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 cleanup(void *p)
  28 {
  29         pthread_t self = p;
  30         __syscall(SYS_timer_delete, self->result);
  31 }
  32
  33 static void *start(void *arg)
  34 {
  35         pthread_t self = __pthread_self();
  36         struct start_args *args = arg;
  37
  38         /* Reuse no-longer-needed thread structure fields to avoid
  39          * needing the timer address in the signal handler. */
  40         self->start = (void *(*)(void *))args->sev->sigev_notify_function;
  41         self->start_arg = args->sev->sigev_value.sival_ptr;
  42         self->result = (void *)-1;
  43
  44         pthread_cleanup_push(cleanup, self);
  45         pthread_barrier_wait(&args->b);
  46         pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, 0);
  47         /* Loop on async-signal-safe cancellation point */
  48         for (;;) sleep(1000000000);
  49         pthread_cleanup_pop(0);
  50         return 0;
  51 }
  52
  53 int timer_create(clockid_t clk, struct sigevent *evp, timer_t *res)
  54 {
  55         pthread_t td;
  56         pthread_attr_t attr;
  57         int r;
  58         struct start_args args;
  59         struct ksigevent ksev, *ksevp=0;
  60         int timerid;
  61
  62         switch (evp ? evp->sigev_notify : SIGEV_SIGNAL) {
  63         case SIGEV_NONE:
  64         case SIGEV_SIGNAL:
  65                 if (evp) {
  66                         ksev.sigev_value = evp->sigev_value;
  67                         ksev.sigev_signo = evp->sigev_signo;
  68                         ksev.sigev_notify = evp->sigev_notify;
  69                         ksev.sigev_tid = 0;
  70                         ksevp = &ksev;
  71                 }
  72                 if (syscall(SYS_timer_create, clk, ksevp, &timerid) < 0)
  73                         return -1;
  74                 *res = (void *)timerid;
  75                 break;
  76         case SIGEV_THREAD:
  77                 if (evp->sigev_notify_attributes)
  78                         attr = *evp->sigev_notify_attributes;
  79                 else
  80                         pthread_attr_init(&attr);
  81                 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
  82                 pthread_barrier_init(&args.b, 0, 2);
  83                 args.sev = evp;
  84                 r = pthread_create(&td, &attr, start, &args);
  85                 if (r) {
  86                         errno = r;
  87                         return -1;
  88                 }
  89                 ksev.sigev_value.sival_ptr = 0;
  90                 ksev.sigev_signo = SIGCANCEL;
  91                 ksev.sigev_notify = 4; /* SIGEV_THREAD_ID */
  92                 ksev.sigev_tid = td->tid;
  93                 r = syscall(SYS_timer_create, clk, &ksev, &timerid);
  94                 pthread_barrier_wait(&args.b);
  95                 if (r < 0) {
  96                         pthread_cancel(td);
  97                         return -1;
  98                 }
  99                 td->result = (void *)timerid;
 100                 *res = td;
 101                 break;
 102         default:
 103                 errno = EINVAL;
 104                 return -1;
 105         }
 106
 107         return 0;
 108 }