@@ -96,6 +96,7 @@ libpthread-routines = nptl-init vars events version \
old_pthread_atfork pthread_atfork \
pthread_getcpuclockid \
pthread_clock_gettime pthread_clock_settime \
+ shm-directory \
sem_init sem_destroy \
sem_open sem_close sem_unlink \
sem_getvalue \
@@ -270,5 +270,6 @@ libpthread {
__pthread_initialize_minimal;
__pthread_clock_gettime; __pthread_clock_settime;
__pthread_unwind; __pthread_get_minstack;
+ __shm_directory;
}
}
@@ -18,8 +18,6 @@
#include <errno.h>
#include <fcntl.h>
-#include <mntent.h>
-#include <paths.h>
#include <pthread.h>
#include <search.h>
#include <semaphore.h>
@@ -30,98 +28,8 @@
#include <unistd.h>
#include <sys/mman.h>
#include <sys/stat.h>
-#include <sys/statfs.h>
-#include <linux_fsinfo.h>
#include "semaphoreP.h"
-
-
-
-/* Information about the mount point. */
-struct mountpoint_info mountpoint attribute_hidden;
-
-/* This is the default mount point. */
-static const char defaultmount[] = "/dev/shm";
-/* This is the default directory. */
-static const char defaultdir[] = "/dev/shm/sem.";
-
-/* Protect the `mountpoint' variable above. */
-pthread_once_t __namedsem_once attribute_hidden = PTHREAD_ONCE_INIT;
-
-
-/* Determine where the shmfs is mounted (if at all). */
-void
-attribute_hidden
-__where_is_shmfs (void)
-{
- char buf[512];
- struct statfs f;
- struct mntent resmem;
- struct mntent *mp;
- FILE *fp;
-
- /* The canonical place is /dev/shm. This is at least what the
- documentation tells everybody to do. */
- if (__statfs (defaultmount, &f) == 0 && (f.f_type == SHMFS_SUPER_MAGIC
- || f.f_type == RAMFS_MAGIC))
- {
- /* It is in the normal place. */
- mountpoint.dir = (char *) defaultdir;
- mountpoint.dirlen = sizeof (defaultdir) - 1;
-
- return;
- }
-
- /* OK, do it the hard way. Look through the /proc/mounts file and if
- this does not exist through /etc/fstab to find the mount point. */
- fp = __setmntent ("/proc/mounts", "r");
- if (__glibc_unlikely (fp == NULL))
- {
- fp = __setmntent (_PATH_MNTTAB, "r");
- if (__glibc_unlikely (fp == NULL))
- /* There is nothing we can do. Blind guesses are not helpful. */
- return;
- }
-
- /* Now read the entries. */
- while ((mp = __getmntent_r (fp, &resmem, buf, sizeof buf)) != NULL)
- /* The original name is "shm" but this got changed in early Linux
- 2.4.x to "tmpfs". */
- if (strcmp (mp->mnt_type, "tmpfs") == 0
- || strcmp (mp->mnt_type, "shm") == 0)
- {
- /* Found it. There might be more than one place where the
- filesystem is mounted but one is enough for us. */
- size_t namelen;
-
- /* First make sure this really is the correct entry. At least
- some versions of the kernel give wrong information because
- of the implicit mount of the shmfs for SysV IPC. */
- if (__statfs (mp->mnt_dir, &f) != 0 || (f.f_type != SHMFS_SUPER_MAGIC
- && f.f_type != RAMFS_MAGIC))
- continue;
-
- namelen = strlen (mp->mnt_dir);
-
- if (namelen == 0)
- /* Hum, maybe some crippled entry. Keep on searching. */
- continue;
-
- mountpoint.dir = (char *) malloc (namelen + 4 + 2);
- if (mountpoint.dir != NULL)
- {
- char *cp = __mempcpy (mountpoint.dir, mp->mnt_dir, namelen);
- if (cp[-1] != '/')
- *cp++ = '/';
- cp = stpcpy (cp, "sem.");
- mountpoint.dirlen = cp - mountpoint.dir;
- }
-
- break;
- }
-
- /* Close the stream. */
- __endmntent (fp);
-}
+#include <shm-directory.h>
/* Comparison function for search of existing mapping. */
@@ -217,8 +125,9 @@ check_add_mapping (const char *name, size_t namelen, int fd, sem_t *existing)
if (result != existing && existing != SEM_FAILED && existing != MAP_FAILED)
{
/* Do not disturb errno. */
- INTERNAL_SYSCALL_DECL (err);
- INTERNAL_SYSCALL (munmap, err, 2, existing, sizeof (sem_t));
+ int save = errno;
+ munmap (existing, sizeof (sem_t));
+ errno = save;
}
return result;
@@ -228,42 +137,17 @@ check_add_mapping (const char *name, size_t namelen, int fd, sem_t *existing)
sem_t *
sem_open (const char *name, int oflag, ...)
