/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2005 Stanislav Sedov
 * 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 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/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>

#include <geom/geom.h>
#include <geom/geom_dbg.h>
#include <geom/label/g_label.h>

#define EXT2FS_SB_OFFSET        1024
#define EXT2_SUPER_MAGIC        0xef53
#define EXT2_DYNAMIC_REV        1

typedef struct e2sb {
        uint8_t         fake1[56];
        uint16_t        s_magic;
        uint8_t         fake2[18];
        uint32_t        s_rev_level;
        uint8_t         fake3[40];
        char            s_volume_name[16];
} e2sb_t;

static void
g_label_ext2fs_taste(struct g_consumer *cp, char *label, size_t size)
{
        struct g_provider *pp;
        e2sb_t *fs;
        char *s_volume_name;

        g_topology_assert_not();
        pp = cp->provider;
        label[0] = '\0';

        KASSERT(pp->sectorsize != 0, ("Tasting a disk with 0 sectorsize"));
        if (pp->sectorsize < sizeof(*fs))
                return;
        if ((EXT2FS_SB_OFFSET % pp->sectorsize) != 0)
                return;

        fs = g_read_data(cp, EXT2FS_SB_OFFSET, pp->sectorsize, NULL);
        if (fs == NULL)
                return;

        /* Check for magic and versio n*/
        if (fs->s_magic == EXT2_SUPER_MAGIC &&
            fs->s_rev_level == EXT2_DYNAMIC_REV) {
                G_LABEL_DEBUG(1, "ext2fs file system detected on %s.",
                    pp->name);
        } else {
                goto exit_free;
        }

        s_volume_name = fs->s_volume_name;
        /* Terminate label */
        s_volume_name[sizeof(fs->s_volume_name) - 1] = '\0';

        if (s_volume_name[0] == '/')
                s_volume_name += 1;

        /* Check for volume label */
        if (s_volume_name[0] == '\0')
                goto exit_free;

        strlcpy(label, s_volume_name, size);

exit_free:
        g_free(fs);
}

struct g_label_desc g_label_ext2fs = {
        .ld_taste = g_label_ext2fs_taste,
        .ld_dirprefix = "ext2fs/",
        .ld_enabled = 1
};

G_LABEL_INIT(ext2fs, g_label_ext2fs, "Create device nodes for EXT2FS volumes");