// http://pubs.opengroup.org/onlinepubs/9699919799/functions/timer_delete.html
int timer_delete(timer_t id) {
int rc = __timer_delete(to_kernel_timer_id(id));
if (rc == -1) {
return -1;
}
PosixTimer* timer = reinterpret_cast<PosixTimer*>(id);
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);
}
return 0;
}
// http://pubs.opengroup.org/onlinepubs/9699919799/functions/timer_getoverrun.html
int timer_getoverrun(timer_t id) {
return __timer_getoverrun(to_kernel_timer_id(id));
}
// http://pubs.opengroup.org/onlinepubs/9699919799/functions/timer_getoverrun.html
int timer_settime(timer_t id, int flags, const itimerspec* ts, itimerspec* ots) {
return __timer_settime(to_kernel_timer_id(id), flags, ts, ots);
}
// http://pubs.opengroup.org/onlinepubs/9699919799/functions/timer_getoverrun.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_create.html
int timer_create(clockid_t clock_id, sigevent* evp, timer_t* timer_id) {
PosixTimer* timer = reinterpret_cast<PosixTimer*>(malloc(sizeof(PosixTimer)));
if (timer == NULL) {
return -1;
}
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 (timer->sigev_notify != SIGEV_THREAD) {
if (__timer_create(clock_id, evp, &timer->kernel_timer_id) == -1) {
free(timer);
return -1;
}
*timer_id = timer;
return 0;
}
// Otherwise, this must be SIGEV_THREAD timer...
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 (timer->callback == NULL) {
free(timer);
errno = EINVAL;
return -1;
}
// Create this timer's thread.
pthread_attr_t thread_attributes;
if (evp->sigev_notify_attributes == NULL) {
pthread_attr_init(&thread_attributes);
} else {
thread_attributes = *reinterpret_cast<pthread_attr_t*>(evp->sigev_notify_attributes);
}
pthread_attr_setdetachstate(&thread_attributes, PTHREAD_CREATE_DETACHED);
// We start the thread with TIMER_SIGNAL blocked by blocking the signal here and letting it
// inherit. If it tried to block the signal itself, there would be a race.
kernel_sigset_t sigset;
sigaddset(sigset.get(), TIMER_SIGNAL);
kernel_sigset_t old_sigset;
pthread_sigmask(SIG_BLOCK, sigset.get(), old_sigset.get());
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(timer);
errno = rc;
return -1;
}
sigevent se = *evp;
se.sigev_signo = TIMER_SIGNAL;
se.sigev_notify = SIGEV_THREAD_ID;
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(timer));
pthread_setname_np(timer->callback_thread, name);
*timer_id = timer;
return 0;
}
// http://pubs.opengroup.org/onlinepubs/9699919799/functions/timer_create.html
int timer_create(clockid_t clock_id, sigevent* evp, timer_t* timer_id) {
PosixTimer* timer = reinterpret_cast<PosixTimer*>(malloc(sizeof(PosixTimer)));
if (timer == nullptr) {
return -1;
}
timer->sigev_notify = (evp == nullptr) ? SIGEV_SIGNAL : evp->sigev_notify;
// If not a SIGEV_THREAD timer, the kernel can handle it without our help.
if (timer->sigev_notify != SIGEV_THREAD) {
if (__timer_create(clock_id, evp, &timer->kernel_timer_id) == -1) {
free(timer);
return -1;
}
*timer_id = timer;
return 0;
}
// Otherwise, this must be SIGEV_THREAD timer...
timer->callback = evp->sigev_notify_function;
timer->callback_argument = evp->sigev_value;
atomic_init(&timer->deleted, false);
// Check arguments that the kernel doesn't care about but we do.
if (timer->callback == nullptr) {
free(timer);
errno = EINVAL;
return -1;
}
// Create this timer's thread.
pthread_attr_t thread_attributes;
if (evp->sigev_notify_attributes == nullptr) {
pthread_attr_init(&thread_attributes);
} else {
thread_attributes = *reinterpret_cast<pthread_attr_t*>(evp->sigev_notify_attributes);
}
pthread_attr_setdetachstate(&thread_attributes, PTHREAD_CREATE_DETACHED);
// We start the thread with TIMER_SIGNAL blocked by blocking the signal here and letting it
// inherit. If it tried to block the signal itself, there would be a race.
sigset64_t sigset = {};
sigaddset64(&sigset, TIMER_SIGNAL);
sigset64_t old_sigset;
// Use __rt_sigprocmask instead of sigprocmask64 to avoid filtering out TIMER_SIGNAL.
__rt_sigprocmask(SIG_BLOCK, &sigset, &old_sigset, sizeof(sigset));
int rc = pthread_create(&timer->callback_thread, &thread_attributes, __timer_thread_start, timer);
__rt_sigprocmask(SIG_SETMASK, &old_sigset, nullptr, sizeof(old_sigset));
if (rc != 0) {
free(timer);
errno = rc;
return -1;
}
sigevent se = *evp;
se.sigev_signo = TIMER_SIGNAL;
se.sigev_notify = SIGEV_THREAD_ID;
se.sigev_notify_thread_id = pthread_gettid_np(timer->callback_thread);
if (__timer_create(clock_id, &se, &timer->kernel_timer_id) == -1) {
__timer_thread_stop(timer);
return -1;
}
// Give the thread a specific meaningful name.
// It can't do this itself because the kernel timer isn't created until after it's running.
char name[16]; // 16 is the kernel-imposed limit.
snprintf(name, sizeof(name), "POSIX timer %d", to_kernel_timer_id(timer));
pthread_setname_np(timer->callback_thread, name);
*timer_id = timer;
return 0;
}