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

	/*
	 * For now, ext4 requires a journal -- but this may change
	 * soon if we get that patch from Google.  :-)
	 */
	if ((sb->s_feature_compat
	     & __cpu_to_le32(EXT3_FEATURE_COMPAT_HAS_JOURNAL)) == 0)
		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;
}

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},
	{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	niro	532	/*
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	niro	815	#include <ctype.h>
16	niro	532	#include <string.h>
17			#include <unistd.h>
18			#include <fcntl.h>
19			#include <endian.h>
20			#include <netinet/in.h>
21	niro	815	#include <sys/utsname.h>
22	niro	532	#include <sys/vfs.h>
23
24			#define cpu_to_be32(x) __cpu_to_be32(x) /* Needed by romfs_fs.h */
25
26			#include "romfs_fs.h"
27			#include "cramfs_fs.h"
28			#include "minix_fs.h"
29			#include "ext2_fs.h"
30			#include "ext3_fs.h"
31			#include "xfs_sb.h"
32			#include "luks_fs.h"
33			#include "lvm2_sb.h"
34			#include "iso9660_sb.h"
35	niro	815	#include "squashfs_fs.h"
36			#include "gfs2_fs.h"
37			#include "ocfs2_fs.h"
38			#include "nilfs_fs.h"
39	niro	532
40			/*
41			* Slightly cleaned up version of jfs_superblock to
42			* avoid pulling in other kernel header files.
43			*/
44			#include "jfs_superblock.h"
45
46			/*
47			* reiserfs_fs.h is too sick to include directly.
48			* Use a cleaned up version.
49			*/
50			#include "reiserfs_fs.h"
51	niro	815	#include "reiser4_fs.h"
52	niro	532
53			#include "fstype.h"
54
55			#define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
56
57			#define BLOCK_SIZE 1024
58
59			/* Swap needs the definition of block size */
60			#include "swap_fs.h"
61
62			static int gzip_image(const void buf, unsigned long long bytes)
63			{
64			const unsigned char *p = buf;
65
66			if (p[0] == 037 && (p[1] == 0213 \|\| p[1] == 0236)) {
67			/* The length of a gzip stream can only be determined
68			by processing the whole stream */
69			*bytes = 0ULL;
70			return 1;
71			}
72			return 0;
73			}
74
75			static int cramfs_image(const void buf, unsigned long long bytes)
76			{
77			const struct cramfs_super sb = (const struct cramfs_super )buf;
78
79			if (sb->magic == CRAMFS_MAGIC) {
80			if (sb->flags & CRAMFS_FLAG_FSID_VERSION_2)
81			*bytes = (unsigned long long)sb->fsid.blocks << 10;
82			else
83			*bytes = 0;
84			return 1;
85			}
86			return 0;
87			}
88
89			static int romfs_image(const void buf, unsigned long long bytes)
90			{
91			const struct romfs_super_block *sb =
92			(const struct romfs_super_block *)buf;
93
94			if (sb->word0 == ROMSB_WORD0 && sb->word1 == ROMSB_WORD1) {
95			*bytes = __be32_to_cpu(sb->size);
96			return 1;
97			}
98			return 0;
99			}
100
101			static int minix_image(const void buf, unsigned long long bytes)
102			{
103			const struct minix_super_block *sb =
104			(const struct minix_super_block *)buf;
105
106			if (sb->s_magic == MINIX_SUPER_MAGIC \|\|
107			sb->s_magic == MINIX_SUPER_MAGIC2) {
108			*bytes = (unsigned long long)sb->s_nzones
109			<< (sb->s_log_zone_size + 10);
110			return 1;
111			}
112			return 0;
113			}
114
115	niro	815	/*
116			* Check to see if a filesystem is in /proc/filesystems.
