1 /*
2 * openfs.c --- open an ext2 filesystem
3 *
4 * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
5 *
6 * %Begin-Header%
7 * This file may be redistributed under the terms of the GNU Library
8 * General Public License, version 2.
9 * %End-Header%
10 */
11
12 #include "config.h"
13 #include <stdio.h>
14 #include <string.h>
15 #if HAVE_UNISTD_H
16 #include <unistd.h>
17 #endif
18 #include <fcntl.h>
19 #include <time.h>
20 #if HAVE_SYS_STAT_H
21 #include <sys/stat.h>
22 #endif
23 #if HAVE_SYS_TYPES_H
24 #include <sys/types.h>
25 #endif
26 #ifdef HAVE_ERRNO_H
27 #include <errno.h>
28 #endif
29
30 #include "ext2_fs.h"
31
32
33 #include "ext2fs.h"
34 #include "e2image.h"
35
ext2fs_descriptor_block_loc2(ext2_filsys fs,blk64_t group_block,dgrp_t i)36 blk64_t ext2fs_descriptor_block_loc2(ext2_filsys fs, blk64_t group_block,
37 dgrp_t i)
38 {
39 int bg;
40 int has_super = 0, group_zero_adjust = 0;
41 blk64_t ret_blk;
42
43 /*
44 * On a bigalloc FS with 1K blocks, block 0 is reserved for non-ext4
45 * stuff, so adjust for that if we're being asked for group 0.
46 */
47 if (i == 0 && fs->blocksize == 1024 && EXT2FS_CLUSTER_RATIO(fs) > 1)
48 group_zero_adjust = 1;
49
50 if (!ext2fs_has_feature_meta_bg(fs->super) ||
51 (i < fs->super->s_first_meta_bg))
52 return group_block + i + 1 + group_zero_adjust;
53
54 bg = EXT2_DESC_PER_BLOCK(fs->super) * i;
55 if (ext2fs_bg_has_super(fs, bg))
56 has_super = 1;
57 ret_blk = ext2fs_group_first_block2(fs, bg);
58 /*
59 * If group_block is not the normal value, we're trying to use
60 * the backup group descriptors and superblock --- so use the
61 * alternate location of the second block group in the
62 * metablock group. Ideally we should be testing each bg
63 * descriptor block individually for correctness, but we don't
64 * have the infrastructure in place to do that.
65 */
66 if (group_block != fs->super->s_first_data_block &&
67 ((ret_blk + has_super + fs->super->s_blocks_per_group) <
68 ext2fs_blocks_count(fs->super))) {
69 ret_blk += fs->super->s_blocks_per_group;
70
71 /*
72 * If we're going to jump forward a block group, make sure
73 * that we adjust has_super to account for the next group's
74 * backup superblock (or lack thereof).
75 */
76 if (ext2fs_bg_has_super(fs, bg + 1))
77 has_super = 1;
78 else
79 has_super = 0;
80 }
81 return ret_blk + has_super + group_zero_adjust;
82 }
83
ext2fs_descriptor_block_loc(ext2_filsys fs,blk_t group_block,dgrp_t i)84 blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i)
85 {
86 return ext2fs_descriptor_block_loc2(fs, group_block, i);
87 }
88
ext2fs_open(const char * name,int flags,int superblock,unsigned int block_size,io_manager manager,ext2_filsys * ret_fs)89 errcode_t ext2fs_open(const char *name, int flags, int superblock,
90 unsigned int block_size, io_manager manager,
91 ext2_filsys *ret_fs)
92 {
93 return ext2fs_open2(name, 0, flags, superblock, block_size,
94 manager, ret_fs);
95 }
96
block_sha_map_free_entry(void * data)97 static void block_sha_map_free_entry(void *data)
98 {
99 free(data);
100 return;
101 }
102
103 /*
104 * Note: if superblock is non-zero, block-size must also be non-zero.
105 * Superblock and block_size can be zero to use the default size.
106 *
107 * Valid flags for ext2fs_open()
108 *
109 * EXT2_FLAG_RW - Open the filesystem for read/write.
