1/* Emulate waitpid on systems that just have wait. 2 Copyright (C) 1994, 1995, 1998, 1999 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; see the file COPYING. 16 If not, write to the Free Software Foundation, 17 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ 18 19#if HAVE_CONFIG_H 20# include <config.h> 21#endif 22 23#include <sys/types.h> 24#include <errno.h> 25#ifndef errno 26extern int errno; 27#endif 28 29#define WAITPID_CHILDREN 8 30static pid_t waited_pid[WAITPID_CHILDREN]; 31static int waited_status[WAITPID_CHILDREN]; 32 33pid_t 34waitpid (pid_t pid, int *stat_loc, int options) 35{ 36 int i; 37 pid_t p; 38 39 if (!options && (pid == -1 || 0 < pid)) 40 { 41 /* If we have already waited for this child, return it immediately. */ 42 for (i = 0; i < WAITPID_CHILDREN; i++) 43 { 44 p = waited_pid[i]; 45 if (p && (p == pid || pid == -1)) 46 { 47 waited_pid[i] = 0; 48 goto success; 49 } 50 } 51 52 /* The child has not returned yet; wait for it, accumulating status. */ 53 for (i = 0; i < WAITPID_CHILDREN; i++) 54 if (! waited_pid[i]) 55 { 56 p = wait (&waited_status[i]); 57 if (p < 0) 58 return p; 59 if (p == pid || pid == -1) 60 goto success; 61 waited_pid[i] = p; 62 } 63 } 64 65 /* We cannot emulate this wait call, e.g. because of too many children. */ 66 errno = EINVAL; 67 return -1; 68 69success: 70 if (stat_loc) 71 *stat_loc = waited_status[i]; 72 return p; 73} 74