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([2804:1b3:a7c1:7e99:732:4c6b:2122:8111]) by smtp.gmail.com with ESMTPSA id v23-20020a056830091700b00670641eb272sm872939ott.20.2023.01.26.11.29.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Jan 2023 11:30:00 -0800 (PST) To: libc-alpha@sourceware.org, "Andreas K . Huettel" Subject: [PATCH v4 2/5] linux: Set internal DIR filepos as off64_t (BZ #23960, BZ #24050) Date: Thu, 26 Jan 2023 16:29:50 -0300 Message-Id: <20230126192953.2990973-3-adhemerval.zanella@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230126192953.2990973-1-adhemerval.zanella@linaro.org> References: <20230126192953.2990973-1-adhemerval.zanella@linaro.org> MIME-Version: 1.0 X-Spam-Status: No, score=-12.4 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Adhemerval Zanella via Libc-alpha From: Adhemerval Zanella Netto Reply-To: Adhemerval Zanella Errors-To: libc-alpha-bounces+incoming=patchwork.ozlabs.org@sourceware.org Sender: "Libc-alpha" It allows to obtain the expected entry offset on telldir and set it correctly on seekdir on platforms where long int is smaller than off64_t. On such cases telldir mantains an internal list that maps the DIR object off64_t offsets to the returned long int (the function return value). The seekdir will then set the correct offset from the internal list using the telldir as the list key. It also removes the overflow check on readdir and the returned value will be truncated by the non-LFS off_t size. As Joseph has noted in BZ #23960 comment #22, d_off is an opaque value and since telldir/seekdir works regardless of the returned dirent d_off value. Finally it removes the requirement to check for overflow values on telldir (BZ #24050). Checked on x86_64-linux-gnu, i686-linux-gnu, powerpc-linux-gnu, and arm-linux-gnueabihf. --- dirent/tst-seekdir.c | 8 ++ sysdeps/unix/sysv/linux/Makefile | 1 + sysdeps/unix/sysv/linux/closedir.c | 3 + sysdeps/unix/sysv/linux/dirstream.h | 6 +- sysdeps/unix/sysv/linux/opendir.c | 3 + sysdeps/unix/sysv/linux/rewinddir.c | 5 + sysdeps/unix/sysv/linux/seekdir.c | 36 ++++- sysdeps/unix/sysv/linux/telldir.c | 45 +++++- sysdeps/unix/sysv/linux/telldir.h | 65 +++++++++ sysdeps/unix/sysv/linux/tst-opendir-nolfs.c | 146 ++++++++++++++++++++ 10 files changed, 310 insertions(+), 8 deletions(-) create mode 100644 sysdeps/unix/sysv/linux/telldir.h create mode 100644 sysdeps/unix/sysv/linux/tst-opendir-nolfs.c diff --git a/dirent/tst-seekdir.c b/dirent/tst-seekdir.c index dcdd699b09..222a83407a 100644 --- a/dirent/tst-seekdir.c +++ b/dirent/tst-seekdir.c @@ -41,6 +41,14 @@ do_test (void) if (i == 400) break; } + if (i != 400) + { + /* Non-lfs opendir skips entries that can not be represented (for + instance if d_off is not an offset but rather an internal filesystem + representation. For this case there is no point in continue the + testcase. */ + return 77; + } printf ("going back past 4-th entry...\n"); diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile index f298878e8f..33708f910b 100644 --- a/sysdeps/unix/sysv/linux/Makefile +++ b/sysdeps/unix/sysv/linux/Makefile @@ -465,6 +465,7 @@ ifeq ($(subdir),dirent) sysdep_routines += getdirentries getdirentries64 tests += \ tst-getdents64 \ + tst-opendir-nolfs \ tst-readdir64-compat \ # tests endif # $(subdir) == dirent diff --git a/sysdeps/unix/sysv/linux/closedir.c b/sysdeps/unix/sysv/linux/closedir.c index 8adbc99892..c637e022fe 100644 --- a/sysdeps/unix/sysv/linux/closedir.c +++ b/sysdeps/unix/sysv/linux/closedir.c @@ -50,6 +50,9 @@ __closedir (DIR *dirp) #if !_DIRENT_MATCHES_DIRENT64 free (dirp->tbuffer); #endif +#ifndef __LP64__ + dirstream_loc_clear (&dirp->locs); +#endif free ((void *) dirp); diff --git a/sysdeps/unix/sysv/linux/dirstream.h b/sysdeps/unix/sysv/linux/dirstream.h index cd8bc56276..5fa07d3d66 100644 --- a/sysdeps/unix/sysv/linux/dirstream.h +++ b/sysdeps/unix/sysv/linux/dirstream.h @@ -21,6 +21,7 @@ #include #include +#include /* Directory stream type. @@ -37,7 +38,7 @@ struct __dirstream size_t size; /* Total valid data in the block. */ size_t offset; /* Current offset into the block. */ - off_t filepos; /* Position of next entry to read. */ + off64_t filepos; /* Position of