| /* POSIX barrier implementation for LinuxThreads. |
| Copyright (C) 2000, 2003 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Kaz Kylheku <kaz@ashi.footprints.net>, 2000. |
| |
| The GNU C 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 2.1 of the |
| License, or (at your option) any later version. |
| |
| The GNU C 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 the GNU C Library; see the file COPYING.LIB. If not, |
| write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| Boston, MA 02111-1307, USA. */ |
| |
| #include <errno.h> |
| #include "pthread.h" |
| #include "internals.h" |
| #include "spinlock.h" |
| #include "queue.h" |
| #include "restart.h" |
| |
| int |
| pthread_barrier_wait(pthread_barrier_t *barrier) |
| { |
| pthread_descr self = thread_self(); |
| pthread_descr temp_wake_queue, th; |
| int result = 0; |
| |
| __pthread_lock(&barrier->__ba_lock, self); |
| |
| /* If the required number of threads have achieved rendezvous... */ |
| if (barrier->__ba_present >= barrier->__ba_required - 1) |
| { |
| /* ... then this last caller shall be the serial thread */ |
| result = PTHREAD_BARRIER_SERIAL_THREAD; |
| /* Copy and clear wait queue and reset barrier. */ |
| temp_wake_queue = barrier->__ba_waiting; |
| barrier->__ba_waiting = NULL; |
| barrier->__ba_present = 0; |
| } |
| else |
| { |
| result = 0; |
| barrier->__ba_present++; |
| enqueue(&barrier->__ba_waiting, self); |
| } |
| |
| __pthread_unlock(&barrier->__ba_lock); |
| |
| if (result == 0) |
| { |
| /* Non-serial threads have to suspend */ |
| suspend(self); |
| /* We don't bother dealing with cancellation because the POSIX |
| spec for barriers doesn't mention that pthread_barrier_wait |
| is a cancellation point. */ |
| } |
| else |
| { |
| /* Serial thread wakes up all others. */ |
| while ((th = dequeue(&temp_wake_queue)) != NULL) |
| restart(th); |
| } |
| |
| return result; |
| } |
| |
| int |
| pthread_barrier_init(pthread_barrier_t *barrier, |
| const pthread_barrierattr_t *attr, |
| unsigned int count) |
| { |
| if (count == 0) |
| return EINVAL; |
| |
| __pthread_init_lock(&barrier->__ba_lock); |
| barrier->__ba_required = count; |
| barrier->__ba_present = 0; |
| barrier->__ba_waiting = NULL; |
| return 0; |
| } |
| |
| int |
| pthread_barrier_destroy(pthread_barrier_t *barrier) |
| { |
| if (barrier->__ba_waiting != NULL) return EBUSY; |
| return 0; |
| } |
| |
| int |
| pthread_barrierattr_init(pthread_barrierattr_t *attr) |
| { |
| attr->__pshared = PTHREAD_PROCESS_PRIVATE; |
| return 0; |
| } |
| |
| int |
| pthread_barrierattr_destroy(pthread_barrierattr_t *attr) |
| { |
| return 0; |
| } |
| |
| int |
| __pthread_barrierattr_getpshared(const pthread_barrierattr_t *attr, |
| int *pshared) |
| { |
| *pshared = PTHREAD_PROCESS_PRIVATE; |
| return 0; |
| } |
| |
| int |
| pthread_barrierattr_setpshared(pthread_barrierattr_t *attr, int pshared) |
| { |
| if (pshared != PTHREAD_PROCESS_PRIVATE && pshared != PTHREAD_PROCESS_SHARED) |
| return EINVAL; |
| |
| /* For now it is not possible to shared a conditional variable. */ |
| if (pshared != PTHREAD_PROCESS_PRIVATE) |
| return ENOSYS; |
| |
| return 0; |
| } |