110 * EXT2_FLAG_FORCE - Open the filesystem even if some of the
111 * features aren't supported.
112 * EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device
113 * EXT2_FLAG_SKIP_MMP - Open without multi-mount protection check.
114 * EXT2_FLAG_64BITS - Allow 64-bit bitfields (needed for large
115 * filesystems)
116 */
ext2fs_open2(const char * name,const char * io_options,int flags,int superblock,unsigned int block_size,io_manager manager,ext2_filsys * ret_fs)117 errcode_t ext2fs_open2(const char *name, const char *io_options,
118 int flags, int superblock,
119 unsigned int block_size, io_manager manager,
120 ext2_filsys *ret_fs)
121 {
122 ext2_filsys fs;
123 errcode_t retval;
124 unsigned long i, first_meta_bg;
125 __u32 features;
126 unsigned int blocks_per_group, io_flags;
127 blk64_t group_block, blk;
128 char *dest, *cp;
129 int group_zero_adjust = 0;
130 unsigned int inode_size;
131 __u64 groups_cnt;
132 #ifdef WORDS_BIGENDIAN
133 unsigned int groups_per_block;
134 struct ext2_group_desc *gdp;
135 int j;
136 #endif
137 char *time_env;
138
139 EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);
140
141 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
142 if (retval)
143 return retval;
144
145 memset(fs, 0, sizeof(struct struct_ext2_filsys));
146 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
147 fs->flags = flags;
148 /* don't overwrite sb backups unless flag is explicitly cleared */
149 fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;
150 fs->umask = 022;
151
152 time_env = getenv("E2FSPROGS_FAKE_TIME");
153 if (time_env)
154 fs->now = strtoul(time_env, NULL, 0);
155
156 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
157 if (retval)
158 goto cleanup;
159 strcpy(fs->device_name, name);
160 cp = strchr(fs->device_name, '?');
161 if (!io_options && cp) {
162 *cp++ = 0;
163 io_options = cp;
164 }
165
166 io_flags = 0;
167 if (flags & EXT2_FLAG_RW)
168 io_flags |= IO_FLAG_RW;
169 if (flags & EXT2_FLAG_EXCLUSIVE)
170 io_flags |= IO_FLAG_EXCLUSIVE;
171 if (flags & EXT2_FLAG_DIRECT_IO)
172 io_flags |= IO_FLAG_DIRECT_IO;
173 retval = manager->open(fs->device_name, io_flags, &fs->io);
174 if (retval)
175 goto cleanup;
176 if (io_options &&
177 (retval = io_channel_set_options(fs->io, io_options)))
178 goto cleanup;
179 fs->image_io = fs->io;
180 fs->io->app_data = fs;
181 retval = io_channel_alloc_buf(fs->io, -SUPERBLOCK_SIZE, &fs->super);
182 if (retval)
183 goto cleanup;
184 if (flags & EXT2_FLAG_IMAGE_FILE) {
185 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr),
186 &fs->image_header);
187 if (retval)
188 goto cleanup;
189 retval = io_channel_read_blk(fs->io, 0,
190 -(int)sizeof(struct ext2_image_hdr),
191 fs->image_header);
192 if (retval)
193 goto cleanup;
194 if (ext2fs_le32_to_cpu(fs->image_header->magic_number) != EXT2_ET_MAGIC_E2IMAGE)
195 return EXT2_ET_MAGIC_E2IMAGE;
196 superblock = 1;
197 block_size = ext2fs_le32_to_cpu(fs->image_header->fs_blocksize);
198 }
199
200 /*
201 * If the user specifies a specific block # for the
202 * superblock, then he/she must also specify the block size!
203 * Otherwise, read the master superblock located at offset
204 * SUPERBLOCK_OFFSET from the start of the partition.
205 *
206 * Note: we only save a backup copy of the superblock if we
207 * are reading the superblock from the primary superblock location.
