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 27extern int errno; 28#endif 29 30#define WAITPID_CHILDREN 8 31static pid_t waited_pid[WAITPID_CHILDREN]; 32static int waited_status[WAITPID_CHILDREN]; 33 34pid_t 35waitpid (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 70success: 71 if (stat_loc) 72 *stat_loc = waited_status[i]; 73 return p; 74} 75