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         if (self->cancel)
  47                 return 0;
  48         for (;;) {
  49                 siginfo_t si;
  50                 while (sigwaitinfo(SIGTIMER_SET, &si) < 0);
  51                 if (si.si_code == SI_TIMER && !setjmp(jb)) {
  52                         pthread_cleanup_push(cleanup_fromsig, jb);
  53                         notify(val);
  54                         pthread_cleanup_pop(1);
  55                 }
  56                 if (self->timer_id < 0) break;
  57         }
  58         __syscall(SYS_timer_delete, self->timer_id & INT_MAX);
  59         return 0;
  60 }
  61
  62 int timer_create(clockid_t clk, struct sigevent *restrict evp, timer_t *restrict res)
  63 {
  64         static volatile int init = 0;
  65         pthread_t td;
  66         pthread_attr_t attr;
  67         int r;
  68         struct start_args args;
  69         struct ksigevent ksev, *ksevp=0;
  70         int timerid;
  71         sigset_t set;
  72
  73         switch (evp ? evp->sigev_notify : SIGEV_SIGNAL) {
  74         case SIGEV_NONE:
  75         case SIGEV_SIGNAL:
  76         case SIGEV_THREAD_ID:
  77                 if (evp) {
  78                         ksev.sigev_value = evp->sigev_value;
  79                         ksev.sigev_signo = evp->sigev_signo;
  80                         ksev.sigev_notify = evp->sigev_notify;
  81                         if (evp->sigev_notify == SIGEV_THREAD_ID)
  82                                 ksev.sigev_tid = evp->sigev_notify_thread_id;
  83                         else
  84                                 ksev.sigev_tid = 0;
  85                         ksevp = &ksev;
  86                 }
  87                 if (syscall(SYS_timer_create, clk, ksevp, &timerid) < 0)
  88                         return -1;
  89                 *res = (void *)(intptr_t)timerid;
  90                 break;
  91         case SIGEV_THREAD:
  92                 if (!init) {
  93                         struct sigaction sa = { .sa_handler = SIG_DFL };
  94                         __libc_sigaction(SIGTIMER, &sa, 0);
  95                         a_store(&init, 1);
  96                 }
  97                 if (evp->sigev_notify_attributes)
  98                         attr = *evp->sigev_notify_attributes;
  99                 else
 100                         pthread_attr_init(&attr);
 101                 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
 102                 pthread_barrier_init(&args.b, 0, 2);
 103                 args.sev = evp;
 104
 105                 __block_app_sigs(&set);
 106                 __syscall(SYS_rt_sigprocmask, SIG_BLOCK, SIGTIMER_SET, 0, _NSIG/8);
 107                 r = pthread_create(&td, &attr, start, &args);
 108                 __restore_sigs(&set);
 109                 if (r) {
 110                         errno = r;
 111                         return -1;
 112                 }
 113
 114                 ksev.sigev_value.sival_ptr = 0;
 115                 ksev.sigev_signo = SIGTIMER;
 116                 ksev.sigev_notify = SIGEV_THREAD_ID;
 117                 ksev.sigev_tid = td->tid;
 118                 if (syscall(SYS_timer_create, clk, &ksev, &timerid) < 0) {
 119                         timerid = -1;
 120                         td->cancel = 1;
 121                 }
 122                 td->timer_id = timerid;
 123                 pthread_barrier_wait(&args.b);
 124                 if (timerid < 0) return -1;
 125                 *res = (void *)(INTPTR_MIN | (uintptr_t)td>>1);
 126                 break;
 127         default:
 128                 errno = EINVAL;
 129                 return -1;
 130         }
 131
 132         return 0;
 133 }