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
97 /*
98 * Note: if superblock is non-zero, block-size must also be non-zero.
99 * Superblock and block_size can be zero to use the default size.
100 *
101 * Valid flags for ext2fs_open()
102 *
103 * EXT2_FLAG_RW - Open the filesystem for read/write.
104 * EXT2_FLAG_FORCE - Open the filesystem even if some of the
105 * features aren't supported.
106 * EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device
107 * EXT2_FLAG_SKIP_MMP - Open without multi-mount protection check.
108 * EXT2_FLAG_64BITS - Allow 64-bit bitfields (needed for large
109 * filesystems)
110 */
ext2fs_open2(const char * name,const char * io_options,int flags,int superblock,unsigned int block_size,io_manager manager,ext2_filsys * ret_fs)111 errcode_t ext2fs_open2(const char *name, const char *io_options,
112 int flags, int superblock,
113 unsigned int block_size, io_manager manager,
114 ext2_filsys *ret_fs)
115 {
116 ext2_filsys fs;
117 errcode_t retval;
118 unsigned long i, first_meta_bg;
119 __u32 features;
120 unsigned int blocks_per_group, io_flags;
121 blk64_t group_block, blk;
122 char *dest, *cp;
123 int group_zero_adjust = 0;
124 #ifdef WORDS_BIGENDIAN
125 unsigned int groups_per_block;
126 struct ext2_group_desc *gdp;
127 int j;
128 #endif
129 char *time_env;
130
131 EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);
132
133 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
134 if (retval)
135 return retval;
136
137 memset(fs, 0, sizeof(struct struct_ext2_filsys));
138 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
139 fs->flags = flags;
140 /* don't overwrite sb backups unless flag is explicitly cleared */
141 fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;
142 fs->umask = 022;
143
144 time_env = getenv("E2FSPROGS_FAKE_TIME");
145 if (time_env)
146 fs->now = strtoul(time_env, NULL, 0);
147
148 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
149 if (retval)
150 goto cleanup;
151 strcpy(fs->device_name, name);
152 cp = strchr(fs->device_name, '?');
153 if (!io_options && cp) {
154 *cp++ = 0;
155 io_options = cp;
156 }
157
158 io_flags = 0;
159 if (flags & EXT2_FLAG_RW)
160 io_flags |= IO_FLAG_RW;
161 if (flags & EXT2_FLAG_EXCLUSIVE)
162 io_flags |= IO_FLAG_EXCLUSIVE;
163 if (flags & EXT2_FLAG_DIRECT_IO)
164 io_flags |= IO_FLAG_DIRECT_IO;
165 retval = manager->open(fs->device_name, io_flags, &fs->io);
166 if (retval)
167 goto cleanup;
168 if (io_options &&
169 (retval = io_channel_set_options(fs->io, io_options)))
170 goto cleanup;
171 fs->image_io = fs->io;
172 fs->io->app_data = fs;
173 retval = io_channel_alloc_buf(fs->io, -SUPERBLOCK_SIZE, &fs->super);
174 if (retval)
175 goto cleanup;
176 if (flags & EXT2_FLAG_IMAGE_FILE) {
177 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr),
178 &fs->image_header);
179 if (retval)
180 goto cleanup;
181 retval = io_channel_read_blk(fs->io, 0,
182 -(int)sizeof(struct ext2_image_hdr),
183 fs->image_header);
184 if (retval)
185 goto cleanup;
186 if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE)
187 return EXT2_ET_MAGIC_E2IMAGE;
188 superblock = 1;
189 block_size = fs->image_header->fs_blocksize;
190 }
191
192 /*
193 * If the user specifies a specific block # for the
194 * superblock, then he/she must also specify the block size!
195 * Otherwise, read the master superblock located at offset
196 * SUPERBLOCK_OFFSET from the start of the partition.
197 *
198 * Note: we only save a backup copy of the superblock if we
199 * are reading the superblock from the primary superblock location.