next entry to read. */ int errcode; /* Delayed error code. */ @@ -45,6 +46,9 @@ struct __dirstream char *tbuffer; /* Translation buffer for non-LFS calls. */ size_t tbuffer_size; /* Size of translation buffer. */ #endif +#ifndef __LP64__ + struct dirstream_loc_t locs; /* off64_t to long int map for telldir. */ +#endif /* Directory block. We must make sure that this block starts at an address that is aligned adequately enough to store diff --git a/sysdeps/unix/sysv/linux/opendir.c b/sysdeps/unix/sysv/linux/opendir.c index 2badafd888..01c05f0c6c 100644 --- a/sysdeps/unix/sysv/linux/opendir.c +++ b/sysdeps/unix/sysv/linux/opendir.c @@ -150,6 +150,9 @@ __alloc_dir (int fd, bool close_fd, int flags, dirp->offset = 0; dirp->filepos = 0; dirp->errcode = 0; +#ifndef __LP64__ + dirstream_loc_init (&dirp->locs); +#endif return dirp; } diff --git a/sysdeps/unix/sysv/linux/rewinddir.c b/sysdeps/unix/sysv/linux/rewinddir.c index c0fb7aa765..1b158a584f 100644 --- a/sysdeps/unix/sysv/linux/rewinddir.c +++ b/sysdeps/unix/sysv/linux/rewinddir.c @@ -33,6 +33,11 @@ __rewinddir (DIR *dirp) dirp->offset = 0; dirp->size = 0; dirp->errcode = 0; + +#ifndef __LP64__ + dirstream_loc_clear (&dirp->locs); +#endif + #if IS_IN (libc) __libc_lock_unlock (dirp->lock); #endif diff --git a/sysdeps/unix/sysv/linux/seekdir.c b/sysdeps/unix/sysv/linux/seekdir.c index 939ccc4447..3494ea3d78 100644 --- a/sysdeps/unix/sysv/linux/seekdir.c +++ b/sysdeps/unix/sysv/linux/seekdir.c @@ -22,14 +22,40 @@ #include /* Seek to position POS in DIRP. */ -/* XXX should be __seekdir ? */ void seekdir (DIR *dirp, long int pos) { + off64_t filepos; + __libc_lock_lock (dirp->lock); - (void) __lseek (dirp->fd, pos, SEEK_SET); - dirp->size = 0; - dirp->offset = 0; - dirp->filepos = pos; + +#ifndef __LP64__ + union dirstream_packed dsp = { .l = pos }; + if (dsp.p.is_packed == 1) + filepos = dsp.p.info; + else + { + size_t index = dsp.p.info; + + if (index >= dirstream_loc_size (&dirp->locs)) + { + __libc_lock_unlock (dirp->lock); + return; + } + struct dirstream_loc *loc = dirstream_loc_at (&dirp->locs, index); + filepos = loc->filepos; + } +#else + filepos = pos; +#endif + + if (dirp->filepos != filepos) + { + __lseek64 (dirp->fd, filepos, SEEK_SET); + dirp->filepos = filepos; + dirp->offset = 0; + dirp->size = 0; + } + __libc_lock_unlock (dirp->lock); } diff --git a/sysdeps/unix/sysv/linux/telldir.c b/sysdeps/unix/sysv/linux/telldir.c index 1e5c129e9f..c5a0301a98 100644 --- a/sysdeps/unix/sysv/linux/telldir.c +++ b/sysdeps/unix/sysv/linux/telldir.c @@ -18,16 +18,57 @@ #include #include +#include /* Return the current position of DIRP. */ long int telldir (DIR *dirp) { long int ret; - __libc_lock_lock (dirp->lock); + +#ifndef __LP64__ + /* If the directory position fits in the packet structure, returns it. + Otherwise, check if the position is already been recorded in the + dynamic array. If not, add the new record. */ + + union dirstream_packed dsp; + + if (dirp->filepos < (1U << 31)) + { + dsp.p.is_packed = 1; + dsp.p.info = dirp->filepos; + } + else + { + dsp.l = -1; + + size_t i; + for (i = 0; i < dirstream_loc_size (&dirp->locs); i++) + { + struct dirstream_loc *loc = dirstream_loc_at (&dirp->locs, i); + if (loc->filepos == dirp->filepos) + break; + } + if (i == dirstream_loc_size (&dirp->locs)) + { + dirstream_loc_add (&dirp->locs, + (struct dirstream_loc) { dirp->filepos }); + if (!dirstream_loc_has_failed (&dirp->locs)) + { + dsp.p.is_packed = 0; + /* This assignment might overflow, however most likely ENOMEM + would happen long before. */ + dsp.p.info = i; + } + } + } + + ret = dsp.l; + +#else ret = dirp->filepos; +#endif __libc_lock_unlock (dirp->lock); - return ret; } diff --git a/sysdeps/unix/sysv/linux/telldir.h b/sysdeps/unix/sysv/linux/telldir.h new file mode 100644 index 0000000000..1ae8410804 --- /dev/null +++ b/sysdeps/unix/sysv/linux/telldir.h @@ -0,0 +1,65 @@ +/* Linux internal telldir definitions. + Copyright (C) 2023 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 + . */ + +#ifndef _TELLDIR_H +#define _TELLDIR_H 1 + +#ifndef __LP64__ + +/* On platforms where 'long int' is smaller than 'off64_t' this is how the + returned value is encoded and returned by 