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

   1 #include <time.h>
   2 #include "pthread_impl.h"
   3
   4 struct ksigevent {
   5         union sigval sigev_value;
   6         int sigev_signo;
   7         int sigev_notify;
   8         int sigev_tid;
   9 };
  10
  11 struct start_args {
  12         pthread_barrier_t b;
  13         struct sigevent *sev;
  14 };
  15
  16 void __sigtimer_handler(pthread_t self)
  17 {
  18         int st;
  19         void (*notify)(union sigval) = (void (*)(union sigval))self->start;
  20         union sigval val = { .sival_ptr = self->start_arg };
  21
  22         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &st);
  23         notify(val);
  24         pthread_setcancelstate(st, 0);
  25 }
  26
  27 static void *start(void *arg)
  28 {
  29         pthread_t self = __pthread_self();
  30         struct start_args *args = arg;
  31
  32         /* Reuse no-longer-needed thread structure fields to avoid
  33          * needing the timer address in the signal handler. */
  34         self->start = (void *(*)(void *))args->sev->sigev_notify_function;
  35         self->start_arg = args->sev->sigev_value.sival_ptr;
  36         self->result = (void *)-1;
  37
  38         pthread_barrier_wait(&args->b);
  39         pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, 0);
  40         /* Loop on async-signal-safe cancellation point */
  41         for (;;) sleep(1);
  42         return 0;
  43 }
  44
  45 int timer_create(clockid_t clk, struct sigevent *evp, timer_t *res)
  46 {
  47         struct sigevent sev = {
  48                 .sigev_notify = SIGEV_SIGNAL,
  49                 .sigev_signo = SIGALRM
  50         };
  51         pthread_t td;
  52         pthread_attr_t attr;
  53         int r;
  54         struct start_args args;
  55         timer_t t;
  56         struct ksigevent ksev;
  57         int timerid;
  58
  59         if (evp) sev = *evp;
  60
  61         switch (sev.sigev_notify) {
  62         case SIGEV_NONE:
  63         case SIGEV_SIGNAL:
  64                 ksev.sigev_value = evp ? sev.sigev_value
  65                         : (union sigval){.sival_ptr=t};
  66                 ksev.sigev_signo = sev.sigev_signo;
  67                 ksev.sigev_notify = sev.sigev_notify;
  68                 ksev.sigev_tid = 0;
  69                 if (syscall(SYS_timer_create, clk, &ksev, &timerid) < 0)
  70                         return -1;
  71                 *res = (void *)(2*timerid+1);
  72                 break;
  73         case SIGEV_THREAD:
  74                 if (sev.sigev_notify_attributes)
  75                         attr = *sev.sigev_notify_attributes;
  76                 else
  77                         pthread_attr_init(&attr);
  78                 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
  79                 pthread_barrier_init(&args.b, 0, 2);
  80                 args.sev = &sev;
  81                 r = pthread_create(&td, &attr, start, &args);
  82                 if (r) {
  83                         errno = r;
  84                         return -1;
  85                 }
  86                 ksev.sigev_value.sival_ptr = 0;
  87                 ksev.sigev_signo = SIGCANCEL;
  88                 ksev.sigev_notify = 4; /* SIGEV_THREAD_ID */
  89                 ksev.sigev_tid = td->tid;
  90                 r = syscall(SYS_timer_create, clk, &ksev, &timerid);
  91                 pthread_barrier_wait(&args.b);
  92                 if (r < 0) {
  93                         pthread_cancel(td);
  94                         return -1;
  95                 }
  96                 td->result = (void *)timerid;
  97                 *res = td;
  98                 break;
  99         default:
 100                 errno = EINVAL;
 101                 return -1;
 102         }
 103
 104         return 0;
 105 }