usr/src/sbin/mount_portal/mount_portal.c

/*
 * Copyright (c) 1992, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software donated to Berkeley by
 * Jan-Simon Pendry.
 *
 * 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
char copyright[] =
"@(#) Copyright (c) 1992, 1993, 1994\n\
        The Regents of the University of California.  All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)mount_portal.c      8.6 (Berkeley) 4/26/95";
#endif /* not lint */

#include <sys/param.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/syslog.h>
#include <sys/mount.h>

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

#include "mntopts.h"
#include "pathnames.h"
#include "portald.h"

struct mntopt mopts[] = {
        MOPT_STDOPTS,
        { NULL }
};

static void usage __P((void));

static sig_atomic_t readcf;     /* Set when SIGHUP received */

static void sigchld(sig)
int sig;
{
        pid_t pid;

        while ((pid = waitpid((pid_t) -1, (int *) 0, WNOHANG)) > 0)
                ;
        if (pid < 0 && errno != ECHILD)
                syslog(LOG_WARNING, "waitpid: %s", strerror(errno));
}

int
main(argc, argv)
        int argc;
        char *argv[];
{
        struct portal_args args;
        struct sockaddr_un un;
        char *conf;
        char *mountpt;
        int mntflags = 0;
        char tag[32];

        qelem q;
        int rc;
        int so;
        int error = 0;

        /*
         * Crack command line args
         */
        int ch;

        while ((ch = getopt(argc, argv, "o:")) != EOF) {
                switch (ch) {
                case 'o':
                        getmntopts(optarg, mopts, &mntflags, 0);
                        break;
                default:
                        error = 1;
                        break;
                }
        }

        if (optind != (argc - 2))
                error = 1;

        if (error)
                usage();

        /*
         * Get config file and mount point
         */
        conf = argv[optind];
        mountpt = argv[optind+1];

        /*
         * Construct the listening socket
         */
        un.sun_family = AF_UNIX;
        if (sizeof(_PATH_TMPPORTAL) >= sizeof(un.sun_path)) {
                fprintf(stderr, "mount_portal: portal socket name too long\n");
                exit(1);
        }
        strcpy(un.sun_path, _PATH_TMPPORTAL);
        mktemp(un.sun_path);
        un.sun_len = strlen(un.sun_path);

        so = socket(AF_UNIX, SOCK_STREAM, 0);
        if (so < 0) {
                fprintf(stderr, "mount_portal: socket: %s\n", strerror(errno));
                exit(1);
        }
        (void) unlink(un.sun_path);
        if (bind(so, (struct sockaddr *) &un, sizeof(un)) < 0)
                err(1, NULL);
        (void) unlink(un.sun_path);

        (void) listen(so, 5);

        args.pa_socket = so;
        sprintf(tag, "portal:%d", getpid());
        args.pa_config = tag;

        rc = mount("portal", mountpt, mntflags, &args);
        if (rc < 0)
                err(1, NULL);

        /*
         * Everything is ready to go - now is a good time to fork
         */
        daemon(0, 0);

        /*
         * Start logging (and change name)
         */
        openlog("portald", LOG_CONS|LOG_PID, LOG_DAEMON);

        q.q_forw = q.q_back = &q;
        readcf = 1;

        signal(SIGCHLD, sigchld);

        /*
         * Just loop waiting for new connections and activating them
         */
        for (;;) {
                struct sockaddr_un un2;
                int len2 = sizeof(un2);
                int so2;
                pid_t pid;
                fd_set fdset;
                int rc;

                /*
                 * Check whether we need to re-read the configuration file
                 */
                if (readcf) {
                        readcf = 0;
                        conf_read(&q, conf);
                        continue;
                }

                /*
                 * Accept a new connection
                 * Will get EINTR if a signal has arrived, so just
                 * ignore that error code
                 */
                FD_SET(so, &fdset);
                rc = select(so+1, &fdset, (void *) 0, (void *) 0, (void *) 0);
                if (rc < 0) {
                        if (errno == EINTR)
                                continue;
                        syslog(LOG_ERR, "select: %s", strerror(errno));
                        exit(1);
                }
                if (rc == 0)
                        break;
                so2 = accept(so, (struct sockaddr *) &un2, &len2);
                if (so2 < 0) {
                        /*
                         * The unmount function does a shutdown on the socket
                         * which will generated ECONNABORTED on the accept.
                         */
                        if (errno == ECONNABORTED)
                                break;
                        if (errno != EINTR) {
                                syslog(LOG_ERR, "accept: %s", strerror(errno));
                                exit(1);
                        }
                        continue;
                }

                /*
                 * Now fork a new child to deal with the connection
                 */
        eagain:;
                switch (pid = fork()) {
                case -1:
                        if (errno == EAGAIN) {
                                sleep(1);
                                goto eagain;
                        }
                        syslog(LOG_ERR, "fork: %s", strerror(errno));
                        break;
                case 0:
                        (void) close(so);
                        activate(&q, so2);
                        exit(0);
                default:
                        (void) close(so2);
                        break;
                }
        }
        syslog(LOG_INFO, "%s unmounted", mountpt);
        exit(0);
}

static void
usage()
{
        (void)fprintf(stderr,
                "usage: mount_portal [-o options] config mount-point\n");
        exit(1);
}