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).
 *
 * MINIX, ext3 and Reiserfs bits are currently untested.
 */

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

/*
 * 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 "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;
}

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 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 = __le32_to_cpu(sb->s_size);
		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;
}

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},
	{1, "ext3", ext3_image},
	{1, "ext2", ext2_image},
	{1, "minix", minix_image},
	{8, "reiserfs", reiserfs_image},
	{64, "reiserfs", reiserfs_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	* MINIX, ext3 and Reiserfs bits are currently untested.
13	*/
14
15	#include <sys/types.h>
16	#include <stdio.h>
17	#include <string.h>
18	#include <unistd.h>
19	#include <fcntl.h>
20	#include <endian.h>
21	#include <netinet/in.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 "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
36	/*
37	* Slightly cleaned up version of jfs_superblock to
38	* avoid pulling in other kernel header files.
39	*/
40	#include "jfs_superblock.h"
41
42	/*
43	* reiserfs_fs.h is too sick to include directly.
44	* Use a cleaned up version.
45	*/
46	#include "reiserfs_fs.h"
47
48	#include "fstype.h"
49
50	#define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
51
52	#define BLOCK_SIZE 1024
53
54	/* Swap needs the definition of block size */
55	#include "swap_fs.h"
56
57	static int gzip_image(const void buf, unsigned long long bytes)
58	{
59	const unsigned char *p = buf;
60
61	if (p[0] == 037 && (p[1] == 0213 \|\| p[1] == 0236)) {
62	/* The length of a gzip stream can only be determined
63	by processing the whole stream */
64	*bytes = 0ULL;
65	return 1;
66	}
67	return 0;
68	}
69
70	static int cramfs_image(const void buf, unsigned long long bytes)
71	{
72	const struct cramfs_super sb = (const struct cramfs_super )buf;
73
74	if (sb->magic == CRAMFS_MAGIC) {
75	if (sb->flags & CRAMFS_FLAG_FSID_VERSION_2)
76	*bytes = (unsigned long long)sb->fsid.blocks << 10;
77	else
78	*bytes = 0;
79	return 1;
80	}
81	return 0;
82	}
83
84	static int romfs_image(const void buf, unsigned long long bytes)
85	{
86	const struct romfs_super_block *sb =
87	(const struct romfs_super_block *)buf;
88
89	if (sb->word0 == ROMSB_WORD0 && sb->word1 == ROMSB_WORD1) {
90	*bytes = __be32_to_cpu(sb->size);
91	return 1;
92	}
93	return 0;
94	}
95
96	static int minix_image(const void buf, unsigned long long bytes)
97	{
98	const struct minix_super_block *sb =
99	(const struct minix_super_block *)buf;
100
101	if (sb->s_magic == MINIX_SUPER_MAGIC \|\|
102	sb->s_magic == MINIX_SUPER_MAGIC2) {
103	*bytes = (unsigned long long)sb->s_nzones
104	<< (sb->s_log_zone_size + 10);
105	return 1;
106	}
107	return 0;
108	}
109
110	static int ext3_image(const void buf, unsigned long long bytes)
111	{
112	const struct ext3_super_block *sb =
113	(const struct ext3_super_block *)buf;
114
115	if (sb->s_magic == __cpu_to_le16(EXT2_SUPER_MAGIC) &&
116	sb->
117	s_feature_compat & __cpu_to_le32(EXT3_FEATURE_COMPAT_HAS_JOURNAL)) {
118	*bytes = (unsigned long long)__le32_to_cpu(sb->s_blocks_count)
119	<< (10 + __le32_to_cpu(sb->s_log_block_size));
120	return 1;
121	}
122	return 0;
123	}
124
125	static int ext2_image(const void buf, unsigned long long bytes)
126	{
127	const struct ext2_super_block *sb =
128	(const struct ext2_super_block *)buf;
129
130	if (sb->s_magic == __cpu_to_le16(EXT2_SUPER_MAGIC)) {
131	*bytes = (unsigned long long)__le32_to_cpu(sb->s_blocks_count)
132	<< (10 + __le32_to_cpu(sb->s_log_block_size));
133	return 1;
134	}
135	return 0;
136	}
137
138	static int reiserfs_image(const void buf, unsigned long long bytes)
139	{
140	const struct reiserfs_super_block *sb =
141	(const struct reiserfs_super_block *)buf;
142
143	if (memcmp(REISERFS_MAGIC(sb), REISERFS_SUPER_MAGIC_STRING,
144	sizeof(REISERFS_SUPER_MAGIC_STRING) - 1) == 0 \|\|
145	memcmp(REISERFS_MAGIC(sb), REISER2FS_SUPER_MAGIC_STRING,
146	sizeof(REISER2FS_SUPER_MAGIC_STRING) - 1) == 0 \|\|
147	memcmp(REISERFS_MAGIC(sb), REISER2FS_JR_SUPER_MAGIC_STRING,
148	sizeof(REISER2FS_JR_SUPER_MAGIC_STRING) - 1) == 0) {
149	bytes = (unsigned long long)REISERFS_BLOCK_COUNT(sb)
150	REISERFS_BLOCKSIZE(sb);
151	return 1;
152	}
153	return 0;
154	}
155
156	static int xfs_image(const void buf, unsigned long long bytes)
157	{
158	const struct xfs_sb sb = (const struct xfs_sb )buf;
