1994-05-27 12:33:43 +00:00
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/*
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* Copyright (c) 1983, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Edward Wang at The University of California, Berkeley.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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static char sccsid[] = "@(#)wwspawn.c 8.1 (Berkeley) 6/6/93";
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#endif /* not lint */
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#include "ww.h"
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1998-08-05 09:01:29 +00:00
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#include <signal.h>
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1994-05-27 12:33:43 +00:00
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/*
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Make window(1) actually work again. It has been broken for quite some
time now.
For whatever reason, the kernel seems to have generated SIGIOs
previously without an initial fcntl(...,F_SETOWN), but does no longer.
This caused window(1) to wait indefinitely for input.
Also, undo rev 1.3 of wwspawn.c, it was not well-thought, and
apparently not even tested at all. The blindly (even in a nonsensical
place like the comment on top of the function) applied replacement of
vfork() by fork() totally ignored that window(1) *does* abuse the
feature of vfork() where a modification of the parent's address space
is possible (in this case, to notify the parent of an erred exec*).
Also, with vfork(), it is guaranteed that the parent is only woken up
after the exec*() happened, where the replacement by fork() made the
parent to almost always become runnable again before the child, in
which case the parent simply told `subprocess died'. Unfortunately,
working around _this_ seems to be a lot more of redesign work compared
to little gained value, so i think relying on the specifics of vfork()
is the simpler way.
Submitted by: Philipp Mergenthaler <un1i@rz.uni-karlsruhe.de>
1999-03-02 19:08:09 +00:00
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* There is a dead lock with vfork and closing of pseudo-ports.
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1994-05-27 12:33:43 +00:00
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* So we have to be sneaky about error reporting.
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*/
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wwspawn(wp, file, argv)
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register struct ww *wp;
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char *file;
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char **argv;
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{
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int pid;
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int ret;
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char erred = 0;
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int s;
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s = sigblock(sigmask(SIGCHLD));
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Make window(1) actually work again. It has been broken for quite some
time now.
For whatever reason, the kernel seems to have generated SIGIOs
previously without an initial fcntl(...,F_SETOWN), but does no longer.
This caused window(1) to wait indefinitely for input.
Also, undo rev 1.3 of wwspawn.c, it was not well-thought, and
apparently not even tested at all. The blindly (even in a nonsensical
place like the comment on top of the function) applied replacement of
vfork() by fork() totally ignored that window(1) *does* abuse the
feature of vfork() where a modification of the parent's address space
is possible (in this case, to notify the parent of an erred exec*).
Also, with vfork(), it is guaranteed that the parent is only woken up
after the exec*() happened, where the replacement by fork() made the
parent to almost always become runnable again before the child, in
which case the parent simply told `subprocess died'. Unfortunately,
working around _this_ seems to be a lot more of redesign work compared
to little gained value, so i think relying on the specifics of vfork()
is the simpler way.
Submitted by: Philipp Mergenthaler <un1i@rz.uni-karlsruhe.de>
1999-03-02 19:08:09 +00:00
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switch (pid = vfork()) {
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1994-05-27 12:33:43 +00:00
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case -1:
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wwerrno = WWE_SYS;
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ret = -1;
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break;
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case 0:
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if (wwenviron(wp) >= 0)
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execvp(file, argv);
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erred = 1;
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_exit(1);
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default:
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if (erred) {
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wwerrno = WWE_SYS;
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ret = -1;
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} else {
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wp->ww_pid = pid;
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wp->ww_state = WWS_HASPROC;
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ret = pid;
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}
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}
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(void) sigsetmask(s);
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if (wp->ww_socket >= 0) {
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(void) close(wp->ww_socket);
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wp->ww_socket = -1;
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}
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return ret;
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}
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