diff --git a/libc/bionic/posix_timers.cpp b/libc/bionic/posix_timers.cpp index e9190b2c6..59933ec78 100644 --- a/libc/bionic/posix_timers.cpp +++ b/libc/bionic/posix_timers.cpp @@ -63,7 +63,6 @@ struct PosixTimer { pthread_t callback_thread; void (*callback)(sigval_t); sigval_t callback_argument; - volatile int exiting; }; static __kernel_timer_t to_kernel_timer_id(timer_t timer) { @@ -90,8 +89,7 @@ static void* __timer_thread_start(void* arg) { timer->callback(timer->callback_argument); } else if (si.si_code == SI_TKILL) { // This signal was sent because someone wants us to exit. - timer->exiting = 1; - __futex_wake(&timer->exiting, INT32_MAX); + free(timer); return NULL; } } @@ -99,46 +97,35 @@ static void* __timer_thread_start(void* arg) { static void __timer_thread_stop(PosixTimer* timer) { pthread_kill(timer->callback_thread, TIMER_SIGNAL); - - // If this is being called from within the callback thread, do nothing else. - if (pthread_self() != timer->callback_thread) { - // We can't pthread_join because POSIX says "the threads created in response to a timer - // expiration are created detached, or in an unspecified way if the thread attribute's - // detachstate is PTHREAD_CREATE_JOINABLE". - while (timer->exiting == 0) { - __futex_wait(&timer->exiting, 0, NULL); - } - } } // http://pubs.opengroup.org/onlinepubs/9699919799/functions/timer_create.html int timer_create(clockid_t clock_id, sigevent* evp, timer_t* timer_id) { - PosixTimer* new_timer = reinterpret_cast(malloc(sizeof(PosixTimer))); - if (new_timer == NULL) { + PosixTimer* timer = reinterpret_cast(malloc(sizeof(PosixTimer))); + if (timer == NULL) { return -1; } - new_timer->sigev_notify = (evp == NULL) ? SIGEV_SIGNAL : evp->sigev_notify; + timer->sigev_notify = (evp == NULL) ? SIGEV_SIGNAL : evp->sigev_notify; // If not a SIGEV_THREAD timer, the kernel can handle it without our help. - if (new_timer->sigev_notify != SIGEV_THREAD) { - if (__timer_create(clock_id, evp, &new_timer->kernel_timer_id) == -1) { - free(new_timer); + if (timer->sigev_notify != SIGEV_THREAD) { + if (__timer_create(clock_id, evp, &timer->kernel_timer_id) == -1) { + free(timer); return -1; } - *timer_id = new_timer; + *timer_id = timer; return 0; } // Otherwise, this must be SIGEV_THREAD timer... - new_timer->callback = evp->sigev_notify_function; - new_timer->callback_argument = evp->sigev_value; - new_timer->exiting = 0; + timer->callback = evp->sigev_notify_function; + timer->callback_argument = evp->sigev_value; // Check arguments that the kernel doesn't care about but we do. - if (new_timer->callback == NULL) { - free(new_timer); + if (timer->callback == NULL) { + free(timer); errno = EINVAL; return -1; } @@ -159,12 +146,12 @@ int timer_create(clockid_t clock_id, sigevent* evp, timer_t* timer_id) { kernel_sigset_t old_sigset; pthread_sigmask(SIG_BLOCK, sigset.get(), old_sigset.get()); - int rc = pthread_create(&new_timer->callback_thread, &thread_attributes, __timer_thread_start, new_timer); + int rc = pthread_create(&timer->callback_thread, &thread_attributes, __timer_thread_start, timer); pthread_sigmask(SIG_SETMASK, old_sigset.get(), NULL); if (rc != 0) { - free(new_timer); + free(timer); errno = rc; return -1; } @@ -172,20 +159,19 @@ int timer_create(clockid_t clock_id, sigevent* evp, timer_t* timer_id) { sigevent se = *evp; se.sigev_signo = TIMER_SIGNAL; se.sigev_notify = SIGEV_THREAD_ID; - se.sigev_notify_thread_id = __pthread_gettid(new_timer->callback_thread); - if (__timer_create(clock_id, &se, &new_timer->kernel_timer_id) == -1) { - __timer_thread_stop(new_timer); - free(new_timer); + se.sigev_notify_thread_id = __pthread_gettid(timer->callback_thread); + if (__timer_create(clock_id, &se, &timer->kernel_timer_id) == -1) { + __timer_thread_stop(timer); return -1; } // Give the thread a meaningful name. // It can't do this itself because the kernel timer isn't created until after it's running. char name[32]; - snprintf(name, sizeof(name), "POSIX interval timer %d", to_kernel_timer_id(new_timer)); - pthread_setname_np(new_timer->callback_thread, name); + snprintf(name, sizeof(name), "POSIX interval timer %d", to_kernel_timer_id(timer)); + pthread_setname_np(timer->callback_thread, name); - *timer_id = new_timer; + *timer_id = timer; return 0; } @@ -197,14 +183,14 @@ int timer_delete(timer_t id) { } PosixTimer* timer = reinterpret_cast(id); - - // Make sure the timer's thread has exited before we free the timer data. if (timer->sigev_notify == SIGEV_THREAD) { + // Stopping the timer's thread frees the timer data when it's safe. __timer_thread_stop(timer); + } else { + // For timers without threads, we can just free right away. + free(timer); } - free(timer); - return 0; }