mirror of https://github.com/sheumann/hush.git
146 lines
3.6 KiB
C
146 lines
3.6 KiB
C
/* Emulate waitpid on systems that just have wait.
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Adapted from code in GNU Diffutils 2.8.1, with
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enhancements and changes for GNO by Stephen Heumann.
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Copyright (C) 1994, 1995, 1998, 1999 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; see the file COPYING.
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If not, write to the Free Software Foundation,
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59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <sys/signal.h>
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#include <unistd.h>
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#include <errno.h>
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#ifdef __GNO__
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typedef union wait wait_status_t;
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#else
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typedef int wait_status_t;
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#endif
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#ifndef __GNO__
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#define alarm10(tenths) ualarm((tenths) * 10000, 0)
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#endif
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#define WAITPID_CHILDREN 8
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static pid_t waited_pid[WAITPID_CHILDREN];
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static int waited_status[WAITPID_CHILDREN];
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static int ran_sighandler;
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#ifdef __ORCAC__
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# pragma databank 1
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#endif
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#ifdef __GNO__
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static void handle_alarm(int sig, int code)
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#else
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static void handle_alarm(int sig)
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#endif
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{
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/* We're racing with the call to wait(). In case we get the
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* signal before it starts, arrange to send another one.
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*/
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alarm10(2);
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ran_sighandler = 1;
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}
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#ifdef __ORCAC__
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# pragma databank 0
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#endif
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pid_t waitpid_emul (pid_t pid, int *stat_loc, int options)
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{
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int i;
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pid_t p;
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if (pid == -1 || 0 < pid) {
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/* If we have already waited for this child, return it immediately. */
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for (i = 0; i < WAITPID_CHILDREN; i++) {
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p = waited_pid[i];
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if (p && (p == pid || pid == -1)) {
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waited_pid[i] = 0;
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goto success;
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}
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}
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/* The child has not returned yet; wait for it, accumulating status. */
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for (i = 0; i < WAITPID_CHILDREN; i++) {
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if (! waited_pid[i]) {
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sig_t prev_sig;
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int prev_errno;
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restart:
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if (options & WNOHANG) {
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/* Arrange for a signal to interrupt the wait to simulate
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* non-blocking semantics. This might cause spurious
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* failures to detect finished children if the wait() call
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* is slow, but this is about the best we can do.
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*/
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prev_errno = errno;
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ran_sighandler = 0;
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prev_sig = signal(SIGALRM, handle_alarm);
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alarm10(2);
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}
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p = wait ((wait_status_t*)&waited_status[i]);
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if (options & WNOHANG) {
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int wait_errno = errno;
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alarm10(0);
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signal(SIGALRM, prev_sig);
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if (p == -1 && wait_errno == EINTR && ran_sighandler) {
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/* Assume we were interrupted by our alarm, so treat this
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* as a successful return with no finished child found. */
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errno = prev_errno;
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return 0;
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} else {
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errno = wait_errno;
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}
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}
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if (p == -1 && errno == EINTR) {
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/* Hush originally set SA_RESTART option on all caught signals.
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* GNO doesn't have this, so try to emulate it here. */
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goto restart;
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}
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if (p < 0)
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return p;
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if (p == pid || pid == -1)
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goto success;
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waited_pid[i] = p;
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}
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}
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}
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/* We cannot emulate this wait call, e.g. because of too many children. */
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errno = EINVAL;
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return -1;
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success:
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if (stat_loc)
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*stat_loc = waited_status[i];
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return p;
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}
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pid_t wait_emul (int *stat_loc)
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{
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return waitpid_emul(-1, stat_loc, 0);
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}
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