kinit/fstype/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 the filesystems listed below in the struct
 * "imagetype images" (in the order they are listed).
 */

#include <sys/types.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <endian.h>
#include <netinet/in.h>
#include <sys/utsname.h>
#include <sys/vfs.h>

#define cpu_to_be32(x) __cpu_to_be32(x)	/* Needed by romfs_fs.h */

#include "btrfs.h"
#include "cramfs_fs.h"
#include "ext2_fs.h"
#include "ext3_fs.h"
#include "gfs2_fs.h"
#include "iso9660_sb.h"
#include "luks_fs.h"
#include "lvm2_sb.h"
#include "minix_fs.h"
#include "nilfs_fs.h"
#include "ocfs2_fs.h"
#include "romfs_fs.h"
#include "squashfs_fs.h"
#include "xfs_sb.h"

/*
 * Slightly cleaned up version of jfs_superblock to
 * avoid pulling in other kernel header files.
 */
#include "jfs_superblock.h"

/*
 * reiserfs_fs.h is too sick to include directly.
 * Use a cleaned up version.
 */
#include "reiserfs_fs.h"
#include "reiser4_fs.h"

#include "fstype.h"

#define ARRAY_SIZE(x)	(sizeof(x) / sizeof(x[0]))

#define BLOCK_SIZE 1024

/* Swap needs the definition of block size */
#include "swap_fs.h"

static int gzip_image(const void *buf, unsigned long long *bytes)
{
	const unsigned char *p = buf;

	if (p[0] == 037 && (p[1] == 0213 || p[1] == 0236)) {
		/* The length of a gzip stream can only be determined
		   by processing the whole stream */
		*bytes = 0ULL;
		return 1;
	}
	return 0;
}

static int cramfs_image(const void *buf, unsigned long long *bytes)
{
	const struct cramfs_super *sb = (const struct cramfs_super *)buf;

	if (sb->magic == CRAMFS_MAGIC) {
		if (sb->flags & CRAMFS_FLAG_FSID_VERSION_2)
			*bytes = (unsigned long long)sb->fsid.blocks << 10;
		else
			*bytes = 0;
		return 1;
	}
	return 0;
}

static int romfs_image(const void *buf, unsigned long long *bytes)
{
	const struct romfs_super_block *sb =
	    (const struct romfs_super_block *)buf;

	if (sb->word0 == ROMSB_WORD0 && sb->word1 == ROMSB_WORD1) {
		*bytes = __be32_to_cpu(sb->size);
		return 1;
	}
	return 0;
}

static int minix_image(const void *buf, unsigned long long *bytes)
{
	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) {
		*bytes = (unsigned long long)sb->s_nzones
		    << (sb->s_log_zone_size + 10);
		return 1;
	}
	return 0;
}

/*
 * Check to see if a filesystem is in /proc/filesystems.
 * Returns 1 if found, 0 if not
 */
static int fs_proc_check(const char *fs_name)
{
	FILE	*f;
	char	buf[80], *cp, *t;

	f = fopen("/proc/filesystems", "r");
	if (!f)
		return (0);
	while (fgets(buf, sizeof(buf), f)) {
		cp = buf;
		if (!isspace(*cp)) {
			while (*cp && !isspace(*cp))
				cp++;
		}
		while (*cp && isspace(*cp))
			cp++;
		if ((t = strchr(cp, '\n')) != NULL)
			*t = 0;
		if ((t = strchr(cp, '\t')) != NULL)
			*t = 0;
		if ((t = strchr(cp, ' ')) != NULL)
			*t = 0;
		if (!strcmp(fs_name, cp)) {
			fclose(f);
			return (1);
		}
	}
	fclose(f);
	return (0);
}

/*
 * Check to see if a filesystem is available as a module
 * Returns 1 if found, 0 if not
 */
static int check_for_modules(const char *fs_name)
{
	struct utsname	uts;
	FILE		*f;
	char		buf[1024], *cp, *t;
	int		i;

	if (uname(&uts))
		return (0);
	snprintf(buf, sizeof(buf), "/lib/modules/%s/modules.dep", uts.release);

	f = fopen(buf, "r");
	if (!f)
		return (0);
	while (fgets(buf, sizeof(buf), f)) {
		if ((cp = strchr(buf, ':')) != NULL)
			*cp = 0;
		else
			continue;
		if ((cp = strrchr(buf, '/')) != NULL)
			cp++;
		i = strlen(cp);
		if (i > 3) {
			t = cp + i - 3;
			if (!strcmp(t, ".ko"))
				*t = 0;
		}
		if (!strcmp(cp, fs_name)) {
			fclose(f);
			return (1);
		}
	}
	fclose(f);
	return (0);
}

static int base_ext4_image(const void *buf, unsigned long long *bytes,
			   int *test_fs)
{
	const struct ext3_super_block *sb =
		(const struct ext3_super_block *)buf;

	if (sb->s_magic != __cpu_to_le16(EXT2_SUPER_MAGIC))
		return 0;

