NPTL: Refactor named semaphore code to use shm-directory.h
This commit is contained in:
Roland McGrath
parent
c76d1ff514
commit
e4f639e4a1
31
ChangeLog
31
ChangeLog
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@ -1,3 +1,34 @@
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2014-12-12 Roland McGrath <roland@hack.frob.com>
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* sysdeps/posix/shm-directory.h (SHM_GET_NAME): Take new argument
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PREFIX, string constant to insert between directory and name.
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* sysdeps/posix/shm_open.c: Update caller.
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* sysdeps/posix/shm_unlink.c: Likewise.
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* nptl/semaphoreP.h (struct mountpoint_info): Type removed.
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(__where_is_shmfs, mountpoint, __namedsem_once): Declarations removed.
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(SEM_SHM_PREFIX): New macro.
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* sysdeps/posix/Makefile (librt-routines): Add shm-directory only if
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[$(have-thread-library) = no].
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* nptl/Makefile (libpthread-routines): Add shm-directory.
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* nptl/Versions (GLIBC_PRIVATE): Add __shm_directory.
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* sysdeps/nptl/shm-directory.h: New file.
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* sysdeps/posix/shm-directory.c
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[IS_IN (libpthread)] (__shm_directory): Add hidden_def.
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* sysdeps/unix/sysv/linux/shm-directory.c: Likewise.
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* nptl/sem_open.c (check_add_mapping): Use munmap function rather than
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INTERNAL_SYSCALL.
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(__where_is_shmfs): Function removed.
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(mountpoint, defaultmount, defaultdir, __namedsem_once):
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Variables removed.
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(sem_open): Use __libc_close function rather than INTERNAL_SYSCALL.
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Use SHM_GET_NAME.
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* nptl/sem_unlink.c: Prototypify. Use SHM_GET_NAME.
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* sysdeps/nptl/bits/libc-lockP.h [IS_IN (libpthread)]
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(PTFAVAIL, __libc_ptf_call, __libc_ptf_call_always): Define as
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unconditional for use inside libpthread.
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[IS_IN (libpthread)]: Include <nptl/pthreadP.h>.
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2014-12-12 Roland McGrath <roland@hack.frob.com>
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* nptl/pthread_getaffinity.c: New file.
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@ -96,6 +96,7 @@ libpthread-routines = nptl-init vars events version \
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old_pthread_atfork pthread_atfork \
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pthread_getcpuclockid \
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pthread_clock_gettime pthread_clock_settime \
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shm-directory \
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sem_init sem_destroy \
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sem_open sem_close sem_unlink \
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sem_getvalue \
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@ -270,5 +270,6 @@ libpthread {
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__pthread_initialize_minimal;
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__pthread_clock_gettime; __pthread_clock_settime;
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__pthread_unwind; __pthread_get_minstack;
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__shm_directory;
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}
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}
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143
nptl/sem_open.c
143
nptl/sem_open.c
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@ -18,8 +18,6 @@
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#include <errno.h>
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#include <fcntl.h>
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#include <mntent.h>
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#include <paths.h>
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#include <pthread.h>
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#include <search.h>
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#include <semaphore.h>
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@ -30,98 +28,8 @@
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#include <unistd.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <sys/statfs.h>
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#include <linux_fsinfo.h>
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#include "semaphoreP.h"
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/* Information about the mount point. */
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struct mountpoint_info mountpoint attribute_hidden;
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/* This is the default mount point. */
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static const char defaultmount[] = "/dev/shm";
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/* This is the default directory. */
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static const char defaultdir[] = "/dev/shm/sem.";
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/* Protect the `mountpoint' variable above. */
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pthread_once_t __namedsem_once attribute_hidden = PTHREAD_ONCE_INIT;
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/* Determine where the shmfs is mounted (if at all). */
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void
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attribute_hidden
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__where_is_shmfs (void)
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{
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char buf[512];
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struct statfs f;
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struct mntent resmem;
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struct mntent *mp;
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FILE *fp;
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/* The canonical place is /dev/shm. This is at least what the
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documentation tells everybody to do. */
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if (__statfs (defaultmount, &f) == 0 && (f.f_type == SHMFS_SUPER_MAGIC
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|| f.f_type == RAMFS_MAGIC))
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{
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/* It is in the normal place. */
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mountpoint.dir = (char *) defaultdir;
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mountpoint.dirlen = sizeof (defaultdir) - 1;
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return;
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}
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/* OK, do it the hard way. Look through the /proc/mounts file and if
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this does not exist through /etc/fstab to find the mount point. */