200 */
201 if (superblock) {
202 if (!block_size) {
203 retval = EXT2_ET_INVALID_ARGUMENT;
204 goto cleanup;
205 }
206 io_channel_set_blksize(fs->io, block_size);
207 group_block = superblock;
208 fs->orig_super = 0;
209 } else {
210 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
211 superblock = 1;
212 group_block = 0;
213 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super);
214 if (retval)
215 goto cleanup;
216 }
217 retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE,
218 fs->super);
219 if (retval)
220 goto cleanup;
221 if (fs->orig_super)
222 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE);
223
224 if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS)) {
225 retval = 0;
226 if (!ext2fs_verify_csum_type(fs, fs->super))
227 retval = EXT2_ET_UNKNOWN_CSUM;
228 if (!ext2fs_superblock_csum_verify(fs, fs->super))
229 retval = EXT2_ET_SB_CSUM_INVALID;
230 }
231
232 #ifdef WORDS_BIGENDIAN
233 fs->flags |= EXT2_FLAG_SWAP_BYTES;
234 ext2fs_swap_super(fs->super);
235 #else
236 if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
237 retval = EXT2_ET_UNIMPLEMENTED;
238 goto cleanup;
239 }
240 #endif
241
242 if (fs->super->s_magic != EXT2_SUPER_MAGIC)
243 retval = EXT2_ET_BAD_MAGIC;
244 if (retval)
245 goto cleanup;
246
247 if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) {
248 retval = EXT2_ET_REV_TOO_HIGH;
249 goto cleanup;
250 }
251
252 /*
253 * Check for feature set incompatibility
254 */
255 if (!(flags & EXT2_FLAG_FORCE)) {
256 features = fs->super->s_feature_incompat;
257 #ifdef EXT2_LIB_SOFTSUPP_INCOMPAT
258 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
259 features &= ~EXT2_LIB_SOFTSUPP_INCOMPAT;
260 #endif
261 if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
262 retval = EXT2_ET_UNSUPP_FEATURE;
263 goto cleanup;
264 }
265
266 features = fs->super->s_feature_ro_compat;
267 #ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT
268 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
269 features &= ~EXT2_LIB_SOFTSUPP_RO_COMPAT;
270 #endif
271 if ((flags & EXT2_FLAG_RW) &&
272 (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {
273 retval = EXT2_ET_RO_UNSUPP_FEATURE;
274 goto cleanup;
275 }
276
277 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) &&
278 ext2fs_has_feature_journal_dev(fs->super)) {
279 retval = EXT2_ET_UNSUPP_FEATURE;
280 goto cleanup;
281 }
282 }
283
284 if ((fs->super->s_log_block_size + EXT2_MIN_BLOCK_LOG_SIZE) >
285 EXT2_MAX_BLOCK_LOG_SIZE) {
286 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
287 goto cleanup;
288 }
289
290 /*
291 * bigalloc requires cluster-aware bitfield operations, which at the
292 * moment means we need EXT2_FLAG_64BITS.
