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
   6 struct ksigevent {
   7         union sigval sigev_value;
   8         int sigev_signo;
   9         int sigev_notify;
  10         int sigev_tid;
  11 };
  12
  13 struct start_args {
  14         pthread_barrier_t b;
  15         struct sigevent *sev;
  16 };
  17
  18 static void dummy_0()
  19 {
  20 }
  21 weak_alias(dummy_0, __pthread_tsd_run_dtors);
  22
  23 static void cleanup_fromsig(void *p)
  24 {
  25         pthread_t self = __pthread_self();
  26         __pthread_tsd_run_dtors();
  27         self->cancel = 0;
  28         self->cancelbuf = 0;
  29         self->canceldisable = 0;
  30         self->cancelasync = 0;
  31         __reset_tls();
  32         longjmp(p, 1);
  33 }
  34
  35 static void install_handler()
  36 {
  37         struct sigaction sa = {
  38                 .sa_handler = SIG_DFL,
  39         };
  40         __libc_sigaction(SIGTIMER, &sa, 0);
  41 }
  42
  43 static void *start(void *arg)
  44 {
  45         pthread_t self = __pthread_self();
  46         struct start_args *args = arg;
  47         jmp_buf jb;
  48
  49         void (*notify)(union sigval) = args->sev->sigev_notify_function;
  50         union sigval val = args->sev->sigev_value;
  51
  52         pthread_barrier_wait(&args->b);
  53         for (;;) {
  54                 siginfo_t si;
  55                 while (sigwaitinfo(SIGTIMER_SET, &si) < 0);
  56                 if (si.si_code == SI_TIMER && !setjmp(jb)) {
  57                         pthread_cleanup_push(cleanup_fromsig, jb);
  58                         notify(val);
  59                         pthread_cleanup_pop(1);
  60                 }
  61                 if (self->timer_id < 0) break;
  62         }
  63         __syscall(SYS_timer_delete, self->timer_id & INT_MAX);
  64         return 0;
  65 }
  66
  67 int timer_create(clockid_t clk, struct sigevent *restrict evp, timer_t *restrict res)
  68 {
  69         static pthread_once_t once = PTHREAD_ONCE_INIT;
  70         pthread_t td;
  71         pthread_attr_t attr;
  72         int r;
  73         struct start_args args;
  74         struct ksigevent ksev, *ksevp=0;
  75         int timerid;
  76         sigset_t set;
  77
  78         switch (evp ? evp->sigev_notify : SIGEV_SIGNAL) {
  79         case SIGEV_NONE:
  80         case SIGEV_SIGNAL:
  81                 if (evp) {
  82                         ksev.sigev_value = evp->sigev_value;
  83                         ksev.sigev_signo = evp->sigev_signo;
  84                         ksev.sigev_notify = evp->sigev_notify;
  85                         ksev.sigev_tid = 0;
  86                         ksevp = &ksev;
  87                 }
  88                 if (syscall(SYS_timer_create, clk, ksevp, &timerid) < 0)
  89                         return -1;
  90                 *res = (void *)(intptr_t)timerid;
  91                 break;
  92         case SIGEV_THREAD:
  93                 pthread_once(&once, install_handler);
  94                 if (evp->sigev_notify_attributes)
  95                         attr = *evp->sigev_notify_attributes;
  96                 else
  97                         pthread_attr_init(&attr);
  98                 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
  99                 pthread_barrier_init(&args.b, 0, 2);
 100                 args.sev = evp;
 101
 102                 __block_app_sigs(&set);
 103                 __syscall(SYS_rt_sigprocmask, SIG_BLOCK, SIGTIMER_SET, 0, _NSIG/8);
 104                 r = pthread_create(&td, &attr, start, &args);
 105                 __restore_sigs(&set);
 106                 if (r) {
 107                         errno = r;
 108                         return -1;
 109                 }
 110
 111                 ksev.sigev_value.sival_ptr = 0;
 112                 ksev.sigev_signo = SIGTIMER;
 113                 ksev.sigev_notify = 4; /* SIGEV_THREAD_ID */
 114                 ksev.sigev_tid = td->tid;
 115                 if (syscall(SYS_timer_create, clk, &ksev, &timerid) < 0)
 116                         timerid = -1;
 117                 td->timer_id = timerid;
 118                 pthread_barrier_wait(&args.b);
 119                 if (timerid < 0) return -1;
 120                 *res = (void *)(INTPTR_MIN | (uintptr_t)td>>1);
 121                 break;
 122         default:
 123                 errno = EINVAL;
 124                 return -1;
 125         }
 126
 127         return 0;
 128 }