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
26 #include "ext2_fs.h"
27
28
29 #include "ext2fs.h"
30 #include "e2image.h"
31
ext2fs_descriptor_block_loc(ext2_filsys fs,blk_t group_block,dgrp_t i)32 blk_t ext2fs_descriptor_block_loc(ext2_filsys fs, blk_t group_block, dgrp_t i)
33 {
34 int bg;
35 int has_super = 0;
36 int ret_blk;
37
38 if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) ||
39 (i < fs->super->s_first_meta_bg))
40 return (group_block + i + 1);
41
42 bg = EXT2_DESC_PER_BLOCK(fs->super) * i;
43 if (ext2fs_bg_has_super(fs, bg))
44 has_super = 1;
45 ret_blk = ext2fs_group_first_block(fs, bg) + has_super;
46 /*
47 * If group_block is not the normal value, we're trying to use
48 * the backup group descriptors and superblock --- so use the
49 * alternate location of the second block group in the
50 * metablock group. Ideally we should be testing each bg
51 * descriptor block individually for correctness, but we don't
52 * have the infrastructure in place to do that.
53 */
54 if (group_block != fs->super->s_first_data_block &&
55 ((ret_blk + fs->super->s_blocks_per_group) <
56 fs->super->s_blocks_count))
57 ret_blk += fs->super->s_blocks_per_group;
58 return ret_blk;
59 }
60
ext2fs_open(const char * name,int flags,int superblock,unsigned int block_size,io_manager manager,ext2_filsys * ret_fs)61 errcode_t ext2fs_open(const char *name, int flags, int superblock,
62 unsigned int block_size, io_manager manager,
63 ext2_filsys *ret_fs)
64 {
65 return ext2fs_open2(name, 0, flags, superblock, block_size,
66 manager, ret_fs);
67 }
68
69 /*
70 * Note: if superblock is non-zero, block-size must also be non-zero.
71 * Superblock and block_size can be zero to use the default size.
72 *
73 * Valid flags for ext2fs_open()
74 *
75 * EXT2_FLAG_RW - Open the filesystem for read/write.
76 * EXT2_FLAG_FORCE - Open the filesystem even if some of the
77 * features aren't supported.
78 * EXT2_FLAG_JOURNAL_DEV_OK - Open an ext3 journal device
79 */
ext2fs_open2(const char * name,const char * io_options,int flags,int superblock,unsigned int block_size,io_manager manager,ext2_filsys * ret_fs)80 errcode_t ext2fs_open2(const char *name, const char *io_options,
81 int flags, int superblock,
82 unsigned int block_size, io_manager manager,
83 ext2_filsys *ret_fs)
84 {
85 ext2_filsys fs;
86 errcode_t retval;
87 unsigned long i, first_meta_bg;
88 __u32 features;
89 int groups_per_block, blocks_per_group, io_flags;
90 blk_t group_block, blk;
91 char *dest, *cp;
92 #ifdef WORDS_BIGENDIAN
93 struct ext2_group_desc *gdp;
94 int j;
95 #endif
96
97 EXT2_CHECK_MAGIC(manager, EXT2_ET_MAGIC_IO_MANAGER);
98
99 retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
100 if (retval)
101 return retval;
102
103 memset(fs, 0, sizeof(struct struct_ext2_filsys));
104 fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
105 fs->flags = flags;
106 /* don't overwrite sb backups unless flag is explicitly cleared */
107 fs->flags |= EXT2_FLAG_MASTER_SB_ONLY;
108 fs->umask = 022;
109 retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
110 if (retval)
111 goto cleanup;
112 strcpy(fs->device_name, name);
113 cp = strchr(fs->device_name, '?');
114 if (!io_options && cp) {
115 *cp++ = 0;
116 io_options = cp;
117 }
118
119 io_flags = 0;
120 if (flags & EXT2_FLAG_RW)
121 io_flags |= IO_FLAG_RW;
122 if (flags & EXT2_FLAG_EXCLUSIVE)
123 io_flags |= IO_FLAG_EXCLUSIVE;
124 if (flags & EXT2_FLAG_DIRECT_IO)
125 io_flags |= IO_FLAG_DIRECT_IO;
126 retval = manager->open(fs->device_name, io_flags, &fs->io);
127 if (retval)
128 goto cleanup;
129 if (io_options &&
130 (retval = io_channel_set_options(fs->io, io_options)))
131 goto cleanup;
132 fs->image_io = fs->io;
133 fs->io->app_data = fs;
134 retval = ext2fs_get_memalign(SUPERBLOCK_SIZE, 512, &fs->super);
135 if (retval)
136 goto cleanup;
137 if (flags & EXT2_FLAG_IMAGE_FILE) {
138 retval = ext2fs_get_mem(sizeof(struct ext2_image_hdr),
139 &fs->image_header);
140 if (retval)
141 goto cleanup;
142 retval = io_channel_read_blk(fs->io, 0,
143 -(int)sizeof(struct ext2_image_hdr),
144 fs->image_header);
145 if (retval)
146 goto cleanup;
147 if (fs->image_header->magic_number != EXT2_ET_MAGIC_E2IMAGE)
148 return EXT2_ET_MAGIC_E2IMAGE;
149 superblock = 1;
150 block_size = fs->image_header->fs_blocksize;
151 }
152
153 /*
154 * If the user specifies a specific block # for the
155 * superblock, then he/she must also specify the block size!