	/* There is at least one feature not supported by ext3 */
	if ((sb->s_feature_incompat
	     & __cpu_to_le32(EXT3_FEATURE_INCOMPAT_UNSUPPORTED)) ||
	    (sb->s_feature_ro_compat
	     & __cpu_to_le32(EXT3_FEATURE_RO_COMPAT_UNSUPPORTED))) {
		*bytes = (unsigned long long)__le32_to_cpu(sb->s_blocks_count)
			<< (10 + __le32_to_cpu(sb->s_log_block_size));
		*test_fs = (sb->s_flags &
			    __cpu_to_le32(EXT2_FLAGS_TEST_FILESYS)) != 0;
		return 1;
	}
	return 0;
}

static int ext4_image(const void *buf, unsigned long long *bytes)
{
	int ret, test_fs, ext4dev_present, ext4_present;

	ret = base_ext4_image(buf, bytes, &test_fs);
	if (ret == 0)
		return 0;
	ext4dev_present = (fs_proc_check("ext4dev") ||
			   check_for_modules("ext4dev"));
	ext4_present = (fs_proc_check("ext4") || check_for_modules("ext4"));
	if ((test_fs || !ext4_present) && ext4dev_present)
		return 0;
	return 1;
}

static int ext4dev_image(const void *buf, unsigned long long *bytes)
{
	int ret, test_fs, ext4dev_present, ext4_present;

	ret = base_ext4_image(buf, bytes, &test_fs);
	if (ret == 0)
		return 0;
	ext4dev_present = (fs_proc_check("ext4dev") ||
			   check_for_modules("ext4dev"));
	ext4_present = (fs_proc_check("ext4") || check_for_modules("ext4"));
	if ((!test_fs || !ext4dev_present) && ext4_present)
		return 0;
	return 1;
}

static int ext3_image(const void *buf, unsigned long long *bytes)
{
	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)) {
		*bytes = (unsigned long long)__le32_to_cpu(sb->s_blocks_count)
		    << (10 + __le32_to_cpu(sb->s_log_block_size));
		return 1;
	}
	return 0;
}

static int ext2_image(const void *buf, unsigned long long *bytes)
{
	const struct ext2_super_block *sb =
	    (const struct ext2_super_block *)buf;

	if (sb->s_magic == __cpu_to_le16(EXT2_SUPER_MAGIC)) {
		*bytes = (unsigned long long)__le32_to_cpu(sb->s_blocks_count)
		    << (10 + __le32_to_cpu(sb->s_log_block_size));
		return 1;
	}
	return 0;
}

static int reiserfs_image(const void *buf, unsigned long long *bytes)
{
	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) {
		*bytes = (unsigned long long)REISERFS_BLOCK_COUNT(sb) *
		    REISERFS_BLOCKSIZE(sb);
		return 1;
	}
	return 0;
}

static int reiser4_image(const void *buf, unsigned long long *bytes)
{
	const struct reiser4_master_sb *sb =
		(const struct reiser4_master_sb *)buf;

	if (memcmp(sb->ms_magic, REISER4_SUPER_MAGIC_STRING,
		sizeof(REISER4_SUPER_MAGIC_STRING) - 1) == 0) {
		*bytes = (unsigned long long) __le32_to_cpu(sb->ms_format) *
			__le32_to_cpu(sb->ms_blksize);
		return 1;
	}
	return 0;
}

static int xfs_image(const void *buf, unsigned long long *bytes)
{
	const struct xfs_sb *sb = (const struct xfs_sb *)buf;

	if (__be32_to_cpu(sb->sb_magicnum) == XFS_SB_MAGIC) {
		*bytes = __be64_to_cpu(sb->sb_dblocks) *
		    __be32_to_cpu(sb->sb_blocksize);
		return 1;
	}
	return 0;
}

static int jfs_image(const void *buf, unsigned long long *bytes)
{
	const struct jfs_superblock *sb = (const struct jfs_superblock *)buf;

	if (!memcmp(sb->s_magic, JFS_MAGIC, 4)) {
		*bytes = __le64_to_cpu(sb->s_size) << __le16_to_cpu(sb->s_l2pbsize);
		return 1;
	}
	return 0;
}

static int luks_image(const void *buf, unsigned long long *blocks)
{
	const struct luks_partition_header *lph =
	    (const struct luks_partition_header *)buf;