208 */
209 if (superblock) {
210 if (!block_size) {
211 retval = EXT2_ET_INVALID_ARGUMENT;
212 goto cleanup;
213 }
214 io_channel_set_blksize(fs->io, block_size);
215 group_block = superblock;
216 fs->orig_super = 0;
217 } else {
218 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
219 superblock = 1;
220 group_block = 0;
221 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super);
222 if (retval)
223 goto cleanup;
224 }
225 retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE,
226 fs->super);
227 if (retval)
228 goto cleanup;
229 if (fs->orig_super)
230 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE);
231
232 if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)) {
233 retval = 0;
234 if (!ext2fs_verify_csum_type(fs, fs->super))
235 retval = EXT2_ET_UNKNOWN_CSUM;
236 if (!ext2fs_superblock_csum_verify(fs, fs->super))
237 retval = EXT2_ET_SB_CSUM_INVALID;
238 }
239
240 #ifdef WORDS_BIGENDIAN
241 fs->flags |= EXT2_FLAG_SWAP_BYTES;
242 ext2fs_swap_super(fs->super);
243 #else
244 if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
245 retval = EXT2_ET_UNIMPLEMENTED;
246 goto cleanup;
247 }
248 #endif
249
250 if (fs->super->s_magic != EXT2_SUPER_MAGIC)
251 retval = EXT2_ET_BAD_MAGIC;
252 if (retval)
253 goto cleanup;
254
255 if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) {
256 retval = EXT2_ET_REV_TOO_HIGH;
257 goto cleanup;
258 }
259
260 /*
261 * Check for feature set incompatibility
262 */
263 if (!(flags & EXT2_FLAG_FORCE)) {
264 features = fs->super->s_feature_incompat;
265 #ifdef EXT2_LIB_SOFTSUPP_INCOMPAT
266 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
267 features &= ~EXT2_LIB_SOFTSUPP_INCOMPAT;
268 #endif
269 if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
270 retval = EXT2_ET_UNSUPP_FEATURE;
271 goto cleanup;
272 }
273
274 features = fs->super->s_feature_ro_compat;
275 #ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT
276 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
277 features &= ~EXT2_LIB_SOFTSUPP_RO_COMPAT;
278 #endif
279 if ((flags & EXT2_FLAG_RW) &&
280 (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {
281 retval = EXT2_ET_RO_UNSUPP_FEATURE;
282 goto cleanup;
283 }
284
285 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) &&
286 ext2fs_has_feature_journal_dev(fs->super)) {
287 retval = EXT2_ET_UNSUPP_FEATURE;
288 goto cleanup;
289 }
290 }
291
292 if (fs->super->s_log_block_size >
293 (unsigned) (EXT2_MAX_BLOCK_LOG_SIZE - EXT2_MIN_BLOCK_LOG_SIZE)) {
294 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
295 goto cleanup;
296 }
297
298 /*
299 * bigalloc requires cluster-aware bitfield operations, which at the
300 * moment means we need EXT2_FLAG_64BITS.
301 */
302 if (ext2fs_has_feature_bigalloc(fs->super) &&
303 !(flags & EXT2_FLAG_64BITS)) {
304 retval = EXT2_ET_CANT_USE_LEGACY_BITMAPS;
305 goto cleanup;
306 }
307
308 if (!ext2fs_has_feature_bigalloc(fs->super) &&
309 (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) {
310 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
311 goto cleanup;
312 }
313 fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(fs->super);
314 inode_size = EXT2_INODE_SIZE(fs->super);
315 if ((inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
316 (inode_size > fs->blocksize) ||
317 (inode_size & (inode_size - 1))) {
318 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
319 goto cleanup;
320 }
321
322 /* Enforce the block group descriptor size */
323 if (ext2fs_has_feature_64bit(fs->super)) {
324 if (fs->super->s_desc_size < EXT2_MIN_DESC_SIZE_64BIT) {
325 retval = EXT2_ET_BAD_DESC_SIZE;
326 goto cleanup;
327 }
328 }
329
330 fs->cluster_ratio_bits = fs->super->s_log_cluster_size -
331 fs->super->s_log_block_size;
332 if (EXT2_BLOCKS_PER_GROUP(fs->super) !=
333 EXT2_CLUSTERS_PER_GROUP(fs->super) << fs->cluster_ratio_bits) {
334 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
335 goto cleanup;
336 }
337 fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) *
338 EXT2_INODE_SIZE(fs->super) +
339 EXT2_BLOCK_SIZE(fs->super) - 1) /
340 EXT2_BLOCK_SIZE(fs->super));
341 if (block_size) {
342 if (block_size != fs->blocksize) {
343 retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE;
344 goto cleanup;
345 }
346 }
347 /*
348 * Set the blocksize to the filesystem's blocksize.
