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authorMike Frysinger <vapier@gentoo.org>2005-11-15 03:13:04 (GMT)
committerMike Frysinger <vapier@gentoo.org>2005-11-15 03:13:04 (GMT)
commita9f5aa1cc96fc2c71f19a9c3e9dcbee0e78f83ca (patch)
tree2c5d251bdfd06d0a76cec9fc507b1873b4bbbdad /libpthread/linuxthreads.old/condvar.c
parentfd6dde5a19092be5bb1990dadd5c595d2ed0b3aa (diff)
rename current stable linuxthreads to linuxthreads.old to prepare for import of latest glibc version
Diffstat (limited to 'libpthread/linuxthreads.old/condvar.c')
-rw-r--r--libpthread/linuxthreads.old/condvar.c296
1 files changed, 296 insertions, 0 deletions
diff --git a/libpthread/linuxthreads.old/condvar.c b/libpthread/linuxthreads.old/condvar.c
new file mode 100644
index 0000000..f9c46a3
--- /dev/null
+++ b/libpthread/linuxthreads.old/condvar.c
@@ -0,0 +1,296 @@
+/* Linuxthreads - a simple clone()-based implementation of Posix */
+/* threads for Linux. */
+/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */
+/* and Pavel Krauz (krauz@fsid.cvut.cz). */
+/* */
+/* This program is free software; you can redistribute it and/or */
+/* modify it under the terms of the GNU Library General Public License */
+/* as published by the Free Software Foundation; either version 2 */
+/* of the License, or (at your option) any later version. */
+/* */
+/* This program 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 Library General Public License for more details. */
+
+/* Condition variables */
+
+#include <errno.h>
+#include <sched.h>
+#include <stddef.h>
+#include <sys/time.h>
+#include "pthread.h"
+#include "internals.h"
+#include "spinlock.h"
+#include "queue.h"
+#include "restart.h"
+
+int pthread_cond_init(pthread_cond_t *cond,
+ const pthread_condattr_t *cond_attr)
+{
+ __pthread_init_lock(&cond->__c_lock);
+ cond->__c_waiting = NULL;
+ return 0;
+}
+
+int pthread_cond_destroy(pthread_cond_t *cond)
+{
+ if (cond->__c_waiting != NULL) return EBUSY;
+ return 0;
+}
+
+/* Function called by pthread_cancel to remove the thread from
+ waiting on a condition variable queue. */
+
+static int cond_extricate_func(void *obj, pthread_descr th)
+{
+ volatile pthread_descr self = thread_self();
+ pthread_cond_t *cond = obj;
+ int did_remove = 0;
+
+ __pthread_lock(&cond->__c_lock, self);
+ did_remove = remove_from_queue(&cond->__c_waiting, th);
+ __pthread_unlock(&cond->__c_lock);
+
+ return did_remove;
+}
+
+int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
+{
+ volatile pthread_descr self = thread_self();
+ pthread_extricate_if extr;
+ int already_canceled = 0;
+ int spurious_wakeup_count;
+
+ /* Check whether the mutex is locked and owned by this thread. */
+ if (mutex->__m_kind != PTHREAD_MUTEX_TIMED_NP
+ && mutex->__m_kind != PTHREAD_MUTEX_ADAPTIVE_NP
+ && mutex->__m_owner != self)
+ return EINVAL;
+
+ /* Set up extrication interface */
+ extr.pu_object = cond;
+ extr.pu_extricate_func = cond_extricate_func;
+
+ /* Register extrication interface */
+ THREAD_SETMEM(self, p_condvar_avail, 0);
+ __pthread_set_own_extricate_if(self, &extr);
+
+ /* Atomically enqueue thread for waiting, but only if it is not
+ canceled. If the thread is canceled, then it will fall through the
+ suspend call below, and then call pthread_exit without
+ having to worry about whether it is still on the condition variable queue.
