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for SIGEV_THREAD timer threads, replace signal handler with sigwaitinfo
authorRich Felker <dalias@aerifal.cx>
Fri, 15 Feb 2019 20:23:11 +0000 (15:23 -0500)
committerRich Felker <dalias@aerifal.cx>
Fri, 15 Feb 2019 20:23:11 +0000 (15:23 -0500)
this eliminates some ugly hacks that were repurposing the start
function and start argument fields in the pthread structure for timer
use, and the need to longjmp out of a signal handler.

src/time/timer_create.c
src/time/timer_delete.c

index d9fbaee..9421957 100644 (file)
@@ -34,16 +34,6 @@ static void cleanup_fromsig(void *p)
 
 static void timer_handler(int sig, siginfo_t *si, void *ctx)
 {
-       pthread_t self = __pthread_self();
-       jmp_buf jb;
-       void (*notify)(union sigval) = (void (*)(union sigval))self->start;
-       union sigval val = { .sival_ptr = self->start_arg };
-
-       if (!setjmp(jb) && si->si_code == SI_TIMER) {
-               pthread_cleanup_push(cleanup_fromsig, jb);
-               notify(val);
-               pthread_cleanup_pop(1);
-       }
 }
 
 static void install_handler()
@@ -59,20 +49,24 @@ static void *start(void *arg)
 {
        pthread_t self = __pthread_self();
        struct start_args *args = arg;
-       int id;
+       int id = self->timer_id;
+       jmp_buf jb;
 
-       /* Reuse no-longer-needed thread structure fields to avoid
-        * needing the timer address in the signal handler. */
-       self->start = (void *(*)(void *))args->sev->sigev_notify_function;
-       self->start_arg = args->sev->sigev_value.sival_ptr;
+       void (*notify)(union sigval) = args->sev->sigev_notify_function;
+       union sigval val = args->sev->sigev_value;
 
        pthread_barrier_wait(&args->b);
-       if ((id = self->timer_id) >= 0) {
-               __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK,
-                       SIGTIMER_SET, 0, _NSIG/8);
-               __wait(&self->timer_id, 0, id, 1);
-               __syscall(SYS_timer_delete, id);
+       for (;;) {
+               siginfo_t si;
+               while (sigwaitinfo(SIGTIMER_SET, &si) < 0);
+               if (si.si_code == SI_TIMER && !setjmp(jb)) {
+                       pthread_cleanup_push(cleanup_fromsig, jb);
+                       notify(val);
+                       pthread_cleanup_pop(1);
+               }
+               if (self->timer_id < 0) break;
        }
+       __syscall(SYS_timer_delete, id);
        return 0;
 }
 
@@ -112,6 +106,7 @@ int timer_create(clockid_t clk, struct sigevent *restrict evp, timer_t *restrict
                args.sev = evp;
 
                __block_app_sigs(&set);
+               __syscall(SYS_rt_sigprocmask, SIG_BLOCK, SIGTIMER_SET, 0, _NSIG/8);
                r = pthread_create(&td, &attr, start, &args);
                __restore_sigs(&set);
                if (r) {
index 7c97eeb..b0bfac0 100644 (file)
@@ -7,7 +7,7 @@ int timer_delete(timer_t t)
        if ((intptr_t)t < 0) {
                pthread_t td = (void *)((uintptr_t)t << 1);
                a_store(&td->timer_id, td->timer_id | INT_MIN);
-               __wake(&td->timer_id, 1, 1);
+               __syscall(SYS_tkill, td->tid, SIGTIMER);
                return 0;
        }
        return __syscall(SYS_timer_delete, t);