117			* Returns 1 if found, 0 if not
118			*/
119			static int fs_proc_check(const char *fs_name)
120			{
121			FILE *f;
122			char buf[80], cp, t;
123
124			f = fopen("/proc/filesystems", "r");
125			if (!f)
126			return (0);
127			while (fgets(buf, sizeof(buf), f)) {
128			cp = buf;
129			if (!isspace(*cp)) {
130			while (cp && !isspace(cp))
131			cp++;
132			}
133			while (cp && isspace(cp))
134			cp++;
135			if ((t = strchr(cp, '\n')) != NULL)
136			*t = 0;
137			if ((t = strchr(cp, '\t')) != NULL)
138			*t = 0;
139			if ((t = strchr(cp, ' ')) != NULL)
140			*t = 0;
141			if (!strcmp(fs_name, cp)) {
142			fclose(f);
143			return (1);
144			}
145			}
146			fclose(f);
147			return (0);
148			}
149
150			/*
151			* Check to see if a filesystem is available as a module
152			* Returns 1 if found, 0 if not
153			*/
154			static int check_for_modules(const char *fs_name)
155			{
156			struct utsname uts;
157			FILE *f;
158			char buf[1024], cp, t;
159			int i;
160
161			if (uname(&uts))
162			return (0);
163			snprintf(buf, sizeof(buf), "/lib/modules/%s/modules.dep", uts.release);
164
165			f = fopen(buf, "r");
166			if (!f)
167			return (0);
168			while (fgets(buf, sizeof(buf), f)) {
169			if ((cp = strchr(buf, ':')) != NULL)
170			*cp = 0;
171			else
172			continue;
173			if ((cp = strrchr(buf, '/')) != NULL)
174			cp++;
175			i = strlen(cp);
176			if (i > 3) {
177			t = cp + i - 3;
178			if (!strcmp(t, ".ko"))
179			*t = 0;
180			}
181			if (!strcmp(cp, fs_name)) {
182			fclose(f);
183			return (1);
184			}
185			}
186			fclose(f);
187			return (0);
188			}
189
190			static int base_ext4_image(const void buf, unsigned long long bytes,
191			int *test_fs)
192			{
193			const struct ext3_super_block *sb =
194			(const struct ext3_super_block *)buf;
195
196			if (sb->s_magic != __cpu_to_le16(EXT2_SUPER_MAGIC))
197			return 0;
198
199			/*
200			* For now, ext4 requires a journal -- but this may change
201			* soon if we get that patch from Google. :-)
202			*/
203			if ((sb->s_feature_compat
204			& __cpu_to_le32(EXT3_FEATURE_COMPAT_HAS_JOURNAL)) == 0)
205			return 0;
206
207			/* There is at least one feature not supported by ext3 */
208			if ((sb->s_feature_incompat
209			& __cpu_to_le32(EXT3_FEATURE_INCOMPAT_UNSUPPORTED)) \|\|
210			(sb->s_feature_ro_compat
211			& __cpu_to_le32(EXT3_FEATURE_RO_COMPAT_UNSUPPORTED))) {
212			*bytes = (unsigned long long)__le32_to_cpu(sb->s_blocks_count)
213			<< (10 + __le32_to_cpu(sb->s_log_block_size));
214			*test_fs = (sb->s_flags &
215			__cpu_to_le32(EXT2_FLAGS_TEST_FILESYS)) != 0;
216			return 1;
217			}
218			return 0;
219			}
220
221			static int ext4_image(const void buf, unsigned long long bytes)
222			{
223			int ret, test_fs, ext4dev_present, ext4_present;
224
225			ret = base_ext4_image(buf, bytes, &test_fs);
226			if (ret == 0)
227			return 0;
228			ext4dev_present = (fs_proc_check("ext4dev") \|\|
229			check_for_modules("ext4dev"));
230			ext4_present = (fs_proc_check("ext4") \|\| check_for_modules("ext4"));
231			if ((test_fs \|\| !ext4_present) && ext4dev_present)
232			return 0;
233			return 1;
234			}
235
