nsz Git - musl/blob - src/time/timer_create.c

   1 #include <time.h>
   2 #include <setjmp.h>
   3 #include <limits.h>
   4 #include "pthread_impl.h"
   5 #include "atomic.h"
   6
   7 struct ksigevent {
   8         union sigval sigev_value;
   9         int sigev_signo;
  10         int sigev_notify;
  11         int sigev_tid;
  12 };
  13
  14 struct start_args {
  15         pthread_barrier_t b;
  16         struct sigevent *sev;
  17 };
  18
  19 static void dummy_0()
  20 {
  21 }
  22 weak_alias(dummy_0, __pthread_tsd_run_dtors);
  23
  24 static void cleanup_fromsig(void *p)
  25 {
  26         pthread_t self = __pthread_self();
  27         __pthread_tsd_run_dtors();
  28         self->cancel = 0;
  29         self->cancelbuf = 0;
  30         self->canceldisable = 0;
  31         self->cancelasync = 0;
  32         __reset_tls();
  33         longjmp(p, 1);
  34 }
  35
  36 static void *start(void *arg)
  37 {
  38         pthread_t self = __pthread_self();
  39         struct start_args *args = arg;
  40         jmp_buf jb;
  41
  42         void (*notify)(union sigval) = args->sev->sigev_notify_function;
  43         union sigval val = args->sev->sigev_value;
  44
  45         pthread_barrier_wait(&args->b);
  46         for (;;) {
  47                 siginfo_t si;
  48                 while (sigwaitinfo(SIGTIMER_SET, &si) < 0);
  49                 if (si.si_code == SI_TIMER && !setjmp(jb)) {
  50                         pthread_cleanup_push(cleanup_fromsig, jb);
  51                         notify(val);
  52                         pthread_cleanup_pop(1);
  53                 }
  54                 if (self->timer_id < 0) break;
  55         }
  56         __syscall(SYS_timer_delete, self->timer_id & INT_MAX);
  57         return 0;
  58 }
  59
  60 int timer_create(clockid_t clk, struct sigevent *restrict evp, timer_t *restrict res)
  61 {
  62         volatile static int init = 0;
  63         pthread_t td;
  64         pthread_attr_t attr;
  65         int r;
  66         struct start_args args;
  67         struct ksigevent ksev, *ksevp=0;
  68         int timerid;
  69         sigset_t set;
  70
  71         switch (evp ? evp->sigev_notify : SIGEV_SIGNAL) {
  72         case SIGEV_NONE:
  73         case SIGEV_SIGNAL:
  74                 if (evp) {
  75                         ksev.sigev_value = evp->sigev_value;
  76                         ksev.sigev_signo = evp->sigev_signo;
  77                         ksev.sigev_notify = evp->sigev_notify;
  78                         ksev.sigev_tid = 0;
  79                         ksevp = &ksev;
  80                 }
  81                 if (syscall(SYS_timer_create, clk, ksevp, &timerid) < 0)
  82                         return -1;
  83                 *res = (void *)(intptr_t)timerid;
  84                 break;
  85         case SIGEV_THREAD:
  86                 if (!init) {
  87                         struct sigaction sa = { .sa_handler = SIG_DFL };
  88                         __libc_sigaction(SIGTIMER, &sa, 0);
  89                         a_store(&init, 1);
  90                 }
  91                 if (evp->sigev_notify_attributes)
  92                         attr = *evp->sigev_notify_attributes;
  93                 else
  94                         pthread_attr_init(&attr);
  95                 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
  96                 pthread_barrier_init(&args.b, 0, 2);
  97                 args.sev = evp;
  98
  99                 __block_app_sigs(&set);
 100                 __syscall(SYS_rt_sigprocmask, SIG_BLOCK, SIGTIMER_SET, 0, _NSIG/8);
 101                 r = pthread_create(&td, &attr, start, &args);
 102                 __restore_sigs(&set);
 103                 if (r) {
 104                         errno = r;
 105                         return -1;
 106                 }
 107
 108                 ksev.sigev_value.sival_ptr = 0;
 109                 ksev.sigev_signo = SIGTIMER;
 110                 ksev.sigev_notify = 4; /* SIGEV_THREAD_ID */
 111                 ksev.sigev_tid = td->tid;
 112                 if (syscall(SYS_timer_create, clk, &ksev, &timerid) < 0)
 113                         timerid = -1;
 114                 td->timer_id = timerid;
 115                 pthread_barrier_wait(&args.b);
 116                 if (timerid < 0) return -1;
 117                 *res = (void *)(INTPTR_MIN | (uintptr_t)td>>1);
 118                 break;
 119         default:
 120                 errno = EINVAL;
 121                 return -1;
 122         }
 123
 124         return 0;
 125 }