{
- char *finalname;
- sem_t *result = SEM_FAILED;
int fd;
+ sem_t *result;
- /* Determine where the shmfs is mounted. */
- __pthread_once (&__namedsem_once, __where_is_shmfs);
-
- /* If we don't know the mount points there is nothing we can do. Ever. */
- if (mountpoint.dir == NULL)
- {
- __set_errno (ENOSYS);
- return SEM_FAILED;
- }
-
- /* Construct the filename. */
- while (name[0] == '/')
- ++name;
-
- if (name[0] == '\0')
- {
- /* The name "/" is not supported. */
- __set_errno (EINVAL);
- return SEM_FAILED;
- }
- size_t namelen = strlen (name) + 1;
-
- /* Create the name of the final file. */
- finalname = (char *) alloca (mountpoint.dirlen + namelen);
- __mempcpy (__mempcpy (finalname, mountpoint.dir, mountpoint.dirlen),
- name, namelen);
+ /* Create the name of the final file in local variable SHM_NAME. */
+ SHM_GET_NAME (EINVAL, SEM_FAILED, SEM_SHM_PREFIX);
/* If the semaphore object has to exist simply open it. */
if ((oflag & O_CREAT) == 0 || (oflag & O_EXCL) == 0)
{
try_again:
- fd = __libc_open (finalname,
+ fd = __libc_open (shm_name,
(oflag & ~(O_CREAT|O_ACCMODE)) | O_NOFOLLOW | O_RDWR);
if (fd == -1)
@@ -317,8 +201,8 @@ sem_open (const char *name, int oflag, ...)
memset ((char *) &sem.initsem + sizeof (struct new_sem), '\0',
sizeof (sem_t) - sizeof (struct new_sem));
- tmpfname = (char *) alloca (mountpoint.dirlen + 6 + 1);
- char *xxxxxx = __mempcpy (tmpfname, mountpoint.dir, mountpoint.dirlen);
+ tmpfname = __alloca (shm_dirlen + sizeof SEM_SHM_PREFIX + 6);
+ char *xxxxxx = __mempcpy (tmpfname, shm_dir, shm_dirlen);
int retries = 0;
#define NRETRIES 50
@@ -361,7 +245,7 @@ sem_open (const char *name, int oflag, ...)
fd, 0)) != MAP_FAILED)
{
/* Create the file. Don't overwrite an existing file. */
- if (link (tmpfname, finalname) != 0)
+ if (link (tmpfname, shm_name) != 0)
{
/* Undo the mapping. */
(void) munmap (result, sizeof (sem_t));
@@ -402,8 +286,9 @@ sem_open (const char *name, int oflag, ...)
