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 #ifdef WORDS_BIGENDIAN
131 unsigned int groups_per_block;
132 struct ext2_group_desc *gdp;
133 int j;
134 #endif
135 char *time_env;
136
137 EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);
138
139 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
140 if (retval)
141 return retval;
142
143 memset(fs, 0, sizeof(struct struct_ext2_filsys));
144 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
145 fs->flags = flags;
146 /* don't overwrite sb backups unless flag is explicitly cleared */
147 fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;
148 fs->umask = 022;
149
150 time_env = getenv("E2FSPROGS_FAKE_TIME");
151 if (time_env)
152 fs->now = strtoul(time_env, NULL, 0);
153
154 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
155 if (retval)
156 goto cleanup;
157 strcpy(fs->device_name, name);
158 cp = strchr(fs->device_name, '?');
159 if (!io_options && cp) {
160 *cp++ = 0;
161 io_options = cp;
162 }
163
164 io_flags = 0;
165 if (flags & EXT2_FLAG_RW)
166 io_flags |= IO_FLAG_RW;
167 if (flags & EXT2_FLAG_EXCLUSIVE)
168 io_flags |= IO_FLAG_EXCLUSIVE;
169 if (flags & EXT2_FLAG_DIRECT_IO)
170 io_flags |= IO_FLAG_DIRECT_IO;
171 retval = manager->open(fs->device_name, io_flags, &fs->io);
172 if (retval)
173 goto cleanup;
174 if (io_options &&
175 (retval = io_channel_set_options(fs->io, io_options)))
176 goto cleanup;
177 fs->image_io = fs->io;
178 fs->io->app_data = fs;
179 retval = io_channel_alloc_buf(fs->io, -SUPERBLOCK_SIZE, &fs->super);
180 if (retval)
181 goto cleanup;
182 if (flags & EXT2_FLAG_IMAGE_FILE) {
183 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr),
184 &fs->image_header);
185 if (retval)
186 goto cleanup;
187 retval = io_channel_read_blk(fs->io, 0,
188 -(int)sizeof(struct ext2_image_hdr),
189 fs->image_header);
190 if (retval)
191 goto cleanup;
192 if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE)
193 return EXT2_ET_MAGIC_E2IMAGE;
194 superblock = 1;
195 block_size = fs->image_header->fs_blocksize;
196 }
197
198 /*
199 * If the user specifies a specific block # for the
200 * superblock, then he/she must also specify the block size!
201 * Otherwise, read the master superblock located at offset
202 * SUPERBLOCK_OFFSET from the start of the partition.
203 *
204 * Note: we only save a backup copy of the superblock if we
205 * are reading the superblock from the primary superblock location.
206 */
207 if (superblock) {
208 if (!block_size) {
209 retval = EXT2_ET_INVALID_ARGUMENT;
210 goto cleanup;
211 }
212 io_channel_set_blksize(fs->io, block_size);
213 group_block = superblock;
214 fs->orig_super = 0;
215 } else {
216 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
217 superblock = 1;
218 group_block = 0;
219 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super);
220 if (retval)
221 goto cleanup;
222 }
223 retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE,
224 fs->super);
225 if (retval)
226 goto cleanup;
227 if (fs->orig_super)
228 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE);
229
230 if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)) {
231 retval = 0;
232 if (!ext2fs_verify_csum_type(fs, fs->super))
233 retval = EXT2_ET_UNKNOWN_CSUM;
234 if (!ext2fs_superblock_csum_verify(fs, fs->super))
235 retval = EXT2_ET_SB_CSUM_INVALID;
236 }
237
238 #ifdef WORDS_BIGENDIAN
239 fs->flags |= EXT2_FLAG_SWAP_BYTES;
240 ext2fs_swap_super(fs->super);
241 #else
242 if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
243 retval = EXT2_ET_UNIMPLEMENTED;
244 goto cleanup;
245 }
246 #endif
247
248 if (fs->super->s_magic != EXT2_SUPER_MAGIC)
249 retval = EXT2_ET_BAD_MAGIC;
250 if (retval)
251 goto cleanup;
252
253 if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) {
254 retval = EXT2_ET_REV_TOO_HIGH;
255 goto cleanup;
256 }
257
258 /*
259 * Check for feature set incompatibility
260 */
261 if (!(flags & EXT2_FLAG_FORCE)) {
262 features = fs->super->s_feature_incompat;
263 #ifdef EXT2_LIB_SOFTSUPP_INCOMPAT
264 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
265 features &= ~EXT2_LIB_SOFTSUPP_INCOMPAT;
266 #endif
267 if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
268 retval = EXT2_ET_UNSUPP_FEATURE;
269 goto cleanup;
270 }
271
272 features = fs->super->s_feature_ro_compat;
273 #ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT
274 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
275 features &= ~EXT2_LIB_SOFTSUPP_RO_COMPAT;
276 #endif
277 if ((flags & EXT2_FLAG_RW) &&
278 (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {
279 retval = EXT2_ET_RO_UNSUPP_FEATURE;
280 goto cleanup;
281 }
282
283 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) &&
284 ext2fs_has_feature_journal_dev(fs->super)) {
285 retval = EXT2_ET_UNSUPP_FEATURE;
286 goto cleanup;
287 }
288 }
289
290 if ((fs->super->s_log_block_size + EXT2_MIN_BLOCK_LOG_SIZE) >
291 EXT2_MAX_BLOCK_LOG_SIZE) {
292 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
293 goto cleanup;
294 }
295
296 /*
297 * bigalloc requires cluster-aware bitfield operations, which at the
298 * moment means we need EXT2_FLAG_64BITS.