236			static int ext4dev_image(const void buf, unsigned long long bytes)
237			{
238			int ret, test_fs, ext4dev_present, ext4_present;
239
240			ret = base_ext4_image(buf, bytes, &test_fs);
241			if (ret == 0)
242			return 0;
243			ext4dev_present = (fs_proc_check("ext4dev") \|\|
244			check_for_modules("ext4dev"));
245			ext4_present = (fs_proc_check("ext4") \|\| check_for_modules("ext4"));
246			if ((!test_fs \|\| !ext4dev_present) && ext4_present)
247			return 0;
248			return 1;
249			}
250
251	niro	532	static int ext3_image(const void buf, unsigned long long bytes)
252			{
253			const struct ext3_super_block *sb =
254			(const struct ext3_super_block *)buf;
255
256			if (sb->s_magic == __cpu_to_le16(EXT2_SUPER_MAGIC) &&
257			sb->
258			s_feature_compat & __cpu_to_le32(EXT3_FEATURE_COMPAT_HAS_JOURNAL)) {
259			*bytes = (unsigned long long)__le32_to_cpu(sb->s_blocks_count)
260			<< (10 + __le32_to_cpu(sb->s_log_block_size));
261			return 1;
262			}
263			return 0;
264			}
265
266			static int ext2_image(const void buf, unsigned long long bytes)
267			{
268			const struct ext2_super_block *sb =
269			(const struct ext2_super_block *)buf;
270
271			if (sb->s_magic == __cpu_to_le16(EXT2_SUPER_MAGIC)) {
272			*bytes = (unsigned long long)__le32_to_cpu(sb->s_blocks_count)
273			<< (10 + __le32_to_cpu(sb->s_log_block_size));
274			return 1;
275			}
276			return 0;
277			}
278
279			static int reiserfs_image(const void buf, unsigned long long bytes)
280			{
281			const struct reiserfs_super_block *sb =
282			(const struct reiserfs_super_block *)buf;
283
284			if (memcmp(REISERFS_MAGIC(sb), REISERFS_SUPER_MAGIC_STRING,
285			sizeof(REISERFS_SUPER_MAGIC_STRING) - 1) == 0 \|\|
286			memcmp(REISERFS_MAGIC(sb), REISER2FS_SUPER_MAGIC_STRING,
287			sizeof(REISER2FS_SUPER_MAGIC_STRING) - 1) == 0 \|\|
288			memcmp(REISERFS_MAGIC(sb), REISER2FS_JR_SUPER_MAGIC_STRING,
289			sizeof(REISER2FS_JR_SUPER_MAGIC_STRING) - 1) == 0) {
290			bytes = (unsigned long long)REISERFS_BLOCK_COUNT(sb)
291			REISERFS_BLOCKSIZE(sb);
292			return 1;
293			}
294			return 0;
295			}
296
297	niro	815	static int reiser4_image(const void buf, unsigned long long bytes)
298			{
299			const struct reiser4_master_sb *sb =
300			(const struct reiser4_master_sb *)buf;
301
302			if (memcmp(sb->ms_magic, REISER4_SUPER_MAGIC_STRING,
303			sizeof(REISER4_SUPER_MAGIC_STRING) - 1) == 0) {
304			bytes = (unsigned long long) __le32_to_cpu(sb->ms_format)
305			__le32_to_cpu(sb->ms_blksize);
306			return 1;
307			}
308			return 0;
309			}
310
311	niro	532	static int xfs_image(const void buf, unsigned long long bytes)
312			{
313			const struct xfs_sb sb = (const struct xfs_sb )buf;
314
315			if (__be32_to_cpu(sb->sb_magicnum) == XFS_SB_MAGIC) {
316			bytes = __be64_to_cpu(sb->sb_dblocks)
317			__be32_to_cpu(sb->sb_blocksize);
318			return 1;
319			}
320			return 0;
321			}
322
323			static int jfs_image(const void buf, unsigned long long bytes)
324			{
325			const struct jfs_superblock sb = (const struct jfs_superblock )buf;
326
327			if (!memcmp(sb->s_magic, JFS_MAGIC, 4)) {
328	niro	815	*bytes = __le64_to_cpu(sb->s_size) << __le16_to_cpu(sb->s_l2pbsize);
329	niro	532	return 1;