349 */
350 io_channel_set_blksize(fs->io, fs->blocksize);
351
352 /*
353 * If this is an external journal device, don't try to read
354 * the group descriptors, because they're not there.
355 */
356 if (ext2fs_has_feature_journal_dev(fs->super)) {
357 fs->group_desc_count = 0;
358 *ret_fs = fs;
359 return 0;
360 }
361
362 if (EXT2_INODES_PER_GROUP(fs->super) == 0) {
363 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
364 goto cleanup;
365 }
366 /* Precompute the FS UUID to seed other checksums */
367 ext2fs_init_csum_seed(fs);
368
369 /*
370 * Read group descriptors
371 */
372 blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super);
373 if (blocks_per_group == 0 ||
374 blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) ||
375 fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) ||
376 EXT2_DESC_PER_BLOCK(fs->super) == 0 ||
377 fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) {
378 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
379 goto cleanup;
380 }
381 groups_cnt = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) -
382 fs->super->s_first_data_block,
383 blocks_per_group);
384 if (groups_cnt >> 32) {
385 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
386 goto cleanup;
387 }
388 fs->group_desc_count = groups_cnt;
389 if (!(flags & EXT2_FLAG_IGNORE_SB_ERRORS) &&
390 (__u64)fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) !=
391 fs->super->s_inodes_count) {
392 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
393 goto cleanup;
394 }
395 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
396 EXT2_DESC_PER_BLOCK(fs->super));
397 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
398 &fs->group_desc);
399 if (retval)
400 goto cleanup;
401 if (!group_block)
402 group_block = fs->super->s_first_data_block;
403 /*
404 * On a FS with a 1K blocksize, block 0 is reserved for bootloaders
405 * so we must increment block numbers to any group 0 items.
406 *
407 * However, we cannot touch group_block directly because in the meta_bg
408 * case, the ext2fs_descriptor_block_loc2() function will interpret
409 * group_block != s_first_data_block to mean that we want to access the
410 * backup group descriptors. This is not what we want if the caller
411 * set superblock == 0 (i.e. auto-detect the superblock), which is
412 * what's going on here.
413 */
414 if (group_block == 0 && fs->blocksize == 1024)
415 group_zero_adjust = 1;
416 dest = (char *) fs->group_desc;
417 #ifdef WORDS_BIGENDIAN
418 groups_per_block = EXT2_DESC_PER_BLOCK(fs->super);
419 #endif
420 if (ext2fs_has_feature_meta_bg(fs->super) &&
421 !(flags & EXT2_FLAG_IMAGE_FILE)) {
422 first_meta_bg = fs->super->s_first_meta_bg;
423 if (first_meta_bg > fs->desc_blocks)
424 first_meta_bg = fs->desc_blocks;
425 } else
426 first_meta_bg = fs->desc_blocks;
427 if (first_meta_bg) {
428 retval = io_channel_read_blk(fs->io, group_block +
429 group_zero_adjust + 1,
430 first_meta_bg, dest);
431 if (retval)
432 goto cleanup;
433 #ifdef WORDS_BIGENDIAN
434 gdp = (struct ext2_group_desc *) dest;
435 for (j=0; j < groups_per_block*first_meta_bg; j++) {
436 gdp = ext2fs_group_desc(fs, fs->group_desc, j);
437 ext2fs_swap_group_desc2(fs, gdp);
438 }
439 #endif
440 dest += fs->blocksize*first_meta_bg;
441 }
442
443 for (i = first_meta_bg ; i < fs->desc_blocks; i++) {
444 blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
445 io_channel_cache_readahead(fs->io, blk, 1);
446 }
447
448 for (i=first_meta_bg ; i < fs->desc_blocks; i++) {
