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Diffstat (limited to 'libpthread/linuxthreads/semaphore.c')
-rw-r--r--libpthread/linuxthreads/semaphore.c159
1 files changed, 128 insertions, 31 deletions
diff --git a/libpthread/linuxthreads/semaphore.c b/libpthread/linuxthreads/semaphore.c
index 0297b3a1e..0038ddd2a 100644
--- a/libpthread/linuxthreads/semaphore.c
+++ b/libpthread/linuxthreads/semaphore.c
@@ -14,6 +14,8 @@
/* Semaphores a la POSIX 1003.1b */
+#include <features.h>
+#define __USE_GNU
#include <errno.h>
#include "pthread.h"
#include "semaphore.h"
@@ -32,7 +34,7 @@ int __new_sem_init(sem_t *sem, int pshared, unsigned int value)
errno = ENOSYS;
return -1;
}
- __pthread_init_lock((struct _pthread_fastlock *) &sem->__sem_lock);
+ __pthread_init_lock(&sem->__sem_lock);
sem->__sem_value = value;
sem->__sem_waiting = NULL;
return 0;
@@ -47,9 +49,9 @@ static int new_sem_extricate_func(void *obj, pthread_descr th)
sem_t *sem = obj;
int did_remove = 0;
- __pthread_lock((struct _pthread_fastlock *) &sem->__sem_lock, self);
+ __pthread_lock(&sem->__sem_lock, self);
did_remove = remove_from_queue(&sem->__sem_waiting, th);
- __pthread_unlock((struct _pthread_fastlock *) &sem->__sem_lock);
+ __pthread_unlock(&sem->__sem_lock);
return did_remove;
}
@@ -59,35 +61,50 @@ int __new_sem_wait(sem_t * sem)
volatile pthread_descr self = thread_self();
pthread_extricate_if extr;
int already_canceled = 0;
+ int spurious_wakeup_count;
/* Set up extrication interface */
extr.pu_object = sem;
extr.pu_extricate_func = new_sem_extricate_func;
- __pthread_lock((struct _pthread_fastlock *) &sem->__sem_lock, self);
+ __pthread_lock(&sem->__sem_lock, self);
if (sem->__sem_value > 0) {
sem->__sem_value--;
- __pthread_unlock((struct _pthread_fastlock *) &sem->__sem_lock);
+ __pthread_unlock(&sem->__sem_lock);
return 0;
}
/* Register extrication interface */
- __pthread_set_own_extricate_if(self, &extr);
+ THREAD_SETMEM(self, p_sem_avail, 0);
+ __pthread_set_own_extricate_if(self, &extr);
/* Enqueue only if not already cancelled. */
if (!(THREAD_GETMEM(self, p_canceled)
&& THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE))
enqueue(&sem->__sem_waiting, self);
else
already_canceled = 1;
- __pthread_unlock((struct _pthread_fastlock *) &sem->__sem_lock);
+ __pthread_unlock(&sem->__sem_lock);
if (already_canceled) {
- __pthread_set_own_extricate_if(self, 0);
+ __pthread_set_own_extricate_if(self, 0);
pthread_exit(PTHREAD_CANCELED);
- }
+ }
/* Wait for sem_post or cancellation, or fall through if already canceled */
- suspend(self);
- __pthread_set_own_extricate_if(self, 0);
+ spurious_wakeup_count = 0;
+ while (1)
+ {
+ suspend(self);
+ if (THREAD_GETMEM(self, p_sem_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);
/* Terminate only if the wakeup came from cancellation. */
/* Otherwise ignore cancellation because we got the semaphore. */
@@ -105,7 +122,7 @@ int __new_sem_trywait(sem_t * sem)
{
int retval;
- __pthread_lock((struct _pthread_fastlock *) &sem->__sem_lock, NULL);
+ __pthread_lock(&sem->__sem_lock, NULL);
if (sem->__sem_value == 0) {
errno = EAGAIN;
retval = -1;
@@ -113,7 +130,7 @@ int __new_sem_trywait(sem_t * sem)
sem->__sem_value--;
retval = 0;
}
- __pthread_unlock((struct _pthread_fastlock *) &sem->__sem_lock);
+ __pthread_unlock(&sem->__sem_lock);
return retval;
}
@@ -124,19 +141,21 @@ int __new_sem_post(sem_t * sem)
struct pthread_request request;
if (THREAD_GETMEM(self, p_in_sighandler) == NULL) {
- __pthread_lock((struct _pthread_fastlock *) &sem->__sem_lock, self);
+ __pthread_lock(&sem->__sem_lock, self);
if (sem->__sem_waiting == NULL) {
if (sem->__sem_value >= SEM_VALUE_MAX) {
/* Overflow */
errno = ERANGE;
