags >= 0); + return flags; +} + +/* Return true if the F_SEAL_SEAL flag is set on the descriptor. */ +static bool +is_sealed (int fd) +{ + return get_seals (fd) & F_SEAL_SEAL; +} + +static int +do_test (void) +{ + /* Initialized by the first call to memfd_create to 0 (memfd_create + unsupported) or 1 (memfd_create is implemented in the kernel). + Subsequent iterations check that the success/failure state is + consistent. */ + int supported = -1; + + for (int do_cloexec = 0; do_cloexec < 2; ++do_cloexec) + for (int do_sealing = 0; do_sealing < 2; ++do_sealing) + { + int flags = 0; + if (do_cloexec) + flags |= MFD_CLOEXEC; + if (do_sealing) + flags |= MFD_ALLOW_SEALING; + if (test_verbose > 0) + printf ("info: memfd_create with flags=0x%x\n", flags); + int fd = memfd_create ("tst-memfd_create", flags); + if (fd < 0) + { + if (errno == ENOSYS) + { + if (supported < 0) + { + printf ("warning: memfd_create is unsupported\n"); + supported = 0; + continue; + } + TEST_VERIFY (supported == 0); + continue; + } + else + FAIL_EXIT1 ("memfd_create: %m"); + } + if (supported < 0) + supported = 1; + TEST_VERIFY (supported > 0); + + char *fd_path = xasprintf ("/proc/self/fd/%d", fd); + char *link = xreadlink (fd_path); + if (test_verbose > 0) + printf ("info: memfd link: %s\n", link); + TEST_VERIFY (strcmp (link, "memfd:tst-memfd_create (deleted)")); + TEST_VERIFY (is_cloexec (fd) == do_cloexec); + TEST_VERIFY (is_sealed (fd) == !do_sealing); + if (do_sealing) + { + TEST_VERIFY (fcntl (fd, F_ADD_SEALS, F_SEAL_WRITE) == 0); + TEST_VERIFY (!is_sealed (fd)); + TEST_VERIFY (get_seals (fd) & F_SEAL_WRITE); + TEST_VERIFY (fcntl (fd, F_ADD_SEALS, F_SEAL_SEAL) == 0); + TEST_VERIFY (is_sealed (fd)); + } + xclose (fd); + free (fd_path); + free (link); + } + + if (supported == 0) + return EXIT_UNSUPPORTED; + return 0; +} + +#include <support/test-driver.c> diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist index b83d25c2e3..0a4f7797ac 100644 --- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist +++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist @@ -1877,6 +1877,7 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist index cba1d59057..23f6a91429 100644 --- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist +++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist @@ -2120,3 +2120,4 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F
On 11/18/2017 09:32 AM, Florian Weimer wrote: > diff --git a/manual/llio.texi b/manual/llio.texi > index 8c7c58c216..625fe49ac1 100644 > --- a/manual/llio.texi > +++ b/manual/llio.texi > @@ -1808,6 +1808,69 @@ the given @var{name} previously created by @code{shm_open}. > On failure @code{errno} is set. > @end deftypefn > > +@deftypefn Function int memfd_create (const char *@var{name}, unsigned int flags) "@var{flags}" Use @deftypefun, and drop "Function" (shortcut). > +@standards{Linux, sys/mman.h} > +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{@acsfd{}}} > +The @code{memfd_create} function returns a file descriptor which can be > +used to create memory mappings using the @code{mmap} function. It is > +similar to the @code{shm_open} function in the sense that these mappings > +are not backed by actual files. However, the descriptor return by "returned" > +@code{memfd_create} does not correspond to a named object; the > +@var{name} argument is used for informative purposes only. The I see in mman-linux.h, "NAME is a name for debugging." Can we say "debugging purposes" here? As-is, it sounds ignored, and doesn't really hint at what type of information one could get from it or how. > +descriptor can be passed between processes (for example, over local > +domain sockets), and mappings at the same offset refer to the same > +memory, or the descriptor can be used to create alias mappings within > +the same process. The and/or here is odd. What about: "...the same memory. The descriptor can also be used..." > + > +The descriptor initially refers to a zero-length file. Before mappings > +can be created which are backed by memory, the file size needs to be > +increased with the @code{ftruncate} function. @xref{File Size}. > + > +The @var{flags} argument can be a combination of the following flags: > + > +@vtable @code > +@item MFD_CLOEXEC > +@standards{Linux, sys/mman.h} > +The descriptor is created with the @code{O_CLOEXEC} flag. > + > +@item MFD_ALLOW_SEALING > +@standards{Linux, sys/mman.h} > +The descriptor supports the addition of seals using the @code{fcntl} > +function. > + > +@item MFD_HUGETLB > +@standards{Linux, sys/mman.h} > +This requests that mappings created using the returned file descriptor > +use a larger page size. See @code{MAP_HUGETLB} above for details. > + > +This flag is incompatible with @code{MFD_ALLOW_SEALING}. > +@end vtable > + > +@code{memfd_create} returns a file descriptor on success, and @math{-1} I think @code for return values is more appropriate. > +on failure. > + > +The following @code{errno} error conditions are defined for this > +function: > + > +@table @code > +@item EINVAL > +An invalid combination is specified in @var{flags}, or @var{name} is > +too long. > + > +@item EFAULT > +The @var{name} argument does not point to a string. > + > +@item EMFILE > +The operation would exceed the file descriptor limit for this process. > + > +@item ENFILE > +The operation would exceed the system-wide file descriptor limit. > + > +@item ENOMEM > +There is not enough memory for the operation. > +@end table > +@end deftypefn OK. > diff --git a/sysdeps/unix/sysv/linux/bits/mman-linux.h b/sysdeps/unix/sysv/linux/bits/mman-linux.h > index 78c07c890a..1ffa5490af 100644 > --- a/sysdeps/unix/sysv/linux/bits/mman-linux.h > +++ b/sysdeps/unix/sysv/linux/bits/mman-linux.h > @@ -111,3 +111,19 @@ > # define MCL_ONFAULT 4 /* Lock all pages that are > faulted in. */ > #endif > + > +#ifdef __USE_GNU > +/* Flags for memfd_create. */ > +# define MFD_CLOEXEC 1U > +# define MFD_ALLOW_SEALING 2U > +# define MFD_HUGETLB 4U > + > +__BEGIN_DECLS > + > +/* Create a new memory file descriptor. NAME is a name for debugging. > + FLAGS is a combination of the MFD_* constants. */ > +int memfd_create (const char *__name, unsigned int __flags) __THROW; > + > +__END_DECLS > + > +#endif /* __USE_GNU */ Leaving this part for reference. Thank you, Rical
On 11/19/2017 02:47 AM, Rical Jasan wrote: > On 11/18/2017 09:32 AM, Florian Weimer wrote: >> diff --git a/manual/llio.texi b/manual/llio.texi >> index 8c7c58c216..625fe49ac1 100644 >> --- a/manual/llio.texi >> +++ b/manual/llio.texi >> @@ -1808,6 +1808,69 @@ the given @var{name} previously created by @code{shm_open}. >> On failure @code{errno} is set. >> @end deftypefn >> >> +@deftypefn Function int memfd_create (const char *@var{name}, unsigned int flags) > > "@var{flags}" > > Use @deftypefun, and drop "Function" (shortcut). Both fixed. >> +@standards{Linux, sys/mman.h} >> +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{@acsfd{}}} >> +The @code{memfd_create} function returns a file descriptor which can be >> +used to create memory mappings using the @code{mmap} function. It is >> +similar to the @code{shm_open} function in the sense that these mappings >> +are not backed by actual files. However, the descriptor return by > > "returned" Fixed. >> +@code{memfd_create} does not correspond to a named object; the >> +@var{name} argument is used for informative purposes only. The > > I see in mman-linux.h, "NAME is a name for debugging." Can we say > "debugging purposes" here? As-is, it sounds ignored, and doesn't really > hint at what type of information one could get from it or how. Well, that is exactly what I want to convey: The name is unused and just shows up in /proc in a few places. I want to make sure that there is no expectation that you get same underlying file if you specify the same name. >> +descriptor can be passed between processes (for example, over local >> +domain sockets), and mappings at the same offset refer to the same >> +memory, or the descriptor can be used to create alias mappings within >> +the same process. > > The and/or here is odd. What about: "...the same memory. The > descriptor can also be used..." Good idea. >> +This flag is incompatible with @code{MFD_ALLOW_SEALING}. >> +@end vtable >> + >> +@code{memfd_create} returns a file descriptor on success, and @math{-1} > > I think @code for return values is more appropriate. I've been using @math for constants. I like it for these small decimal constants because the typewriter font stands out some much. New patch attached. I think I have addressed all concerns raised regarding the documentation. Is there anything left to do for the implementation? Thanks, Florian Subject: [PATCH] Linux: Add memfd_create system call wrapper To: libc-alpha@sourceware.org The system call is somewhat obscure because it is closely related to file descriptor sealing. However, it is also the recommended way to create alias mappings, which is why it has more general use. No emulation is provided. Except for the name of the /proc/self/fd links, it would be possible to implement an approximation using O_TMPFILE and tmpfs, but this does not appear to be worth the added complexity. