/*      $NetBSD: automount.c,v 1.4 2022/05/04 11:27:54 tkusumi Exp $    */

/*-
* Copyright (c) 2017 The NetBSD Foundation, Inc.
* Copyright (c) 2016 The DragonFly Project
* Copyright (c) 2014 The FreeBSD Foundation
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Tomohiro Kusumi <[email protected]>.
*
* This software was developed by Edward Tomasz Napierala under sponsorship
* from the FreeBSD Foundation.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: automount.c,v 1.4 2022/05/04 11:27:54 tkusumi Exp $");

#include <sys/types.h>
#include <sys/mount.h>
#include <sys/statvfs.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fs/autofs/autofs_mount.h>

#include "common.h"

static int
unmount_by_statfs(const struct statvfs *sb, bool force)
{
       int error, flags;

       log_debugx("unmounting %s", sb->f_mntonname);

       flags = 0;
       if (force)
               flags |= MNT_FORCE;
       error = unmount(sb->f_mntonname, flags);
       if (error != 0)
               log_warn("cannot unmount %s", sb->f_mntonname);

       return error;
}

static const struct statvfs *
find_statfs(const struct statvfs *mntbuf, int nitems, const char *mountpoint)
{
       int i;

       for (i = 0; i < nitems; i++) {
               if (strcmp(mntbuf[i].f_mntonname, mountpoint) == 0)
                       return mntbuf + i;
       }

       return NULL;
}

static void
mount_autofs(const char *from, const char *fspath, const char *options,
   const char *prefix)
{
       struct autofs_args args;
       int error;

       create_directory(fspath);

       log_debugx("mounting %s on %s, prefix \"%s\", options \"%s\"",
           from, fspath, prefix, options);

       memset(&args, 0, sizeof(args));
       args.from = __UNCONST(from);
       args.master_options = __UNCONST(options);
       args.master_prefix = __UNCONST(prefix);

       error = mount("autofs", fspath, 0, &args, sizeof(args));
       if (error != 0)
               log_err(1, "cannot mount %s on %s", from, fspath);
}

static void
mount_if_not_already(const struct node *n, const char *map, const char *options,
   const char *prefix, const struct statvfs *mntbuf, int nitems)
{
       const struct statvfs *sb;
       char *mountpoint;
       char *from;
       int ret;

       ret = asprintf(&from, "map %s", map);
       if (ret < 0)
               log_err(1, "asprintf");

       mountpoint = node_path(n);
       sb = find_statfs(mntbuf, nitems, mountpoint);
       if (sb != NULL) {
               if (strcmp(sb->f_fstypename, "autofs") != 0) {
                       log_debugx("unknown filesystem mounted "
                           "on %s; mounting", mountpoint);
                       /*
                        * XXX: Compare options and 'from',
                        *      and update the mount if necessary.
                        */
               } else {
                       log_debugx("autofs already mounted "
                           "on %s", mountpoint);
                       free(from);
                       free(mountpoint);
                       return;
               }
       } else {
               log_debugx("nothing mounted on %s; mounting",
                   mountpoint);
       }

       mount_autofs(from, mountpoint, options, prefix);
       free(from);
       free(mountpoint);
}

static void
mount_unmount(struct node *root)
{
       struct statvfs *mntbuf;
       struct node *n, *n2;
       int i, nitems;
       static char rootdir[] = "/";

       nitems = getmntinfo(&mntbuf, MNT_WAIT);
       if (nitems <= 0)
               log_err(1, "getmntinfo");

       log_debugx("unmounting stale autofs mounts");

       for (i = 0; i < nitems; i++) {
               if (strcmp(mntbuf[i].f_fstypename, "autofs") != 0) {
                       log_debugx("skipping %s, filesystem type is not autofs",
                           mntbuf[i].f_mntonname);
                       continue;
               }

               n = node_find(root, mntbuf[i].f_mntonname);
               if (n != NULL) {
                       log_debugx("leaving autofs mounted on %s",
                           mntbuf[i].f_mntonname);
                       continue;
               }

               log_debugx("autofs mounted on %s not found "
                   "in new configuration; unmounting", mntbuf[i].f_mntonname);
               unmount_by_statfs(&(mntbuf[i]), false);
       }

       log_debugx("mounting new autofs mounts");

