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am 05ed7048: am 1f136571: Merge "Fix the POSIX timers fix."

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* commit '05ed7048ad9be79bdbf27d076a4d8cd4000f7e98':
  Fix the POSIX timers fix.
This commit is contained in:
Elliott Hughes 2014-04-02 16:36:28 +00:00 committed by Android Git Automerger
commit 130a02e116
1 changed files with 24 additions and 38 deletions
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62
libc/bionic/posix_timers.cpp
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@ -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<PosixTimer*>(malloc(sizeof(PosixTimer)));
if (new_timer == NULL) {
PosixTimer* timer = reinterpret_cast<PosixTimer*>(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<PosixTimer*>(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;
}