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