       TAILQ_FOREACH(n, &root->n_children, n_next) {
               if (!node_is_direct_map(n)) {
                       mount_if_not_already(n, n->n_map, n->n_options,
                           n->n_key, mntbuf, nitems);
                       continue;
               }

               TAILQ_FOREACH(n2, &n->n_children, n_next) {
                       mount_if_not_already(n2, n->n_map, n->n_options,
                           rootdir, mntbuf, nitems);
               }
       }
}

static void
flush_autofs(const char *fspath)
{
       int error;

       log_debugx("flushing %s", fspath);

       error = mount("autofs", fspath, MNT_UPDATE, NULL, 0);
       if (error != 0)
               log_err(1, "cannot flush %s", fspath);
}

static void
flush_caches(void)
{
       struct statvfs *mntbuf;
       int i, nitems;

       nitems = getmntinfo(&mntbuf, MNT_WAIT);
       if (nitems <= 0)
               log_err(1, "getmntinfo");

       log_debugx("flushing autofs caches");

       for (i = 0; i < nitems; i++) {
               if (strcmp(mntbuf[i].f_fstypename, "autofs") != 0) {
                       log_debugx("skipping %s, filesystem type is not autofs",
                           mntbuf[i].f_mntonname);
                       continue;
               }

               flush_autofs(mntbuf[i].f_mntonname);
       }
}

static void
unmount_automounted(bool force)
{
       struct statvfs *mntbuf;
       int i, nitems;

       nitems = getmntinfo(&mntbuf, MNT_WAIT);
       if (nitems <= 0)
               log_err(1, "getmntinfo");

       log_debugx("unmounting automounted filesystems");

       for (i = 0; i < nitems; i++) {
               if (strcmp(mntbuf[i].f_fstypename, "autofs") == 0) {
                       log_debugx("skipping %s, filesystem type is autofs",
                           mntbuf[i].f_mntonname);
                       continue;
               }

               if ((mntbuf[i].f_flag & MNT_AUTOMOUNTED) == 0) {
                       log_debugx("skipping %s, not automounted",
                           mntbuf[i].f_mntonname);
                       continue;
               }

               unmount_by_statfs(&(mntbuf[i]), force);
       }
}

__dead static void
usage_automount(void)
{

       fprintf(stderr, "Usage: %s [-D name=value][-o opts][-Lcfuv]\n",
           getprogname());
       exit(1);
}

int
main_automount(int argc, char **argv)
{
       struct node *root;
       int ch, debug = 0, show_maps = 0;
       char *options = NULL;
       bool do_unmount = false, force_unmount = false, flush = false;

       /*
        * Note that in automount(8), the only purpose of variable
        * handling is to aid in debugging maps (automount -L).
        */
       defined_init();

       while ((ch = getopt(argc, argv, "D:Lfco:uv")) != -1) {
               switch (ch) {
               case 'D':
                       defined_parse_and_add(optarg);
                       break;
               case 'L':
                       show_maps++;
                       break;
               case 'c':
                       flush = true;
                       break;
               case 'f':
                       force_unmount = true;
                       break;
               case 'o':
                       options = concat(options, ',', optarg);
                       break;
               case 'u':
                       do_unmount = true;
                       break;
               case 'v':
                       debug++;
                       break;
               case '?':
               default:
                       usage_automount();
               }
       }
       argc -= optind;
       if (argc != 0)
               usage_automount();

       if (force_unmount && !do_unmount)
               usage_automount();

       log_init(debug);

       if (flush) {
               flush_caches();
               return 0;
       }

       if (do_unmount) {
               unmount_automounted(force_unmount);
               return 0;
       }

       root = node_new_root();
       parse_master(root, AUTO_MASTER_PATH);

       if (show_maps) {
               if (show_maps > 1) {
                       node_expand_indirect_maps(root);
                       node_expand_ampersand(root, NULL);
               }
               node_expand_defined(root);
               node_print(root, options);
               return 0;
       }

       mount_unmount(root);

       return 0;
}

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