449 blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
450 retval = io_channel_read_blk64(fs->io, blk, 1, dest);
451 if (retval)
452 goto cleanup;
453 #ifdef WORDS_BIGENDIAN
454 for (j=0; j < groups_per_block; j++) {
455 gdp = ext2fs_group_desc(fs, fs->group_desc,
456 i * groups_per_block + j);
457 ext2fs_swap_group_desc2(fs, gdp);
458 }
459 #endif
460 dest += fs->blocksize;
461 }
462
463 fs->stride = fs->super->s_raid_stride;
464
465 /*
466 * If recovery is from backup superblock, Clear _UNININT flags &
467 * reset bg_itable_unused to zero
468 */
469 if (superblock > 1 && ext2fs_has_group_desc_csum(fs)) {
470 dgrp_t group;
471
472 for (group = 0; group < fs->group_desc_count; group++) {
473 ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
474 ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
475 ext2fs_bg_itable_unused_set(fs, group, 0);
476 /* The checksum will be reset later, but fix it here
477 * anyway to avoid printing a lot of spurious errors. */
478 ext2fs_group_desc_csum_set(fs, group);
479 }
480 if (fs->flags & EXT2_FLAG_RW)
481 ext2fs_mark_super_dirty(fs);
482 }
483
484 if (ext2fs_has_feature_mmp(fs->super) &&
485 !(flags & EXT2_FLAG_SKIP_MMP) &&
486 (flags & (EXT2_FLAG_RW | EXT2_FLAG_EXCLUSIVE))) {
487 retval = ext2fs_mmp_start(fs);
488 if (retval) {
489 fs->flags |= EXT2_FLAG_SKIP_MMP; /* just do cleanup */
490 ext2fs_mmp_stop(fs);
491 goto cleanup;
492 }
493 }
494
495 if (fs->flags & EXT2_FLAG_SHARE_DUP) {
496 fs->block_sha_map = ext2fs_hashmap_create(ext2fs_djb2_hash,
497 block_sha_map_free_entry, 4096);
498 if (!fs->block_sha_map) {
499 retval = EXT2_ET_NO_MEMORY;
500 goto cleanup;
501 }
502 ext2fs_set_feature_shared_blocks(fs->super);
503 }
504
505 fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR;
506 *ret_fs = fs;
507
508 return 0;
509 cleanup:
510 if (!(flags & EXT2_FLAG_NOFREE_ON_ERROR)) {
511 ext2fs_free(fs);
512 fs = NULL;
513 }
514 *ret_fs = fs;
515 return retval;
516 }
517
518 /*
519 * Set/get the filesystem data I/O channel.
520 *
521 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true.
522 */
ext2fs_get_data_io(ext2_filsys fs,io_channel * old_io)523 errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io)
524 {
525 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
526 return EXT2_ET_NOT_IMAGE_FILE;
527 if (old_io) {
528 *old_io = (fs->image_io == fs->io) ? 0 : fs->io;
529 }
530 return 0;
531 }
532
ext2fs_set_data_io(ext2_filsys fs,io_channel new_io)533 errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io)
534 {
535 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
536 return EXT2_ET_NOT_IMAGE_FILE;
537 fs->io = new_io ? new_io : fs->image_io;
538 return 0;
539 }
540
ext2fs_rewrite_to_io(ext2_filsys fs,io_channel new_io)541 errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io)
542 {
543 errcode_t err;
544
545 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
546 return EXT2_ET_NOT_IMAGE_FILE;
547 err = io_channel_set_blksize(new_io, fs->blocksize);
548 if (err)
549 return err;
550 if ((new_io == fs->image_io) || (new_io == fs->io))
551 return 0;
552 if ((fs->image_io != fs->io) &&
553 fs->image_io)
554 io_channel_close(fs->image_io);
555 if (fs->io)
556 io_channel_close(fs->io);
557 fs->io = fs->image_io = new_io;
558 fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW |
559 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY;
560 fs->flags &= ~EXT2_FLAG_IMAGE_FILE;
561 return 0;
562 }
563