293 */
294 if (ext2fs_has_feature_bigalloc(fs->super) &&
295 !(flags & EXT2_FLAG_64BITS)) {
296 retval = EXT2_ET_CANT_USE_LEGACY_BITMAPS;
297 goto cleanup;
298 }
299
300 if (!ext2fs_has_feature_bigalloc(fs->super) &&
301 (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) {
302 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
303 goto cleanup;
304 }
305 fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(fs->super);
306 if (EXT2_INODE_SIZE(fs->super) < EXT2_GOOD_OLD_INODE_SIZE) {
307 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
308 goto cleanup;
309 }
310
311 /* Enforce the block group descriptor size */
312 if (ext2fs_has_feature_64bit(fs->super)) {
313 if (fs->super->s_desc_size < EXT2_MIN_DESC_SIZE_64BIT) {
314 retval = EXT2_ET_BAD_DESC_SIZE;
315 goto cleanup;
316 }
317 } else {
318 if (fs->super->s_desc_size &&
319 fs->super->s_desc_size != EXT2_MIN_DESC_SIZE) {
320 retval = EXT2_ET_BAD_DESC_SIZE;
321 goto cleanup;
322 }
323 }
324
325 fs->cluster_ratio_bits = fs->super->s_log_cluster_size -
326 fs->super->s_log_block_size;
327 if (EXT2_BLOCKS_PER_GROUP(fs->super) !=
328 EXT2_CLUSTERS_PER_GROUP(fs->super) << fs->cluster_ratio_bits) {
329 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
330 goto cleanup;
331 }
332 fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) *
333 EXT2_INODE_SIZE(fs->super) +
334 EXT2_BLOCK_SIZE(fs->super) - 1) /
335 EXT2_BLOCK_SIZE(fs->super));
336 if (block_size) {
337 if (block_size != fs->blocksize) {
338 retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE;
339 goto cleanup;
340 }
341 }
342 /*
343 * Set the blocksize to the filesystem's blocksize.
344 */
345 io_channel_set_blksize(fs->io, fs->blocksize);
346
347 /*
348 * If this is an external journal device, don't try to read
349 * the group descriptors, because they're not there.
350 */
351 if (ext2fs_has_feature_journal_dev(fs->super)) {
352 fs->group_desc_count = 0;
353 *ret_fs = fs;
354 return 0;
355 }
356
357 if (EXT2_INODES_PER_GROUP(fs->super) == 0) {
358 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
359 goto cleanup;
360 }
361 /* Precompute the FS UUID to seed other checksums */
362 ext2fs_init_csum_seed(fs);
363
364 /*
365 * Read group descriptors
366 */
367 blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super);
368 if (blocks_per_group == 0 ||
369 blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) ||
370 fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) ||
371 EXT2_DESC_PER_BLOCK(fs->super) == 0 ||
372 fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) {
373 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
374 goto cleanup;
375 }
376 fs->group_desc_count = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) -
377 fs->super->s_first_data_block,
378 blocks_per_group);
379 if (fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) !=
380 fs->super->s_inodes_count) {
381 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
382 goto cleanup;
383 }
384 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
385 EXT2_DESC_PER_BLOCK(fs->super));
386 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
387 &fs->group_desc);
388 if (retval)
389 goto cleanup;
390 if (!group_block)
391 group_block = fs->super->s_first_data_block;
392 /*
393 * On a FS with a 1K blocksize, block 0 is reserved for bootloaders
394 * so we must increment block numbers to any group 0 items.
395 *
396 * However, we cannot touch group_block directly because in the meta_bg
397 * case, the ext2fs_descriptor_block_loc2() function will interpret
398 * group_block != s_first_data_block to mean that we want to access the
399 * backup group descriptors. This is not what we want if the caller
400 * set superblock == 0 (i.e. auto-detect the superblock), which is
401 * what's going on here.
