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Diffstat (limited to 'libpthread/nptl/sem_open.c')
-rw-r--r--libpthread/nptl/sem_open.c404
1 files changed, 0 insertions, 404 deletions
diff --git a/libpthread/nptl/sem_open.c b/libpthread/nptl/sem_open.c
deleted file mode 100644
index a4b2f5b3a..000000000
--- a/libpthread/nptl/sem_open.c
+++ /dev/null
@@ -1,404 +0,0 @@
-/* Copyright (C) 2002, 2003 Free Software Foundation, Inc.
- This file is part of the GNU C Library.
- Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
-
- 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, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
-
-#include <errno.h>
-#include <fcntl.h>
-#include <mntent.h>
-#include <paths.h>
-#include <pthread.h>
-#include <search.h>
-#include <semaphore.h>
-#include <stdarg.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#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)
- {
- /* 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 (__builtin_expect (fp == NULL, 0))
- {
- fp = __setmntent (_PATH_MNTTAB, "r");
- if (__builtin_expect (fp == NULL, 0))
- /* 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)
- 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);
-}
-
-
-/* Comparison function for search of existing mapping. */
-int
-attribute_hidden
-__sem_search (const void *a, const void *b)
-{
- const struct inuse_sem *as = (const struct inuse_sem *) a;
- const struct inuse_sem *bs = (const struct inuse_sem *) b;
-
- if (as->ino != bs->ino)
- /* Cannot return the difference the type is larger than int. */
- return as->ino < bs->ino ? -1 : (as->ino == bs->ino ? 0 : 1);
-
- if (as->dev != bs->dev)
- /* Cannot return the difference the type is larger than int. */
- return as->dev < bs->dev ? -1 : (as->dev == bs->dev ? 0 : 1);
-
- return strcmp (as->name, bs->name);
-}
-
-
-/* The search tree for existing mappings. */
-void *__sem_mappings attribute_hidden;
-
-/* Lock to protect the search tree. */
-lll_lock_t __sem_mappings_lock = LLL_LOCK_INITIALIZER;
-
-
-/* Search for existing mapping and if possible add the one provided. */
-static sem_t *
-check_add_mapping (const char *name, size_t namelen, int fd, sem_t *existing)
-{
- sem_t *result = SEM_FAILED;
-
- /* Get the information about the file. */
- struct stat64 st;
- if (__fxstat64 (_STAT_VER, fd, &st) == 0)
- {
- /* Get the lock. */
- lll_lock (__sem_mappings_lock);
-
- /* Search for an existing mapping given the information we have. */
- struct inuse_sem *fake;
- fake = (struct inuse_sem *) alloca (sizeof (*fake) + namelen);
- memcpy (fake->name, name, namelen);
- fake->dev = st.st_dev;
- fake->ino = st.st_ino;
-
- struct inuse_sem **foundp = tfind (fake, &__sem_mappings, __sem_search);
- if (foundp != NULL)
- {
- /* There is already a mapping. Use it. */
- result = (*foundp)->sem;
- ++(*foundp)->refcnt;
- }
- else
- {
- /* We haven't found a mapping. Install ione. */
- struct inuse_sem *newp;
-
- newp = (struct inuse_sem *) malloc (sizeof (*newp) + namelen);
- if (newp != NULL)
- {
- /* If the caller hasn't provided any map it now. */
- if (existing == SEM_FAILED)
- existing = (sem_t *) mmap (NULL, sizeof (sem_t),
- PROT_READ | PROT_WRITE, MAP_SHARED,
- fd, 0);
-
- newp->dev = st.st_dev;
- newp->ino = st.st_ino;
- newp->refcnt = 1;
- newp->sem = existing;
- memcpy (newp->name, name, namelen);
-
- /* Insert the new value. */
- if (existing != MAP_FAILED
- && tsearch (newp, &__sem_mappings, __sem_search) != NULL)
- /* Successful. */
- result = existing;
- else
- /* Something went wrong while inserting the new
- value. We fail completely. */
- free (newp);
- }
- }
-
- /* Release the lock. */
- lll_unlock (__sem_mappings_lock);
- }
-
- 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));
- }
-
- return result;
-}
-
-
-sem_t *
-sem_open (const char *name, int oflag, ...)