if (fd != -1)
{
/* Do not disturb errno. */
- INTERNAL_SYSCALL_DECL (err);
- INTERNAL_SYSCALL (close, err, 1, fd);
+ int save = errno;
+ close (fd);
+ errno = save;
}
return result;
@@ -22,44 +22,16 @@
#include <string.h>
#include <unistd.h>
#include "semaphoreP.h"
-
+#include <shm-directory.h>
int
-sem_unlink (name)
- const char *name;
+sem_unlink (const char *name)
{
- char *fname;
- size_t namelen;
-
- /* Determine where the shmfs is mounted. */
- __pthread_once (&__namedsem_once, __where_is_shmfs);
-
- /* If we don't know the mount points there is nothing we can do. Ever. */
- if (mountpoint.dir == NULL)
- {
- __set_errno (ENOSYS);
- return -1;
- }
-
/* Construct the filename. */
- while (name[0] == '/')
- ++name;
-
- if (name[0] == '\0')
- {
- /* The name "/" is not supported. */
- __set_errno (ENOENT);
- return -1;
- }
- namelen = strlen (name);
-
- /* Create the name of the file. */
- fname = (char *) alloca (mountpoint.dirlen + namelen + 1);
- __mempcpy (__mempcpy (fname, mountpoint.dir, mountpoint.dirlen),
- name, namelen + 1);
+ SHM_GET_NAME (ENOENT, -1, SEM_SHM_PREFIX);
/* Now try removing it. */
- int ret = unlink (fname);
+ int ret = unlink (shm_name);
if (ret < 0 && errno == EPERM)
__set_errno (EACCES);
return ret;
@@ -19,13 +19,7 @@
#include <semaphore.h>
#include "pthreadP.h"
-
-/* Mount point of the shared memory filesystem. */
-struct mountpoint_info
-{
- char *dir;
- size_t dirlen;
-};
+#define SEM_SHM_PREFIX "sem."
/* Keeping track of currently used mappings. */
struct inuse_sem
@@ -38,11 +32,6 @@ struct inuse_sem
};
-/* Variables used in multiple interfaces. */
-extern struct mountpoint_info mountpoint attribute_hidden;
-
-extern pthread_once_t __namedsem_once attribute_hidden;
-
/* The search tree for existing mappings. */
extern void *__sem_mappings attribute_hidden;
@@ -50,9 +39,6 @@ extern void *__sem_mappings attribute_hidden;
extern int __sem_mappings_lock attribute_hidden;
-/* Initializer for mountpoint. */
-extern void __where_is_shmfs (void) attribute_hidden;
-
/* Comparison function for search in tree with existing mappings. */
extern int __sem_search (const void *a, const void *b) attribute_hidden;
@@ -4,6 +4,8 @@ TMP_MAX = 238328
L_ctermid = 9
L_cuserid = 9
-ifeq ($(subdir),rt)
+ifeq ($(subdir)|$(have-thread-library),rt|no)
+# With NPTL, this lives in libpthread so it can be used for sem_open too.
+# Without NPTL, it's just private in librt.
librt-routines += shm-directory
endif
@@ -36,9 +36,10 @@ extern const char *__shm_directory (size_t *len);
strlen (NAME) + 1. If NAME is invalid, it sets errno to
ERRNO_FOR_INVALID and returns RETVAL_FOR_INVALID. Finally, it defines
the local variable SHM_NAME, giving the absolute file name of the shm
- file corresponding to NAME. */
+ file corresponding to NAME. PREFIX is a string constant used as a
+ prefix on NAME. */
-#define SHM_GET_NAME(errno_for_invalid, retval_for_invalid) \
+#define SHM_GET_NAME(errno_for_invalid, retval_for_invalid, prefix) \
size_t shm_dirlen; \
const char *shm_dir = __shm_directory (&shm_dirlen); \
/* If we don't know what directory to use, there is nothing we can do. */ \
@@ -57,7 +58,9 @@ extern const char *__shm_directory (size_t *len);
__set_errno (errno_for_invalid); \
return retval_for_invalid; \
} \
- char *shm_name = __alloca (shm_dirlen + namelen); \
- __mempcpy (__mempcpy (shm_name, shm_dir, shm_dirlen), name, namelen)
+ char *shm_name = __alloca (shm_dirlen + sizeof prefix - 1 + namelen); \
+ __mempcpy (__mempcpy (__mempcpy (shm_name, shm_dir, shm_dirlen), \
+ prefix, sizeof prefix - 1), \
+ name, namelen)
#endif /* shm-directory.h */
@@ -32,7 +32,7 @@
int
shm_open (const char *name, int oflag, mode_t mode)
{
- SHM_GET_NAME (EINVAL, -1);
+ SHM_GET_NAME (EINVAL, -1, "");
# ifdef O_NOFOLLOW
oflag |= O_NOFOLLOW;
@@ -32,7 +32,7 @@
int
shm_unlink (const char *name)
{
- SHM_GET_NAME (ENOENT, -1);
+ SHM_GET_NAME (ENOENT, -1, "");
int result = unlink (shm_name);
if (result < 0 && errno == EPERM)