nptl/pthread_mutex_lock.c

   1 /* Copyright (C) 2002 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_lock (mutex)
  27      pthread_mutex_t *mutex;
  28 {
  29   struct pthread *pd = THREAD_SELF;
  30
  31   switch (__builtin_expect (mutex->__data.__kind, PTHREAD_MUTEX_TIMED_NP))
  32     {
  33       /* Recursive mutex.  */
  34     case PTHREAD_MUTEX_RECURSIVE_NP:
  35       /* Check whether we already hold the mutex.  */
  36       if (mutex->__data.__owner == pd)
  37         {
  38           /* Just bump the counter.  */
  39           if (__builtin_expect (mutex->__data.__count + 1 == 0, 0))
  40             /* Overflow of the counter.  */
  41             return EAGAIN;
  42
  43           ++mutex->__data.__count;
  44         }
  45       else
  46         {
  47           /* We have to get the mutex.  */
  48           lll_mutex_lock (mutex->__data.__lock);
  49
  50           /* Record the ownership.  */
  51           mutex->__data.__owner = pd;
  52           mutex->__data.__count = 1;
  53         }
  54       break;
  55
  56       /* Error checking mutex.  */
  57     case PTHREAD_MUTEX_ERRORCHECK_NP:
  58       /* Check whether we already hold the mutex.  */
  59       if (mutex->__data.__owner == pd)
  60         return EDEADLK;
  61
  62       /* FALLTHROUGH */
  63
  64     default:
  65       /* Correct code cannot set any other type.  */
  66     case PTHREAD_MUTEX_TIMED_NP:
  67     case PTHREAD_MUTEX_ADAPTIVE_NP:
  68       /* Normal mutex.  */
  69       lll_mutex_lock (mutex->__data.__lock);
  70       /* Record the ownership.  */
  71       mutex->__data.__owner = pd;
  72       break;
  73     }
  74
  75   return 0;
  76 }
  77 strong_alias (__pthread_mutex_lock, pthread_mutex_lock)