cmd/mailx/popen.c

	popen.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * 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) 1984, 1986, 1987, 1988, 1989 AT&T */
/*    All Rights Reserved   */


/*
 * University Copyright- Copyright (c) 1982, 1986, 1988
 * The Regents of the University of California
 * All Rights Reserved
 *
 * University Acknowledgment- Portions of this document are derived from
 * software developed by the University of California, Berkeley, and its
 * contributors.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

/*
 * mailx -- a modified version of a University of California at Berkeley
 *  mail program
 *
 * npopen() and npclose()
 *
 * stolen from C library, modified to use SHELL variable
 */


#include <stdio.h>
#include <signal.h>
#include <fcntl.h>

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

#ifdef VMUNIX
#define sigset  signal
#else
extern void (*sigset())();
#endif
#ifdef preSVr4
extern FILE *fdopen();
extern int execlp(), fork(), pipe(), close(), fcntl();
#ifndef sun
typedef int pid_t;
#endif
#else
# include <unistd.h>
# include <wait.h>
#endif
static pid_t popen_pid[20];

FILE *
npopen(char *cmd, char *mode)
{
    int p[2];
    register pid_t pid;
    register int myside, yourside;
    char *Shell, *value(char *);

    if ((Shell = value("SHELL")) == NULL || *Shell=='\0')
#ifdef preSVr4
        Shell = "/bin/sh";
#else
        Shell = "/usr/bin/sh";
#endif
    if(pipe(p) < 0)
        return(NULL);
    myside = tst(p[WTR], p[RDR]);
    yourside = tst(p[RDR], p[WTR]);
    if((pid = fork()) == 0) {
        /* myside and yourside reverse roles in child */
        int stdio;

        stdio = tst(0, 1);
        (void) close(myside);
        (void) close(stdio);
        (void) fcntl(yourside, 0, stdio);
        (void) close(yourside);
        (void) execlp(Shell, Shell, "-c", cmd, (char *)0);
        perror(Shell);
        _exit(1);
    }
    if(pid == (pid_t)-1)
        return(NULL);
    popen_pid[myside] = pid;
    (void) close(yourside);
    return(fdopen(myside, mode));
}

int
npclose(FILE *ptr)
{
    register int f;
    register pid_t r;
    int status;
    void (*istat)(int), (*qstat)(int);

    f = fileno(ptr);
    (void) fclose(ptr);
    istat = sigset(SIGINT, SIG_IGN);
    qstat = sigset(SIGQUIT, SIG_IGN);
    while((r = wait(&status)) != popen_pid[f] && r != (pid_t)-1)
        ;
    if(r == (pid_t)-1)
        status = -1;
    (void) sigset(SIGINT, istat);
    (void) sigset(SIGQUIT, qstat);
    return(status);
}