nptl/sem_unlink.c

   1 /* Copyright (C) 2002-2014 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <semaphore.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24 #include "semaphoreP.h"
  25
  26
  27 int
  28 sem_unlink (name)
  29      const char *name;
  30 {
  31   char *fname;
  32   size_t namelen;
  33
  34   /* Determine where the shmfs is mounted.  */
  35   __pthread_once (&__namedsem_once, __where_is_shmfs);
  36
  37   /* If we don't know the mount points there is nothing we can do.  Ever.  */
  38   if (mountpoint.dir == NULL)
  39     {
  40       __set_errno (ENOSYS);
  41       return -1;
  42     }
  43
  44   /* Construct the filename.  */
  45   while (name[0] == '/')
  46     ++name;
  47
  48   if (name[0] == '\0')
  49     {
  50       /* The name "/" is not supported.  */
  51       __set_errno (ENOENT);
  52       return -1;
  53     }
  54   namelen = strlen (name);
  55
  56   /* Create the name of the file.  */
  57   fname = (char *) alloca (mountpoint.dirlen + namelen + 1);
  58   __mempcpy (__mempcpy (fname, mountpoint.dir, mountpoint.dirlen),
  59              name, namelen + 1);
  60
  61   /* Now try removing it.  */
  62   int ret = unlink (fname);
  63   if (ret < 0 && errno == EPERM)
  64     __set_errno (EACCES);
  65   return ret;
  66 }