156 * Otherwise, read the master superblock located at offset
157 * SUPERBLOCK_OFFSET from the start of the partition.
158 *
159 * Note: we only save a backup copy of the superblock if we
160 * are reading the superblock from the primary superblock location.
161 */
162 if (superblock) {
163 if (!block_size) {
164 retval = EXT2_ET_INVALID_ARGUMENT;
165 goto cleanup;
166 }
167 io_channel_set_blksize(fs->io, block_size);
168 group_block = superblock;
169 fs->orig_super = 0;
170 } else {
171 io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET);
172 superblock = 1;
173 group_block = 0;
174 retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->orig_super);
175 if (retval)
176 goto cleanup;
177 }
178 retval = io_channel_read_blk(fs->io, superblock, -SUPERBLOCK_SIZE,
179 fs->super);
180 if (retval)
181 goto cleanup;
182 if (fs->orig_super)
183 memcpy(fs->orig_super, fs->super, SUPERBLOCK_SIZE);
184
185 #ifdef WORDS_BIGENDIAN
186 fs->flags |= EXT2_FLAG_SWAP_BYTES;
187 ext2fs_swap_super(fs->super);
188 #else
189 if (fs->flags & EXT2_FLAG_SWAP_BYTES) {
190 retval = EXT2_ET_UNIMPLEMENTED;
191 goto cleanup;
192 }
193 #endif
194
195 if (fs->super->s_magic != EXT2_SUPER_MAGIC) {
196 retval = EXT2_ET_BAD_MAGIC;
197 goto cleanup;
198 }
199 if (fs->super->s_rev_level > EXT2_LIB_CURRENT_REV) {
200 retval = EXT2_ET_REV_TOO_HIGH;
201 goto cleanup;
202 }
203
204 /*
205 * Check for feature set incompatibility
206 */
207 if (!(flags & EXT2_FLAG_FORCE)) {
208 features = fs->super->s_feature_incompat;
209 #ifdef EXT2_LIB_SOFTSUPP_INCOMPAT
210 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
211 features &= !EXT2_LIB_SOFTSUPP_INCOMPAT;
212 #endif
213 if (features & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
214 retval = EXT2_ET_UNSUPP_FEATURE;
215 goto cleanup;
216 }
217
218 features = fs->super->s_feature_ro_compat;
219 #ifdef EXT2_LIB_SOFTSUPP_RO_COMPAT
220 if (flags & EXT2_FLAG_SOFTSUPP_FEATURES)
221 features &= !EXT2_LIB_SOFTSUPP_RO_COMPAT;
222 #endif
223 if ((flags & EXT2_FLAG_RW) &&
224 (features & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP)) {
225 retval = EXT2_ET_RO_UNSUPP_FEATURE;
226 goto cleanup;
227 }
228
229 if (!(flags & EXT2_FLAG_JOURNAL_DEV_OK) &&
230 (fs->super->s_feature_incompat &
231 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) {
232 retval = EXT2_ET_UNSUPP_FEATURE;
233 goto cleanup;
234 }
235 }
236
237 if ((fs->super->s_log_block_size + EXT2_MIN_BLOCK_LOG_SIZE) >
238 EXT2_MAX_BLOCK_LOG_SIZE) {
239 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
240 goto cleanup;
241 }
242 fs->blocksize = EXT2_BLOCK_SIZE(fs->super);
243 if (EXT2_INODE_SIZE(fs->super) < EXT2_GOOD_OLD_INODE_SIZE) {
244 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
245 goto cleanup;
246 }
247 fs->fragsize = EXT2_FRAG_SIZE(fs->super);
248 fs->inode_blocks_per_group = ((EXT2_INODES_PER_GROUP(fs->super) *
249 EXT2_INODE_SIZE(fs->super) +
250 EXT2_BLOCK_SIZE(fs->super) - 1) /
251 EXT2_BLOCK_SIZE(fs->super));
252 if (block_size) {
253 if (block_size != fs->blocksize) {
254 retval = EXT2_ET_UNEXPECTED_BLOCK_SIZE;
255 goto cleanup;
256 }
257 }
258 /*
259 * Set the blocksize to the filesystem's blocksize.
260 */
261 io_channel_set_blksize(fs->io, fs->blocksize);
262
263 /*
264 * If this is an external journal device, don't try to read
265 * the group descriptors, because they're not there.