299 */
300 if (ext2fs_has_feature_bigalloc(fs->super) &&
301 !(flags & EXT2_FLAG_64BITS)) {
302 retval = EXT2_ET_CANT_USE_LEGACY_BITMAPS;
303 goto cleanup;
304 }
305
306 if (!ext2fs_has_feature_bigalloc(fs->super) &&
307 (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) {
308 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
309 goto cleanup;
310 }
311 fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(fs->super);
312 if (EXT2_INODE_SIZE(fs->super) < EXT2_GOOD_OLD_INODE_SIZE) {
313 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
314 goto cleanup;
315 }
316
317 /* Enforce the block group descriptor size */
318 if (ext2fs_has_feature_64bit(fs->super)) {
319 if (fs->super->s_desc_size < EXT2_MIN_DESC_SIZE_64BIT) {
320 retval = EXT2_ET_BAD_DESC_SIZE;
321 goto cleanup;
322 }
323 } else {
324 if (fs->super->s_desc_size &&
325 fs->super->s_desc_size != EXT2_MIN_DESC_SIZE) {
326 retval = EXT2_ET_BAD_DESC_SIZE;
327 goto cleanup;
328 }
329 }
330
331 fs->cluster_ratio_bits = fs->super->s_log_cluster_size -
332 fs->super->s_log_block_size;
333 if (EXT2_BLOCKS_PER_GROUP(fs->super) !=
334 EXT2_CLUSTERS_PER_GROUP(fs->super) << fs->cluster_ratio_bits) {
335 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
336 goto cleanup;
337 }
338 fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) *
339 EXT2_INODE_SIZE(fs->super) +
340 EXT2_BLOCK_SIZE(fs->super) - 1) /
341 EXT2_BLOCK_SIZE(fs->super));
342 if (block_size) {
343 if (block_size != fs->blocksize) {
344 retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE;
345 goto cleanup;
346 }
347 }
348 /*
349 * Set the blocksize to the filesystem's blocksize.
350 */
351 io_channel_set_blksize(fs->io, fs->blocksize);
352
353 /*
354 * If this is an external journal device, don't try to read
355 * the group descriptors, because they're not there.
356 */
357 if (ext2fs_has_feature_journal_dev(fs->super)) {
358 fs->group_desc_count = 0;
359 *ret_fs = fs;
360 return 0;
361 }
362
363 if (EXT2_INODES_PER_GROUP(fs->super) == 0) {
364 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
365 goto cleanup;
366 }
367 /* Precompute the FS UUID to seed other checksums */
368 ext2fs_init_csum_seed(fs);
369
370 /*
371 * Read group descriptors
372 */
373 blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super);
374 if (blocks_per_group == 0 ||
375 blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) ||
376 fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) ||
377 EXT2_DESC_PER_BLOCK(fs->super) == 0 ||
378 fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) {
379 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
380 goto cleanup;
381 }
382 fs->group_desc_count = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) -
383 fs->super->s_first_data_block,
384 blocks_per_group);
385 if (fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) !=
386 fs->super->s_inodes_count) {
387 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
388 goto cleanup;
389 }
390 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
391 EXT2_DESC_PER_BLOCK(fs->super));
392 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
393 &fs->group_desc);
394 if (retval)
395 goto cleanup;
396 if (!group_block)
397 group_block = fs->super->s_first_data_block;
398 /*
399 * On a FS with a 1K blocksize, block 0 is reserved for bootloaders
400 * so we must increment block numbers to any group 0 items.
401 *
402 * However, we cannot touch group_block directly because in the meta_bg
403 * case, the ext2fs_descriptor_block_loc2() function will interpret
404 * group_block != s_first_data_block to mean that we want to access the
405 * backup group descriptors. This is not what we want if the caller
406 * set superblock == 0 (i.e. auto-detect the superblock), which is
407 * what's going on here.