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com> 2017-11-19 Florian Weimer <fweimer@redhat.com> Linux: Add memfd_create system call wrapper * sysdeps/unix/sysv/linux/Makefile [misc] (tests): Add tst-memfd_create. * sysdeps/unix/sysv/linux/bits/mman-linux.h [__USE_GNU] (MFD_CLOEXEC, MFD_ALLOW_SEALING): Define. [__USE_GNU] (memfd_create): Declare. * sysdeps/unix/sysv/linux/Versions (GLIBC_2.27): Add memfd_create. * sysdeps/unix/sysv/linux/syscalls.list (memfd_create): Add. * sysdeps/unix/sysv/linux/tst-memfd_create.c: New file. * sysdeps/unix/sysv/linux/**.abilist: Update. * manual/llio.texi (Memory-mapped I/O): Document memfd_create. diff --git a/NEWS b/NEWS index 1c5da21327..3d453644d9 100644 --- a/NEWS +++ b/NEWS @@ -35,6 +35,9 @@ Major new features: are the same interfaces added in version 2.26 for some platforms where this format is supported but is not the format of long double. +* glibc now provides the <sys/memfd.h> header file and the memfd_create + system call. + Deprecated and removed features, and other changes affecting compatibility: * On GNU/Linux, the obsolete Linux constant PTRACE_SEIZE_DEVEL is no longer diff --git a/manual/llio.texi b/manual/llio.texi index 7dd4e0680d..9ecb891713 100644 --- a/manual/llio.texi +++ b/manual/llio.texi @@ -1757,6 +1757,69 @@ the given @var{name} previously created by @code{shm_open}. On failure @code{errno} is set. @end deftypefn +@deftypefun int memfd_create (const char *@var{name}, unsigned int @var{flags}) +@standards{Linux, sys/mman.h} +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{@acsfd{}}} +The @code{memfd_create} function returns a file descriptor which can be +used to create memory mappings using the @code{mmap} function. It is +similar to the @code{shm_open} function in the sense that these mappings +are not backed by actual files. However, the descriptor returned by +@code{memfd_create} does not correspond to a named object; the +@var{name} argument is used for informative purposes only. The +descriptor can be passed between processes (for example, over local +domain sockets), and mappings at the same offset refer to the same +memor. The descriptor can also be used to create alias mappings within +the same process. + +The descriptor initially refers to a zero-length file. Before mappings +can be created which are backed by memory, the file size needs to be +increased with the @code{ftruncate} function. @xref{File Size}. + +The @var{flags} argument can be a combination of the following flags: + +@vtable @code +@item MFD_CLOEXEC +@standards{Linux, sys/mman.h} +The descriptor is created with the @code{O_CLOEXEC} flag. + +@item MFD_ALLOW_SEALING +@standards{Linux, sys/mman.h} +The descriptor supports the addition of seals using the @code{fcntl} +function. + +@item MFD_HUGETLB +@standards{Linux, sys/mman.h} +This requests that mappings created using the returned file descriptor +use a larger page size. See @code{MAP_HUGETLB} above for details. + +This flag is incompatible with @code{MFD_ALLOW_SEALING}. +@end vtable + +@code{memfd_create} returns a file descriptor on success, and @math{-1} +on failure. + +The following @code{errno} error conditions are defined for this +function: + +@table @code +@item EINVAL +An invalid combination is specified in @var{flags}, or @var{name} is +too long. + +@item EFAULT +The @var{name} argument does not point to a string. + +@item EMFILE +The operation would exceed the file descriptor limit for this process. + +@item ENFILE +The operation would exceed the system-wide file descriptor limit. + +@item ENOMEM +There is not enough memory for the operation. +@end table +@end deftypefun + @node Waiting for I/O @section Waiting for Input or Output @cindex waiting for input or output diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile index c6675b3aa5..c484d2688a 100644 --- a/sysdeps/unix/sysv/linux/Makefile +++ b/sysdeps/unix/sysv/linux/Makefile @@ -44,7 +44,7 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \ tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \ tst-quota tst-sync_file_range tst-sysconf-iov_max tst-ttyname \ - test-errno-linux + test-errno-linux tst-memfd_create # Generate the list of SYS_* macros for the system calls (__NR_* # macros). The file syscall-names.list contains all possible system diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions index d3dbcde8c9..6f2fe516d7 100644 --- a/sysdeps/unix/sysv/linux/Versions +++ b/sysdeps/unix/sysv/linux/Versions @@ -166,6 +166,9 @@ libc { GLIBC_2.15 { process_vm_readv; process_vm_writev; } + GLIBC_2.27 { + memfd_create; + } GLIBC_PRIVATE { # functions used in other libraries __syscall_rt_sigqueueinfo; diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist index ed598aedac..140ca28abc 100644 --- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist +++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist @@ -2106,6 +2106,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist index 4e57f36bcf..f698e1b2f4 100644 --- a/sysdeps/unix/sysv/linux/alpha/libc.abilist +++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist @@ -2017,6 +2017,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/arm/libc.abilist b/sysdeps/unix/sysv/linux/arm/libc.abilist index 5b70e1bfc9..8a8af3e3e4 100644 --- a/sysdeps/unix/sysv/linux/arm/libc.abilist +++ b/sysdeps/unix/sysv/linux/arm/libc.abilist @@ -107,6 +107,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.4 GLIBC_2.4 A GLIBC_2.4 _Exit F GLIBC_2.4 _IO_2_1_stderr_ D 0xa0 diff --git a/sysdeps/unix/sysv/linux/bits/mman-linux.h b/sysdeps/unix/sysv/linux/bits/mman-linux.h index 78c07c890a..1ffa5490af 100644 --- a/sysdeps/unix/sysv/linux/bits/mman-linux.h +++ b/sysdeps/unix/sysv/linux/bits/mman-linux.h @@ -111,3 +111,19 @@ # define MCL_ONFAULT 4 /* Lock all pages that are faulted in. */ #endif + +#ifdef __USE_GNU +/* Flags for memfd_create. */ +# define MFD_CLOEXEC 1U +# define MFD_ALLOW_SEALING 2U +# define MFD_HUGETLB 4U + +__BEGIN_DECLS + +/* Create a new memory file descriptor. NAME is a name for debugging. + FLAGS is a combination of the MFD_* constants. */ +int memfd_create (const char *__name, unsigned int __flags) __THROW; + +__END_DECLS + +#endif /* __USE_GNU */ diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist index 6a2500a8b3..5b81a6cd7d 100644 --- a/sysdeps/unix/sysv/linux/hppa/libc.abilist +++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist @@ -1871,6 +1871,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist index 9ab4e3642a..51ead9e867 100644 --- a/sysdeps/unix/sysv/linux/i386/libc.abilist +++ b/sysdeps/unix/sysv/linux/i386/libc.abilist @@ -2036,6 +2036,7 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist index 81bb623fe8..78b4ee8d40 100644 --- a/sysdeps/unix/sysv/linux/ia64/libc.abilist +++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist @@ -1900,6 +1900,7 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist index 5a33b57390..d9c97779e4 100644 --- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist +++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist @@ -108,6 +108,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.4 GLIBC_2.4 A GLIBC_2.4 _Exit F GLIBC_2.4 _IO_2_1_stderr_ D 0x98 diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist index 50a86e74fa..4acbf7eeed 100644 --- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist +++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist @@ -1985,6 +1985,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/microblaze/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/libc.abilist index 250ef305c3..93f02f08ce 100644 --- a/sysdeps/unix/sysv/linux/microblaze/libc.abilist +++ b/sysdeps/unix/sysv/linux/microblaze/libc.abilist @@ -2106,3 +2106,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist index 87a1dc4ad7..795e85de70 100644 --- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist @@ -1960,6 +1960,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist index f2b35f250e..dc714057b7 100644 --- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist @@ -1958,6 +1958,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist index ade654dbea..ce7bc9b175 100644 --- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist @@ -1956,6 +1956,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist index 56032c3f82..3fdd85eace 100644 --- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist @@ -1951,6 +1951,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/nios2/libc.abilist b/sysdeps/unix/sysv/linux/nios2/libc.abilist index c599dd9212..3e0bcb2a5c 100644 --- a/sysdeps/unix/sysv/linux/nios2/libc.abilist +++ b/sysdeps/unix/sysv/linux/nios2/libc.abilist @@ -2147,3 +2147,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist index 385409aa6e..375c69d9d1 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist @@ -1989,6 +1989,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist index e99cb454b5..a88172a906 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist @@ -1994,6 +1994,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist index 173672ab5e..fa026a332c 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist @@ -2201,3 +2201,4 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist index 8a654436ab..838f395d78 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist @@ -108,6 +108,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 _Exit F GLIBC_2.3 _IO_2_1_stderr_ D 0xe0 diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist index dbd411ceb1..41b79c496a 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist +++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist @@ -1989,6 +1989,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist index 5617784ca0..68251a0e69 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist +++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist @@ -1890,6 +1890,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/sh/libc.abilist b/sysdeps/unix/sysv/linux/sh/libc.abilist index 0f840e6e88..bc1aae275e 100644 --- a/sysdeps/unix/sysv/linux/sh/libc.abilist +++ b/sysdeps/unix/sysv/linux/sh/libc.abilist @@ -1875,6 +1875,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist index bb7e1042c7..93e6d092ac 100644 --- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist +++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist @@ -1982,6 +1982,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist index 4053b0a51c..b11d6764d4 100644 --- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist +++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist @@ -1919,6 +1919,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list index 8bfb080d80..40c4fbb9ea 100644 --- a/sysdeps/unix/sysv/linux/syscalls.list +++ b/sysdeps/unix/sysv/linux/syscalls.list @@ -109,3 +109,4 @@ setns EXTRA setns i:ii setns process_vm_readv EXTRA process_vm_readv i:ipipii process_vm_readv process_vm_writev EXTRA process_vm_writev i:ipipii process_vm_writev +memfd_create EXTRA memfd_create i:si memfd_create diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist index 38a96d3a02..e9eb4ff7bd 100644 --- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist +++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist index 572b917d7d..8f08e909cd 100644 --- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist +++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist index 38a96d3a02..e9eb4ff7bd 100644 --- a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist +++ b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/tst-memfd_create.c b/sysdeps/unix/sysv/linux/tst-memfd_create.c new file mode 100644 index 0000000000..fd173ff71d --- /dev/null +++ b/sysdeps/unix/sysv/linux/tst-memfd_create.c @@ -0,0 +1,121 @@ +/* Test for the memfd_create system call. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <errno.h> +#include <fcntl.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <support/check.h> +#include <support/support.h> +#include <support/test-driver.h> +#include <support/xunistd.h> +#include <sys/mman.h> + +/* Return true if the descriptor has the FD_CLOEXEC flag set. */ +static bool +is_cloexec (int fd) +{ + int flags = fcntl (fd, F_GETFD); + TEST_VERIFY (flags >= 0); + return flags & FD_CLOEXEC; +} + +/* Return the seals set on FD. */ +static int +get_seals (int fd) +{ + int flags = fcntl (fd, F_GET_SEALS); + TEST_VERIFY (flags >= 0); + return flags; +} + +/* Return true if the F_SEAL_SEAL flag is set on the descriptor. */ +static bool +is_sealed (int fd) +{ + return get_seals (fd) & F_SEAL_SEAL; +} + +static int +do_test (void) +{ + /* Initialized by the first call to memfd_create to 0 (memfd_create + unsupported) or 1 (memfd_create is implemented in the kernel). + Subsequent iterations check that the success/failure state is + consistent. */ + int supported = -1; + + for (int do_cloexec = 0; do_cloexec < 2; ++do_cloexec) + for (int do_sealing = 0; do_sealing < 2; ++do_sealing) + { + int flags = 0; + if (do_cloexec) + flags |= MFD_CLOEXEC; + if (do_sealing) + flags |= MFD_ALLOW_SEALING; + if (test_verbose > 0) + printf ("info: memfd_create with flags=0x%x\n", flags); + int fd = memfd_create ("tst-memfd_create", flags); + if (fd < 0) + { + if (errno == ENOSYS) + { + if (supported < 0) + { + printf ("warning: memfd_create is unsupported\n"); + supported = 0; + continue; + } + TEST_VERIFY (supported == 0); + continue; + } + else + FAIL_EXIT1 ("memfd_create: %m"); + } + if (supported < 0) + supported = 1; + TEST_VERIFY (supported > 0); + + char *fd_path = xasprintf ("/proc/self/fd/%d", fd); + char *link = xreadlink (fd_path); + if (test_verbose > 0) + printf ("info: memfd link: %s\n", link); + TEST_VERIFY (strcmp (link, "memfd:tst-memfd_create (deleted)")); + TEST_VERIFY (is_cloexec (fd) == do_cloexec); + TEST_VERIFY (is_sealed (fd) == !do_sealing); + if (do_sealing) + { + TEST_VERIFY (fcntl (fd, F_ADD_SEALS, F_SEAL_WRITE) == 0); + TEST_VERIFY (!is_sealed (fd)); + TEST_VERIFY (get_seals (fd) & F_SEAL_WRITE); + TEST_VERIFY (fcntl (fd, F_ADD_SEALS, F_SEAL_SEAL) == 0); + TEST_VERIFY (is_sealed (fd)); + } + xclose (fd); + free (fd_path); + free (link); + } + + if (supported == 0) + return EXIT_UNSUPPORTED; + return 0; +} + +#include <support/test-driver.c> diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist index b83d25c2e3..0a4f7797ac 100644 --- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist +++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist @@ -1877,6 +1877,7 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist index cba1d59057..23f6a91429 100644 --- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist +++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist @@ -2120,3 +2120,4 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F
On 11/19/2017 05:49 AM, Florian Weimer wrote: >>> +@code{memfd_create} does not correspond to a named object; the >>> +@var{name} argument is used for informative purposes only. The >> >> I see in mman-linux.h, "NAME is a name for debugging." Can we say >> "debugging purposes" here? As-is, it sounds ignored, and doesn't really >> hint at what type of information one could get from it or how. > > Well, that is exactly what I want to convey: The name is unused and just > shows up in /proc in a few places. I want to make sure that there is no > expectation that you get same underlying file if you specify the same name. Why not say that explicitly? Suggestion: "However, the descriptor returned by @code{memfd_create} does not correspond to a named object; the @var{name} argument is used for debugging purposes only (e.g., will appear in @file{/proc}), and separate invocations of @code{memfd_create} with the same @var{name} will not return descriptors for the same region of memory." > memfd_create.patch ... > diff --git a/manual/llio.texi b/manual/llio.texi > index 7dd4e0680d..9ecb891713 100644 > --- a/manual/llio.texi > +++ b/manual/llio.texi > @@ -1757,6 +1757,69 @@ the given @var{name} previously created by @code{shm_open}. > On failure @code{errno} is set. > @end deftypefn > > +@deftypefun int memfd_create (const char *@var{name}, unsigned int @var{flags}) > +@standards{Linux, sys/mman.h} > +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{@acsfd{}}} > +The @code{memfd_create} function returns a file descriptor which can be > +used to create memory mappings using the @code{mmap} function. It is > +similar to the @code{shm_open} function in the sense that these mappings > +are not backed by actual files. However, the descriptor returned by > +@code{memfd_create} does not correspond to a named object; the > +@var{name} argument is used for informative purposes only. The > +descriptor can be passed between processes (for example, over local > +domain sockets), and mappings at the same offset refer to the same > +memor. The descriptor can also be used to create alias mappings within lost a "y" here Rical
On 19/11/2017 11:49, Florian Weimer wrote: > On 11/19/2017 02:47 AM, Rical Jasan wrote: >> On 11/18/2017 09:32 AM, Florian Weimer wrote: >>> diff --git a/manual/llio.texi b/manual/llio.texi >>> index 8c7c58c216..625fe49ac1 100644 >>> --- a/manual/llio.texi >>> +++ b/manual/llio.texi >>> @@ -1808,6 +1808,69 @@ the given @var{name} previously created by @code{shm_open}. >>>  On failure @code{errno} is set. >>>  @end deftypefn >>>  +@deftypefn Function int memfd_create (const char *@var{name}, unsigned int flags) >> >> "@var{flags}" >> >> Use @deftypefun, and drop "Function" (shortcut). > > Both fixed. > >>> +@standards{Linux, sys/mman.h} >>> +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{@acsfd{}}} >>> +The @code{memfd_create} function returns a file descriptor which can be >>> +used to create memory mappings using the @code{mmap} function. It is >>> +similar to the @code{shm_open} function in the sense that these mappings >>> +are not backed by actual files. However, the descriptor return by >> >> "returned" > > Fixed. > >>> +@code{memfd_create} does not correspond to a named object; the >>> +@var{name} argument is used for informative purposes only. The >> >> I see in mman-linux.h, "NAME is a name for debugging." Can we say >> "debugging purposes" here? As-is, it sounds ignored, and doesn't really >> hint at what type of information one could get from it or how. > > Well, that is exactly what I want to convey: The name is unused and just shows up in /proc in a few places. I want to make sure that there is no expectation that you get same underlying file if you specify the same name. > >>> +descriptor can be passed between processes (for example, over local >>> +domain sockets), and mappings at the same offset refer to the same >>> +memory, or the descriptor can be used to create alias mappings within >>> +the same process. >> >> The and/or here is odd. What about: "...the same memory. The >> descriptor can also be used..." > > Good idea. > >>> +This flag is incompatible with @code{MFD_ALLOW_SEALING}. >>> +@end vtable >>> + >>> +@code{memfd_create} returns a file descriptor on success, and @math{-1} >> >> I think @code for return values is more appropriate. > > I've been using @math for constants. I like it for these small decimal constants because the typewriter font stands out some much. > > New patch attached. I think I have addressed all concerns raised regarding the documentation. Is there anything left to do for the implementation? > > Thanks, > Florian > > memfd_create.patch > > > Subject: [PATCH] Linux: Add memfd_create system call wrapper > To: libc-alpha@sourceware.org > > The system call is somewhat obscure because it is closely related > to file descriptor sealing. However, it is also the recommended > way to create alias mappings, which is why it has more general use. > > No emulation is provided. Except for the name of the > /proc/self/fd links, it would be possible to implement an > approximation using O_TMPFILE and tmpfs, but this does not appear > to be worth the added complexity. > > Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com> > > 2017-11-19 Florian Weimer <fweimer@redhat.com> > > Linux: Add memfd_create system call wrapper > * sysdeps/unix/sysv/linux/Makefile [misc] (tests): Add > tst-memfd_create. > * sysdeps/unix/sysv/linux/bits/mman-linux.h [__USE_GNU] > (MFD_CLOEXEC, MFD_ALLOW_SEALING): Define. > [__USE_GNU] (memfd_create): Declare. > * sysdeps/unix/sysv/linux/Versions (GLIBC_2.27): Add memfd_create. > * sysdeps/unix/sysv/linux/syscalls.list (memfd_create): Add. > * sysdeps/unix/sysv/linux/tst-memfd_create.c: New file. > * sysdeps/unix/sysv/linux/**.abilist: Update. > * manual/llio.texi (Memory-mapped I/O): Document memfd_create. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > > diff --git a/NEWS b/NEWS > index 1c5da21327..3d453644d9 100644 > --- a/NEWS > +++ b/NEWS > @@ -35,6 +35,9 @@ Major new features: > are the same interfaces added in version 2.26 for some platforms where > this format is supported but is not the format of long double. > > +* glibc now provides the <sys/memfd.h> header file and the memfd_create > + system call. > + > Deprecated and removed features, and other changes affecting compatibility: > > * On GNU/Linux, the obsolete Linux constant PTRACE_SEIZE_DEVEL is no longer > diff --git a/manual/llio.texi b/manual/llio.texi > index 7dd4e0680d..9ecb891713 100644 > --- a/manual/llio.texi > +++ b/manual/llio.texi > @@ -1757,6 +1757,69 @@ the given @var{name} previously created by @code{shm_open}. > On failure @code{errno} is set. > @end deftypefn > > +@deftypefun int memfd_create (const char *@var{name}, unsigned int @var{flags}) > +@standards{Linux, sys/mman.h} > +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{@acsfd{}}} > +The @code{memfd_create} function returns a file descriptor which can be > +used to create memory mappings using the @code{mmap} function. It is > +similar to the @code{shm_open} function in the sense that these mappings > +are not backed by actual files. However, the descriptor returned by > +@code{memfd_create} does not correspond to a named object; the > +@var{name} argument is used for informative purposes only. The > +descriptor can be passed between processes (for example, over local > +domain sockets), and mappings at the same offset refer to the same > +memor. The descriptor can also be used to create alias mappings within > +the same process. > + > +The descriptor initially refers to a zero-length file. Before mappings > +can be created which are backed by memory, the file size needs to be > +increased with the @code{ftruncate} function. @xref{File Size}. > + > +The @var{flags} argument can be a combination of the following flags: > + > +@vtable @code > +@item MFD_CLOEXEC > +@standards{Linux, sys/mman.h} > +The descriptor is created with the @code{O_CLOEXEC} flag. > + > +@item MFD_ALLOW_SEALING > +@standards{Linux, sys/mman.h} > +The descriptor supports the addition of seals using the @code{fcntl} > +function. > + > +@item MFD_HUGETLB > +@standards{Linux, sys/mman.h} > +This requests that mappings created using the returned file descriptor > +use a larger page size. See @code{MAP_HUGETLB} above for details. > + > +This flag is incompatible with @code{MFD_ALLOW_SEALING}. > +@end vtable > + > +@code{memfd_create} returns a file descriptor on success, and @math{-1} > +on failure. > + > +The following @code{errno} error conditions are defined for this > +function: > + > +@table @code > +@item EINVAL > +An invalid combination is specified in @var{flags}, or @var{name} is > +too long. > + > +@item EFAULT > +The @var{name} argument does not point to a string. > + > +@item EMFILE > +The operation would exceed the file descriptor limit for this process. > + > +@item ENFILE > +The operation would exceed the system-wide file descriptor limit. > + > +@item ENOMEM > +There is not enough memory for the operation. > +@end table > +@end deftypefun > + > @node Waiting for I/O > @section Waiting for Input or Output > @cindex waiting for input or output > diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile > index c6675b3aa5..c484d2688a 100644 > --- a/sysdeps/unix/sysv/linux/Makefile > +++ b/sysdeps/unix/sysv/linux/Makefile > @@ -44,7 +44,7 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \ > > tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \ > tst-quota tst-sync_file_range tst-sysconf-iov_max tst-ttyname \ > - test-errno-linux > + test-errno-linux tst-memfd_create > > # Generate the list of SYS_* macros for the system calls (__NR_* > # macros). The file syscall-names.list contains all possible system > diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions > index d3dbcde8c9..6f2fe516d7 100644 > --- a/sysdeps/unix/sysv/linux/Versions > +++ b/sysdeps/unix/sysv/linux/Versions > @@ -166,6 +166,9 @@ libc { > GLIBC_2.15 { > process_vm_readv; process_vm_writev; > } > + GLIBC_2.27 { > + memfd_create; > + } > GLIBC_PRIVATE { > # functions used in other libraries > __syscall_rt_sigqueueinfo; > diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist > index ed598aedac..140ca28abc 100644 > --- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist > @@ -2106,6 +2106,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist > index 4e57f36bcf..f698e1b2f4 100644 > --- a/sysdeps/unix/sysv/linux/alpha/libc.abilist > +++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist > @@ -2017,6 +2017,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/arm/libc.abilist b/sysdeps/unix/sysv/linux/arm/libc.abilist > index 5b70e1bfc9..8a8af3e3e4 100644 > --- a/sysdeps/unix/sysv/linux/arm/libc.abilist > +++ b/sysdeps/unix/sysv/linux/arm/libc.abilist > @@ -107,6 +107,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.4 GLIBC_2.4 A > GLIBC_2.4 _Exit F > GLIBC_2.4 _IO_2_1_stderr_ D 0xa0 > diff --git a/sysdeps/unix/sysv/linux/bits/mman-linux.h b/sysdeps/unix/sysv/linux/bits/mman-linux.h > index 78c07c890a..1ffa5490af 100644 > --- a/sysdeps/unix/sysv/linux/bits/mman-linux.h > +++ b/sysdeps/unix/sysv/linux/bits/mman-linux.h > @@ -111,3 +111,19 @@ > # define MCL_ONFAULT 4 /* Lock all pages that are > faulted in. */ > #endif > + > +#ifdef __USE_GNU > +/* Flags for memfd_create. */ > +# define MFD_CLOEXEC 1U > +# define MFD_ALLOW_SEALING 2U > +# define MFD_HUGETLB 4U > + > +__BEGIN_DECLS > + > +/* Create a new memory file descriptor. NAME is a name for debugging. > + FLAGS is a combination of the MFD_* constants. */ > +int memfd_create (const char *__name, unsigned int __flags) __THROW; > + > +__END_DECLS > + > +#endif /* __USE_GNU */ > diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist > index 6a2500a8b3..5b81a6cd7d 100644 > --- a/sysdeps/unix/sysv/linux/hppa/libc.abilist > +++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist > @@ -1871,6 +1871,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist > index 9ab4e3642a..51ead9e867 100644 > --- a/sysdeps/unix/sysv/linux/i386/libc.abilist > +++ b/sysdeps/unix/sysv/linux/i386/libc.abilist > @@ -2036,6 +2036,7 @@ GLIBC_2.26 wcstof128_l F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist > index 81bb623fe8..78b4ee8d40 100644 > --- a/sysdeps/unix/sysv/linux/ia64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist > @@ -1900,6 +1900,7 @@ GLIBC_2.26 wcstof128_l F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist > index 5a33b57390..d9c97779e4 100644 > --- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist > +++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist > @@ -108,6 +108,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.4 GLIBC_2.4 A > GLIBC_2.4 _Exit F > GLIBC_2.4 _IO_2_1_stderr_ D 0x98 > diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist > index 50a86e74fa..4acbf7eeed 100644 > --- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist > +++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist > @@ -1985,6 +1985,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/microblaze/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/libc.abilist > index 250ef305c3..93f02f08ce 100644 > --- a/sysdeps/unix/sysv/linux/microblaze/libc.abilist > +++ b/sysdeps/unix/sysv/linux/microblaze/libc.abilist > @@ -2106,3 +2106,4 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist > index 87a1dc4ad7..795e85de70 100644 > --- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist > +++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist > @@ -1960,6 +1960,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist > index f2b35f250e..dc714057b7 100644 > --- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist > +++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist > @@ -1958,6 +1958,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist > index ade654dbea..ce7bc9b175 100644 > --- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist > +++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist > @@ -1956,6 +1956,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist > index 56032c3f82..3fdd85eace 100644 > --- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist > @@ -1951,6 +1951,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/nios2/libc.abilist b/sysdeps/unix/sysv/linux/nios2/libc.abilist > index c599dd9212..3e0bcb2a5c 100644 > --- a/sysdeps/unix/sysv/linux/nios2/libc.abilist > +++ b/sysdeps/unix/sysv/linux/nios2/libc.abilist > @@ -2147,3 +2147,4 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist > index 385409aa6e..375c69d9d1 100644 > --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist > +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist > @@ -1989,6 +1989,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist > index e99cb454b5..a88172a906 100644 > --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist > +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist > @@ -1994,6 +1994,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist > index 173672ab5e..fa026a332c 100644 > --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist > +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist > @@ -2201,3 +2201,4 @@ GLIBC_2.26 wcstof128_l F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist > index 8a654436ab..838f395d78 100644 > --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist > @@ -108,6 +108,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 _Exit F > GLIBC_2.3 _IO_2_1_stderr_ D 0xe0 > diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist > index dbd411ceb1..41b79c496a 100644 > --- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist > +++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist > @@ -1989,6 +1989,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist > index 5617784ca0..68251a0e69 100644 > --- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist > @@ -1890,6 +1890,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/sh/libc.abilist b/sysdeps/unix/sysv/linux/sh/libc.abilist > index 0f840e6e88..bc1aae275e 100644 > --- a/sysdeps/unix/sysv/linux/sh/libc.abilist > +++ b/sysdeps/unix/sysv/linux/sh/libc.abilist > @@ -1875,6 +1875,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist > index bb7e1042c7..93e6d092ac 100644 > --- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist > +++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist > @@ -1982,6 +1982,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist > index 4053b0a51c..b11d6764d4 100644 > --- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist > @@ -1919,6 +1919,7 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.27 strfromf128 F > GLIBC_2.27 strtof128 F > GLIBC_2.27 strtof128_l F > diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list > index 8bfb080d80..40c4fbb9ea 100644 > --- a/sysdeps/unix/sysv/linux/syscalls.list > +++ b/sysdeps/unix/sysv/linux/syscalls.list > @@ -109,3 +109,4 @@ setns EXTRA setns i:ii setns > > process_vm_readv EXTRA process_vm_readv i:ipipii process_vm_readv > process_vm_writev EXTRA process_vm_writev i:ipipii process_vm_writev > +memfd_create EXTRA memfd_create i:si memfd_create > diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist > index 38a96d3a02..e9eb4ff7bd 100644 > --- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist > +++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist > @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist > index 572b917d7d..8f08e909cd 100644 > --- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist > @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > diff --git a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist > index 38a96d3a02..e9eb4ff7bd 100644 > --- a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist > +++ b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist > @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > diff --git a/sysdeps/unix/sysv/linux/tst-memfd_create.c b/sysdeps/unix/sysv/linux/tst-memfd_create.c > new file mode 100644 > index 0000000000..fd173ff71d > --- /dev/null > +++ b/sysdeps/unix/sysv/linux/tst-memfd_create.c > @@ -0,0 +1,121 @@ > +/* Test for the memfd_create system call. > + Copyright (C) 2017 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + <http://www.gnu.org/licenses/>. */ > + > +#include <errno.h> > +#include <fcntl.h> > +#include <stdbool.h> > +#include <stdio.h> > +#include <stdlib.h> > +#include <string.h> > +#include <support/check.h> > +#include <support/support.h> > +#include <support/test-driver.h> > +#include <support/xunistd.h> > +#include <sys/mman.h> > + > +/* Return true if the descriptor has the FD_CLOEXEC flag set. */ > +static bool > +is_cloexec (int fd) > +{ > + int flags = fcntl (fd, F_GETFD); > + TEST_VERIFY (flags >= 0); > + return flags & FD_CLOEXEC; > +} > + > +/* Return the seals set on FD. */ > +static int > +get_seals (int fd) > +{ > + int flags = fcntl (fd, F_GET_SEALS); > + TEST_VERIFY (flags >= 0); > + return flags; > +} > + > +/* Return true if the F_SEAL_SEAL flag is set on the descriptor. */ > +static bool > +is_sealed (int fd) > +{ > + return get_seals (fd) & F_SEAL_SEAL; > +} > + > +static int > +do_test (void) > +{ > + /* Initialized by the first call to memfd_create to 0 (memfd_create > + unsupported) or 1 (memfd_create is implemented in the kernel). > + Subsequent iterations check that the success/failure state is > + consistent. */ > + int supported = -1; > + > + for (int do_cloexec = 0; do_cloexec < 2; ++do_cloexec) > + for (int do_sealing = 0; do_sealing < 2; ++do_sealing) > + { > + int flags = 0; > + if (do_cloexec) > + flags |= MFD_CLOEXEC; > + if (do_sealing) > + flags |= MFD_ALLOW_SEALING; > + if (test_verbose > 0) > + printf ("info: memfd_create with flags=0x%x\n", flags); > + int fd = memfd_create ("tst-memfd_create", flags); > + if (fd < 0) > + { > + if (errno == ENOSYS) > + { > + if (supported < 0) > + { > + printf ("warning: memfd_create is unsupported\n"); > + supported = 0; > + continue; > + } > + TEST_VERIFY (supported == 0); > + continue; > + } > + else > + FAIL_EXIT1 ("memfd_create: %m"); > + } > + if (supported < 0) > + supported = 1; > + TEST_VERIFY (supported > 0); > + > + char *fd_path = xasprintf ("/proc/self/fd/%d", fd); > + char *link = xreadlink (fd_path); > + if (test_verbose > 0) > + printf ("info: memfd link: %s\n", link); > + TEST_VERIFY (strcmp (link, "memfd:tst-memfd_create (deleted)")); > + TEST_VERIFY (is_cloexec (fd) == do_cloexec); > + TEST_VERIFY (is_sealed (fd) == !do_sealing); > + if (do_sealing) > + { > + TEST_VERIFY (fcntl (fd, F_ADD_SEALS, F_SEAL_WRITE) == 0); > + TEST_VERIFY (!is_sealed (fd)); > + TEST_VERIFY (get_seals (fd) & F_SEAL_WRITE); > + TEST_VERIFY (fcntl (fd, F_ADD_SEALS, F_SEAL_SEAL) == 0); > + TEST_VERIFY (is_sealed (fd)); > + } > + xclose (fd); > + free (fd_path); > + free (link); > + } > + > + if (supported == 0) > + return EXIT_UNSUPPORTED; > + return 0; > +} > + > +#include <support/test-driver.c> > diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist > index b83d25c2e3..0a4f7797ac 100644 > --- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist > +++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist > @@ -1877,6 +1877,7 @@ GLIBC_2.26 wcstof128_l F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F > GLIBC_2.3 GLIBC_2.3 A > GLIBC_2.3 __ctype_b_loc F > GLIBC_2.3 __ctype_tolower_loc F > diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist > index cba1d59057..23f6a91429 100644 > --- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist > +++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist > @@ -2120,3 +2120,4 @@ GLIBC_2.26 wcstof128_l F > GLIBC_2.27 GLIBC_2.27 A > GLIBC_2.27 glob F > GLIBC_2.27 glob64 F > +GLIBC_2.27 memfd_create F >
This breaks the testsuite build for hppa, which does not use mman-linux.h
(i.e. the new declarations also need to be added to the hppa bits/mman.h).
