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glibc  2.9
sem_unlink.c
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00001 /* Copyright (C) 2002, 2004 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
00004 
00005    The GNU C Library is free software; you can redistribute it and/or
00006    modify it under the terms of the GNU Lesser General Public
00007    License as published by the Free Software Foundation; either
00008    version 2.1 of the License, or (at your option) any later version.
00009 
00010    The GNU C Library is distributed in the hope that it will be useful,
00011    but WITHOUT ANY WARRANTY; without even the implied warranty of
00012    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013    Lesser General Public License for more details.
00014 
00015    You should have received a copy of the GNU Lesser General Public
00016    License along with the GNU C Library; if not, write to the Free
00017    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00018    02111-1307 USA.  */
00019 
00020 #include <errno.h>
00021 #include <semaphore.h>
00022 #include <stdlib.h>
00023 #include <string.h>
00024 #include <unistd.h>
00025 #include "semaphoreP.h"
00026 
00027 
00028 int
00029 sem_unlink (name)
00030      const char *name;
00031 {
00032   char *fname;
00033   size_t namelen;
00034 
00035   /* Determine where the shmfs is mounted.  */
00036   INTUSE(__pthread_once) (&__namedsem_once, __where_is_shmfs);
00037 
00038   /* If we don't know the mount points there is nothing we can do.  Ever.  */
00039   if (mountpoint.dir == NULL)
00040     {
00041       __set_errno (ENOSYS);
00042       return -1;
00043     }
00044 
00045   /* Construct the filename.  */
00046   while (name[0] == '/')
00047     ++name;
00048 
00049   if (name[0] == '\0')
00050     {
00051       /* The name "/" is not supported.  */
00052       __set_errno (ENOENT);
00053       return -1;
00054     }
00055   namelen = strlen (name);
00056 
00057   /* Create the name of the file.  */
00058   fname = (char *) alloca (mountpoint.dirlen + namelen + 1);
00059   __mempcpy (__mempcpy (fname, mountpoint.dir, mountpoint.dirlen),
00060             name, namelen + 1);
00061 
00062   /* Now try removing it.  */
00063   int ret = unlink (fname);
00064   if (ret < 0 && errno == EPERM)
00065     __set_errno (EACCES);
00066   return ret;
00067 }