	if (!memcmp(lph->magic, LUKS_MAGIC, LUKS_MAGIC_L)) {
		/* FSSIZE is dictated by the underlying fs, not by LUKS */
		*blocks = 0;
		return 1;
	}
	return 0;
}

static int swap_image(const void *buf, unsigned long long *blocks)
{
	const struct swap_super_block *ssb =
	    (const struct swap_super_block *)buf;

	if (!memcmp(ssb->magic, SWAP_MAGIC_1, SWAP_MAGIC_L) ||
	    !memcmp(ssb->magic, SWAP_MAGIC_2, SWAP_MAGIC_L)) {
		*blocks = 0;
		return 1;
	}
	return 0;
}

static int suspend_image(const void *buf, unsigned long long *blocks)
{
	const struct swap_super_block *ssb =
	    (const struct swap_super_block *)buf;

	if (!memcmp(ssb->magic, SUSP_MAGIC_1, SUSP_MAGIC_L) ||
	    !memcmp(ssb->magic, SUSP_MAGIC_2, SUSP_MAGIC_L) ||
	    !memcmp(ssb->magic, SUSP_MAGIC_U, SUSP_MAGIC_L)) {
		*blocks = 0;
		return 1;
	}
	return 0;
}

static int lvm2_image(const void *buf, unsigned long long *blocks)
{
	const struct lvm2_super_block *lsb;
	int i;

	/* We must check every 512 byte sector */
	for (i = 0; i < BLOCK_SIZE; i += 0x200) {
		lsb = (const struct lvm2_super_block *)(buf + i);

		if (!memcmp(lsb->magic, LVM2_MAGIC, LVM2_MAGIC_L) &&
		    !memcmp(lsb->type, LVM2_TYPE, LVM2_TYPE_L)) {
			/* This is just one of possibly many PV's */
			*blocks = 0;
			return 1;
		}
	}

	return 0;
}

static int iso_image(const void *buf, unsigned long long *blocks)
{
	const struct iso_volume_descriptor *isovd =
	    (const struct iso_volume_descriptor *)buf;
	const struct iso_hs_volume_descriptor *isohsvd =
	    (const struct iso_hs_volume_descriptor *)buf;

	if (!memcmp(isovd->id, ISO_MAGIC, ISO_MAGIC_L) ||
	    !memcmp(isohsvd->id, ISO_HS_MAGIC, ISO_HS_MAGIC_L)) {
		*blocks = 0;
		return 1;
	}
	return 0;
}

static int squashfs_image(const void *buf, unsigned long long *blocks)
{
	const struct squashfs_super_block *sb =
		(const struct squashfs_super_block *)buf;

	if (sb->s_magic == SQUASHFS_MAGIC
	    || sb->s_magic == SQUASHFS_MAGIC_SWAP
	    || sb->s_magic == SQUASHFS_MAGIC_LZMA
	    || sb->s_magic == SQUASHFS_MAGIC_LZMA_SWAP) {
		*blocks = (unsigned long long) sb->bytes_used;
		return 1;
	}
	return 0;
}

static int gfs2_image(const void *buf, unsigned long long *bytes)
{
	const struct gfs2_sb *sb =
		(const struct gfs2_sb *)buf;

	if (__be32_to_cpu(sb->sb_header.mh_magic) == GFS2_MAGIC
		&& (__be32_to_cpu(sb->sb_fs_format) == GFS2_FORMAT_FS
		|| __be32_to_cpu(sb->sb_fs_format) == GFS2_FORMAT_MULTI)) {
		*bytes = 0; /* cpu_to_be32(sb->sb_bsize) * ?; */
		return 1;
	}
	return 0;
}

static int ocfs2_image(const void *buf, unsigned long long *bytes)
{
	const struct ocfs2_dinode *sb =
		(const struct ocfs2_dinode *)buf;

	if (!memcmp(sb->i_signature, OCFS2_SUPER_BLOCK_SIGNATURE,
			sizeof(OCFS2_SUPER_BLOCK_SIGNATURE) - 1)) {
		*bytes = 0;
		return 1;
	}
	return 0;
}

static int nilfs2_image(const void *buf, unsigned long long *bytes)
{
	const struct nilfs_super_block *sb =
	    (const struct nilfs_super_block *)buf;

	if (sb->s_magic == __cpu_to_le16(NILFS_SUPER_MAGIC) &&
	    sb->s_rev_level == __cpu_to_le32(2)) {
		*bytes = (unsigned long long)__le64_to_cpu(sb->s_dev_size);
		return 1;
	}
	return 0;
}

static int btrfs_image(const void *buf, unsigned long long *bytes)
{
	const struct btrfs_super_block *sb =
	    (const struct btrfs_super_block *)buf;

	if (!memcmp(sb->magic, BTRFS_MAGIC, BTRFS_MAGIC_L)) {
		*bytes = (unsigned long long)__le64_to_cpu(sb->total_bytes);
		return 1;
	}
	return 0;
}

struct imagetype {
	off_t block;
	const char name[12];
	int (*identify) (const void *, unsigned long long *);
};

