/* * pthread_mutex_lock.c * * Description: * This translation unit implements mutual exclusion (mutex) primitives. * * -------------------------------------------------------------------------- * * Pthreads-win32 - POSIX Threads Library for Win32 * Copyright(C) 1998 John E. Bossom * Copyright(C) 1999,2003 Pthreads-win32 contributors * * Contact Email: rpj@callisto.canberra.edu.au * * The current list of contributors is contained * in the file CONTRIBUTORS included with the source * code distribution. The list can also be seen at the * following World Wide Web location: * http://sources.redhat.com/pthreads-win32/contributors.html * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library in the file COPYING.LIB; * if not, write to the Free Software Foundation, Inc., * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA */ #ifndef _UWIN # include <process.h> #endif #include "pthread.h" #include "implement.h" static INLINE int ptw32_semwait (sem_t * sem) /* * ------------------------------------------------------ * DESCRIPTION * This function waits on a POSIX semaphore. If the * semaphore value is greater than zero, it decreases * its value by one. If the semaphore value is zero, then * the calling thread (or process) is blocked until it can * successfully decrease the value. * * Unlike sem_wait(), this routine is non-cancelable. * * RESULTS * 0 successfully decreased semaphore, * -1 failed, error in errno. * ERRNO * EINVAL 'sem' is not a valid semaphore, * ENOSYS semaphores are not supported, * EINTR the function was interrupted by a signal, * EDEADLK a deadlock condition was detected. * * ------------------------------------------------------ */ { int result = 0; DWORD status; if (sem == NULL) { result = EINVAL; } else { #ifdef NEED_SEM status = WaitForSingleObject( (*sem)->event, INFINITE ); #else /* NEED_SEM */ status = WaitForSingleObject( (*sem)->sem, INFINITE ); #endif if (status == WAIT_OBJECT_0) { #ifdef NEED_SEM ptw32_decrease_semaphore(sem); #endif /* NEED_SEM */ return 0; } else { result = EINVAL; } } if (result != 0) { errno = result; return -1; } return 0; } /* ptw32_semwait */ int pthread_mutex_lock(pthread_mutex_t *mutex) { int result = 0; pthread_mutex_t mx; if (mutex == NULL || *mutex == NULL) { return EINVAL; } /* * We do a quick check to see if we need to do more work * to initialise a static mutex. We check * again inside the guarded section of ptw32_mutex_check_need_init() * to avoid race conditions. */ if (*mutex == PTHREAD_MUTEX_INITIALIZER) { if ((result = ptw32_mutex_check_need_init(mutex)) != 0) { return(result); } } mx = *mutex; if ( 0 == InterlockedIncrement( &mx->lock_idx ) ) { mx->recursive_count = 1; mx->ownerThread = (mx->kind != PTHREAD_MUTEX_FAST_NP ? pthread_self() : (pthread_t) PTW32_MUTEX_OWNER_ANONYMOUS); } else { if ( mx->kind != PTHREAD_MUTEX_FAST_NP && pthread_equal( mx->ownerThread, pthread_self() ) ) { (void) InterlockedDecrement( &mx->lock_idx ); if( mx->kind == PTHREAD_MUTEX_RECURSIVE_NP ) { mx->recursive_count++; } else { result = EDEADLK; } } else { if (ptw32_semwait( &mx->wait_sema ) == 0) { mx->recursive_count = 1; mx->ownerThread = (mx->kind != PTHREAD_MUTEX_FAST_NP ? pthread_self() : (pthread_t) PTW32_MUTEX_OWNER_ANONYMOUS); } else { result = errno; } } } return(result); }