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 <stdio.h>
13 #include <string.h>
14 #if HAVE_UNISTD_H
15 #include <unistd.h>
16 #endif
17 #include <fcntl.h>
18 #include <time.h>
19 #if HAVE_SYS_STAT_H
20 #include <sys/stat.h>
21 #endif
22 #if HAVE_SYS_TYPES_H
23 #include <sys/types.h>
24 #endif
25 #ifdef HAVE_ERRNO_H
26 #include <errno.h>
27 #endif
28
29 #include "ext2_fs.h"
30
31
32 #include "ext2fs.h"
33 #include "e2image.h"
34
ext2fs_descriptor_block_loc2(ext2_filsys fs,blk64_t group_block,dgrp_t i)35 blk64_t ext2fs_descriptor_block_loc2(ext2_filsys fs, blk64_t group_block,
36 dgrp_t i)
37 {
38 int bg;
39 int has_super = 0;
40 blk64_t ret_blk;
41
42 if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) ||
43 (i < fs->super->s_first_meta_bg))
44 return (group_block + i + 1);
45
46 bg = EXT2_DESC_PER_BLOCK(fs->super) * i;
47 if (ext2fs_bg_has_super(fs, bg))
48 has_super = 1;
49 ret_blk = ext2fs_group_first_block2(fs, bg) + has_super;
50 /*
51 * If group_block is not the normal value, we're trying to use
52 * the backup group descriptors and superblock --- so use the
53 * alternate location of the second block group in the
54 * metablock group. Ideally we should be testing each bg
55 * descriptor block individually for correctness, but we don't
56 * have the infrastructure in place to do that.
57 */
58 if (group_block != fs->super->s_first_data_block &&
59 ((ret_blk + fs->super->s_blocks_per_group) <
60 ext2fs_blocks_count(fs->super)))
61 ret_blk += fs->super->s_blocks_per_group;
62 return ret_blk;
63 }
64
ext2fs_descriptor_block_loc(ext2_filsys fs,blk_t group_block,dgrp_t i)65 blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i)
66 {
67 return ext2fs_descriptor_block_loc2(fs, group_block, i);
68 }
69
ext2fs_open(const char * name,int flags,int superblock,unsigned int block_size,io_manager manager,ext2_filsys * ret_fs)70 errcode_t ext2fs_open(const char *name, int flags, int superblock,
71 unsigned int block_size, io_manager manager,
72 ext2_filsys *ret_fs)
73 {
74 return ext2fs_open2(name, 0, flags, superblock, block_size,
75 manager, ret_fs);
76 }
77
78 /*
79 * Note: if superblock is non-zero, block-size must also be non-zero.
80 * Superblock and block_size can be zero to use the default size.
81 *
82 * Valid flags for ext2fs_open()
83 *
84 * EXT2_FLAG_RW - Open the filesystem for read/write.
85 * EXT2_FLAG_FORCE - Open the filesystem even if some of the
86 * features aren't supported.
87 * EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device
88 * EXT2_FLAG_SKIP_MMP - Open without multi-mount protection check.