- __pthread_unlock((struct _pthread_fastlock *) &sem->__sem_lock);
+ __pthread_unlock(&sem->__sem_lock);
return -1;
}
sem->__sem_value++;
- __pthread_unlock((struct _pthread_fastlock *) &sem->__sem_lock);
+ __pthread_unlock(&sem->__sem_lock);
} else {
th = dequeue(&sem->__sem_waiting);
- __pthread_unlock((struct _pthread_fastlock *) &sem->__sem_lock);
+ __pthread_unlock(&sem->__sem_lock);
+ th->p_sem_avail = 1;
+ WRITE_MEMORY_BARRIER();
restart(th);
}
} else {
@@ -150,8 +169,8 @@ int __new_sem_post(sem_t * sem)
}
request.req_kind = REQ_POST;
request.req_args.post = sem;
- __libc_write(__pthread_manager_request,
- (char *) &request, sizeof(request));
+ TEMP_FAILURE_RETRY(__libc_write(__pthread_manager_request,
+ (char *) &request, sizeof(request)));
}
return 0;
}
@@ -189,21 +208,99 @@ int sem_unlink(const char *name)
return -1;
}
-#if defined PIC && DO_VERSIONING
-default_symbol_version (__new_sem_init, sem_init, GLIBC_2.1);
-default_symbol_version (__new_sem_wait, sem_wait, GLIBC_2.1);
-default_symbol_version (__new_sem_trywait, sem_trywait, GLIBC_2.1);
-default_symbol_version (__new_sem_post, sem_post, GLIBC_2.1);
-default_symbol_version (__new_sem_getvalue, sem_getvalue, GLIBC_2.1);
-default_symbol_version (__new_sem_destroy, sem_destroy, GLIBC_2.1);
-#else
-# ifdef weak_alias
+int sem_timedwait(sem_t *sem, const struct timespec *abstime)
+{
+ pthread_descr self = thread_self();
+ pthread_extricate_if extr;
+ int already_canceled = 0;
+ int spurious_wakeup_count;
+
+ __pthread_lock(&sem->__sem_lock, self);
+ if (sem->__sem_value > 0) {
+ --sem->__sem_value;
+ __pthread_unlock(&sem->__sem_lock);
+ return 0;
+ }
+
+ if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000) {
+ /* The standard requires that if the function would block and the
+ time value is illegal, the function returns with an error. */
+ __pthread_unlock(&sem->__sem_lock);
+ return EINVAL;
+ }
+
+ /* Set up extrication interface */
+ extr.pu_object = sem;
+ extr.pu_extricate_func = new_sem_extricate_func;
+
+ /* Register extrication interface */
+ THREAD_SETMEM(self, p_sem_avail, 0);
+ __pthread_set_own_extricate_if(self, &extr);
+ /* Enqueue only if not already cancelled. */
+ if (!(THREAD_GETMEM(self, p_canceled)
+ && THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE))
+ enqueue(&sem->__sem_waiting, self);
+ else
+ already_canceled = 1;
+ __pthread_unlock(&sem->__sem_lock);
+
+ if (already_canceled) {
+ __pthread_set_own_extricate_if(self, 0);
+ pthread_exit(PTHREAD_CANCELED);
+ }
+
+ spurious_wakeup_count = 0;
+ while (1)
+ {
+ if (timedsuspend(self, abstime) == 0) {
+ int was_on_queue;
+
+ /* __pthread_lock will queue back any spurious restarts that
+ may happen to it. */
+
+ __pthread_lock(&sem->__sem_lock, self);
+ was_on_queue = remove_from_queue(&sem->__sem_waiting, self);
+ __pthread_unlock(&sem->__sem_lock);
+
+ if (was_on_queue) {
+ __pthread_set_own_extricate_if(self, 0);
+ return ETIMEDOUT;
+ }
+
+ /* Eat the outstanding restart() from the signaller */
+ suspend(self);
+ }
+
+ if (THREAD_GETMEM(self, p_sem_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);
+
+ /* Terminate only if the wakeup came from cancellation. */
+ /* Otherwise ignore cancellation because we got the semaphore. */
+
+ 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_exit(PTHREAD_CANCELED);
+ }
+ /* We got the semaphore */
+ return 0;
+}
+
+
weak_alias (__new_sem_init, sem_init)
weak_alias (__new_sem_wait, sem_wait)
weak_alias (__new_sem_trywait, sem_trywait)
weak_alias (__new_sem_post, sem_post)
weak_alias (__new_sem_getvalue, sem_getvalue)
weak_alias (__new_sem_destroy, sem_destroy)
-# endif
-#endif
-
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-27 19:31:23 +0000