1  /* Create a periodic timer.
       2     Copyright (C) 2021-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <support/check.h>
      20  #include <support/support.h>
      21  #include <support/xsignal.h>
      22  #include <time.h>
      23  
      24  static void
      25  dummy_alrm_handler (int sig)
      26  {
      27  }
      28  
      29  timer_t
      30  support_create_timer (uint64_t sec, long int nsec, bool repeat,
      31  		      void (*callback)(int))
      32  {
      33    struct sigaction sa;
      34    sa.sa_handler = callback != NULL ? callback : dummy_alrm_handler;
      35    sigemptyset (&sa.sa_mask);
      36    sa.sa_flags = 0;
      37    xsigaction (SIGALRM, &sa, NULL);
      38  
      39    struct sigevent ev = {
      40      .sigev_notify = SIGEV_SIGNAL,
      41      .sigev_signo = SIGALRM
      42    };
      43    timer_t timerid;
      44    int r = timer_create (CLOCK_REALTIME, &ev, &timerid);
      45    if (r == -1)
      46      FAIL_EXIT1 ("timer_create: %m");
      47  
      48    /* Single timer with 0.1s.  */
      49    struct itimerspec its =
      50      {
      51        { .tv_sec = repeat ? sec : 0, .tv_nsec = repeat ? nsec : 0 },
      52        { .tv_sec = sec, .tv_nsec = nsec }
      53      };
      54    r = timer_settime (timerid, 0, &its, NULL);
      55    if (r == -1)
      56      FAIL_EXIT1 ("timer_settime: %m");
      57  
      58    return timerid;
      59  }
      60  
      61  /* Disable the timer TIMER.  */
      62  void
      63  support_delete_timer (timer_t timer)
      64  {
      65    int r = timer_delete (timer);
      66    if (r == -1)
      67      FAIL_EXIT1 ("timer_delete: %m");
      68    xsignal (SIGALRM, SIG_DFL);
      69  }