'telldir'. If the directory + offset can be enconded in 31 bits it is returned in the 'info' member + with 'is_packed' set to 1. + + Otherwise, the 'info' member describes an index in a dynamic array at + 'DIR' structure. */ + +union dirstream_packed +{ + long int l; + struct + { + unsigned long is_packed:1; + unsigned long info:31; + } p; +}; + +_Static_assert (sizeof (long int) == sizeof (union dirstream_packed), + "sizeof (long int) != sizeof (union dirstream_packed)"); + +/* telldir maintains a list of offsets that describe the obtained diretory + position if it can fit this information in the returned 'dirstream_packed' + struct. */ + +struct dirstream_loc +{ + off64_t filepos; +}; + +# define DYNARRAY_STRUCT dirstream_loc_t +# define DYNARRAY_ELEMENT struct dirstream_loc +# define DYNARRAY_PREFIX dirstream_loc_ +# include +#else + +_Static_assert (sizeof (long int) == sizeof (off64_t), + "sizeof (long int) != sizeof (off64_t)"); + +#endif /* __LP64__ */ + +#endif /* _TELLDIR_H */ diff --git a/sysdeps/unix/sysv/linux/tst-opendir-nolfs.c b/sysdeps/unix/sysv/linux/tst-opendir-nolfs.c new file mode 100644 index 0000000000..52e18171a7 --- /dev/null +++ b/sysdeps/unix/sysv/linux/tst-opendir-nolfs.c @@ -0,0 +1,146 @@ +/* Check multiple telldir and seekdir. + Copyright (C) 2023 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 + . */ + +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +/* Some filesystems returns an arbitrary value for d_off direnty entry (ext4 + for instance, where the value is an internal hash key). The idea of create + a large number of file is to try trigger a overflow d_off value in a entry + to check if telldir/seekdir does work corretly in such case. */ +static const char *dirname; +/* The 2 extra files are '.' and '..'. */ +static const size_t nfiles = (1<<14) + 2; + +static inline bool +in_ino_t_range (ino64_t v) +{ + ino_t s = v; + return s == v; +} + +static inline bool +in_off_t_range (off64_t v) +{ + off_t s = v; + return s == v; +} + +static void +do_prepare (int argc, char *argv[]) +{ + dirname = support_create_temp_directory ("tst-opendir-nolfs-"); + + for (size_t i = 0; i < nfiles - 2; i++) + { + int fd = create_temp_file_in_dir ("tempfile.", dirname, NULL); + TEST_VERIFY_EXIT (fd > 0); + close (fd); + } +} +#define PREPARE do_prepare + +static int +do_test (void) +{ + DIR *dirp = opendir (dirname); + TEST_VERIFY_EXIT (dirp != NULL); + + long int *tdirp = xmalloc (nfiles * sizeof (long int)); + struct dirent **ddirp = xmalloc (nfiles * sizeof (struct dirent *)); + + /* For non-LFS, the entry is skipped if it can not be converted. */ + int count = 0; + for (; count < nfiles; count++) + { + tdirp[count] = telldir (dirp); + struct dirent *dp = readdir (dirp); + if (dp == NULL) + break; + ddirp[count] = xmalloc (dp->d_reclen); + memcpy (ddirp[count], dp, dp->d_reclen); + } + + closedir (dirp); + + /* Check against the getdents64 syscall. */ + int fd = xopen (dirname, O_RDONLY | O_DIRECTORY, 0); + int i = 0; + while (true) + { + struct + { + char buffer[1024]; + struct dirent64 pad; + } data; + + ssize_t ret = getdents64 (fd, &data.buffer, sizeof (data.buffer)); + if (ret < 0) + FAIL_EXIT1 ("getdents64: %m"); + if (ret == 0) + break; + + char *current = data.buffer; + char *end = data.buffer + ret; + while (current != end) + { + struct dirent64 entry; + memcpy (&entry, current, sizeof (entry)); + /* Truncate overlong strings. */ + entry.d_name[sizeof (entry.d_name) - 1] = '\0'; + TEST_VERIFY (strlen (entry.d_name) < sizeof (entry.d_name) - 1); + + if (in_ino_t_range (entry.d_ino) && in_off_t_range (entry.d_off)) + { + TEST_COMPARE_STRING (entry.d_name, ddirp[i]->d_name); + TEST_COMPARE (entry.d_ino, ddirp[i]->d_ino); + TEST_COMPARE (entry.d_off, ddirp[i]->d_off); + TEST_COMPARE (entry.d_type, ddirp[i]->d_type); + + /* Offset zero is reserved for the first entry. */ + TEST_VERIFY (entry.d_off != 0); + + TEST_VERIFY_EXIT (entry.d_reclen <= end - current); + i++; + } + + current += entry.d_reclen; + } + } + + /* direntries_read has been called more than once. */ + TEST_COMPARE (count, i); + + free (tdirp); + for (int i = 0; i < count; i++) + free (ddirp[i]); + free (ddirp); + + return 0; +} + +#include