330			}
331			return 0;
332			}
333
334			static int luks_image(const void buf, unsigned long long blocks)
335			{
336			const struct luks_partition_header *lph =
337			(const struct luks_partition_header *)buf;
338
339			if (!memcmp(lph->magic, LUKS_MAGIC, LUKS_MAGIC_L)) {
340			/* FSSIZE is dictated by the underlying fs, not by LUKS */
341			*blocks = 0;
342			return 1;
343			}
344			return 0;
345			}
346
347			static int swap_image(const void buf, unsigned long long blocks)
348			{
349			const struct swap_super_block *ssb =
350			(const struct swap_super_block *)buf;
351
352			if (!memcmp(ssb->magic, SWAP_MAGIC_1, SWAP_MAGIC_L) \|\|
353			!memcmp(ssb->magic, SWAP_MAGIC_2, SWAP_MAGIC_L)) {
354			*blocks = 0;
355			return 1;
356			}
357			return 0;
358			}
359
360			static int suspend_image(const void buf, unsigned long long blocks)
361			{
362			const struct swap_super_block *ssb =
363			(const struct swap_super_block *)buf;
364
365			if (!memcmp(ssb->magic, SUSP_MAGIC_1, SUSP_MAGIC_L) \|\|
366			!memcmp(ssb->magic, SUSP_MAGIC_2, SUSP_MAGIC_L) \|\|
367			!memcmp(ssb->magic, SUSP_MAGIC_U, SUSP_MAGIC_L)) {
368			*blocks = 0;
369			return 1;
370			}
371			return 0;
372			}
373
374			static int lvm2_image(const void buf, unsigned long long blocks)
375			{
376			const struct lvm2_super_block *lsb;
377			int i;
378
379			/* We must check every 512 byte sector */
380			for (i = 0; i < BLOCK_SIZE; i += 0x200) {
381			lsb = (const struct lvm2_super_block *)(buf + i);
382
383			if (!memcmp(lsb->magic, LVM2_MAGIC, LVM2_MAGIC_L) &&
384			!memcmp(lsb->type, LVM2_TYPE, LVM2_TYPE_L)) {
385			/* This is just one of possibly many PV's */
386			*blocks = 0;
387			return 1;
388			}
389			}
390
391			return 0;
392			}
393
394			static int iso_image(const void buf, unsigned long long blocks)
395			{
396			const struct iso_volume_descriptor *isovd =
397			(const struct iso_volume_descriptor *)buf;
398			const struct iso_hs_volume_descriptor *isohsvd =
399			(const struct iso_hs_volume_descriptor *)buf;
400
401			if (!memcmp(isovd->id, ISO_MAGIC, ISO_MAGIC_L) \|\|
402			!memcmp(isohsvd->id, ISO_HS_MAGIC, ISO_HS_MAGIC_L)) {
403			*blocks = 0;
404			return 1;
405			}
406			return 0;
407			}
408
409	niro	815	static int squashfs_image(const void buf, unsigned long long blocks)
410			{
411			const struct squashfs_super_block *sb =
412			(const struct squashfs_super_block *)buf;
413
414			if (sb->s_magic == SQUASHFS_MAGIC
415			\|\| sb->s_magic == SQUASHFS_MAGIC_SWAP
416			\|\| sb->s_magic == SQUASHFS_MAGIC_LZMA
417			\|\| sb->s_magic == SQUASHFS_MAGIC_LZMA_SWAP) {
418			*blocks = (unsigned long long) sb->bytes_used;
419			return 1;
420			}
421			return 0;
422			}
423
424			static int gfs2_image(const void buf, unsigned long long bytes)
425			{
426			const struct gfs2_sb *sb =
427			(const struct gfs2_sb *)buf;
428
429			if (__be32_to_cpu(sb->sb_header.mh_magic) == GFS2_MAGIC
430			&& (__be32_to_cpu(sb->sb_fs_format) == GFS2_FORMAT_FS
431			\|\| __be32_to_cpu(sb->sb_fs_format) == GFS2_FORMAT_MULTI)) {
432			bytes = 0; / cpu_to_be32(sb->sb_bsize) * ?; */
433			return 1;
434			}
435			return 0;
436			}
437