+ This depends on pthread_cancel setting p_canceled before calling the
+ extricate function. */
+
+ __pthread_lock(&cond->__c_lock, self);
+ if (!(THREAD_GETMEM(self, p_canceled)
+ && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE))
+ enqueue(&cond->__c_waiting, self);
+ else
+ already_canceled = 1;
+ __pthread_unlock(&cond->__c_lock);
+
+ if (already_canceled) {
+ __pthread_set_own_extricate_if(self, 0);
+ pthread_exit(PTHREAD_CANCELED);
+ }
+
+ pthread_mutex_unlock(mutex);
+
+ spurious_wakeup_count = 0;
+ while (1)
+ {
+ suspend(self);
+ if (THREAD_GETMEM(self, p_condvar_avail) == 0
+ && (THREAD_GETMEM(self, p_woken_by_cancel) == 0
+ || THREAD_GETMEM(self, p_cancelstate) != PTHREAD_CANCEL_ENABLE))
+ {
+ /* Count resumes that don't belong to us. */
+ spurious_wakeup_count++;
+ continue;
+ }
+ break;
+ }
+
+ __pthread_set_own_extricate_if(self, 0);
+
+ /* Check for cancellation again, to provide correct cancellation
+ point behavior */
+
+ if (THREAD_GETMEM(self, p_woken_by_cancel)
+ && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE) {
+ THREAD_SETMEM(self, p_woken_by_cancel, 0);
+ pthread_mutex_lock(mutex);
+ pthread_exit(PTHREAD_CANCELED);
+ }
+
+ /* Put back any resumes we caught that don't belong to us. */
+ while (spurious_wakeup_count--)
+ restart(self);
+
+ pthread_mutex_lock(mutex);
+ return 0;
+}
+
+static int
+pthread_cond_timedwait_relative(pthread_cond_t *cond,
+ pthread_mutex_t *mutex,
+ const struct timespec * abstime)
+{
+ volatile pthread_descr self = thread_self();
+ int already_canceled = 0;
+ pthread_extricate_if extr;
+ int spurious_wakeup_count;
+
+ /* Check whether the mutex is locked and owned by this thread. */
+ if (mutex->__m_kind != PTHREAD_MUTEX_TIMED_NP
+ && mutex->__m_kind != PTHREAD_MUTEX_ADAPTIVE_NP
+ && mutex->__m_owner != self)
+ return EINVAL;
+
+ /* Set up extrication interface */
+ extr.pu_object = cond;
+ extr.pu_extricate_func = cond_extricate_func;
+
+ /* Register extrication interface */
+ THREAD_SETMEM(self, p_condvar_avail, 0);
+ __pthread_set_own_extricate_if(self, &extr);
+
+ /* Enqueue to wait on the condition and check for cancellation. */
+ __pthread_lock(&cond->__c_lock, self);
+ if (!(THREAD_GETMEM(self, p_canceled)
+ && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE))
+ enqueue(&cond->__c_waiting, self);
+ else
+ already_canceled = 1;
+ __pthread_unlock(&cond->__c_lock);
+
+ if (already_canceled) {
+ __pthread_set_own_extricate_if(self, 0);
+ pthread_exit(PTHREAD_CANCELED);
+ }
+
+ pthread_mutex_unlock(mutex);
+
+ spurious_wakeup_count = 0;
+ while (1)
+ {
+ if (!timedsuspend(self, abstime)) {
+ int was_on_queue;
+
+ /* __pthread_lock will queue back any spurious restarts that
+ may happen to it. */
+
+ __pthread_lock(&cond->__c_lock, self);
+ was_on_queue = remove_from_queue(&cond->__c_waiting, self);
+ __pthread_unlock(&cond->__c_lock);
+
+ if (was_on_queue) {
+ __pthread_set_own_extricate_if(self, 0);
+ pthread_mutex_lock(mutex);
+ return ETIMEDOUT;
+ }
+
+ /* Eat the outstanding restart() from the signaller */
+ suspend(self);
+ }
+
+ if (THREAD_GETMEM(self, p_condvar_avail) == 0
+ && (THREAD_GETMEM(self, p_woken_by_cancel) == 0
+ || THREAD_GETMEM(self, p_cancelstate) != PTHREAD_CANCEL_ENABLE))
+ {
+ /* Count resumes that don't belong to us. */
+ spurious_wakeup_count++;
+ continue;
+ }
+ break;
+ }
+
+ __pthread_set_own_extricate_if(self, 0);
+
+ /* The remaining logic is the same as in other cancellable waits,
+ such as pthread_join sem_wait or pthread_cond wait. */
+
+ if (THREAD_GETMEM(self, p_woken_by_cancel)
+ && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE) {
+ THREAD_SETMEM(self, p_woken_by_cancel, 0);
+ pthread_mutex_lock(mutex);
+ pthread_exit(PTHREAD_CANCELED);
+ }
+
+ /* Put back any resumes we caught that don't belong to us. */
+ while (spurious_wakeup_count--)
+ restart(self);
+
+ pthread_mutex_lock(mutex);
+ return 0;
+}
+
+int pthread_cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
+ const struct timespec * abstime)
+{
+ /* Indirect call through pointer! */
+ return pthread_cond_timedwait_relative(cond, mutex, abstime);
+}
+
+int pthread_cond_signal(pthread_cond_t *cond)
+{
+ pthread_descr th;
+
+ __pthread_lock(&cond->__c_lock, NULL);
+ th = dequeue(&cond->__c_waiting);
+ __pthread_unlock(&cond->__c_lock);
+ if (th != NULL) {
+ th->p_condvar_avail = 1;
+ WRITE_MEMORY_BARRIER();
+ restart(th);
+ }
+ return 0;
+}
+
+int pthread_cond_broadcast(pthread_cond_t *cond)
+{
+ pthread_descr tosignal, th;
+
+ __pthread_lock(&cond->__c_lock, NULL);
+ /* Copy the current state of the waiting queue and empty it */
+ tosignal = cond->__c_waiting;
+ cond->__c_waiting = NULL;
+ __pthread_unlock(&cond->__c_lock);
+ /* Now signal each process in the queue */
+ while ((th = dequeue(&tosignal)) != NULL) {
+ th->p_condvar_avail = 1;
+ WRITE_MEMORY_BARRIER();
+ restart(th);
+ }
+ return 0;
+}
+
+int pthread_condattr_init(pthread_condattr_t *attr)
+{
+ return 0;
+}
+
+int pthread_condattr_destroy(pthread_condattr_t *attr)
+{
+ return 0;
+}
+
+int pthread_condattr_getpshared (const pthread_condattr_t *attr, int *pshared)
+{
+ *pshared = PTHREAD_PROCESS_PRIVATE;
+ return 0;
+}
+
+int pthread_condattr_setpshared (pthread_condattr_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;
+}