159
160	if (__be32_to_cpu(sb->sb_magicnum) == XFS_SB_MAGIC) {
161	bytes = __be64_to_cpu(sb->sb_dblocks)
162	__be32_to_cpu(sb->sb_blocksize);
163	return 1;
164	}
165	return 0;
166	}
167
168	static int jfs_image(const void buf, unsigned long long bytes)
169	{
170	const struct jfs_superblock sb = (const struct jfs_superblock )buf;
171
172	if (!memcmp(sb->s_magic, JFS_MAGIC, 4)) {
173	*bytes = __le32_to_cpu(sb->s_size);
174	return 1;
175	}
176	return 0;
177	}
178
179	static int luks_image(const void buf, unsigned long long blocks)
180	{
181	const struct luks_partition_header *lph =
182	(const struct luks_partition_header *)buf;
183
184	if (!memcmp(lph->magic, LUKS_MAGIC, LUKS_MAGIC_L)) {
185	/* FSSIZE is dictated by the underlying fs, not by LUKS */
186	*blocks = 0;
187	return 1;
188	}
189	return 0;
190	}
191
192	static int swap_image(const void buf, unsigned long long blocks)
193	{
194	const struct swap_super_block *ssb =
195	(const struct swap_super_block *)buf;
196
197	if (!memcmp(ssb->magic, SWAP_MAGIC_1, SWAP_MAGIC_L) \|\|
198	!memcmp(ssb->magic, SWAP_MAGIC_2, SWAP_MAGIC_L)) {
199	*blocks = 0;
200	return 1;
201	}
202	return 0;
203	}
204
205	static int suspend_image(const void buf, unsigned long long blocks)
206	{
207	const struct swap_super_block *ssb =
208	(const struct swap_super_block *)buf;
209
210	if (!memcmp(ssb->magic, SUSP_MAGIC_1, SUSP_MAGIC_L) \|\|
211	!memcmp(ssb->magic, SUSP_MAGIC_2, SUSP_MAGIC_L) \|\|
212	!memcmp(ssb->magic, SUSP_MAGIC_U, SUSP_MAGIC_L)) {
213	*blocks = 0;
214	return 1;
215	}
216	return 0;
217	}
218
219	static int lvm2_image(const void buf, unsigned long long blocks)
220	{
221	const struct lvm2_super_block *lsb;
222	int i;
223
224	/* We must check every 512 byte sector */
225	for (i = 0; i < BLOCK_SIZE; i += 0x200) {
226	lsb = (const struct lvm2_super_block *)(buf + i);
227
228	if (!memcmp(lsb->magic, LVM2_MAGIC, LVM2_MAGIC_L) &&
229	!memcmp(lsb->type, LVM2_TYPE, LVM2_TYPE_L)) {
230	/* This is just one of possibly many PV's */
231	*blocks = 0;
232	return 1;
233	}
234	}
235
236	return 0;
237	}
238
239	static int iso_image(const void buf, unsigned long long blocks)
240	{
241	const struct iso_volume_descriptor *isovd =
242	(const struct iso_volume_descriptor *)buf;
243	const struct iso_hs_volume_descriptor *isohsvd =
244	(const struct iso_hs_volume_descriptor *)buf;
245
246	if (!memcmp(isovd->id, ISO_MAGIC, ISO_MAGIC_L) \|\|
247	!memcmp(isohsvd->id, ISO_HS_MAGIC, ISO_HS_MAGIC_L)) {
248	*blocks = 0;
249	return 1;
250	}
251	return 0;
252	}
253
254	struct imagetype {
255	off_t block;
256	const char name[12];
257	int (identify) (const void , unsigned long long *);
258	};
259
260	/*
261	* Note:
262	*
263	* Minix test needs to come after ext3/ext2, since it's possible for
264	* ext3/ext2 to look like minix by pure random chance.
265	*
266	* LVM comes after all other filesystems since it's possible
267	* that an old lvm signature is left on the disk if pvremove
268	* is not used before creating the new fs.
269	*
270	* The same goes for LUKS as for LVM.
271	*/
272	static struct imagetype images[] = {
273	{0, "gzip", gzip_image},
274	{0, "cramfs", cramfs_image},
275	{0, "romfs", romfs_image},
276	{0, "xfs", xfs_image},
277	{1, "ext3", ext3_image},
278	{1, "ext2", ext2_image},
279	{1, "minix", minix_image},
280	{8, "reiserfs", reiserfs_image},
281	{64, "reiserfs", reiserfs_image},
282	{32, "jfs", jfs_image},
283	{32, "iso9660", iso_image},
284	{0, "luks", luks_image},
285	{0, "lvm2", lvm2_image},
286	{1, "lvm2", lvm2_image},
287	{-1, "swap", swap_image},
288	{-1, "suspend", suspend_image},
289	{0, "", NULL}
290	};
291
292	int identify_fs(int fd, const char **fstype,
293	unsigned long long *bytes, off_t offset)
294	{
295	uint64_t buf[BLOCK_SIZE >> 3]; /* 64-bit worst case alignment */
296	off_t cur_block = (off_t) - 1;
297	struct imagetype *ip;
298	int ret;
299	unsigned long long dummy;
300
301	if (!bytes)
302	bytes = &dummy;
303
304	*fstype = NULL;
305	*bytes = 0;
306
307	for (ip = images; ip->identify; ip++) {
308	/* Hack for swap, which apparently is dependent on page size */
309	if (ip->block == -1)
310	ip->block = SWAP_OFFSET();
311
312	if (cur_block != ip->block) {
313	/*
314	* Read block.
315	*/
316	cur_block = ip->block;
317	ret = pread(fd, buf, BLOCK_SIZE,
318	offset + cur_block * BLOCK_SIZE);
319	if (ret != BLOCK_SIZE)
320	return -1; /* error */
321	}
322
323	if (ip->identify(buf, bytes)) {
324	*fstype = ip->name;
325	return 0;
326	}
327	}
328
329	return 1; /* Unknown filesystem */
330	}