external/gpl2/xcvs/dist/lib/waitpid.c

   1 #ifdef HAVE_CONFIG_H
   2 #include "config.h"
   3 #endif
   4
   5 #include "system.h"
   6 #include "wait.h"
   7
   8 #include <stdio.h>
   9
  10 struct unreaped {
  11   pid_t pid;
  12   int status;
  13 };
  14 static struct unreaped *unreaped;
  15 static int n;
  16
  17 static struct unreaped *ualloc (oldptr, n)
  18      struct unreaped *oldptr;
  19      int n;
  20 {
  21   n *= sizeof (struct unreaped);
  22   if (n == 0)
  23     n = 1;
  24   if (oldptr)
  25     oldptr = (struct unreaped *) realloc ((char *) oldptr, n);
  26   else
  27     oldptr = (struct unreaped *) malloc (n);
  28   if (oldptr == 0)
  29     {
  30       fprintf (stderr, "cannot allocate %d bytes\n", n);
  31       exit (1);
  32     }
  33   return oldptr;
  34 }
  35
  36 pid_t waitpid (pid, status, options)
  37      pid_t pid;
  38      int *status;
  39      int options;
  40 {
  41   int i;
  42
  43   /* initialize */
  44   if (unreaped == 0)
  45     {
  46       unreaped = ualloc (unreaped, 1);
  47       unreaped[0].pid = 0;
  48       n = 1;
  49     }
  50
  51   for (i = 0; unreaped[i].pid; i++)
  52     if (unreaped[i].pid == pid)
  53       {
  54         *status = unreaped[i].status;
  55         while (unreaped[i].pid)
  56           {
  57             unreaped[i] = unreaped[i+1];
  58             i++;
  59           }
  60         n--;
  61         return pid;
  62       }
  63
  64   while (1)
  65     {
  66 #ifdef HAVE_WAIT3
  67       pid_t p = wait3 (status, options, (struct rusage *) 0);
  68 #else
  69       pid_t p = wait (status);
  70 #endif
  71
  72       if (p == 0 || p == -1 || p == pid)
  73         return p;
  74
  75       n++;
  76       unreaped = ualloc (unreaped, n);
  77       unreaped[n-1].pid = p;
  78       unreaped[n-1].status = *status;
  79     }
  80 }