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fp = __setmntent ("/proc/mounts", "r");
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if (__glibc_unlikely (fp == NULL))
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{
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fp = __setmntent (_PATH_MNTTAB, "r");
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if (__glibc_unlikely (fp == NULL))
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/* There is nothing we can do. Blind guesses are not helpful. */
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return;
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}
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/* Now read the entries. */
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while ((mp = __getmntent_r (fp, &resmem, buf, sizeof buf)) != NULL)
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/* The original name is "shm" but this got changed in early Linux
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2.4.x to "tmpfs". */
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if (strcmp (mp->mnt_type, "tmpfs") == 0
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|| strcmp (mp->mnt_type, "shm") == 0)
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{
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/* Found it. There might be more than one place where the
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filesystem is mounted but one is enough for us. */
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size_t namelen;
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/* First make sure this really is the correct entry. At least
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some versions of the kernel give wrong information because
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of the implicit mount of the shmfs for SysV IPC. */
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if (__statfs (mp->mnt_dir, &f) != 0 || (f.f_type != SHMFS_SUPER_MAGIC
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&& f.f_type != RAMFS_MAGIC))
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continue;
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namelen = strlen (mp->mnt_dir);
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if (namelen == 0)
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/* Hum, maybe some crippled entry. Keep on searching. */
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continue;
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mountpoint.dir = (char *) malloc (namelen + 4 + 2);
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if (mountpoint.dir != NULL)
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{
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char *cp = __mempcpy (mountpoint.dir, mp->mnt_dir, namelen);
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if (cp[-1] != '/')
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*cp++ = '/';
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cp = stpcpy (cp, "sem.");
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mountpoint.dirlen = cp - mountpoint.dir;
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}
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break;
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}
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/* Close the stream. */
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__endmntent (fp);
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}
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#include <shm-directory.h>
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/* Comparison function for search of existing mapping. */
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@ -217,8 +125,9 @@ check_add_mapping (const char *name, size_t namelen, int fd, sem_t *existing)
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if (result != existing && existing != SEM_FAILED && existing != MAP_FAILED)
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{
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/* Do not disturb errno. */
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INTERNAL_SYSCALL_DECL (err);
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INTERNAL_SYSCALL (munmap, err, 2, existing, sizeof (sem_t));
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int save = errno;
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munmap (existing, sizeof (sem_t));
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errno = save;
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}
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return result;
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@ -228,42 +137,17 @@ check_add_mapping (const char *name, size_t namelen, int fd, sem_t *existing)
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sem_t *
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sem_open (const char *name, int oflag, ...)
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{
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char *finalname;
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sem_t *result = SEM_FAILED;
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int fd;
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sem_t *result;
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/* Determine where the shmfs is mounted. */
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__pthread_once (&__namedsem_once, __where_is_shmfs);
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/* If we don't know the mount points there is nothing we can do. Ever. */
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if (mountpoint.dir == NULL)
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{
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__set_errno (ENOSYS);
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return SEM_FAILED;
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}
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/* Construct the filename. */
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while (name[0] == '/')
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++name;
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if (name[0] == '\0')
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{
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/* The name "/" is not supported. */
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__set_errno (EINVAL);
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return SEM_FAILED;
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}
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size_t namelen = strlen (name) + 1;
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/* Create the name of the final file. */
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finalname = (char *) alloca (mountpoint.dirlen + namelen);
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__mempcpy (__mempcpy (finalname, mountpoint.dir, mountpoint.dirlen),
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name, namelen);
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/* Create the name of the final file in local variable SHM_NAME. */
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SHM_GET_NAME (EINVAL, SEM_FAILED, SEM_SHM_PREFIX);
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/* If the semaphore object has to exist simply open it. */
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if ((oflag & O_CREAT) == 0 || (oflag & O_EXCL) == 0)
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{
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try_again:
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fd = __libc_open (finalname,
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fd = __libc_open (shm_name,
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(oflag & ~(O_CREAT|O_ACCMODE)) | O_NOFOLLOW | O_RDWR);
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if (fd == -1)
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@ -317,8 +201,8 @@ sem_open (const char *name, int oflag, ...)