../sysdeps/unix/sysv/linux/tst-memfd_create.c: In function 'do_test':
../sysdeps/unix/sysv/linux/tst-memfd_create.c:70:20: error: 'MFD_CLOEXEC' undeclared (first use in this function); did you mean 'FD_CLOEXEC'?
flags |= MFD_CLOEXEC;
^~~~~~~~~~~
FD_CLOEXEC
../sysdeps/unix/sysv/linux/tst-memfd_create.c:70:20: note: each undeclared identifier is reported only once for each function it appears in
../sysdeps/unix/sysv/linux/tst-memfd_create.c:72:20: error: 'MFD_ALLOW_SEALING' undeclared (first use in this function); did you mean '_PC_ALLOC_SIZE_MIN'?
flags |= MFD_ALLOW_SEALING;
^~~~~~~~~~~~~~~~~
_PC_ALLOC_SIZE_MIN
../sysdeps/unix/sysv/linux/tst-memfd_create.c:75:18: error: implicit declaration of function 'memfd_create' [-Werror=implicit-function-declaration]
int fd = memfd_create ("tst-memfd_create", flags);
^~~~~~~~~~~~
cc1: all warnings being treated as errors
https://sourceware.org/ml/libc-testresults/2017-q4/msg00352.html
(With non-mainline GCC the build failure still appears, it's just not so
visible as a regression because previously the testsuite build would
complete but with test failures.)
On 11/24/2017 05:16 PM, Joseph Myers wrote: > This breaks the testsuite build for hppa, which does not use mman-linux.h > (i.e. the new declarations also need to be added to the hppa bits/mman.h). I have more declarations and definitions to add which are not arch-specific at all, so I'll prepare a patch which adds another header which contributes to <sys/mman.h>. Thanks, Florian
diff --git a/manual/llio.texi b/manual/llio.texi index e72c53c785..5ab68e1511 100644 --- a/manual/llio.texi +++ b/manual/llio.texi @@ -1775,6 +1775,40 @@ the given @var{name} previously created by @code{shm_open}. On failure @code{errno} is set. @end deftypefn +@deftypefn Function int memfd_create (const char *@var{name}, unsigned int flags) +@standards{Linux, sys/memfd.h} + +The @code{memfd_create} function returns a file descriptor which can be +used to create memory mappings using the @code{mmap} function. It is +similar to the @code{shm_open} function in the sense that these mappings +are not backed by actual files. However, the descriptor return by +@code{memfd_create} does not correspond to a named object; the +@var{name} argument is used for informative purposes only. The +descriptor can be passed between processes (for example, over local +domain sockets), and mappings at the same offset refer to the same +memory, or the descriptor can be used to create alias mappings within +the same process. + +The descriptor initially refers to a zero-length file. Before mappings +can be created which are backed by memory, the file size needs to be +increased with the @code{ftruncate} function. @xref{File Size}. + +The @var{flags} argument can be a combination of the following flags: + +@table @code +@item MFD_CLOEXEC +The descriptor is created with the @code{O_CLOEXEC} flag. + +@item MFD_ALLOW_SEALING +The descriptor supports the addition of seals using the @code{fcntl} +function. +@end table + +The @code{memfd_create} function is specific to Linux. + +@end deftypefn + + @node Waiting for I/O @section Waiting for Input or Output @cindex waiting for input or output diff --git a/support/Makefile b/support/Makefile index 027a663000..dafb1737a4 100644 --- a/support/Makefile +++ b/support/Makefile @@ -109,19 +109,22 @@ libsupport-routines = \ xpthread_once \ xpthread_rwlock_init \ xpthread_rwlock_rdlock \ - xpthread_rwlock_wrlock \ xpthread_rwlock_unlock \ + xpthread_rwlock_wrlock \ xpthread_rwlockattr_init \ xpthread_rwlockattr_setkind_np \ xpthread_sigmask \ xpthread_spin_lock \ xpthread_spin_unlock \ + xreadlink \ xrealloc \ xrecvfrom \ xsendto \ xsetsockopt \ xsocket \ xstrdup \ + xstrndup \ + xunlink \ xwaitpid \ xwrite \ @@ -138,6 +141,7 @@ tests = \ tst-support_capture_subprocess \ tst-support_format_dns_packet \ tst-support_record_failure \ + tst-xreadlink \ ifeq ($(run-built-tests),yes) tests-special = \ diff --git a/support/support.h b/support/support.h index 4b5f04c2cc..bbba803ba1 100644 --- a/support/support.h +++ b/support/support.h @@ -68,6 +68,7 @@ void *xrealloc (void *p, size_t n); char *xasprintf (const char *format, ...) __attribute__ ((format (printf, 1, 2), malloc)); char *xstrdup (const char *); +char *xstrndup (const char *, size_t); __END_DECLS diff --git a/support/support_chroot.c b/support/support_chroot.c index f3ef551b05..f6fad18f33 100644 --- a/support/support_chroot.c +++ b/support/support_chroot.c @@ -46,10 +46,11 @@ support_chroot_create (struct support_chroot_configuration conf) { struct support_chroot *chroot = xmalloc (sizeof (*chroot)); - chroot->path_chroot = xasprintf ("%s/tst-resolv-res_init-XXXXXX", test_dir); - if (mkdtemp (chroot->path_chroot) == NULL) - FAIL_EXIT1 ("mkdtemp (\"%s\"): %m", chroot->path_chroot); - add_temp_file (chroot->path_chroot); + { + char *template = xasprintf ("%s/tst-resolv-res_init-XXXXXX", test_dir); + chroot->path_chroot = support_create_temp_directory (template); + free (template); + } /* Create the /etc directory in the chroot environment. */ char *path_etc = xasprintf ("%s/etc", chroot->path_chroot); diff --git a/support/temp_file.c b/support/temp_file.c index fdb2477ab9..cbd54e2e17 100644 --- a/support/temp_file.c +++ b/support/temp_file.c @@ -86,6 +86,19 @@ create_temp_file (const char *base, char **filename) return fd; } +char * +support_create_temp_directory (const char *base) +{ + char *base_copy = xstrdup (base); + if (mkdtemp (base_copy) == NULL) + { + printf ("error: mkdtemp (\"%s\"): %m", base); + exit (1); + } + add_temp_file (base_copy); + return base_copy; +} + /* Helper functions called by the test skeleton follow. */ void diff --git a/support/temp_file.h b/support/temp_file.h index 6fed8df1ea..dfefe585de 100644 --- a/support/temp_file.h +++ b/support/temp_file.h @@ -32,6 +32,11 @@ void add_temp_file (const char *name); *FILENAME. */ int create_temp_file (const char *base, char **filename); +/* Create a temporary directory and schedule it for deletion. BASE + must end with the six characters "XXXXXX". Return the name of the + temporary directory. The caller should free the string. */ +char *support_create_temp_directory (const char *base); + __END_DECLS #endif /* SUPPORT_TEMP_FILE_H */ diff --git a/support/tst-xreadlink.c b/support/tst-xreadlink.c new file mode 100644 index 0000000000..cb2c12a888 --- /dev/null +++ b/support/tst-xreadlink.c @@ -0,0 +1,72 @@ +/* Test the xreadlink function. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <errno.h> +#include <fcntl.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <support/check.h> +#include <support/support.h> +#include <support/temp_file.h> +#include <support/xunistd.h> + +static int +do_test (void) +{ + char *dir = support_create_temp_directory ("/tmp/tst-xreadlink-XXXXXX"); + char *symlink_name = xasprintf ("%s/symlink", dir); + add_temp_file (symlink_name); + + /* The limit 10000 is arbitrary and simply there to prevent an + attempt to exhaust all available disk space. */ + for (int size = 1; size < 10000; ++size) + { + char *contents = xmalloc (size + 1); + for (int i = 0; i < size; ++i) + contents[i] = 'a' + (rand () % 26); + contents[size] = '\0'; + if (symlink (contents, symlink_name) != 0) + { + if (errno == ENAMETOOLONG) + { + printf ("info: ENAMETOOLONG failure at %d bytes\n", size); + free (contents); + break; + } + FAIL_EXIT1 ("symlink (%d bytes): %m", size); + } + + char *readlink_result = xreadlink (symlink_name); + TEST_VERIFY (strcmp (readlink_result, contents) == 0); + free (readlink_result); + xunlink (symlink_name); + free (contents); + } + + /* Create an empty file to suppress the temporary file deletion + warning. */ + xclose (xopen (symlink_name, O_WRONLY | O_CREAT, 0)); + + free (symlink_name); + free (dir); + + return 0; +} + +#include <support/test-driver.c> diff --git a/support/xreadlink.c b/support/xreadlink.c new file mode 100644 index 0000000000..aec58a2aa6 --- /dev/null +++ b/support/xreadlink.c @@ -0,0 +1,44 @@ +/* Error-checking, allocating wrapper for readlink. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <scratch_buffer.h> +#include <support/check.h> +#include <support/support.h> +#include <xunistd.h> + +char * +xreadlink (const char *path) +{ + struct scratch_buffer buf; + scratch_buffer_init (&buf); + + while (true) + { + ssize_t count = readlink (path, buf.data, buf.length); + if (count < 0) + FAIL_EXIT1 ("readlink (\"%s\"): %m", path); + if (count < buf.length) + { + char *result = xstrndup (buf.data, count); + scratch_buffer_free (&buf); + return result; + } + if (!scratch_buffer_grow (&buf)) + FAIL_EXIT1 ("scratch_buffer_grow in xreadlink"); + } +} diff --git a/support/xstrndup.c b/support/xstrndup.c new file mode 100644 index 0000000000..d59a283d25 --- /dev/null +++ b/support/xstrndup.c @@ -0,0 +1,30 @@ +/* strndup with error checking. + Copyright (C) 2016-2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <support/support.h> + +#include <string.h> + +char * +xstrndup (const char *s, size_t length) +{ + char *p = strndup (s, length); + if (p == NULL) + oom_error ("strndup", length); + return p; +} diff --git a/support/xunistd.h b/support/xunistd.h index c947bfd8fb..05c2626a7b 100644 --- a/support/xunistd.h +++ b/support/xunistd.h @@ -38,6 +38,11 @@ int xopen (const char *path, int flags, mode_t); void xstat (const char *path, struct stat64 *); void xmkdir (const char *path, mode_t); void xchroot (const char *path); +void xunlink (const char *path); + +/* Read the link at PATH. The caller should free the returned string + with free. */ +char *xreadlink (const char *path); /* Close the file descriptor. Ignore EINTR errors, but terminate the process on other errors. */ diff --git a/support/xunlink.c b/support/xunlink.c new file mode 100644 index 0000000000..f94ee118cf --- /dev/null +++ b/support/xunlink.c @@ -0,0 +1,27 @@ +/* Error-checking wrapper for unlink. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <support/check.h> +#include <support/xunistd.h> + +void +xunlink (const char *path) +{ + if (unlink (path) != 0) + FAIL_EXIT1 ("unlink (\"%s\"): %m", path); +} diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile index 0c8a009b5e..3a5515d092 100644 --- a/sysdeps/unix/sysv/linux/Makefile +++ b/sysdeps/unix/sysv/linux/Makefile @@ -39,7 +39,7 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \ sys/klog.h \ sys/user.h sys/prctl.h \ sys/kd.h sys/soundcard.h sys/vt.h \ - sys/quota.h sys/fsuid.h \ + sys/quota.h sys/fsuid.h sys/memfd.h \ scsi/sg.h scsi/scsi.h scsi/scsi_ioctl.h sys/pci.h \ sys/raw.h sys/personality.h sys/epoll.h \ bits/a.out.h sys/inotify.h sys/signalfd.h sys/eventfd.h \ @@ -50,7 +50,8 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \ bits/siginfo-arch.h bits/siginfo-consts-arch.h tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \ - tst-quota tst-sync_file_range test-errno-linux tst-sysconf-iov_max + tst-quota tst-sync_file_range test-errno-linux tst-sysconf-iov_max \ + tst-memfd_create # Generate the list of SYS_* macros for the system calls (__NR_* # macros). The file syscall-names.list contains all possible system diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions index 6c9e06f4f9..992c19729f 100644 --- a/sysdeps/unix/sysv/linux/Versions +++ b/sysdeps/unix/sysv/linux/Versions @@ -166,6 +166,9 @@ libc { GLIBC_2.15 { process_vm_readv; process_vm_writev; } + GLIBC_2.27 { + memfd_create; + } GLIBC_PRIVATE { # functions used in other libraries __syscall_rt_sigqueueinfo; diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist index ed598aedac..140ca28abc 100644 --- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist +++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist @@ -2106,6 +2106,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist index 4e57f36bcf..f698e1b2f4 100644 --- a/sysdeps/unix/sysv/linux/alpha/libc.abilist +++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist @@ -2017,6 +2017,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/arm/libc.abilist b/sysdeps/unix/sysv/linux/arm/libc.abilist index 5b70e1bfc9..8a8af3e3e4 100644 --- a/sysdeps/unix/sysv/linux/arm/libc.abilist +++ b/sysdeps/unix/sysv/linux/arm/libc.abilist @@ -107,6 +107,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.4 GLIBC_2.4 A GLIBC_2.4 _Exit F GLIBC_2.4 _IO_2_1_stderr_ D 0xa0 diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist index 6a2500a8b3..5b81a6cd7d 100644 --- a/sysdeps/unix/sysv/linux/hppa/libc.abilist +++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist @@ -1871,6 +1871,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist index 9ab4e3642a..51ead9e867 100644 --- a/sysdeps/unix/sysv/linux/i386/libc.abilist +++ b/sysdeps/unix/sysv/linux/i386/libc.abilist @@ -2036,6 +2036,7 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist index 81bb623fe8..78b4ee8d40 100644 --- a/sysdeps/unix/sysv/linux/ia64/libc.abilist +++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist @@ -1900,6 +1900,7 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist index 5a33b57390..d9c97779e4 100644 --- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist +++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist @@ -108,6 +108,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.4 GLIBC_2.4 A GLIBC_2.4 _Exit F GLIBC_2.4 _IO_2_1_stderr_ D 0x98 diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist index 50a86e74fa..4acbf7eeed 100644 --- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist +++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist @@ -1985,6 +1985,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/microblaze/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/libc.abilist index 250ef305c3..93f02f08ce 100644 --- a/sysdeps/unix/sysv/linux/microblaze/libc.abilist +++ b/sysdeps/unix/sysv/linux/microblaze/libc.abilist @@ -2106,3 +2106,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist index 87a1dc4ad7..795e85de70 100644 --- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist @@ -1960,6 +1960,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist index f2b35f250e..dc714057b7 100644 --- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist @@ -1958,6 +1958,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist index ade654dbea..ce7bc9b175 100644 --- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist @@ -1956,6 +1956,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist index 56032c3f82..3fdd85eace 100644 --- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist +++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist @@ -1951,6 +1951,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/nios2/libc.abilist b/sysdeps/unix/sysv/linux/nios2/libc.abilist index c599dd9212..3e0bcb2a5c 100644 --- a/sysdeps/unix/sysv/linux/nios2/libc.abilist +++ b/sysdeps/unix/sysv/linux/nios2/libc.abilist @@ -2147,3 +2147,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist index 385409aa6e..375c69d9d1 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist @@ -1989,6 +1989,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist index e99cb454b5..a88172a906 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist @@ -1994,6 +1994,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist index 173672ab5e..fa026a332c 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist @@ -2201,3 +2201,4 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist index 8a654436ab..838f395d78 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist @@ -108,6 +108,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 _Exit F GLIBC_2.3 _IO_2_1_stderr_ D 0xe0 diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist index dbd411ceb1..41b79c496a 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist +++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist @@ -1989,6 +1989,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist index 5617784ca0..68251a0e69 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist +++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist @@ -1890,6 +1890,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/sh/libc.abilist b/sysdeps/unix/sysv/linux/sh/libc.abilist index 0f840e6e88..bc1aae275e 100644 --- a/sysdeps/unix/sysv/linux/sh/libc.abilist +++ b/sysdeps/unix/sysv/linux/sh/libc.abilist @@ -1875,6 +1875,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist index bb7e1042c7..93e6d092ac 100644 --- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist +++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist @@ -1982,6 +1982,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist index 4053b0a51c..b11d6764d4 100644 --- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist +++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist @@ -1919,6 +1919,7 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.27 strfromf128 F GLIBC_2.27 strtof128 F GLIBC_2.27 strtof128_l F diff --git a/sysdeps/unix/sysv/linux/sys/memfd.h b/sysdeps/unix/sysv/linux/sys/memfd.h new file mode 100644 index 0000000000..8255ecd7a4 --- /dev/null +++ b/sysdeps/unix/sysv/linux/sys/memfd.h @@ -0,0 +1,28 @@ +/* memfd_create system call and constants. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#ifndef _SYS_MEMFD_H +#define _SYS_MEMFD_H + +#include <linux/memfd.h> + +/* Create a new memory file descriptor. NAME is a name for debugging. + FLAGS is a combination of the MFD_* constants. */ +int memfd_create (const char *__name, unsigned int __flags); + +#endif /* _SYS_MEMFD_H */ diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list index 8bfb080d80..40c4fbb9ea 100644 --- a/sysdeps/unix/sysv/linux/syscalls.list +++ b/sysdeps/unix/sysv/linux/syscalls.list @@ -109,3 +109,4 @@ setns EXTRA setns i:ii setns process_vm_readv EXTRA process_vm_readv i:ipipii process_vm_readv process_vm_writev EXTRA process_vm_writev i:ipipii process_vm_writev +memfd_create EXTRA memfd_create i:si memfd_create diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist index 38a96d3a02..e9eb4ff7bd 100644 --- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist +++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist index 572b917d7d..8f08e909cd 100644 --- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist +++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist index 38a96d3a02..e9eb4ff7bd 100644 --- a/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist +++ b/sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist @@ -2113,3 +2113,4 @@ GLIBC_2.26 reallocarray F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F diff --git a/sysdeps/unix/sysv/linux/tst-memfd_create.c b/sysdeps/unix/sysv/linux/tst-memfd_create.c new file mode 100644 index 0000000000..709cf46791 --- /dev/null +++ b/sysdeps/unix/sysv/linux/tst-memfd_create.c @@ -0,0 +1,134 @@ +/* Test for the memfd_create system call. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <errno.h> +#include <fcntl.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <support/check.h> +#include <support/support.h> +#include <support/test-driver.h> +#include <support/xunistd.h> +#include <sys/syscall.h> + +#ifndef SYS_memfd_create +static int +do_test (void) +{ + puts ("warning: kernel headers do not support memfd_create"); + return EXIT_UNSUPPORTED; +} + +#else /* SYS_memfd_create */ + +#include <sys/memfd.h> + +/* Return true if the descriptor has the FD_CLOEXEC flag set. */ +static bool +is_cloexec (int fd) +{ + int flags = fcntl (fd, F_GETFD); + TEST_VERIFY (flags >= 0); + return flags & FD_CLOEXEC; +} + +/* Return the seals set on FD. */ +static int +get_seals (int fd) +{ + int flags = fcntl (fd, F_GET_SEALS); + TEST_VERIFY (flags >= 0); + return flags; +} + +/* Return true if the F_SEAL_SEAL flag is set on the descriptor. */ +static bool +is_sealed (int fd) +{ + return get_seals (fd) & F_SEAL_SEAL; +} + +static int +do_test (void) +{ + /* Initialized by the first call to memfd_create to 0 (memfd_create + unsupported) or 1 (memfd_create is implemented in the kernel). + Subsequent iterations check that the success/failure state is + consistent. */ + int supported = -1; + + for (int do_cloexec = 0; do_cloexec < 2; ++do_cloexec) + for (int do_sealing = 0; do_sealing < 2; ++do_sealing) + { + int flags = 0; + if (do_cloexec) + flags |= MFD_CLOEXEC; + if (do_sealing) + flags |= MFD_ALLOW_SEALING; + if (test_verbose > 0) + printf ("info: memfd_create with flags=0x%x\n", flags); + int fd = memfd_create ("tst-memfd_create", flags); + if (fd < 0) + { + if (errno == ENOSYS) + { + if (supported < 0) + { + supported = 0; + continue; + } + TEST_VERIFY (supported == 0); + continue; + } + else + FAIL_EXIT1 ("memfd_create: %m"); + } + if (supported < 0) + supported = 1; + TEST_VERIFY (supported > 0); + + char *fd_path = xasprintf ("/proc/self/fd/%d", fd); + char *link = xreadlink (fd_path); + if (test_verbose > 0) + printf ("info: memfd link: %s\n", link); + TEST_VERIFY (strcmp (link, "memfd:tst-memfd_create (deleted)")); + TEST_VERIFY (is_cloexec (fd) == do_cloexec); + TEST_VERIFY (is_sealed (fd) == !do_sealing); + if (do_sealing) + { + TEST_VERIFY (fcntl (fd, F_ADD_SEALS, F_SEAL_WRITE) == 0); + TEST_VERIFY (!is_sealed (fd)); + TEST_VERIFY (get_seals (fd) & F_SEAL_WRITE); + TEST_VERIFY (fcntl (fd, F_ADD_SEALS, F_SEAL_SEAL) == 0); + TEST_VERIFY (is_sealed (fd)); + } + xclose (fd); + free (fd_path); + free (link); + } + + if (supported == 0) + return EXIT_UNSUPPORTED; + return 0; +} + +#endif /* SYS_memfd_create */ + +#include <support/test-driver.c> diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist index b83d25c2e3..0a4f7797ac 100644 --- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist +++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist @@ -1877,6 +1877,7 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F GLIBC_2.3 GLIBC_2.3 A GLIBC_2.3 __ctype_b_loc F GLIBC_2.3 __ctype_tolower_loc F diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist index cba1d59057..23f6a91429 100644 --- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist +++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist @@ -2120,3 +2120,4 @@ GLIBC_2.26 wcstof128_l F GLIBC_2.27 GLIBC_2.27 A GLIBC_2.27 glob F GLIBC_2.27 glob64 F +GLIBC_2.27 memfd_create F