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