/*
 * Note:
 *
 * Minix test needs to come after ext3/ext2, since it's possible for
 * ext3/ext2 to look like minix by pure random chance.
 *
 * LVM comes after all other filesystems since it's possible
 * that an old lvm signature is left on the disk if pvremove
 * is not used before creating the new fs.
 *
 * The same goes for LUKS as for LVM.
 */
static struct imagetype images[] = {
	{0, "gzip", gzip_image},
	{0, "cramfs", cramfs_image},
	{0, "romfs", romfs_image},
	{0, "xfs", xfs_image},
	{0, "squashfs", squashfs_image},
	{1, "ext4dev", ext4dev_image},
	{1, "ext4", ext4_image},
	{1, "ext3", ext3_image},
	{1, "ext2", ext2_image},
	{1, "minix", minix_image},
	{1, "nilfs2", nilfs2_image},
	{2, "ocfs2", ocfs2_image},
	{8, "reiserfs", reiserfs_image},
	{64, "reiserfs", reiserfs_image},
	{64, "reiser4", reiser4_image},
	{64, "gfs2", gfs2_image},
	{64, "btrfs", btrfs_image},
	{32, "jfs", jfs_image},
	{32, "iso9660", iso_image},
	{0, "luks", luks_image},
	{0, "lvm2", lvm2_image},
	{1, "lvm2", lvm2_image},
	{-1, "swap", swap_image},
	{-1, "suspend", suspend_image},
	{0, "", NULL}
};

int identify_fs(int fd, const char **fstype,
		unsigned long long *bytes, off_t offset)
{
	uint64_t buf[BLOCK_SIZE >> 3];	/* 64-bit worst case alignment */
	off_t cur_block = (off_t) - 1;
	struct imagetype *ip;
	int ret;
	unsigned long long dummy;

	if (!bytes)
		bytes = &dummy;

	*fstype = NULL;
	*bytes = 0;

	for (ip = images; ip->identify; ip++) {
		/* Hack for swap, which apparently is dependent on page size */
		if (ip->block == -1)
			ip->block = SWAP_OFFSET();

		if (cur_block != ip->block) {
			/*
			 * Read block.
			 */
			cur_block = ip->block;
			ret = pread(fd, buf, BLOCK_SIZE,
				    offset + cur_block * BLOCK_SIZE);
			if (ret != BLOCK_SIZE)
				return -1;	/* error */
		}