89 * EXT2_FLAG_64BITS - Allow 64-bit bitfields (needed for large
90 * filesystems)
91 */
ext2fs_open2(const char * name,const char * io_options,int flags,int superblock,unsigned int block_size,io_manager manager,ext2_filsys * ret_fs)92 errcode_t ext2fs_open2(const char *name, const char *io_options,
93 int flags, int superblock,
94 unsigned int block_size, io_manager manager,
95 ext2_filsys *ret_fs)
96 {
97 ext2_filsys fs;
98 errcode_t retval;
99 unsigned long i, first_meta_bg;
100 __u32 features;
101 unsigned int blocks_per_group, io_flags;
102 blk64_t group_block, blk;
103 char *dest, *cp;
104 #ifdef WORDS_BIGENDIAN
105 unsigned int groups_per_block;
106 struct ext2_group_desc *gdp;
107 int j;
108 #endif
109
110 EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);
111
112 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
113 if (retval)
114 return retval;
115
116 memset(fs, 0, sizeof(struct struct_ext2_filsys));
117 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
118 fs->flags = flags;
119 /* don't overwrite sb backups unless flag is explicitly cleared */
120 fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;
121 fs->umask = 022;
122 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
123 if (retval)
124 goto cleanup;
125 strcpy(fs->device_name, name);
126 cp = strchr(fs->device_name, '?');
127 if (!io_options && cp) {
128 *cp++ = 0;
129 io_options = cp;
130 }
131
132 io_flags = 0;
133 if (flags & EXT2_FLAG_RW)
134 io_flags |= IO_FLAG_RW;
135 if (flags & EXT2_FLAG_EXCLUSIVE)
136 io_flags |= IO_FLAG_EXCLUSIVE;
137 if (flags & EXT2_FLAG_DIRECT_IO)
138 io_flags |= IO_FLAG_DIRECT_IO;
139 retval = manager->open(fs->device_name, io_flags, &fs->io);
140 if (retval)
141 goto cleanup;
142 if (io_options &&
143 (retval = io_channel_set_options(fs->io, io_options)))
144 goto cleanup;
145 fs->image_io = fs->io;
146 fs->io->app_data = fs;
147 retval = io_channel_alloc_buf(fs->io, -SUPERBLOCK_SIZE, &fs->super);
148 if (retval)
149 goto cleanup;
150 if (flags & EXT2_FLAG_IMAGE_FILE) {
151 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr),
152 &fs->image_header);
153 if (retval)
154 goto cleanup;
155 retval = io_channel_read_blk(fs->io, 0,
156 -(int)sizeof(struct ext2_image_hdr),
157 fs->image_header);
158 if (retval)
159 goto cleanup;
160 if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE)
161 return EXT2_ET_MAGIC_E2IMAGE;
162 superblock = 1;
163 block_size = fs->image_header->fs_blocksize;
164 }
165
166 /*
167 * If the user specifies a specific block # for the
168 * superblock, then he/she must also specify the block size!
169 * Otherwise, read the master superblock located at offset
170 * SUPERBLOCK_OFFSET from the start of the partition.
171 *
172 * Note: we only save a backup copy of the superblock if we
173 * are reading the superblock from the primary superblock location.
174 */
175 if (superblock) {
176 if (!block_size) {
177 retval = EXT2_ET_INVALID_ARGUMENT;
178 goto cleanup;
179 }
180 io_channel_set_blksize(fs->io, block_size);
181 group_block = superblock;
182 fs->orig_super = 0;
183 } else {
184 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
185 superblock = 1;
186 group_block = 0;
187 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super);
188 if (retval)
189 goto cleanup;
190 }
191 retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE,
192 fs->super);
193 if (retval)
194 goto cleanup;
195 if (fs->orig_super)
196 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE);
197
198 #ifdef WORDS_BIGENDIAN
199 fs->flags |= EXT2_FLAG_SWAP_BYTES;
200 ext2fs_swap_super(fs->super);
201 #else
202 if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
203 retval = EXT2_ET_UNIMPLEMENTED;
204 goto cleanup;
205 }
206 #endif
207
208 if (fs->super->s_magic != EXT2_SUPER_MAGIC) {
209 retval = EXT2_ET_BAD_MAGIC;
210 goto cleanup;
211 }
212 if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) {
213 retval = EXT2_ET_REV_TOO_HIGH;
214 goto cleanup;
215 }
216
217 /*
218 * Check for feature set incompatibility
219 */
220 if (!(flags & EXT2_FLAG_FORCE)) {
221 features = fs->super->s_feature_incompat;
222 #ifdef EXT2_LIB_SOFTSUPP_INCOMPAT
223 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
224 features &= ~EXT2_LIB_SOFTSUPP_INCOMPAT;
225 #endif
226 if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
227 retval = EXT2_ET_UNSUPP_FEATURE;
228 goto cleanup;
229 }
230
231 features = fs->super->s_feature_ro_compat;
232 #ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT
233 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
234 features &= ~EXT2_LIB_SOFTSUPP_RO_COMPAT;
235 #endif
236 if ((flags & EXT2_FLAG_RW) &&
237 (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {
238 retval = EXT2_ET_RO_UNSUPP_FEATURE;
239 goto cleanup;
240 }
241
242 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) &&
243 (fs->super->s_feature_incompat &
244 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) {
245 retval = EXT2_ET_UNSUPP_FEATURE;
246 goto cleanup;
247 }
248 }
249
250 if ((fs->super->s_log_block_size + EXT2_MIN_BLOCK_LOG_SIZE) >
251 EXT2_MAX_BLOCK_LOG_SIZE) {
252 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
253 goto cleanup;
254 }
255
256 /*
257 * bigalloc requires cluster-aware bitfield operations, which at the
258 * moment means we need EXT2_FLAG_64BITS.
