Tools/WinSN5.0Ver.iso/NETSCAP.50/WIN1998.ZIP/ns/cmd/xfe/popen.c

C/C++ Source or Header | 1998-04-08 | 5.0 KB | 185 lines

/*
 * Copyright (c) 1988, 1993
 *    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[] = "@(#)popen.c    8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */

#include <sys/param.h>
#include <sys/wait.h>

#include <vfork.h>  /* lwei - need declaration of vfork */
#include <stdio.h>  /* lwei - need declaration of fprintf */
#include <signal.h>
#ifdef SUNOS4
/* lwei - need these declarations */
int fclose();
int sigblock();
int sigsetmask();
int fprintf();
#endif
#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#if 0
#include <paths.h>
#endif
static struct pid {
    struct pid *next;
    FILE *fp;
    pid_t pid;
} *pidlist;

FILE *
popen(program, type)
    const char *program;
    const char *type;
{
    struct pid *cur;
    FILE *iop;
    int pdes[2], pid;

#ifdef DEBUG_lwei
    fprintf (stderr, "xfe popen() is called\n");
#endif

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

    if ((cur = malloc(sizeof(struct pid))) == NULL)
        return (NULL);

    if (pipe(pdes) < 0) {
        free(cur);
        return (NULL);
    }

    switch (pid = vfork()) {
    case -1:            /* Error. */
        (void)close(pdes[0]);
        (void)close(pdes[1]);
        free(cur);
        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]);
        }
#ifdef SUNOS4
        execl("/bin/sh", "sh", "-c", program, NULL);
#else
        /* lwei, _PATH_BSHELL undefined */
        execl(_PATH_BSHELL, "sh", "-c", program, NULL);
#endif
        _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]);
    }

    /* Link into list of file descriptors. */
    cur->fp = iop;
    cur->pid =  pid;
    cur->next = pidlist;
    pidlist = cur;

    return (iop);
}

/*
 * pclose --
 *    Pclose returns -1 if stream is not associated with a `popened' command,
 *    if already `pclosed', or waitpid returns an error.
 */
int
pclose(iop)
    FILE *iop;
{
    register struct pid *cur, *last;
    int omask;
    union wait pstat;
    pid_t pid;

#ifdef DEBUG_lwei
    fprintf (stderr, "xfe pclose() is called\n");
#endif

    (void)fclose(iop);

    /* Find the appropriate file pointer. */
    for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
        if (cur->fp == iop)
            break;
    if (cur == NULL)
        return (-1);

    /* Get the status of the process. */
    omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP));
    do {
        pid = waitpid(cur->pid, (int *) &pstat, 0);
    } while (pid == -1 && errno == EINTR);
    (void)sigsetmask(omask);

    /* Remove the entry from the linked list. */
    if (last == NULL)
        pidlist = cur->next;
    else
        last->next = cur->next;
    free(cur);

    return (pid == -1 ? -1 : pstat.w_status);
}