		if (ip->identify(buf, bytes)) {
			*fstype = ip->name;
			return 0;
		}
	}

	return 1;		/* Unknown filesystem */
}
1	/*
2	* by rmk
3	*
4	* Detect filesystem type (on stdin) and output strings for two
5	* environment variables:
6	* FSTYPE - filesystem type
7	* FSSIZE - filesystem size (if known)
8	*
9	* We currently detect the filesystems listed below in the struct
10	* "imagetype images" (in the order they are listed).
11	*/
12
13	#include <sys/types.h>
14	#include <stdio.h>
15	#include <ctype.h>
16	#include <string.h>
17	#include <unistd.h>
18	#include <fcntl.h>
19	#include <endian.h>
20	#include <netinet/in.h>
21	#include <sys/utsname.h>
22	#include <sys/vfs.h>
23
24	#define cpu_to_be32(x) __cpu_to_be32(x) /* Needed by romfs_fs.h */
25
26	#include "btrfs.h"
27	#include "cramfs_fs.h"
28	#include "ext2_fs.h"
29	#include "ext3_fs.h"
30	#include "gfs2_fs.h"
31	#include "iso9660_sb.h"
32	#include "luks_fs.h"
33	#include "lvm2_sb.h"
34	#include "minix_fs.h"
35	#include "nilfs_fs.h"
36	#include "ocfs2_fs.h"
37	#include "romfs_fs.h"
38	#include "squashfs_fs.h"
39	#include "xfs_sb.h"
40
41	/*
42	* Slightly cleaned up version of jfs_superblock to
43	* avoid pulling in other kernel header files.
44	*/
45	#include "jfs_superblock.h"
46
47	/*
48	* reiserfs_fs.h is too sick to include directly.
49	* Use a cleaned up version.
50	*/
51	#include "reiserfs_fs.h"
52	#include "reiser4_fs.h"
53
54	#include "fstype.h"
55
56	#define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
57
58	#define BLOCK_SIZE 1024
59
60	/* Swap needs the definition of block size */
61	#include "swap_fs.h"
62
63	static int gzip_image(const void buf, unsigned long long bytes)
64	{
65	const unsigned char *p = buf;
66
67	if (p[0] == 037 && (p[1] == 0213 \|\| p[1] == 0236)) {
68	/* The length of a gzip stream can only be determined
69	by processing the whole stream */
70	*bytes = 0ULL;
71	return 1;
72	}
73	return 0;
74	}
75
76	static int cramfs_image(const void buf, unsigned long long bytes)
77	{
78	const struct cramfs_super sb = (const struct cramfs_super )buf;
79
80	if (sb->magic == CRAMFS_MAGIC) {
81	if (sb->flags & CRAMFS_FLAG_FSID_VERSION_2)
82	*bytes = (unsigned long long)sb->fsid.blocks << 10;
83	else
84	*bytes = 0;
85	return 1;
86	}
87	return 0;
88	}
89
90	static int romfs_image(const void buf, unsigned long long bytes)
91	{
92	const struct romfs_super_block *sb =
93	(const struct romfs_super_block *)buf;
94
95	if (sb->word0 == ROMSB_WORD0 && sb->word1 == ROMSB_WORD1) {
96	*bytes = __be32_to_cpu(sb->size);
97	return 1;
98	}
99	return 0;
100	}
101
102	static int minix_image(const void buf, unsigned long long bytes)
103	{
104	const struct minix_super_block *sb =
105	(const struct minix_super_block *)buf;
106
107	if (sb->s_magic == MINIX_SUPER_MAGIC \|\|
108	sb->s_magic == MINIX_SUPER_MAGIC2) {
109	*bytes = (unsigned long long)sb->s_nzones
110	<< (sb->s_log_zone_size + 10);
111	return 1;
112	}
113	return 0;
114	}
115
116	/*
117	* Check to see if a filesystem is in /proc/filesystems.
118	* Returns 1 if found, 0 if not
119	*/
120	static int fs_proc_check(const char *fs_name)
121	{
122	FILE *f;
123	char buf[80], cp, t;
124
125	f = fopen("/proc/filesystems", "r");
126	if (!f)
127	return (0);
128	while (fgets(buf, sizeof(buf), f)) {
129	cp = buf;
130	if (!isspace(*cp)) {
131	while (cp && !isspace(cp))
132	cp++;
133	}
134	while (cp && isspace(cp))
135	cp++;
136	if ((t = strchr(cp, '\n')) != NULL)
137	*t = 0;
138	if ((t = strchr(cp, '\t')) != NULL)
139	*t = 0;
140	if ((t = strchr(cp, ' ')) != NULL)
141	*t = 0;
142	if (!strcmp(fs_name, cp)) {
143	fclose(f);
144	return (1);
145	}
146	}
147	fclose(f);
148	return (0);
149	}
150
151	/*
152	* Check to see if a filesystem is available as a module
