1 /* $NetBSD: waitpid.c,v 1.1.1.1 2016/01/13 03:15:30 christos Exp $ */
2
3 /* Emulate waitpid on systems that just have wait.
4 Copyright (C) 1994, 1995, 1998, 1999 Free Software Foundation, Inc.
5
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
9 any later version.
10
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program; see the file COPYING.
18 If not, write to the Free Software Foundation,
19 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
20
21 #if HAVE_CONFIG_H
22 # include <config.h>
23 #endif
24
25 #include <errno.h>
26 #ifndef errno
27 extern int errno;
28 #endif
29
30 #define WAITPID_CHILDREN 8
31 static pid_t waited_pid[WAITPID_CHILDREN];
32 static int waited_status[WAITPID_CHILDREN];
33
34 pid_t
waitpid(pid_t pid,int * stat_loc,int options)35 waitpid (pid_t pid, int *stat_loc, int options)
36 {
37 int i;
38 pid_t p;
39
40 if (!options && (pid == -1 || 0 < pid))
41 {
42 /* If we have already waited for this child, return it immediately. */
43 for (i = 0; i < WAITPID_CHILDREN; i++)
44 {
45 p = waited_pid[i];
46 if (p && (p == pid || pid == -1))
47 {
48 waited_pid[i] = 0;
49 goto success;
50 }
51 }
52
53 /* The child has not returned yet; wait for it, accumulating status. */
54 for (i = 0; i < WAITPID_CHILDREN; i++)
55 if (! waited_pid[i])
56 {
57 p = wait (&waited_status[i]);
58 if (p < 0)
59 return p;
60 if (p == pid || pid == -1)
61 goto success;
62 waited_pid[i] = p;
63 }
64 }
65
66 /* We cannot emulate this wait call, e.g. because of too many children. */
67 errno = EINVAL;
68 return -1;
69
70 success:
71 if (stat_loc)
72 *stat_loc = waited_status[i];
73 return p;
74 }
75