-{
- char *finalname;
- sem_t *result = SEM_FAILED;
- int fd;
-
- /* Determine where the shmfs is mounted. */
- INTUSE(__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);
-
- /* 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,
- (oflag & ~(O_CREAT|O_ACCMODE)) | O_NOFOLLOW | O_RDWR);
-
- if (fd == -1)
- {
- /* If we are supposed to create the file try this next. */
- if ((oflag & O_CREAT) != 0 && errno == ENOENT)
- goto try_create;
-
- /* Return. errno is already set. */
- }
- else
- /* Check whether we already have this semaphore mapped and
- create one if necessary. */
- result = check_add_mapping (name, namelen, fd, SEM_FAILED);
- }
- else
- {
- /* We have to open a temporary file first since it must have the
- correct form before we can start using it. */
- char *tmpfname;
- mode_t mode;
- unsigned int value;
- va_list ap;
-
- try_create:
- va_start (ap, oflag);
-
- mode = va_arg (ap, mode_t);
- value = va_arg (ap, unsigned int);
-
- va_end (ap);
-
- if (value > SEM_VALUE_MAX)
- {
- __set_errno (EINVAL);
- return SEM_FAILED;
- }
-
- /* Create the initial file content. */
- sem_t initsem;
-
- struct sem *iinitsem = (struct sem *) &initsem;
- iinitsem->count = value;
-
- /* Initialize the remaining bytes as well. */
- memset ((char *) &initsem + sizeof (struct sem), '\0',
- sizeof (sem_t) - sizeof (struct sem));
-
- tmpfname = (char *) alloca (mountpoint.dirlen + 6 + 1);
- char *xxxxxx = __mempcpy (tmpfname, mountpoint.dir, mountpoint.dirlen);
-
- int retries = 0;
-#define NRETRIES 50
- while (1)
- {
- /* Add the suffix for mktemp. */
- strcpy (xxxxxx, "XXXXXX");
-
- /* We really want to use mktemp here. We cannot use mkstemp
- since the file must be opened with a specific mode. The
- mode cannot later be set since then we cannot apply the
- file create mask. */
- if (mktemp (tmpfname) == NULL)
- return SEM_FAILED;
-
- /* Open the file. Make sure we do not overwrite anything. */
- fd = __libc_open (tmpfname, O_RDWR | O_CREAT | O_EXCL, mode);
- if (fd == -1)
- {
- if (errno == EEXIST)
- {
- if (++retries < NRETRIES)
- continue;
-
- __set_errno (EAGAIN);
- }
-
- return SEM_FAILED;
- }
-
- /* We got a file. */
- break;
- }
-
- if (TEMP_FAILURE_RETRY (__libc_write (fd, &initsem, sizeof (sem_t)))
- == sizeof (sem_t)
- /* Map the sem_t structure from the file. */
- && (result = (sem_t *) mmap (NULL, sizeof (sem_t),
- PROT_READ | PROT_WRITE, MAP_SHARED,
- fd, 0)) != MAP_FAILED)
- {
- /* Create the file. Don't overwrite an existing file. */
- if (link (tmpfname, finalname) != 0)
- {
- /* Undo the mapping. */
- (void) munmap (result, sizeof (sem_t));
-
- /* Reinitialize 'result'. */
- result = SEM_FAILED;
-
- /* This failed. If O_EXCL is not set and the problem was
- that the file exists, try again. */
- if ((oflag & O_EXCL) == 0 && errno == EEXIST)
- {
- /* Remove the file. */
- (void) unlink (tmpfname);
-
- /* Close the file. */
- (void) __libc_close (fd);
-
- goto try_again;
- }
- }
- else
- /* Insert the mapping into the search tree. This also
- determines whether another thread sneaked by and already
- added such a mapping despite the fact that we created it. */
- result = check_add_mapping (name, namelen, fd, result);
- }
-
- /* Now remove the temporary name. This should never fail. If
- it fails we leak a file name. Better fix the kernel. */
- (void) unlink (tmpfname);
- }
-
- /* Map the mmap error to the error we need. */
- if (MAP_FAILED != (void *) SEM_FAILED && result == MAP_FAILED)
- result = SEM_FAILED;
-
- /* We don't need the file descriptor anymore. */
- if (fd != -1)
- {
- /* Do not disturb errno. */
- INTERNAL_SYSCALL_DECL (err);
- INTERNAL_SYSCALL (close, err, 1, fd);
- }
-
- return result;
-}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-16 17:18:28 +0000