nptl/sysdeps/pthread/timer_settime.c

   1 /* Copyright (C) 2000, 2001 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Kaz Kylheku <kaz@ashi.footprints.net>.
   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 License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    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; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <errno.h>
  21 #include <pthread.h>
  22 #include <time.h>
  23
  24 #include "posix-timer.h"
  25
  26
  27 /* Set timer TIMERID to VALUE, returning old value in OVLAUE.  */
  28 int
  29 timer_settime (timerid, flags, value, ovalue)
  30      timer_t timerid;
  31      int flags;
  32      const struct itimerspec *value;
  33      struct itimerspec *ovalue;
  34 {
  35   struct timer_node *timer;
  36   struct thread_node *thread = NULL;
  37   struct timespec now;
  38   int have_now = 0, need_wakeup = 0;
  39   int retval = -1;
  40
  41   timer = timer_id2ptr (timerid);
  42   if (timer == NULL)
  43     {
  44       __set_errno (EINVAL);
  45       goto bail;
  46     }
  47
  48   if (value->it_interval.tv_nsec < 0
  49       || value->it_interval.tv_nsec >= 1000000000
  50       || value->it_value.tv_nsec < 0
  51       || value->it_value.tv_nsec >= 1000000000)
  52     {
  53       __set_errno (EINVAL);
  54       goto bail;
  55     }
  56
  57   /* Will need to know current time since this is a relative timer;
  58      might as well make the system call outside of the lock now! */
  59
  60   if ((flags & TIMER_ABSTIME) == 0)
  61     {
  62       clock_gettime (timer->clock, &now);
  63       have_now = 1;
  64     }
  65
  66   pthread_mutex_lock (&__timer_mutex);
  67   timer_addref (timer);
  68
  69   /* One final check of timer validity; this one is possible only
  70      until we have the mutex, because it accesses the inuse flag. */
  71
  72   if (! timer_valid(timer))
  73     {
  74       __set_errno (EINVAL);
  75       goto unlock_bail;
  76     }
  77
  78   if (ovalue != NULL)
  79     {
  80       ovalue->it_interval = timer->value.it_interval;
  81
  82       if (timer->armed)
  83         {
  84           if (! have_now)
  85             {
  86               pthread_mutex_unlock (&__timer_mutex);
  87               clock_gettime (timer->clock, &now);
  88               have_now = 1;
  89               pthread_mutex_lock (&__timer_mutex);
  90               timer_addref (timer);
  91             }
  92
  93           timespec_sub (&ovalue->it_value, &timer->expirytime, &now);
  94         }
  95       else
  96         {
  97           ovalue->it_value.tv_sec = 0;
  98           ovalue->it_value.tv_nsec = 0;
  99         }
 100     }
 101
 102   timer->value = *value;
 103
 104   list_unlink_ip (&timer->links);
 105   timer->armed = 0;
 106
 107   thread = timer->thread;
 108
 109   /* A value of { 0, 0 } causes the timer to be stopped. */
 110   if (value->it_value.tv_sec != 0
 111       || __builtin_expect (value->it_value.tv_nsec != 0, 1))
 112     {
 113       if ((flags & TIMER_ABSTIME) != 0)
 114         /* The user specified the expiration time.  */
 115         timer->expirytime = value->it_value;
 116       else
 117         timespec_add (&timer->expirytime, &now, &value->it_value);
 118
 119       /* Only need to wake up the thread if timer is inserted
 120          at the head of the queue. */
 121       if (thread != NULL)
 122         need_wakeup = __timer_thread_queue_timer (thread, timer);
 123       timer->armed = 1;
 124     }
 125
 126   retval = 0;
 127
 128 unlock_bail:
 129   timer_delref (timer);
 130   pthread_mutex_unlock (&__timer_mutex);
 131
 132 bail:
 133   if (thread != NULL && need_wakeup)
 134     __timer_thread_wakeup (thread);
 135
 136   return retval;
 137 }