153	* Returns 1 if found, 0 if not
154	*/
155	static int check_for_modules(const char *fs_name)
156	{
157	struct utsname uts;
158	FILE *f;
159	char buf[1024], cp, t;
160	int i;
161
162	if (uname(&uts))
163	return (0);
164	snprintf(buf, sizeof(buf), "/lib/modules/%s/modules.dep", uts.release);
165
166	f = fopen(buf, "r");
167	if (!f)
168	return (0);
169	while (fgets(buf, sizeof(buf), f)) {
170	if ((cp = strchr(buf, ':')) != NULL)
171	*cp = 0;
172	else
173	continue;
174	if ((cp = strrchr(buf, '/')) != NULL)
175	cp++;
176	i = strlen(cp);
177	if (i > 3) {
178	t = cp + i - 3;
179	if (!strcmp(t, ".ko"))
180	*t = 0;
181	}
182	if (!strcmp(cp, fs_name)) {
183	fclose(f);
184	return (1);
185	}
186	}
187	fclose(f);
188	return (0);
189	}
190
191	static int base_ext4_image(const void buf, unsigned long long bytes,
192	int *test_fs)
193	{
194	const struct ext3_super_block *sb =
195	(const struct ext3_super_block *)buf;
196
197	if (sb->s_magic != __cpu_to_le16(EXT2_SUPER_MAGIC))
198	return 0;
199
200	/* There is at least one feature not supported by ext3 */
201	if ((sb->s_feature_incompat
202	& __cpu_to_le32(EXT3_FEATURE_INCOMPAT_UNSUPPORTED)) \|\|
203	(sb->s_feature_ro_compat
204	& __cpu_to_le32(EXT3_FEATURE_RO_COMPAT_UNSUPPORTED))) {
205	*bytes = (unsigned long long)__le32_to_cpu(sb->s_blocks_count)
206	<< (10 + __le32_to_cpu(sb->s_log_block_size));
207	*test_fs = (sb->s_flags &
208	__cpu_to_le32(EXT2_FLAGS_TEST_FILESYS)) != 0;
209	return 1;
210	}
211	return 0;
212	}
213
214	static int ext4_image(const void buf, unsigned long long bytes)
215	{
216	int ret, test_fs, ext4dev_present, ext4_present;
217
218	ret = base_ext4_image(buf, bytes, &test_fs);
219	if (ret == 0)
220	return 0;
221	ext4dev_present = (fs_proc_check("ext4dev") \|\|
222	check_for_modules("ext4dev"));
223	ext4_present = (fs_proc_check("ext4") \|\| check_for_modules("ext4"));
224	if ((test_fs \|\| !ext4_present) && ext4dev_present)
225	return 0;
226	return 1;
227	}
228
229	static int ext4dev_image(const void buf, unsigned long long bytes)
230	{
231	int ret, test_fs, ext4dev_present, ext4_present;
232
233	ret = base_ext4_image(buf, bytes, &test_fs);
234	if (ret == 0)
235	return 0;
236	ext4dev_present = (fs_proc_check("ext4dev") \|\|
237	check_for_modules("ext4dev"));
238	ext4_present = (fs_proc_check("ext4") \|\| check_for_modules("ext4"));
239	if ((!test_fs \|\| !ext4dev_present) && ext4_present)
240	return 0;
241	return 1;
242	}
243
244	static int ext3_image(const void buf, unsigned long long bytes)
245	{
246	const struct ext3_super_block *sb =
247	(const struct ext3_super_block *)buf;
248
249	if (sb->s_magic == __cpu_to_le16(EXT2_SUPER_MAGIC) &&
250	sb->
251	s_feature_compat & __cpu_to_le32(EXT3_FEATURE_COMPAT_HAS_JOURNAL)) {
252	*bytes = (unsigned long long)__le32_to_cpu(sb->s_blocks_count)
253	<< (10 + __le32_to_cpu(sb->s_log_block_size));
254	return 1;
255	}
256	return 0;
257	}
258
259	static int ext2_image(const void buf, unsigned long long bytes)
260	{
261	const struct ext2_super_block *sb =
262	(const struct ext2_super_block *)buf;
263
264	if (sb->s_magic == __cpu_to_le16(EXT2_SUPER_MAGIC)) {
265	*bytes = (unsigned long long)__le32_to_cpu(sb->s_blocks_count)
266	<< (10 + __le32_to_cpu(sb->s_log_block_size));
267	return 1;
268	}
269	return 0;
270	}
271
272	static int reiserfs_image(const void buf, unsigned long long bytes)
273	{
274	const struct reiserfs_super_block *sb =
275	(const struct reiserfs_super_block *)buf;
276
277	if (memcmp(REISERFS_MAGIC(sb), REISERFS_SUPER_MAGIC_STRING,
278	sizeof(REISERFS_SUPER_MAGIC_STRING) - 1) == 0 \|\|
279	memcmp(REISERFS_MAGIC(sb), REISER2FS_SUPER_MAGIC_STRING,
280	sizeof(REISER2FS_SUPER_MAGIC_STRING) - 1) == 0 \|\|
281	memcmp(REISERFS_MAGIC(sb), REISER2FS_JR_SUPER_MAGIC_STRING,
