/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*      Copyright (c) 1988 AT&T */
/*        All Rights Reserved   */


/*
 * Copyright (c) 1999 by Sun Microsystems, Inc.
 * All rights reserved.
 */

#include <fcntl.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <libgen.h>
#include "global.h"     /* pid_t, SIGTYPE, shell, and basename() */

#define tst(a, b) (*mode == 'r'? (b) : (a))
#define RDR     0
#define WTR     1

static pid_t popen_pid[20];
static SIGTYPE (*tstat)();

FILE *
mypopen(char *cmd, char *mode)
{
        int     p[2];
        pid_t *poptr;
        int myside, yourside;
        pid_t pid;

        if (pipe(p) < 0)
                return (NULL);
        myside = tst(p[WTR], p[RDR]);
        yourside = tst(p[RDR], p[WTR]);
        if ((pid = fork()) > 0) {
                tstat = signal(SIGTSTP, SIG_DFL);
        } else if (pid == 0) {
                /* myside and yourside reverse roles in child */
                int     stdio;

                /* close all pipes from other popen's */
                for (poptr = popen_pid; poptr < popen_pid+20; poptr++) {
                        if (*poptr)
                                (void) close(poptr - popen_pid);
                }
                stdio = tst(0, 1);
                (void) close(myside);
                (void) close(stdio);
                (void) fcntl(yourside, F_DUPFD, stdio);
                (void) close(yourside);
                (void) execlp(shell, basename(shell), "-c", cmd, 0);
                _exit(1);
        }
        if (pid == -1)
                return (NULL);
        popen_pid[myside] = pid;
        (void) close(yourside);
        return (fdopen(myside, mode));
}

int
mypclose(FILE *ptr)
{
        int f;
        pid_t r;
        int status;
        SIGTYPE (*hstat)(), (*istat)(), (*qstat)();

        f = fileno(ptr);
        (void) fclose(ptr);
        istat = signal(SIGINT, SIG_IGN);
        qstat = signal(SIGQUIT, SIG_IGN);
        hstat = signal(SIGHUP, SIG_IGN);
        while ((r = wait(&status)) != popen_pid[f] && r != -1) {
        }
        if (r == -1)
                status = -1;
        (void) signal(SIGINT, istat);
        (void) signal(SIGQUIT, qstat);
        (void) signal(SIGHUP, hstat);
        (void) signal(SIGTSTP, tstat);
        /* mark this pipe closed */
        popen_pid[f] = 0;
        return (status);
}