blob: 9e4695b4cac496d180cad74f573e468bfa76f391 [file] [log] [blame]
/*
* fstype.c, by rmk
*
* Detect filesystem type (on stdin) and output strings for two
* environment variables:
* FSTYPE - filesystem type
* FSSIZE - filesystem size (if known)
*
* We currently detect (in order):
* gzip, cramfs, romfs, xfs, minix, ext3, ext2, reiserfs
*
* MINIX, ext3 and Reiserfs bits are currently untested.
*/
#include <sys/types.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <endian.h>
#include <netinet/in.h>
#define cpu_to_be32(x) __cpu_to_be32(x) /* Needed by romfs_fs.h */
#include <linux/romfs_fs.h>
#include <linux/cramfs_fs.h>
#include <linux/minix_fs.h>
#define _LINUX_EXT2_FS_SB
#include <linux/ext2_fs.h>
#include "ext3_fs.h"
#include "xfs_sb.h"
/*
* reiserfs_fs.h is too sick to include directly.
* Use a cleaned up version.
*/
#include "reiserfs_fs.h"
char *progname;
#define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
#define BLOCK_SIZE_BITS 10
#define BLOCK_SIZE (1 << BLOCK_SIZE_BITS)
#define BYTES_TO_BLOCKS(x) (((x) + (BLOCK_SIZE - 1)) >> BLOCK_SIZE_BITS)
static int fstype(const char *type, unsigned long size)
{
fprintf(stdout, "FSTYPE=%s\nFSSIZE=%lu\n", type, size);
return 0;
}
static int readfile(int fd, off_t off, void *buf, size_t size)
{
int ret;
if (lseek(fd, off, SEEK_SET) == -1) {
perror("lseek");
return 1;
}
ret = read(fd, buf, size);
if (ret == -1) {
perror("read");
return 1;
}
if (ret != BLOCK_SIZE) {
fprintf(stderr, "%s: short read\n", progname);
return 1;
}
return 0;
}
static int gzip_image(const unsigned char *buf, unsigned long *blocks)
{
if (buf[0] == 037 && (buf[1] == 0213 || buf[1] == 0236)) {
*blocks = 0;
return 1;
}
return 0;
}
static int cramfs_image(const unsigned char *buf, unsigned long *blocks)
{
const struct cramfs_super *sb =
(const struct cramfs_super *)buf;
if (sb->magic == CRAMFS_MAGIC) {
if (sb->flags & CRAMFS_FLAG_FSID_VERSION_2)
*blocks = sb->fsid.blocks;
else
*blocks = 0;
return 1;
}
return 0;
}
static int romfs_image(const unsigned char *buf, unsigned long *blocks)
{
const struct romfs_super_block *sb =
(const struct romfs_super_block *)buf;
if (sb->word0 == ROMSB_WORD0 && sb->word1 == ROMSB_WORD1) {
*blocks = (unsigned long)BYTES_TO_BLOCKS(__be32_to_cpu(sb->size));
return 1;
}
return 0;
}
static int minix_image(const unsigned char *buf, unsigned long *blocks)
{
const struct minix_super_block *sb =
(const struct minix_super_block *)buf;
if (sb->s_magic == MINIX_SUPER_MAGIC ||
sb->s_magic == MINIX_SUPER_MAGIC2) {
*blocks = sb->s_nzones << sb->s_log_zone_size;
return 1;
}
return 0;
}
static int ext3_image(const unsigned char *buf, unsigned long *blocks)
{
const struct ext3_super_block *sb =
(const struct ext3_super_block *)buf;
if (sb->s_magic == __cpu_to_le16(EXT2_SUPER_MAGIC) &&
sb->s_feature_compat & __cpu_to_le32(EXT3_FEATURE_COMPAT_HAS_JOURNAL)) {
*blocks = __le32_to_cpu(sb->s_blocks_count);
return 1;
}
return 0;
}
static int ext2_image(const unsigned char *buf, unsigned long *blocks)
{
const struct ext2_super_block *sb =
(const struct ext2_super_block *)buf;
if (sb->s_magic == __cpu_to_le16(EXT2_SUPER_MAGIC)) {
*blocks = __le32_to_cpu(sb->s_blocks_count);
return 1;
}
return 0;
}
static int reiserfs_image(const unsigned char *buf, unsigned long *blocks)
{
const struct reiserfs_super_block *sb =
(const struct reiserfs_super_block *)buf;
if (memcmp(REISERFS_MAGIC(sb), REISERFS_SUPER_MAGIC_STRING,
sizeof(REISERFS_SUPER_MAGIC_STRING) - 1) == 0 ||
memcmp(REISERFS_MAGIC(sb), REISER2FS_SUPER_MAGIC_STRING,
sizeof(REISER2FS_SUPER_MAGIC_STRING) - 1) == 0 ||
memcmp(REISERFS_MAGIC(sb), REISER2FS_JR_SUPER_MAGIC_STRING,
sizeof(REISER2FS_JR_SUPER_MAGIC_STRING) - 1) == 0) {
*blocks = REISERFS_BLOCK_COUNT(sb) *
(REISERFS_BLOCKSIZE(sb) / BLOCK_SIZE);
return 1;
}
return 0;
}
static int xfs_image(const unsigned char *buf, unsigned long *blocks)
{
const struct xfs_sb *sb =
(const struct xfs_sb *)buf;
if (__be32_to_cpu(sb->sb_magicnum) == XFS_SB_MAGIC) {
*blocks = __be64_to_cpu(sb->sb_dblocks) *
(__be32_to_cpu(sb->sb_blocksize) / BLOCK_SIZE);
return 1;
}
return 0;
}
struct imagetype {
off_t block;
const char name[12];
int (*identify)(const unsigned char *, unsigned long *);
};
static struct imagetype images[] = {
{ 0, "gzip", gzip_image },
{ 0, "cramfs", cramfs_image },
{ 0, "romfs", romfs_image },
{ 0, "xfs", xfs_image },
{ 1, "minix", minix_image },
{ 1, "ext3", ext3_image },
{ 1, "ext2", ext2_image },
{ 8, "reiserfs", reiserfs_image },
{ 64, "reiserfs", reiserfs_image }
};
int main(int argc, char *argv[])
{
unsigned char buf[BLOCK_SIZE];
unsigned long size = 0;
off_t cur_block = (off_t)-1;
unsigned int i;
int ret;
progname = argv[0];
if (argc != 1) {
fprintf(stderr, "Usage: %s < file\n", progname);
return 1;
}
for (i = 0; i < ARRAY_SIZE(images); i++) {
if (cur_block != images[i].block) {
/*
* Read block.
*/
cur_block = images[i].block;
ret = readfile(0, cur_block * BLOCK_SIZE, buf,
BLOCK_SIZE);
if (ret != 0)
return ret;
}
if (images[i].identify(buf, &size))
return fstype(images[i].name, size);
}
fstype("unknown", 0);
return 0;
}