282	sizeof(REISER2FS_JR_SUPER_MAGIC_STRING) - 1) == 0) {
283	bytes = (unsigned long long)REISERFS_BLOCK_COUNT(sb)
284	REISERFS_BLOCKSIZE(sb);
285	return 1;
286	}
287	return 0;
288	}
289
290	static int reiser4_image(const void buf, unsigned long long bytes)
291	{
292	const struct reiser4_master_sb *sb =
293	(const struct reiser4_master_sb *)buf;
294
295	if (memcmp(sb->ms_magic, REISER4_SUPER_MAGIC_STRING,
296	sizeof(REISER4_SUPER_MAGIC_STRING) - 1) == 0) {
297	bytes = (unsigned long long) __le32_to_cpu(sb->ms_format)
298	__le32_to_cpu(sb->ms_blksize);
299	return 1;
300	}
301	return 0;
302	}
303
304	static int xfs_image(const void buf, unsigned long long bytes)
305	{
306	const struct xfs_sb sb = (const struct xfs_sb )buf;
307
308	if (__be32_to_cpu(sb->sb_magicnum) == XFS_SB_MAGIC) {
309	bytes = __be64_to_cpu(sb->sb_dblocks)
310	__be32_to_cpu(sb->sb_blocksize);
311	return 1;
312	}
313	return 0;
314	}
315
316	static int jfs_image(const void buf, unsigned long long bytes)
317	{
318	const struct jfs_superblock sb = (const struct jfs_superblock )buf;
319
320	if (!memcmp(sb->s_magic, JFS_MAGIC, 4)) {
321	*bytes = __le64_to_cpu(sb->s_size) << __le16_to_cpu(sb->s_l2pbsize);
322	return 1;
323	}
324	return 0;
325	}
326
327	static int luks_image(const void buf, unsigned long long blocks)
328	{
329	const struct luks_partition_header *lph =
330	(const struct luks_partition_header *)buf;
331
332	if (!memcmp(lph->magic, LUKS_MAGIC, LUKS_MAGIC_L)) {
333	/* FSSIZE is dictated by the underlying fs, not by LUKS */
334	*blocks = 0;
335	return 1;
336	}
337	return 0;
338	}
339
340	static int swap_image(const void buf, unsigned long long blocks)
341	{
342	const struct swap_super_block *ssb =
343	(const struct swap_super_block *)buf;
344
345	if (!memcmp(ssb->magic, SWAP_MAGIC_1, SWAP_MAGIC_L) \|\|
346	!memcmp(ssb->magic, SWAP_MAGIC_2, SWAP_MAGIC_L)) {
347	*blocks = 0;
348	return 1;
349	}
350	return 0;
351	}
352
353	static int suspend_image(const void buf, unsigned long long blocks)
354	{
355	const struct swap_super_block *ssb =
356	(const struct swap_super_block *)buf;
357
358	if (!memcmp(ssb->magic, SUSP_MAGIC_1, SUSP_MAGIC_L) \|\|
359	!memcmp(ssb->magic, SUSP_MAGIC_2, SUSP_MAGIC_L) \|\|
360	!memcmp(ssb->magic, SUSP_MAGIC_U, SUSP_MAGIC_L)) {
361	*blocks = 0;
362	return 1;
363	}
364	return 0;
365	}
366
367	static int lvm2_image(const void buf, unsigned long long blocks)
368	{
369	const struct lvm2_super_block *lsb;
370	int i;
371
372	/* We must check every 512 byte sector */
373	for (i = 0; i < BLOCK_SIZE; i += 0x200) {
374	lsb = (const struct lvm2_super_block *)(buf + i);
375
376	if (!memcmp(lsb->magic, LVM2_MAGIC, LVM2_MAGIC_L) &&
377	!memcmp(lsb->type, LVM2_TYPE, LVM2_TYPE_L)) {
378	/* This is just one of possibly many PV's */
379	*blocks = 0;
380	return 1;
381	}
382	}
383
384	return 0;
385	}
386
387	static int iso_image(const void buf, unsigned long long blocks)
388	{
389	const struct iso_volume_descriptor *isovd =
390	(const struct iso_volume_descriptor *)buf;
391	const struct iso_hs_volume_descriptor *isohsvd =
392	(const struct iso_hs_volume_descriptor *)buf;
393
394	if (!memcmp(isovd->id, ISO_MAGIC, ISO_MAGIC_L) \|\|
395	!memcmp(isohsvd->id, ISO_HS_MAGIC, ISO_HS_MAGIC_L)) {
396	*blocks = 0;
397	return 1;
398	}
399	return 0;
400	}
401
402	static int squashfs_image(const void buf, unsigned long long blocks)
403	{
404	const struct squashfs_super_block *sb =
405	(const struct squashfs_super_block *)buf;
406
407	if (sb->s_magic == SQUASHFS_MAGIC
408	\|\| sb->s_magic == SQUASHFS_MAGIC_SWAP
409	\|\| sb->s_magic == SQUASHFS_MAGIC_LZMA
410	\|\| sb->s_magic == SQUASHFS_MAGIC_LZMA_SWAP) {
411	*blocks = (unsigned long long) sb->bytes_used;
412	return 1;
413	}
