/*
 * volume_id - reads filesystem label and uuid
 *
 * Copyright (C) 2006 Red Hat, Inc. <redhat.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef _GNU_SOURCE
#define _GNU_SOURCE 1
#endif

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <ctype.h>

#include "libvolume_id.h"
#include "libvolume_id-private.h"

/* Common gfs/gfs2 constants: */
#define GFS_MAGIC		0x01161970
#define GFS_DEFAULT_BSIZE	4096
#define GFS_SUPERBLOCK_OFFSET	(0x10 * GFS_DEFAULT_BSIZE)
#define GFS_METATYPE_SB		1
#define GFS_FORMAT_SB		100
#define GFS_LOCKNAME_LEN	64

/* gfs1 constants: */
#define GFS_FORMAT_FS		1309
#define GFS_FORMAT_MULTI	1401
/* gfs2 constants: */
#define GFS2_FORMAT_FS		1801
#define GFS2_FORMAT_MULTI	1900

struct gfs2_meta_header {
	uint32_t mh_magic;
	uint32_t mh_type;
	uint64_t __pad0;          /* Was generation number in gfs1 */
	uint32_t mh_format;
	uint32_t __pad1;          /* Was incarnation number in gfs1 */
};

struct gfs2_inum {
	uint64_t no_formal_ino;
	uint64_t no_addr;
};

struct gfs2_sb {
	struct gfs2_meta_header sb_header;

	uint32_t sb_fs_format;
	uint32_t sb_multihost_format;
	uint32_t  __pad0;  /* Was superblock flags in gfs1 */

	uint32_t sb_bsize;
	uint32_t sb_bsize_shift;
	uint32_t __pad1;   /* Was journal segment size in gfs1 */

	struct gfs2_inum sb_master_dir; /* Was jindex dinode in gfs1 */
	struct gfs2_inum __pad2; /* Was rindex dinode in gfs1 */
	struct gfs2_inum sb_root_dir;

	char sb_lockproto[GFS_LOCKNAME_LEN];
	char sb_locktable[GFS_LOCKNAME_LEN];

	struct gfs2_inum __pad3; /* Was quota inode in gfs1 */
	struct gfs2_inum __pad4; /* Was licence inode in gfs1 */
	uint8_t sb_uuid[16]; /* The UUID maybe 0 for backwards compat */
} PACKED;

static int uuid_non_zero(const uint8_t *p)
{
	int i;
	for (i = 0; i < 16; i++) {
		if (p[i] != 0)
			return 1;
	}
	return 0;
}

static int volume_id_probe_gfs_generic(struct volume_id *id, uint64_t off, int vers)
{
	struct gfs2_sb *sbd;

	info("probing at offset 0x%" PRIx64 "\n", off);

	sbd = (struct gfs2_sb *)
		volume_id_get_buffer(id, off + GFS_SUPERBLOCK_OFFSET, sizeof(struct gfs2_sb));
	if (sbd == NULL)
		return -1;

	if (be32_to_cpu(sbd->sb_header.mh_magic) == GFS_MAGIC &&
		be32_to_cpu(sbd->sb_header.mh_type) == GFS_METATYPE_SB) {
		if (vers == 1) {
			if (be32_to_cpu(sbd->sb_fs_format) != GFS_FORMAT_FS ||
				be32_to_cpu(sbd->sb_multihost_format) != GFS_FORMAT_MULTI)
				return -1; /* not gfs1 */
			id->type = "gfs";
		}
		else if (vers == 2) {
			if (be32_to_cpu(sbd->sb_fs_format) != GFS2_FORMAT_FS ||
				be32_to_cpu(sbd->sb_multihost_format) != GFS2_FORMAT_MULTI)
				return -1; /* not gfs2 */
			id->type = "gfs2";
		}
		else
			return -1;

		if (strlen(sbd->sb_locktable)) {
			uint8_t *label = (uint8_t *) sbd->sb_locktable;

			volume_id_set_label_raw(id, label, GFS_LOCKNAME_LEN);
			volume_id_set_label_string(id, label, GFS_LOCKNAME_LEN);
		}
		if (vers == 2 && uuid_non_zero(sbd->sb_uuid))
			volume_id_set_uuid(id, sbd->sb_uuid, 0, UUID_DCE);
		strcpy(id->type_version, "1");
		volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
		return 0;
	}
	return -1;
}

int volume_id_probe_gfs(struct volume_id *id, uint64_t off, uint64_t size)
{
	return volume_id_probe_gfs_generic(id, off, 1);
}

int volume_id_probe_gfs2(struct volume_id *id, uint64_t off, uint64_t size)
{
	return volume_id_probe_gfs_generic(id, off, 2);
}