/*      $NetBSD: mount_puffs.c,v 1.5 2016/11/23 14:33:29 pho Exp $      */

/*
 * Copyright (c) 2010 Antti Kantee.  All Rights Reserved.
 *
 * 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 ``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.
 */

/*
 * This is to support -o getargs without having to replicate it in
 * every file server. It also allows puffs filesystems to be mounted
 * via "mount -a".
 */

#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: mount_puffs.c,v 1.5 2016/11/23 14:33:29 pho Exp $");
#endif /* !lint */

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

#include <fs/puffs/puffs_msgif.h>

#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/cdefs.h>
#include <unistd.h>
#include <util.h>

static int
usage(void)
{

        fprintf(stderr, "usage: %s [-o options] program[#source] mountpoint\n", getprogname());
        return 1;
}

static int show_puffs_mount_args(const char *mountpoint)
{
        const char *vtypes[] = { VNODE_TYPES };
        struct puffs_kargs kargs;

        if (mount(MOUNT_PUFFS, mountpoint, MNT_GETARGS, &kargs, sizeof(kargs)) == -1)
                err(1, "mount");

        printf("version=%d, ", kargs.pa_vers);
        printf("flags=0x%x, ", kargs.pa_flags);

        printf("root cookie=%p, ", kargs.pa_root_cookie);
        printf("root type=%s", vtypes[kargs.pa_root_vtype]);

        if (kargs.pa_root_vtype != VDIR)
                printf(", root size=%llu",
                    (unsigned long long)kargs.pa_root_vsize);
        if (kargs.pa_root_vtype == VCHR || kargs.pa_root_vtype == VBLK)
                printf(", root rdev=0x%" PRIx64, (uint64_t)kargs.pa_root_rdev);
        printf("\n");

        return 0;
}

static int
mount_puffs_filesystem(const char *program, const char *opts,
                                        const char *source, const char *mountpoint)
{
        int argc = 0;
        const char **argv;
        int rv = 0;

        /* Construct an argument vector:
         * program [-o opts] [source] mountpoint */
        argv = ecalloc(1 + 2 + 1 + 1, sizeof(*argv));
        argv[argc++] = program;
        if (opts != NULL) {
                argv[argc++] = "-o";
                argv[argc++] = opts;
        }
        if (source != NULL) {
                argv[argc++] = source;
        }
        argv[argc++] = mountpoint;
        argv[argc] = NULL;

        /* We intentionally use execvp(3) here because the program can
         * actually be a basename. */
        if (execvp(program, __UNCONST(argv)) == -1) {
                warn("Cannot execute %s", program);
                rv = 1;
        }

        free(argv);
        return rv;
}

static void add_opt(char **opts, const char *opt)
{
        const size_t orig_len = *opts == NULL ? 0 : strlen(*opts);

        *opts = erealloc(*opts, orig_len + 1 + strlen(opt) + 1);

        if (orig_len == 0) {
                strcpy(*opts, opt);
        }
        else {
                strcat(*opts, ",");
                strcat(*opts, opt);
        }
}

int
main(int argc, char *argv[])
{
        int mntflags = 0;
        int ch;
        char *opts = NULL;
        int rv = 0;

        while ((ch = getopt(argc, argv, "o:")) != -1) {
                switch (ch) {
                case 'o':
                        for (char *opt = optarg; (opt = strtok(opt, ",")) != NULL; opt = NULL) {
                                if (strcmp(opt, "getargs") == 0) {
                                        mntflags |= MNT_GETARGS;
                                        break; /* No need to parse it any further. */
                                }
                                else {
                                        add_opt(&opts, opt);
                                }
                        }
                        break;
                default:
                        rv = usage();
                        goto free_opts;
                }
        }
        argc -= optind;
        argv += optind;

        if (argc != 2) {
                rv = usage();
                goto free_opts;
        }

        if (mntflags & MNT_GETARGS) {
                /* Special case for -o getargs: retrieve kernel arguments for
                 * an already mounted filesystem. */
                rv = show_puffs_mount_args(argv[1]);
        }
        else {
                /* Split the program name and source. This is to allow
                 * filesystems to be mounted via "mount -a" i.e. /etc/fstab */
                char *source  = argv[0];
                char *program = strsep(&source, "#");

                rv = mount_puffs_filesystem(program, opts, source, argv[1]);
        }

free_opts:
        free(opts);
        return rv;
}