414	return 0;
415	}
416
417	static int gfs2_image(const void buf, unsigned long long bytes)
418	{
419	const struct gfs2_sb *sb =
420	(const struct gfs2_sb *)buf;
421
422	if (__be32_to_cpu(sb->sb_header.mh_magic) == GFS2_MAGIC
423	&& (__be32_to_cpu(sb->sb_fs_format) == GFS2_FORMAT_FS
424	\|\| __be32_to_cpu(sb->sb_fs_format) == GFS2_FORMAT_MULTI)) {
425	bytes = 0; / cpu_to_be32(sb->sb_bsize) * ?; */
426	return 1;
427	}
428	return 0;
429	}
430
431	static int ocfs2_image(const void buf, unsigned long long bytes)
432	{
433	const struct ocfs2_dinode *sb =
434	(const struct ocfs2_dinode *)buf;
435
436	if (!memcmp(sb->i_signature, OCFS2_SUPER_BLOCK_SIGNATURE,
437	sizeof(OCFS2_SUPER_BLOCK_SIGNATURE) - 1)) {
438	*bytes = 0;
439	return 1;
440	}
441	return 0;
442	}
443
444	static int nilfs2_image(const void buf, unsigned long long bytes)
445	{
446	const struct nilfs_super_block *sb =
447	(const struct nilfs_super_block *)buf;
448
449	if (sb->s_magic == __cpu_to_le16(NILFS_SUPER_MAGIC) &&
450	sb->s_rev_level == __cpu_to_le32(2)) {
451	*bytes = (unsigned long long)__le64_to_cpu(sb->s_dev_size);
452	return 1;
453	}
454	return 0;
455	}
456
457	static int btrfs_image(const void buf, unsigned long long bytes)
458	{
459	const struct btrfs_super_block *sb =
460	(const struct btrfs_super_block *)buf;
461
462	if (!memcmp(sb->magic, BTRFS_MAGIC, BTRFS_MAGIC_L)) {
463	*bytes = (unsigned long long)__le64_to_cpu(sb->total_bytes);
464	return 1;
465	}
466	return 0;
467	}
468
469	struct imagetype {
470	off_t block;
471	const char name[12];
472	int (identify) (const void , unsigned long long *);
473	};
474
475	/*
476	* Note:
477	*
478	* Minix test needs to come after ext3/ext2, since it's possible for
479	* ext3/ext2 to look like minix by pure random chance.
480	*
481	* LVM comes after all other filesystems since it's possible
482	* that an old lvm signature is left on the disk if pvremove
483	* is not used before creating the new fs.
484	*
485	* The same goes for LUKS as for LVM.
486	*/
487	static struct imagetype images[] = {
488	{0, "gzip", gzip_image},
489	{0, "cramfs", cramfs_image},
490	{0, "romfs", romfs_image},
491	{0, "xfs", xfs_image},
492	{0, "squashfs", squashfs_image},
493	{1, "ext4dev", ext4dev_image},
494	{1, "ext4", ext4_image},
495	{1, "ext3", ext3_image},
496	{1, "ext2", ext2_image},
497	{1, "minix", minix_image},
498	{1, "nilfs2", nilfs2_image},
499	{2, "ocfs2", ocfs2_image},
500	{8, "reiserfs", reiserfs_image},
501	{64, "reiserfs", reiserfs_image},
502	{64, "reiser4", reiser4_image},
503	{64, "gfs2", gfs2_image},
504	{64, "btrfs", btrfs_image},
505	{32, "jfs", jfs_image},
506	{32, "iso9660", iso_image},
507	{0, "luks", luks_image},
508	{0, "lvm2", lvm2_image},
509	{1, "lvm2", lvm2_image},
510	{-1, "swap", swap_image},
511	{-1, "suspend", suspend_image},
512	{0, "", NULL}
513	};
514
515	int identify_fs(int fd, const char **fstype,
516	unsigned long long *bytes, off_t offset)
517	{
518	uint64_t buf[BLOCK_SIZE >> 3]; /* 64-bit worst case alignment */
519	off_t cur_block = (off_t) - 1;
520	struct imagetype *ip;
521	int ret;
522	unsigned long long dummy;
523
524	if (!bytes)
525	bytes = &dummy;
526
527	*fstype = NULL;
528	*bytes = 0;
529
530	for (ip = images; ip->identify; ip++) {
531	/* Hack for swap, which apparently is dependent on page size */
532	if (ip->block == -1)
533	ip->block = SWAP_OFFSET();
534
535	if (cur_block != ip->block) {
536	/*
537	* Read block.
538	*/
539	cur_block = ip->block;
540	ret = pread(fd, buf, BLOCK_SIZE,
541	offset + cur_block * BLOCK_SIZE);
542	if (ret != BLOCK_SIZE)
543	return -1; /* error */
544	}
545
546	if (ip->identify(buf, bytes)) {
547	*fstype = ip->name;
548	return 0;
549	}
550	}
551
552	return 1; /* Unknown filesystem */
553	}