lib/nanosleep.c

   1 /* Provide a replacement for the POSIX nanosleep function.
   2    Copyright (C) 1999, 2000 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 /* written by Jim Meyering */
  19
  20 #include <config.h>
  21 #include <stdio.h>
  22 #include <sys/types.h>
  23 #include <signal.h>
  24
  25 #include <errno.h>
  26 #ifndef errno
  27 extern int errno;
  28 #endif
  29
  30 #if HAVE_UNISTD_H
  31 # include <unistd.h>
  32 #endif
  33
  34 #include "nanosleep.h"
  35
  36 static int suspended;
  37 int first_call = 1;
  38
  39 /* Handle SIGCONT. */
  40
  41 static void
  42 sighandler (int sig)
  43 {
  44   suspended = 1;
  45 }
  46
  47 /* FIXME: comment */
  48
  49 static void
  50 my_usleep (const struct timespec *ts_delay)
  51 {
  52   struct timeval tv_delay;
  53   tv_delay.tv_sec = ts_delay->tv_sec;
  54   tv_delay.tv_usec = ts_delay->tv_nsec / 1000;
  55   select (0, (void *) 0, (void *) 0, (void *) 0, &tv_delay);
  56 }
  57
  58 /* FIXME: comment */
  59
  60 int
  61 nanosleep (const struct timespec *requested_delay,
  62            struct timespec *remaining_delay)
  63 {
  64 #ifdef SA_INTERRUPT
  65   struct sigaction oldact, newact;
  66 #endif
  67
  68   suspended = 0;
  69
  70   /* set up sig handler */
  71   if (first_call)
  72     {
  73 #ifdef SA_INTERRUPT
  74       newact.sa_handler = sighandler;
  75       sigemptyset (&newact.sa_mask);
  76       newact.sa_flags = 0;
  77
  78       sigaction (SIGCONT, NULL, &oldact);
  79       if (oldact.sa_handler != SIG_IGN)
  80         sigaction (SIGCONT, &newact, NULL);
  81 #else
  82       if (signal (SIGCONT, SIG_IGN) != SIG_IGN)
  83         signal (SIGCONT, sighandler);
  84 #endif
  85       first_call = 0;
  86     }
  87
  88   my_usleep (requested_delay);
  89
  90   if (suspended)
  91     {
  92       /* Calculate time remaining.  */
  93       /* FIXME: the code in sleep doesn't use this, so there's no
  94          rush to implement it.  */
  95
  96       errno = EINTR;
  97     }
  98
  99   /* FIXME: Restore sig handler?  */
 100
 101   return suspended;
 102 }