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memset ((char *) &sem.initsem + sizeof (struct new_sem), '\0',
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sizeof (sem_t) - sizeof (struct new_sem));
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tmpfname = (char *) alloca (mountpoint.dirlen + 6 + 1);
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char *xxxxxx = __mempcpy (tmpfname, mountpoint.dir, mountpoint.dirlen);
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tmpfname = __alloca (shm_dirlen + sizeof SEM_SHM_PREFIX + 6);
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char *xxxxxx = __mempcpy (tmpfname, shm_dir, shm_dirlen);
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int retries = 0;
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#define NRETRIES 50
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@ -361,7 +245,7 @@ sem_open (const char *name, int oflag, ...)
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fd, 0)) != MAP_FAILED)
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{
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/* Create the file. Don't overwrite an existing file. */
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if (link (tmpfname, finalname) != 0)
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if (link (tmpfname, shm_name) != 0)
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{
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/* Undo the mapping. */
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(void) munmap (result, sizeof (sem_t));
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@ -402,8 +286,9 @@ sem_open (const char *name, int oflag, ...)
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if (fd != -1)
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{
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/* Do not disturb errno. */
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INTERNAL_SYSCALL_DECL (err);
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INTERNAL_SYSCALL (close, err, 1, fd);
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int save = errno;
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__libc_close (fd);
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errno = save;
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}
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return result;
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@ -22,44 +22,16 @@
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#include <string.h>
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#include <unistd.h>
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#include "semaphoreP.h"
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#include <shm-directory.h>
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int
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sem_unlink (name)
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const char *name;
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sem_unlink (const char *name)
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{
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char *fname;
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size_t namelen;
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/* Determine where the shmfs is mounted. */
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__pthread_once (&__namedsem_once, __where_is_shmfs);
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/* If we don't know the mount points there is nothing we can do. Ever. */
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if (mountpoint.dir == NULL)
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{
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__set_errno (ENOSYS);
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return -1;
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}
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/* Construct the filename. */
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while (name[0] == '/')
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++name;
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if (name[0] == '\0')
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{
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/* The name "/" is not supported. */
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__set_errno (ENOENT);
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return -1;
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}
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namelen = strlen (name);
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/* Create the name of the file. */
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fname = (char *) alloca (mountpoint.dirlen + namelen + 1);
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__mempcpy (__mempcpy (fname, mountpoint.dir, mountpoint.dirlen),
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name, namelen + 1);
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SHM_GET_NAME (ENOENT, -1, SEM_SHM_PREFIX);
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/* Now try removing it. */
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int ret = unlink (fname);
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int ret = unlink (shm_name);
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if (ret < 0 && errno == EPERM)
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__set_errno (EACCES);
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return ret;
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@ -19,13 +19,7 @@
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#include <semaphore.h>
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#include "pthreadP.h"
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/* Mount point of the shared memory filesystem. */
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struct mountpoint_info
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{
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char *dir;
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size_t dirlen;
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};
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#define SEM_SHM_PREFIX "sem."
