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Merge "Change on handling of SIGEV_THREAD timers."

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This commit is contained in:
Yabin Cui
2015-04-16 01:08:24 +00:00
committed by Gerrit Code Review
parent c6ccdfaf1f 95f1ee235a
commit 2587c6a2f0
2 changed files with 92 additions and 92 deletions
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42
libc/bionic/posix_timers.cpp
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@@ -26,14 +26,15 @@
* SUCH DAMAGE.
*/
#include "pthread_internal.h"
#include "private/bionic_futex.h"
#include "private/kernel_sigset_t.h"
#include <errno.h>
#include <malloc.h>
#include <pthread.h>
#include <stdatomic.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
// System calls.
extern "C" int __rt_sigtimedwait(const sigset_t*, siginfo_t*, const struct timespec*, size_t);
@@ -59,11 +60,11 @@ struct PosixTimer {
int sigev_notify;
// These fields are only needed for a SIGEV_THREAD timer.
// The fields below are only needed for a SIGEV_THREAD timer.
pthread_t callback_thread;
void (*callback)(sigval_t);
sigval_t callback_argument;
volatile bool armed;
atomic_bool deleted; // Set when the timer is deleted, to prevent further calling of callback.
};
static __kernel_timer_t to_kernel_timer_id(timer_t timer) {
@@ -85,8 +86,13 @@ static void* __timer_thread_start(void* arg) {
continue;
}
if (si.si_code == SI_TIMER && timer->armed) {
if (si.si_code == SI_TIMER) {
// This signal was sent because a timer fired, so call the callback.
// All events to the callback will be ignored when the timer is deleted.
if (atomic_load(&timer->deleted) == true) {
continue;
}
timer->callback(timer->callback_argument);
} else if (si.si_code == SI_TKILL) {
// This signal was sent because someone wants us to exit.
@@ -97,9 +103,7 @@ static void* __timer_thread_start(void* arg) {
}
static void __timer_thread_stop(PosixTimer* timer) {
// Immediately mark the timer as disarmed so even if some events
// continue to happen, the callback won't be called.
timer->armed = false;
atomic_store(&timer->deleted, true);
pthread_kill(timer->callback_thread, TIMER_SIGNAL);
}
@@ -126,7 +130,7 @@ int timer_create(clockid_t clock_id, sigevent* evp, timer_t* timer_id) {
// Otherwise, this must be SIGEV_THREAD timer...
timer->callback = evp->sigev_notify_function;
timer->callback_argument = evp->sigev_value;
timer->armed = false;
atomic_init(&timer->deleted, false);
// Check arguments that the kernel doesn't care about but we do.
if (timer->callback == NULL) {
@@ -199,25 +203,19 @@ int timer_delete(timer_t id) {
return 0;
}
// http://pubs.opengroup.org/onlinepubs/9699919799/functions/timer_getoverrun.html
// http://pubs.opengroup.org/onlinepubs/9699919799/functions/timer_gettime.html
int timer_gettime(timer_t id, itimerspec* ts) {
return __timer_gettime(to_kernel_timer_id(id), ts);
}
// http://pubs.opengroup.org/onlinepubs/9699919799/functions/timer_getoverrun.html
// http://pubs.opengroup.org/onlinepubs/9699919799/functions/timer_settime.html
// When using timer_settime to disarm a repeatable SIGEV_THREAD timer with a very small
// period (like below 1ms), the kernel may continue to send events to the callback thread
// for a few extra times. This behavior is fine because in POSIX standard: The effect of
// disarming or resetting a timer with pending expiration notifications is unspecified.
int timer_settime(timer_t id, int flags, const itimerspec* ts, itimerspec* ots) {
PosixTimer* timer= reinterpret_cast<PosixTimer*>(id);
int rc = __timer_settime(timer->kernel_timer_id, flags, ts, ots);
if (rc == 0) {
// Mark the timer as either being armed or disarmed. This avoids the
// callback being called after the disarm for SIGEV_THREAD timers only.
if (ts->it_value.tv_sec != 0 || ts->it_value.tv_nsec != 0) {
timer->armed = true;
} else {
timer->armed = false;
}
}
return rc;
return __timer_settime(timer->kernel_timer_id, flags, ts, ots);
}
// http://pubs.opengroup.org/onlinepubs/9699919799/functions/timer_getoverrun.html