diff options
-rw-r--r-- | lib/libkse/thread/thr_once.c | 59 | ||||
-rw-r--r-- | lib/libkse/thread/thr_private.h | 2 | ||||
-rw-r--r-- | lib/libpthread/thread/thr_once.c | 59 | ||||
-rw-r--r-- | lib/libpthread/thread/thr_private.h | 2 |
4 files changed, 104 insertions, 18 deletions
diff --git a/lib/libkse/thread/thr_once.c b/lib/libkse/thread/thr_once.c index 152fdec..ad158d1 100644 --- a/lib/libkse/thread/thr_once.c +++ b/lib/libkse/thread/thr_once.c @@ -38,18 +38,59 @@ __weak_reference(_pthread_once, pthread_once); +#define ONCE_NEVER_DONE PTHREAD_NEEDS_INIT +#define ONCE_DONE PTHREAD_DONE_INIT +#define ONCE_IN_PROGRESS 0x02 +#define ONCE_MASK 0x03 + +static pthread_mutex_t once_lock = PTHREAD_MUTEX_INITIALIZER; +static pthread_cond_t once_cv = PTHREAD_COND_INITIALIZER; + +/* + * POSIX: + * The pthread_once() function is not a cancellation point. However, + * if init_routine is a cancellation point and is canceled, the effect + * on once_control shall be as if pthread_once() was never called. + */ + +static void +once_cancel_handler(void *arg) +{ + pthread_once_t *once_control = arg; + + _pthread_mutex_lock(&once_lock); + once_control->state = ONCE_NEVER_DONE; + _pthread_mutex_unlock(&once_lock); + _pthread_cond_broadcast(&once_cv); +} + int _pthread_once(pthread_once_t *once_control, void (*init_routine) (void)) { - if (once_control->state == PTHREAD_NEEDS_INIT) { - if (_thr_initial == NULL) - _libpthread_init(NULL); - _pthread_mutex_lock(&(once_control->mutex)); - if (once_control->state == PTHREAD_NEEDS_INIT) { - init_routine(); - once_control->state = PTHREAD_DONE_INIT; - } - _pthread_mutex_unlock(&(once_control->mutex)); + int wakeup = 0; + + if (once_control->state == ONCE_DONE) + return (0); + _pthread_mutex_lock(&once_lock); + while (*(volatile int *)&(once_control->state) == ONCE_IN_PROGRESS) + _pthread_cond_wait(&once_cv, &once_lock); + /* + * If previous thread was canceled, then the state still + * could be ONCE_NEVER_DONE, we need to check it again. + */ + if (*(volatile int *)&(once_control->state) == ONCE_NEVER_DONE) { + once_control->state = ONCE_IN_PROGRESS; + _pthread_mutex_unlock(&once_lock); + _pthread_cleanup_push(once_cancel_handler, once_control); + init_routine(); + _pthread_cleanup_pop(0); + _pthread_mutex_lock(&once_lock); + once_control->state = ONCE_DONE; + wakeup = 1; } + _pthread_mutex_unlock(&once_lock); + if (wakeup) + _pthread_cond_broadcast(&once_cv); return (0); } + diff --git a/lib/libkse/thread/thr_private.h b/lib/libkse/thread/thr_private.h index 12ebe90..24c0ed5 100644 --- a/lib/libkse/thread/thr_private.h +++ b/lib/libkse/thread/thr_private.h @@ -1099,6 +1099,8 @@ int _pthread_rwlock_destroy (pthread_rwlock_t *); struct pthread *_pthread_self(void); int _pthread_setspecific(pthread_key_t, const void *); void _pthread_yield(void); +void _pthread_cleanup_push(void (*routine) (void *), void *routine_arg); +void _pthread_cleanup_pop(int execute); struct pthread *_thr_alloc(struct pthread *); void _thr_exit(char *, int, char *); void _thr_exit_cleanup(void); diff --git a/lib/libpthread/thread/thr_once.c b/lib/libpthread/thread/thr_once.c index 152fdec..ad158d1 100644 --- a/lib/libpthread/thread/thr_once.c +++ b/lib/libpthread/thread/thr_once.c @@ -38,18 +38,59 @@ __weak_reference(_pthread_once, pthread_once); +#define ONCE_NEVER_DONE PTHREAD_NEEDS_INIT +#define ONCE_DONE PTHREAD_DONE_INIT +#define ONCE_IN_PROGRESS 0x02 +#define ONCE_MASK 0x03 + +static pthread_mutex_t once_lock = PTHREAD_MUTEX_INITIALIZER; +static pthread_cond_t once_cv = PTHREAD_COND_INITIALIZER; + +/* + * POSIX: + * The pthread_once() function is not a cancellation point. However, + * if init_routine is a cancellation point and is canceled, the effect + * on once_control shall be as if pthread_once() was never called. + */ + +static void +once_cancel_handler(void *arg) +{ + pthread_once_t *once_control = arg; + + _pthread_mutex_lock(&once_lock); + once_control->state = ONCE_NEVER_DONE; + _pthread_mutex_unlock(&once_lock); + _pthread_cond_broadcast(&once_cv); +} + int _pthread_once(pthread_once_t *once_control, void (*init_routine) (void)) { - if (once_control->state == PTHREAD_NEEDS_INIT) { - if (_thr_initial == NULL) - _libpthread_init(NULL); - _pthread_mutex_lock(&(once_control->mutex)); - if (once_control->state == PTHREAD_NEEDS_INIT) { - init_routine(); - once_control->state = PTHREAD_DONE_INIT; - } - _pthread_mutex_unlock(&(once_control->mutex)); + int wakeup = 0; + + if (once_control->state == ONCE_DONE) + return (0); + _pthread_mutex_lock(&once_lock); + while (*(volatile int *)&(once_control->state) == ONCE_IN_PROGRESS) + _pthread_cond_wait(&once_cv, &once_lock); + /* + * If previous thread was canceled, then the state still + * could be ONCE_NEVER_DONE, we need to check it again. + */ + if (*(volatile int *)&(once_control->state) == ONCE_NEVER_DONE) { + once_control->state = ONCE_IN_PROGRESS; + _pthread_mutex_unlock(&once_lock); + _pthread_cleanup_push(once_cancel_handler, once_control); + init_routine(); + _pthread_cleanup_pop(0); + _pthread_mutex_lock(&once_lock); + once_control->state = ONCE_DONE; + wakeup = 1; } + _pthread_mutex_unlock(&once_lock); + if (wakeup) + _pthread_cond_broadcast(&once_cv); return (0); } + diff --git a/lib/libpthread/thread/thr_private.h b/lib/libpthread/thread/thr_private.h index 12ebe90..24c0ed5 100644 --- a/lib/libpthread/thread/thr_private.h +++ b/lib/libpthread/thread/thr_private.h @@ -1099,6 +1099,8 @@ int _pthread_rwlock_destroy (pthread_rwlock_t *); struct pthread *_pthread_self(void); int _pthread_setspecific(pthread_key_t, const void *); void _pthread_yield(void); +void _pthread_cleanup_push(void (*routine) (void *), void *routine_arg); +void _pthread_cleanup_pop(int execute); struct pthread *_thr_alloc(struct pthread *); void _thr_exit(char *, int, char *); void _thr_exit_cleanup(void); |