259 */
260 if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
261 EXT4_FEATURE_RO_COMPAT_BIGALLOC) &&
262 !(flags & EXT2_FLAG_64BITS)) {
263 retval = EXT2_ET_CANT_USE_LEGACY_BITMAPS;
264 goto cleanup;
265 }
266
267 if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
268 EXT4_FEATURE_RO_COMPAT_BIGALLOC) &&
269 (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) {
270 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
271 goto cleanup;
272 }
273 fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(fs->super);
274 if (EXT2_INODE_SIZE(fs->super) < EXT2_GOOD_OLD_INODE_SIZE) {
275 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
276 goto cleanup;
277 }
278 fs->cluster_ratio_bits = fs->super->s_log_cluster_size -
279 fs->super->s_log_block_size;
280 if (EXT2_BLOCKS_PER_GROUP(fs->super) !=
281 EXT2_CLUSTERS_PER_GROUP(fs->super) << fs->cluster_ratio_bits) {
282 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
283 goto cleanup;
284 }
285 fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) *
286 EXT2_INODE_SIZE(fs->super) +
287 EXT2_BLOCK_SIZE(fs->super) - 1) /
288 EXT2_BLOCK_SIZE(fs->super));
289 if (block_size) {
290 if (block_size != fs->blocksize) {
291 retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE;
292 goto cleanup;
293 }
294 }
295 /*
296 * Set the blocksize to the filesystem's blocksize.
297 */
298 io_channel_set_blksize(fs->io, fs->blocksize);
299
300 /*
301 * If this is an external journal device, don't try to read
302 * the group descriptors, because they're not there.
303 */
304 if (fs->super->s_feature_incompat &
305 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
306 fs->group_desc_count = 0;
307 *ret_fs = fs;
308 return 0;
309 }
310
311 if (EXT2_INODES_PER_GROUP(fs->super) == 0) {
312 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
313 goto cleanup;
314 }
315
316 /*
317 * Read group descriptors
318 */
319 blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super);
320 if (blocks_per_group == 0 ||
321 blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) ||
322 fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) ||
323 EXT2_DESC_PER_BLOCK(fs->super) == 0 ||
324 fs->super->s_first_data_block >= ext2fs_blocks_count(fs->super)) {
325 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
326 goto cleanup;
327 }
328 fs->group_desc_count = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) -
329 fs->super->s_first_data_block,
330 blocks_per_group);
331 if (fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) !=
332 fs->super->s_inodes_count) {
333 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
334 goto cleanup;
335 }
336 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
337 EXT2_DESC_PER_BLOCK(fs->super));
338 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
339 &fs->group_desc);
340 if (retval)
341 goto cleanup;
342 if (!group_block)
343 group_block = fs->super->s_first_data_block;
344 if (group_block == 0 && fs->blocksize == 1024)
345 group_block = 1; /* Deal with 1024 blocksize && bigalloc */
346 dest = (char *) fs->group_desc;
347 #ifdef WORDS_BIGENDIAN
348 groups_per_block = EXT2_DESC_PER_BLOCK(fs->super);
349 #endif
350 if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
351 first_meta_bg = fs->super->s_first_meta_bg;
352 else
353 first_meta_bg = fs->desc_blocks;
354 if (first_meta_bg) {
355 retval = io_channel_read_blk(fs->io, group_block+1,
356 first_meta_bg, dest);
357 if (retval)
358 goto cleanup;
359 #ifdef WORDS_BIGENDIAN
360 gdp = (struct ext2_group_desc *) dest;