402 */
403 if (group_block == 0 && fs->blocksize == 1024)
404 group_zero_adjust = 1;
405 dest = (char *) fs->group_desc;
406 #ifdef WORDS_BIGENDIAN
407 groups_per_block = EXT2_DESC_PER_BLOCK(fs->super);
408 #endif
409 if (ext2fs_has_feature_meta_bg(fs->super)) {
410 first_meta_bg = fs->super->s_first_meta_bg;
411 if (first_meta_bg > fs->desc_blocks)
412 first_meta_bg = fs->desc_blocks;
413 } else
414 first_meta_bg = fs->desc_blocks;
415 if (first_meta_bg) {
416 retval = io_channel_read_blk(fs->io, group_block +
417 group_zero_adjust + 1,
418 first_meta_bg, dest);
419 if (retval)
420 goto cleanup;
421 #ifdef WORDS_BIGENDIAN
422 gdp = (struct ext2_group_desc *) dest;
423 for (j=0; j < groups_per_block*first_meta_bg; j++) {
424 gdp = ext2fs_group_desc(fs, fs->group_desc, j);
425 ext2fs_swap_group_desc2(fs, gdp);
426 }
427 #endif
428 dest += fs->blocksize*first_meta_bg;
429 }
430 for (i=first_meta_bg ; i < fs->desc_blocks; i++) {
431 blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
432 retval = io_channel_read_blk64(fs->io, blk, 1, dest);
433 if (retval)
434 goto cleanup;
435 #ifdef WORDS_BIGENDIAN
436 for (j=0; j < groups_per_block; j++) {
437 gdp = ext2fs_group_desc(fs, fs->group_desc,
438 i * groups_per_block + j);
439 ext2fs_swap_group_desc2(fs, gdp);
440 }
441 #endif
442 dest += fs->blocksize;
443 }
444
445 fs->stride = fs->super->s_raid_stride;
446
447 /*
448 * If recovery is from backup superblock, Clear _UNININT flags &
449 * reset bg_itable_unused to zero
450 */
451 if (superblock > 1 && ext2fs_has_group_desc_csum(fs)) {
452 dgrp_t group;
453
454 for (group = 0; group < fs->group_desc_count; group++) {
455 ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
456 ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
457 ext2fs_bg_itable_unused_set(fs, group, 0);
458 /* The checksum will be reset later, but fix it here
459 * anyway to avoid printing a lot of spurious errors. */
460 ext2fs_group_desc_csum_set(fs, group);
461 }
462 if (fs->flags & EXT2_FLAG_RW)
463 ext2fs_mark_super_dirty(fs);
464 }
465
466 if (ext2fs_has_feature_mmp(fs->super) &&
467 !(flags & EXT2_FLAG_SKIP_MMP) &&
468 (flags & (EXT2_FLAG_RW | EXT2_FLAG_EXCLUSIVE))) {
469 retval = ext2fs_mmp_start(fs);
470 if (retval) {
471 fs->flags |= EXT2_FLAG_SKIP_MMP; /* just do cleanup */
472 ext2fs_mmp_stop(fs);
473 goto cleanup;
474 }
475 }
476
477 fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR;
478 *ret_fs = fs;
479
480 return 0;
481 cleanup:
482 if (!(flags & EXT2_FLAG_NOFREE_ON_ERROR)) {
483 ext2fs_free(fs);
484 fs = NULL;
485 }
486 *ret_fs = fs;
487 return retval;
488 }
489
490 /*
491 * Set/get the filesystem data I/O channel.
492 *
493 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true.
494 */
ext2fs_get_data_io(ext2_filsys fs,io_channel * old_io)495 errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io)
496 {
497 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
498 return EXT2_ET_NOT_IMAGE_FILE;
499 if (old_io) {
500 *old_io = (fs->image_io == fs->io) ? 0 : fs->io;
501 }
502 return 0;
503 }
504
ext2fs_set_data_io(ext2_filsys fs,io_channel new_io)505 errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io)
506 {
507 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
508 return EXT2_ET_NOT_IMAGE_FILE;
509 fs->io = new_io ? new_io : fs->image_io;
510 return 0;
511 }
512
ext2fs_rewrite_to_io(ext2_filsys fs,io_channel new_io)513 errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io)
514 {
515 errcode_t err;
516
517 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
518 return EXT2_ET_NOT_IMAGE_FILE;
519 err = io_channel_set_blksize(new_io, fs->blocksize);
520 if (err)
521 return err;
522 if ((new_io == fs->image_io) || (new_io == fs->io))
523 return 0;
524 if ((fs->image_io != fs->io) &&
525 fs->image_io)
526 io_channel_close(fs->image_io);
527 if (fs->io)
528 io_channel_close(fs->io);
529 fs->io = fs->image_io = new_io;
530 fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW |
531 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY;
532 fs->flags &= ~EXT2_FLAG_IMAGE_FILE;
533 return 0;
534 }
535