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Revision 1.4, Mon Aug 23 21:56:31 1993 UTC (25 years, 2 months ago) by jtc
Branch: MAIN
Changes since 1.3: +1 -4 lines

Don't block SIGINT, SIGQUIT, SIGHUP, etc. in pclose()...
   "Some historical implementations either block or ignore the signals
    SIGINT, SIGQUIT, and SIGHUP while waiting for the child process to
    terminate.  Since this behavior is not described in POSIX.2, such
    implementations are not conforming."

/*
 * Copyright (c) 1988 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software written by Ken Arnold and
 * published in UNIX Review, Vol. 6, No. 8.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
/*static char sccsid[] = "from: @(#)popen.c	5.15 (Berkeley) 2/23/91";*/
static char rcsid[] = "$Id: popen.c,v 1.4 1993/08/23 21:56:31 jtc Exp $";
#endif /* LIBC_SCCS and not lint */

#include <sys/param.h>
#include <sys/wait.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <paths.h>

static pid_t *pids;

FILE *
popen(command, type)
	const char *command;
	const char *type;
{
	FILE *iop;
	int pdes[2], fds, pid;

	if (*type != 'r' && *type != 'w' || type[1]) {
		errno = EINVAL;
		return (NULL);
	}

	if (pids == NULL) {
		if ((fds = getdtablesize()) <= 0)
			return (NULL);
		if ((pids = (pid_t *)malloc((u_int)(fds * sizeof(int)))) == NULL)
			return (NULL);
		bzero((char *)pids, fds * sizeof(pid_t));
	}
	if (pipe(pdes) < 0)
		return (NULL);
	switch (pid = vfork()) {
	case -1:			/* error */
		(void) close(pdes[0]);
		(void) close(pdes[1]);
		return (NULL);
		/* NOTREACHED */
	case 0:				/* child */
		if (*type == 'r') {
			if (pdes[1] != STDOUT_FILENO) {
				(void) dup2(pdes[1], STDOUT_FILENO);
				(void) close(pdes[1]);
			}
			(void) close(pdes[0]);
		} else {
			if (pdes[0] != STDIN_FILENO) {
				(void) dup2(pdes[0], STDIN_FILENO);
				(void) close(pdes[0]);
			}
			(void) close(pdes[1]);
		}
		execl(_PATH_BSHELL, "sh", "-c", command, (char *) 0);
		_exit(127);
		/* NOTREACHED */
	}
	/* parent; assume fdopen can't fail...  */
	if (*type == 'r') {
		iop = fdopen(pdes[0], type);
		(void) close(pdes[1]);
	} else {
		iop = fdopen(pdes[1], type);
		(void) close(pdes[0]);
	}
	pids[fileno(iop)] = pid;
	return (iop);
}

int
pclose(iop)
	FILE *iop;
{
	register int fdes;
	int omask;
	int pstat;
	pid_t pid;

	/*
	 * pclose returns -1 if stream is not associated with a
	 * `popened' command, if already `pclosed', or waitpid
	 * returns an error.
	 */
	if (pids == NULL || pids[fdes = fileno(iop)] == 0)
		return (-1);
	(void) fclose(iop);
	do {
		pid = waitpid(pids[fdes], &pstat, 0);
	} while (pid == -1 && errno == EINTR);
	pids[fdes] = 0;
	return (pid == -1 ? -1 : pstat);
}