nptl/pthread_mutex_unlock.c

   1 /* Copyright (C) 2002, 2003 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include "pthreadP.h"
  22 #include <lowlevellock.h>
  23
  24
  25 int
  26 __pthread_mutex_unlock (mutex)
  27      pthread_mutex_t *mutex;
  28 {
  29   switch (__builtin_expect (mutex->__data.__kind, PTHREAD_MUTEX_TIMED_NP))
  30     {
  31     case PTHREAD_MUTEX_RECURSIVE_NP:
  32       /* Recursive mutex.  */
  33       if (mutex->__data.__owner != THREAD_ID)
  34         return EPERM;
  35
  36       if (--mutex->__data.__count != 0)
  37         /* We still hold the mutex.  */
  38         return 0;
  39       break;
  40
  41     case PTHREAD_MUTEX_ERRORCHECK_NP:
  42       /* Error checking mutex.  */
  43       if (mutex->__data.__owner != THREAD_ID
  44           || ! lll_mutex_islocked (mutex->__data.__lock))
  45         return EPERM;
  46       break;
  47
  48     default:
  49       /* Correct code cannot set any other type.  */
  50     case PTHREAD_MUTEX_TIMED_NP:
  51     case PTHREAD_MUTEX_ADAPTIVE_NP:
  52       /* Normal mutex.  Nothing special to do.  */
  53       break;
  54     }
  55
  56   /* Always reset the owner field.  */
  57   mutex->__data.__owner = NULL;
  58
  59   /* Unlock.  */
  60   lll_mutex_unlock (mutex->__data.__lock);
  61
  62   return 0;
  63 }
  64 strong_alias (__pthread_mutex_unlock, pthread_mutex_unlock)
  65 strong_alias (__pthread_mutex_unlock, __pthread_mutex_unlock_internal)