xref: /freebsd-10.2-release/usr.sbin/fstyp/ext2fs.c

/*-
 * Copyright (c) 2005 Stanislav Sedov
 * Copyright (c) 2014 The FreeBSD Foundation
 * All rights reserved.
 *
 * 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>
__FBSDID("$FreeBSD: releng/10.2/usr.sbin/fstyp/ext2fs.c 277437 2015-01-20 20:44:16Z trasz $");

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#include "fstyp.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;

int
fstyp_ext2fs(FILE *fp, char *label, size_t size)
{
	e2sb_t *fs;
	char *s_volume_name;

	fs = (e2sb_t *)read_buf(fp, EXT2FS_SB_OFFSET, 512);
	if (fs == NULL)
		return (1);

	/* 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 {
		free(fs);
		return (1);
	}

	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;

	strlcpy(label, s_volume_name, size);
	free(fs);

	return (0);
}