408 */
409 if (group_block == 0 && fs->blocksize == 1024)
410 group_zero_adjust = 1;
411 dest = (char *) fs->group_desc;
412 #ifdef WORDS_BIGENDIAN
413 groups_per_block = EXT2_DESC_PER_BLOCK(fs->super);
414 #endif
415 if (ext2fs_has_feature_meta_bg(fs->super)) {
416 first_meta_bg = fs->super->s_first_meta_bg;
417 if (first_meta_bg > fs->desc_blocks)
418 first_meta_bg = fs->desc_blocks;
419 } else
420 first_meta_bg = fs->desc_blocks;
421 if (first_meta_bg) {
422 retval = io_channel_read_blk(fs->io, group_block +
423 group_zero_adjust + 1,
424 first_meta_bg, dest);
425 if (retval)
426 goto cleanup;
427 #ifdef WORDS_BIGENDIAN
428 gdp = (struct ext2_group_desc *) dest;
429 for (j=0; j < groups_per_block*first_meta_bg; j++) {
430 gdp = ext2fs_group_desc(fs, fs->group_desc, j);
431 ext2fs_swap_group_desc2(fs, gdp);
432 }
433 #endif
434 dest += fs->blocksize*first_meta_bg;
435 }
436 for (i=first_meta_bg ; i < fs->desc_blocks; i++) {
437 blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
438 retval = io_channel_read_blk64(fs->io, blk, 1, dest);
439 if (retval)
440 goto cleanup;
441 #ifdef WORDS_BIGENDIAN
442 for (j=0; j < groups_per_block; j++) {
443 gdp = ext2fs_group_desc(fs, fs->group_desc,
444 i * groups_per_block + j);
445 ext2fs_swap_group_desc2(fs, gdp);
446 }
447 #endif
448 dest += fs->blocksize;
449 }
450
451 fs->stride = fs->super->s_raid_stride;
452
453 /*
454 * If recovery is from backup superblock, Clear _UNININT flags &
455 * reset bg_itable_unused to zero
456 */
457 if (superblock > 1 && ext2fs_has_group_desc_csum(fs)) {
458 dgrp_t group;
459
460 for (group = 0; group < fs->group_desc_count; group++) {
461 ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
462 ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
463 ext2fs_bg_itable_unused_set(fs, group, 0);
464 /* The checksum will be reset later, but fix it here
465 * anyway to avoid printing a lot of spurious errors. */
466 ext2fs_group_desc_csum_set(fs, group);
467 }
468 if (fs->flags & EXT2_FLAG_RW)
469 ext2fs_mark_super_dirty(fs);
470 }
471
472 if (ext2fs_has_feature_mmp(fs->super) &&
473 !(flags & EXT2_FLAG_SKIP_MMP) &&
474 (flags & (EXT2_FLAG_RW | EXT2_FLAG_EXCLUSIVE))) {
475 retval = ext2fs_mmp_start(fs);
476 if (retval) {
477 fs->flags |= EXT2_FLAG_SKIP_MMP; /* just do cleanup */
478 ext2fs_mmp_stop(fs);
479 goto cleanup;
480 }
481 }
482
483 if (fs->flags & EXT2_FLAG_SHARE_DUP) {
484 fs->block_sha_map = ext2fs_hashmap_create(ext2fs_djb2_hash,
485 block_sha_map_free_entry, 4096);
486 if (!fs->block_sha_map) {
487 retval = EXT2_ET_NO_MEMORY;
488 goto cleanup;
489 }
490 ext2fs_set_feature_shared_blocks(fs->super);
491 }
492
493 fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR;
494 *ret_fs = fs;
495
496 return 0;
497 cleanup:
498 if (!(flags & EXT2_FLAG_NOFREE_ON_ERROR)) {
499 ext2fs_free(fs);
500 fs = NULL;
501 }
502 *ret_fs = fs;
503 return retval;
504 }
505
506 /*
507 * Set/get the filesystem data I/O channel.
508 *
509 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true.
510 */
ext2fs_get_data_io(ext2_filsys fs,io_channel * old_io)511 errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io)
512 {
513 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
514 return EXT2_ET_NOT_IMAGE_FILE;
515 if (old_io) {
516 *old_io = (fs->image_io == fs->io) ? 0 : fs->io;
517 }
518 return 0;
519 }
520
ext2fs_set_data_io(ext2_filsys fs,io_channel new_io)521 errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io)
522 {
523 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
524 return EXT2_ET_NOT_IMAGE_FILE;
525 fs->io = new_io ? new_io : fs->image_io;
526 return 0;
527 }
528
ext2fs_rewrite_to_io(ext2_filsys fs,io_channel new_io)529 errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io)
530 {
531 errcode_t err;
532
533 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
534 return EXT2_ET_NOT_IMAGE_FILE;
535 err = io_channel_set_blksize(new_io, fs->blocksize);
536 if (err)
537 return err;
538 if ((new_io == fs->image_io) || (new_io == fs->io))
539 return 0;
540 if ((fs->image_io != fs->io) &&
541 fs->image_io)
542 io_channel_close(fs->image_io);
543 if (fs->io)
544 io_channel_close(fs->io);
545 fs->io = fs->image_io = new_io;
546 fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW |
547 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY;
548 fs->flags &= ~EXT2_FLAG_IMAGE_FILE;
549 return 0;
550 }
551