438			static int ocfs2_image(const void buf, unsigned long long bytes)
439			{
440			const struct ocfs2_dinode *sb =
441			(const struct ocfs2_dinode *)buf;
442
443			if (!memcmp(sb->i_signature, OCFS2_SUPER_BLOCK_SIGNATURE,
444			sizeof(OCFS2_SUPER_BLOCK_SIGNATURE) - 1)) {
445			*bytes = 0;
446			return 1;
447			}
448			return 0;
449			}
450
451			static int nilfs2_image(const void buf, unsigned long long bytes)
452			{
453			const struct nilfs_super_block *sb =
454			(const struct nilfs_super_block *)buf;
455
456			if (sb->s_magic == __cpu_to_le16(NILFS_SUPER_MAGIC) &&
457			sb->s_rev_level == __cpu_to_le32(2)) {
458			*bytes = (unsigned long long)__le64_to_cpu(sb->s_dev_size);
459			return 1;
460			}
461			return 0;
462			}
463
464	niro	532	struct imagetype {
465			off_t block;
466			const char name[12];
467			int (identify) (const void , unsigned long long *);
468			};
469
470			/*
471			* Note:
472			*
473			* Minix test needs to come after ext3/ext2, since it's possible for
474			* ext3/ext2 to look like minix by pure random chance.
475			*
476			* LVM comes after all other filesystems since it's possible
477			* that an old lvm signature is left on the disk if pvremove
478			* is not used before creating the new fs.
479			*
480			* The same goes for LUKS as for LVM.
481			*/
482			static struct imagetype images[] = {
483			{0, "gzip", gzip_image},
484			{0, "cramfs", cramfs_image},
485			{0, "romfs", romfs_image},
486			{0, "xfs", xfs_image},
487	niro	815	{0, "squashfs", squashfs_image},
488			{1, "ext4dev", ext4dev_image},
489			{1, "ext4", ext4_image},
490	niro	532	{1, "ext3", ext3_image},
491			{1, "ext2", ext2_image},
492			{1, "minix", minix_image},
493	niro	815	{1, "nilfs2", nilfs2_image},
494			{2, "ocfs2", ocfs2_image},
495	niro	532	{8, "reiserfs", reiserfs_image},
496			{64, "reiserfs", reiserfs_image},
497	niro	815	{64, "reiser4", reiser4_image},
498			{64, "gfs2", gfs2_image},
499	niro	532	{32, "jfs", jfs_image},
500			{32, "iso9660", iso_image},
501			{0, "luks", luks_image},
502			{0, "lvm2", lvm2_image},
503			{1, "lvm2", lvm2_image},
504			{-1, "swap", swap_image},
505			{-1, "suspend", suspend_image},
506			{0, "", NULL}
507			};
508
509			int identify_fs(int fd, const char **fstype,
510			unsigned long long *bytes, off_t offset)
511			{
512			uint64_t buf[BLOCK_SIZE >> 3]; /* 64-bit worst case alignment */
513			off_t cur_block = (off_t) - 1;
514			struct imagetype *ip;
515			int ret;
516			unsigned long long dummy;
517
518			if (!bytes)
519			bytes = &dummy;
520
521			*fstype = NULL;
522			*bytes = 0;
523
524			for (ip = images; ip->identify; ip++) {
525			/* Hack for swap, which apparently is dependent on page size */
526			if (ip->block == -1)
527			ip->block = SWAP_OFFSET();
528
529			if (cur_block != ip->block) {
530			/*
531			* Read block.
532			*/
533			cur_block = ip->block;
534			ret = pread(fd, buf, BLOCK_SIZE,
535			offset + cur_block * BLOCK_SIZE);
536			if (ret != BLOCK_SIZE)
537			return -1; /* error */
538			}
539
540			if (ip->identify(buf, bytes)) {
541			*fstype = ip->name;
542			return 0;
543			}
544			}
545
546			return 1; /* Unknown filesystem */
547			}