361 for (j=0; j < groups_per_block*first_meta_bg; j++) {
362 gdp = ext2fs_group_desc(fs, fs->group_desc, j);
363 ext2fs_swap_group_desc2(fs, gdp);
364 }
365 #endif
366 dest += fs->blocksize*first_meta_bg;
367 }
368 for (i=first_meta_bg ; i < fs->desc_blocks; i++) {
369 blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
370 retval = io_channel_read_blk64(fs->io, blk, 1, dest);
371 if (retval)
372 goto cleanup;
373 #ifdef WORDS_BIGENDIAN
374 for (j=0; j < groups_per_block; j++) {
375 gdp = ext2fs_group_desc(fs, fs->group_desc,
376 i * groups_per_block + j);
377 ext2fs_swap_group_desc2(fs, gdp);
378 }
379 #endif
380 dest += fs->blocksize;
381 }
382
383 fs->stride = fs->super->s_raid_stride;
384
385 /*
386 * If recovery is from backup superblock, Clear _UNININT flags &
387 * reset bg_itable_unused to zero
388 */
389 if (superblock > 1 && EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
390 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
391 dgrp_t group;
392
393 for (group = 0; group < fs->group_desc_count; group++) {
394 ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
395 ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
396 ext2fs_bg_itable_unused_set(fs, group, 0);
397 /* The checksum will be reset later, but fix it here
398 * anyway to avoid printing a lot of spurious errors. */
399 ext2fs_group_desc_csum_set(fs, group);
400 }
401 if (fs->flags & EXT2_FLAG_RW)
402 ext2fs_mark_super_dirty(fs);
403 }
404
405 if ((fs->super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_MMP) &&
406 !(flags & EXT2_FLAG_SKIP_MMP) &&
407 (flags & (EXT2_FLAG_RW | EXT2_FLAG_EXCLUSIVE))) {
408 retval = ext2fs_mmp_start(fs);
409 if (retval) {
410 fs->flags |= EXT2_FLAG_SKIP_MMP; /* just do cleanup */
411 ext2fs_mmp_stop(fs);
412 goto cleanup;
413 }
414 }
415
416 fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR;
417 *ret_fs = fs;
418
419 return 0;
420 cleanup:
421 if (flags & EXT2_FLAG_NOFREE_ON_ERROR)
422 *ret_fs = fs;
423 else
424 ext2fs_free(fs);
425 return retval;
426 }
427
428 /*
429 * Set/get the filesystem data I/O channel.
430 *
431 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true.
432 */
ext2fs_get_data_io(ext2_filsys fs,io_channel * old_io)433 errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io)
434 {
435 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
436 return EXT2_ET_NOT_IMAGE_FILE;
437 if (old_io) {
438 *old_io = (fs->image_io == fs->io) ? 0 : fs->io;
439 }
440 return 0;
441 }
442
ext2fs_set_data_io(ext2_filsys fs,io_channel new_io)443 errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io)
444 {
445 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
446 return EXT2_ET_NOT_IMAGE_FILE;
447 fs->io = new_io ? new_io : fs->image_io;
448 return 0;
449 }
450
ext2fs_rewrite_to_io(ext2_filsys fs,io_channel new_io)451 errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io)
452 {
453 errcode_t err;
454
455 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
456 return EXT2_ET_NOT_IMAGE_FILE;
457 err = io_channel_set_blksize(new_io, fs->blocksize);
458 if (err)
459 return err;
460 if ((new_io == fs->image_io) || (new_io == fs->io))
461 return 0;
462 if ((fs->image_io != fs->io) &&
463 fs->image_io)
464 io_channel_close(fs->image_io);
465 if (fs->io)
466 io_channel_close(fs->io);
467 fs->io = fs->image_io = new_io;
468 fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW |
469 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY;
470 fs->flags &= ~EXT2_FLAG_IMAGE_FILE;
471 return 0;
472 }
473