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 internal_function attribute_hidden
  27 __pthread_mutex_unlock_usercnt (mutex, decr)
  28      pthread_mutex_t *mutex;
  29      int decr;
  30 {
  31   switch (__builtin_expect (mutex->__data.__kind, PTHREAD_MUTEX_TIMED_NP))
  32     {
  33     case PTHREAD_MUTEX_RECURSIVE_NP:
  34       /* Recursive mutex.  */
  35       if (mutex->__data.__owner != THREAD_GETMEM (THREAD_SELF, tid))
  36         return EPERM;
  37
  38       if (--mutex->__data.__count != 0)
  39         /* We still hold the mutex.  */
  40         return 0;
  41       break;
  42
  43     case PTHREAD_MUTEX_ERRORCHECK_NP:
  44       /* Error checking mutex.  */
  45       if (mutex->__data.__owner != THREAD_GETMEM (THREAD_SELF, tid)
  46           || ! lll_mutex_islocked (mutex->__data.__lock))
  47         return EPERM;
  48       break;
  49
  50     default:
  51       /* Correct code cannot set any other type.  */
  52     case PTHREAD_MUTEX_TIMED_NP:
  53     case PTHREAD_MUTEX_ADAPTIVE_NP:
  54       /* Normal mutex.  Nothing special to do.  */
  55       break;
  56     }
  57
  58   /* Always reset the owner field.  */
  59   mutex->__data.__owner = 0;
  60   if (decr)
  61     /* One less user.  */
  62     --mutex->__data.__nusers;
  63
  64   /* Unlock.  */
  65   lll_mutex_unlock (mutex->__data.__lock);
  66
  67   return 0;
  68 }
  69
  70
  71 int
  72 __pthread_mutex_unlock (mutex)
  73      pthread_mutex_t *mutex;
  74 {
  75   return __pthread_mutex_unlock_usercnt (mutex, 1);
  76 }
  77 strong_alias (__pthread_mutex_unlock, pthread_mutex_unlock)
  78 strong_alias (__pthread_mutex_unlock, __pthread_mutex_unlock_internal)