diplodocus.org Git - nmh/blob - sbr/push.c

   1 /* push.c -- push a fork into the background
   2  *
   3  * This code is Copyright (c) 2002, by the authors of nmh.  See the
   4  * COPYRIGHT file in the root directory of the nmh distribution for
   5  * complete copyright information.
   6  */
   7
   8 #include <h/mh.h>
   9 #include <h/signals.h>
  10 #include "m_mktemp.h"
  11
  12
  13 void
  14 push(void)
  15 {
  16     pid_t pid;
  17     int i;
  18
  19     for (i = 0; (pid = fork()) == -1 && i < 5; i++)
  20         sleep (5);
  21
  22     switch (pid) {
  23         case -1:
  24             /* fork error */
  25             inform("unable to fork, so can't push...");
  26             break;
  27
  28         case 0:
  29             /* child, block a few signals and continue */
  30             SIGNAL (SIGHUP, SIG_IGN);
  31             SIGNAL (SIGINT, SIG_IGN);
  32             SIGNAL (SIGQUIT, SIG_IGN);
  33             SIGNAL (SIGTERM, SIG_IGN);
  34 #ifdef SIGTSTP
  35             SIGNAL (SIGTSTP, SIG_IGN);
  36             SIGNAL (SIGTTIN, SIG_IGN);
  37             SIGNAL (SIGTTOU, SIG_IGN);
  38 #endif
  39
  40             unregister_for_removal(0);
  41
  42             if (freopen ("/dev/null", "r", stdin) == NULL) {
  43                 advise ("stdin", "freopen");
  44             }
  45             if (freopen ("/dev/null", "w", stdout) == NULL) {
  46                 advise ("stdout", "freopen");
  47             }
  48             break;
  49
  50         default:
  51             /* parent, just exit */
  52             done (0);
  53     }
  54 }