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util-linux/libblkid/src/superblocks/minix.c

181 lines
4.8 KiB

/*
* Copyright (C) 1999 by Andries Brouwer
* Copyright (C) 1999, 2000, 2003 by Theodore Ts'o
* Copyright (C) 2001 by Andreas Dilger
* Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
* Copyright (C) 2008-2013 Karel Zak <kzak@redhat.com>
*
* This file may be redistributed under the terms of the
* GNU Lesser General Public License.
*/
#include <string.h>
#include "superblocks.h"
#include "minix.h"
#define minix_swab16(doit, num) ((uint16_t) (doit ? swab16(num) : num))
#define minix_swab32(doit, num) ((uint32_t) (doit ? swab32(num) : num))
static int get_minix_version(const unsigned char *data, int *other_endian)
{
const struct minix_super_block *sb = (const struct minix_super_block *) data;
const struct minix3_super_block *sb3 = (const struct minix3_super_block *) data;
int version = 0;
char *endian;
*other_endian = 0;
switch (sb->s_magic) {
case MINIX_SUPER_MAGIC:
case MINIX_SUPER_MAGIC2:
version = 1;
break;
case MINIX2_SUPER_MAGIC:
case MINIX2_SUPER_MAGIC2:
version = 2;
break;
default:
if (sb3->s_magic == MINIX3_SUPER_MAGIC)
version = 3;
break;
}
if (!version) {
*other_endian = 1;
switch (swab16(sb->s_magic)) {
case MINIX_SUPER_MAGIC:
case MINIX_SUPER_MAGIC2:
version = 1;
break;
case MINIX2_SUPER_MAGIC:
case MINIX2_SUPER_MAGIC2:
version = 2;
break;
default:
if (sb3->s_magic == MINIX3_SUPER_MAGIC)
version = 3;
break;
}
}
if (!version)
return -1;
#if defined(WORDS_BIGENDIAN)
endian = *other_endian ? "LE" : "BE";
#else
endian = *other_endian ? "BE" : "LE";
#endif
DBG(LOWPROBE, ul_debug("minix version %d detected [%s]", version,
endian));
return version;
}
static int probe_minix(blkid_probe pr,
const struct blkid_idmag *mag __attribute__((__unused__)))
{
unsigned char *ext;
const unsigned char *data;
int version = 0, swabme = 0;
unsigned long zones, ninodes, imaps, zmaps;
off_t firstz;
size_t zone_size;
data = blkid_probe_get_buffer(pr, 1024,
max(sizeof(struct minix_super_block),
sizeof(struct minix3_super_block)));
if (!data)
return errno ? -errno : 1;
version = get_minix_version(data, &swabme);
switch (version) {
case 1:
case 2: {
const struct minix_super_block *sb = (const struct minix_super_block *) data;
uint16_t state = minix_swab16(swabme, sb->s_state);
if ((state & (MINIX_VALID_FS | MINIX_ERROR_FS)) != state)
return 1;
zones = version == 2 ? minix_swab32(swabme, sb->s_zones) :
minix_swab16(swabme, sb->s_nzones);
ninodes = minix_swab16(swabme, sb->s_ninodes);
imaps = minix_swab16(swabme, sb->s_imap_blocks);
zmaps = minix_swab16(swabme, sb->s_zmap_blocks);
firstz = minix_swab16(swabme, sb->s_firstdatazone);
zone_size = sb->s_log_zone_size;
break;
}
case 3: {
const struct minix3_super_block *sb = (const struct minix3_super_block *) data;
zones = minix_swab32(swabme, sb->s_zones);
ninodes = minix_swab32(swabme, sb->s_ninodes);
imaps = minix_swab16(swabme, sb->s_imap_blocks);
zmaps = minix_swab16(swabme, sb->s_zmap_blocks);
firstz = minix_swab16(swabme, sb->s_firstdatazone);
zone_size = sb->s_log_zone_size;
break;
}
default:
return 1;
}
/* sanity checks to be sure that the FS is really minix.
* see disk-utils/fsck.minix.c read_superblock
*/
if (zone_size != 0 || ninodes == 0 || ninodes == UINT32_MAX)
return 1;
if (imaps * MINIX_BLOCK_SIZE * 8 < ninodes + 1)
return 1;
if (firstz > (off_t) zones)
return 1;
if (zmaps * MINIX_BLOCK_SIZE * 8 < zones - firstz + 1)
return 1;
/* unfortunately, some parts of ext3 is sometimes possible to
* interpreted as minix superblock. So check for extN magic
* string. (For extN magic string and offsets see ext.c.)
*/
ext = blkid_probe_get_buffer(pr, 0x400 + 0x38, 2);
if (!ext)
return errno ? -errno : 1;
else if (memcmp(ext, "\123\357", 2) == 0)
return 1;
blkid_probe_sprintf_version(pr, "%d", version);
return 0;
}
const struct blkid_idinfo minix_idinfo =
{
.name = "minix",
.usage = BLKID_USAGE_FILESYSTEM,
.probefunc = probe_minix,
.magics =
{
/* version 1 - LE */
{ .magic = "\177\023", .len = 2, .kboff = 1, .sboff = 0x10 },
{ .magic = "\217\023", .len = 2, .kboff = 1, .sboff = 0x10 },
/* version 1 - BE */
{ .magic = "\023\177", .len = 2, .kboff = 1, .sboff = 0x10 },
{ .magic = "\023\217", .len = 2, .kboff = 1, .sboff = 0x10 },
/* version 2 - LE */
{ .magic = "\150\044", .len = 2, .kboff = 1, .sboff = 0x10 },
{ .magic = "\170\044", .len = 2, .kboff = 1, .sboff = 0x10 },
/* version 2 - BE */
{ .magic = "\044\150", .len = 2, .kboff = 1, .sboff = 0x10 },
{ .magic = "\044\170", .len = 2, .kboff = 1, .sboff = 0x10 },
/* version 3 - LE */
{ .magic = "\132\115", .len = 2, .kboff = 1, .sboff = 0x18 },
/* version 3 - BE */
{ .magic = "\115\132", .len = 2, .kboff = 1, .sboff = 0x18 },
{ NULL }
}
};