usr/src/libexec/ftpd/popen.c

/*
 * Copyright (c) 1988, 1993, 1994
 *      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.
 *
 */

#ifndef lint
static char sccsid[] = "@(#)popen.c     8.3 (Berkeley) 4/6/94";
#endif /* not lint */

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

#include <errno.h>
#include <glob.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "extern.h"

/*
 * Special version of popen which avoids call to shell.  This ensures noone
 * may create a pipe to a hidden program as a side effect of a list or dir
 * command.
 */
static int *pids;
static int fds;

FILE *
ftpd_popen(program, type)
        char *program, *type;
{
        char *cp;
        FILE *iop;
        int argc, gargc, pdes[2], pid;
        char **pop, *argv[100], *gargv[1000];

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

        if (!pids) {
                if ((fds = getdtablesize()) <= 0)
                        return (NULL);
                if ((pids = (int *)malloc((u_int)(fds * sizeof(int)))) == NULL)
                        return (NULL);
                memset(pids, 0, fds * sizeof(int));
        }
        if (pipe(pdes) < 0)
                return (NULL);

        /* break up string into pieces */
        for (argc = 0, cp = program;; cp = NULL)
                if (!(argv[argc++] = strtok(cp, " \t\n")))
                        break;

        /* glob each piece */
        gargv[0] = argv[0];
        for (gargc = argc = 1; argv[argc]; argc++) {
                glob_t gl;
                int flags = GLOB_BRACE|GLOB_NOCHECK|GLOB_QUOTE|GLOB_TILDE;

                memset(&gl, 0, sizeof(gl));
                if (glob(argv[argc], flags, NULL, &gl))
                        gargv[gargc++] = strdup(argv[argc]);
                else
                        for (pop = gl.gl_pathv; *pop; pop++)
                                gargv[gargc++] = strdup(*pop);
                globfree(&gl);
        }
        gargv[gargc] = NULL;

        iop = NULL;
        switch(pid = vfork()) {
        case -1:                        /* error */
                (void)close(pdes[0]);
                (void)close(pdes[1]);
                goto pfree;
                /* NOTREACHED */
        case 0:                         /* child */
                if (*type == 'r') {
                        if (pdes[1] != STDOUT_FILENO) {
                                dup2(pdes[1], STDOUT_FILENO);
                                (void)close(pdes[1]);
                        }
                        dup2(STDOUT_FILENO, STDERR_FILENO); /* stderr too! */
                        (void)close(pdes[0]);
                } else {
                        if (pdes[0] != STDIN_FILENO) {
                                dup2(pdes[0], STDIN_FILENO);
                                (void)close(pdes[0]);
                        }
                        (void)close(pdes[1]);
                }
                execv(gargv[0], gargv);
                _exit(1);
        }
        /* 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;

pfree:  for (argc = 1; gargv[argc] != NULL; argc++)
                free(gargv[argc]);

        return (iop);
}

int
ftpd_pclose(iop)
        FILE *iop;
{
        int fdes, omask, status;
        pid_t pid;

        /*
         * pclose returns -1 if stream is not associated with a
         * `popened' command, or, if already `pclosed'.
         */
        if (pids == 0 || pids[fdes = fileno(iop)] == 0)
                return (-1);
        (void)fclose(iop);
        omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP));
        while ((pid = waitpid(pids[fdes], &status, 0)) < 0 && errno == EINTR)
                continue;
        (void)sigsetmask(omask);
        pids[fdes] = 0;
        if (pid < 0)
                return (pid);
        if (WIFEXITED(status))
                return (WEXITSTATUS(status));
        return (1);
}