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/* Keeping track of currently used mappings. */
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struct inuse_sem
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@ -38,11 +32,6 @@ struct inuse_sem
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};
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/* Variables used in multiple interfaces. */
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extern struct mountpoint_info mountpoint attribute_hidden;
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extern pthread_once_t __namedsem_once attribute_hidden;
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/* The search tree for existing mappings. */
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extern void *__sem_mappings attribute_hidden;
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@ -50,9 +39,6 @@ extern void *__sem_mappings attribute_hidden;
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extern int __sem_mappings_lock attribute_hidden;
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/* Initializer for mountpoint. */
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extern void __where_is_shmfs (void) attribute_hidden;
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/* Comparison function for search in tree with existing mappings. */
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extern int __sem_search (const void *a, const void *b) attribute_hidden;
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@ -34,6 +34,12 @@
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#include <tls.h>
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#include <pthread-functions.h>
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#if IS_IN (libpthread)
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/* This gets us the declarations of the __pthread_* internal names,
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and hidden_proto for them. */
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# include <nptl/pthreadP.h>
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#endif
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/* Mutex type. */
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#if !IS_IN (libc) && !IS_IN (libpthread)
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typedef pthread_mutex_t __libc_lock_t;
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@ -114,6 +120,12 @@ typedef pthread_key_t __libc_key_t;
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(__libc_pthread_functions_init ? PTHFCT_CALL (ptr_##FUNC, ARGS) : ELSE)
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# define __libc_ptf_call_always(FUNC, ARGS) \
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PTHFCT_CALL (ptr_##FUNC, ARGS)
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#elif IS_IN (libpthread)
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# define PTFAVAIL(NAME) 1
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# define __libc_ptf_call(FUNC, ARGS, ELSE) \
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FUNC ARGS
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# define __libc_ptf_call_always(FUNC, ARGS) \
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FUNC ARGS
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#else
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# define PTFAVAIL(NAME) (NAME != NULL)
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# define __libc_ptf_call(FUNC, ARGS, ELSE) \
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31
sysdeps/nptl/shm-directory.h
Normal file
31
sysdeps/nptl/shm-directory.h
Normal file
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@ -0,0 +1,31 @@
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/* Header for directory for shm/sem files. NPTL version.
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Copyright (C) 2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
|
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef _SHM_DIRECTORY_H
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#include <sysdeps/posix/shm-directory.h>
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/* For NPTL the __shm_directory function lives in libpthread.
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We don't want PLT calls from there. But it's also used from
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librt, so it cannot just be declared hidden. */
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#if IS_IN (libpthread)
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hidden_proto (__shm_directory)
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#endif
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#endif /* shm-directory.h */
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@ -4,6 +4,8 @@ TMP_MAX = 238328
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L_ctermid = 9
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L_cuserid = 9
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ifeq ($(subdir),rt)
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ifeq ($(subdir)|$(have-thread-library),rt|no)
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# With NPTL, this lives in libpthread so it can be used for sem_open too.
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# Without NPTL, it's just private in librt.
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librt-routines += shm-directory
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endif
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@ -31,5 +31,8 @@ __shm_directory (size_t *len)
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*len = sizeof SHMDIR - 1;
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return SHMDIR;
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}
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# if IS_IN (libpthread)
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hidden_def (__shm_directory)
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# endif
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#endif
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@ -36,9 +36,10 @@ extern const char *__shm_directory (size_t *len);
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strlen (NAME) + 1. If NAME is invalid, it sets errno to
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ERRNO_FOR_INVALID and returns RETVAL_FOR_INVALID. Finally, it defines
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the local variable SHM_NAME, giving the absolute file name of the shm
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file corresponding to NAME. */
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file corresponding to NAME. PREFIX is a string constant used as a
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prefix on NAME. */
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#define SHM_GET_NAME(errno_for_invalid, retval_for_invalid) \
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#define SHM_GET_NAME(errno_for_invalid, retval_for_invalid, prefix) \
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size_t shm_dirlen; \
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const char *shm_dir = __shm_directory (&shm_dirlen); \
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/* If we don't know what directory to use, there is nothing we can do. */ \
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@ -57,7 +58,9 @@ extern const char *__shm_directory (size_t *len);
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__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)
|
||||
|
|
|
|||
|
|
@ -133,6 +133,9 @@ __shm_directory (size_t *len)
|
|||
*len = mountpoint.dirlen;
|
||||
return mountpoint.dir;
|
||||
}
|
||||
#if IS_IN (libpthread)
|
||||
hidden_def (__shm_directory)
|
||||
#endif
|
||||
|
||||
|
||||
/* Make sure the table is freed if we want to free everything before
|
||||
|
|
|
|||
Loading…
Reference in a new issue