266 */
267 if (fs->super->s_feature_incompat &
268 EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
269 fs->group_desc_count = 0;
270 *ret_fs = fs;
271 return 0;
272 }
273
274 if (EXT2_INODES_PER_GROUP(fs->super) == 0) {
275 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
276 goto cleanup;
277 }
278
279 /*
280 * Read group descriptors
281 */
282 blocks_per_group = EXT2_BLOCKS_PER_GROUP(fs->super);
283 if (blocks_per_group == 0 ||
284 blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(fs->super) ||
285 fs->inode_blocks_per_group > EXT2_MAX_INODES_PER_GROUP(fs->super) ||
286 EXT2_DESC_PER_BLOCK(fs->super) == 0 ||
287 fs->super->s_first_data_block >= fs->super->s_blocks_count) {
288 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
289 goto cleanup;
290 }
291 fs->group_desc_count = ext2fs_div_ceil(fs->super->s_blocks_count -
292 fs->super->s_first_data_block,
293 blocks_per_group);
294 if (fs->group_desc_count * EXT2_INODES_PER_GROUP(fs->super) !=
295 fs->super->s_inodes_count) {
296 retval = EXT2_ET_CORRUPT_SUPERBLOCK;
297 goto cleanup;
298 }
299 fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
300 EXT2_DESC_PER_BLOCK(fs->super));
301 retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
302 &fs->group_desc);
303 if (retval)
304 goto cleanup;
305 if (!group_block)
306 group_block = fs->super->s_first_data_block;
307 dest = (char *) fs->group_desc;
308 groups_per_block = EXT2_DESC_PER_BLOCK(fs->super);
309 if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
310 first_meta_bg = fs->super->s_first_meta_bg;
311 else
312 first_meta_bg = fs->desc_blocks;
313 if (first_meta_bg) {
314 retval = io_channel_read_blk(fs->io, group_block+1,
315 first_meta_bg, dest);
316 if (retval)
317 goto cleanup;
318 #ifdef WORDS_BIGENDIAN
319 gdp = (struct ext2_group_desc *) dest;
320 for (j=0; j < groups_per_block*first_meta_bg; j++)
321 ext2fs_swap_group_desc(gdp++);
322 #endif
323 dest += fs->blocksize*first_meta_bg;
324 }
325 for (i=first_meta_bg ; i < fs->desc_blocks; i++) {
326 blk = ext2fs_descriptor_block_loc(fs, group_block, i);
327 retval = io_channel_read_blk(fs->io, blk, 1, dest);
328 if (retval)
329 goto cleanup;
330 #ifdef WORDS_BIGENDIAN
331 gdp = (struct ext2_group_desc *) dest;
332 for (j=0; j < groups_per_block; j++)
333 ext2fs_swap_group_desc(gdp++);
334 #endif
335 dest += fs->blocksize;
336 }
337
338 fs->stride = fs->super->s_raid_stride;
339
340 /*
341 * If recovery is from backup superblock, Clear _UNININT flags &
342 * reset bg_itable_unused to zero
343 */
344 if (superblock > 1 && EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
345 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
346 struct ext2_group_desc *gd;
347 for (i = 0, gd = fs->group_desc; i < fs->group_desc_count;
348 i++, gd++) {
349 gd->bg_flags &= ~EXT2_BG_BLOCK_UNINIT;
350 gd->bg_flags &= ~EXT2_BG_INODE_UNINIT;
351 gd->bg_itable_unused = 0;
352 }
353 ext2fs_mark_super_dirty(fs);
354 }
355
356 fs->flags &= ~EXT2_FLAG_NOFREE_ON_ERROR;
357 *ret_fs = fs;
358 return 0;
359 cleanup:
360 if (flags & EXT2_FLAG_NOFREE_ON_ERROR)
361 *ret_fs = fs;
362 else
363 ext2fs_free(fs);
364 return retval;
365 }
366
367 /*
368 * Set/get the filesystem data I/O channel.
369 *
370 * These functions are only valid if EXT2_FLAG_IMAGE_FILE is true.
371 */
ext2fs_get_data_io(ext2_filsys fs,io_channel * old_io)372 errcode_t ext2fs_get_data_io(ext2_filsys fs, io_channel *old_io)
373 {
374 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
375 return EXT2_ET_NOT_IMAGE_FILE;
376 if (old_io) {
377 *old_io = (fs->image_io == fs->io) ? 0 : fs->io;
378 }
379 return 0;
380 }
381
ext2fs_set_data_io(ext2_filsys fs,io_channel new_io)382 errcode_t ext2fs_set_data_io(ext2_filsys fs, io_channel new_io)
383 {
384 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
385 return EXT2_ET_NOT_IMAGE_FILE;
386 fs->io = new_io ? new_io : fs->image_io;
387 return 0;
388 }
389
ext2fs_rewrite_to_io(ext2_filsys fs,io_channel new_io)390 errcode_t ext2fs_rewrite_to_io(ext2_filsys fs, io_channel new_io)
391 {
392 if ((fs->flags & EXT2_FLAG_IMAGE_FILE) == 0)
393 return EXT2_ET_NOT_IMAGE_FILE;
394 fs->io = fs->image_io = new_io;
395 fs->flags |= EXT2_FLAG_DIRTY | EXT2_FLAG_RW |
396 EXT2_FLAG_BB_DIRTY | EXT2_FLAG_IB_DIRTY;
397 fs->flags &= ~EXT2_FLAG_IMAGE_FILE;
398 return 0;
399 }
400