1 /*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "ext4_utils.h"
18 #include "uuid.h"
19 #include "allocate.h"
20 #include "indirect.h"
21 #include "extent.h"
22
23 #include <sparse/sparse.h>
24
25 #include <fcntl.h>
26 #include <inttypes.h>
27 #include <sys/stat.h>
28 #include <sys/types.h>
29 #include <stddef.h>
30 #include <string.h>
31
32 #ifdef USE_MINGW
33 #include <winsock2.h>
34 #else
35 #include <arpa/inet.h>
36 #include <sys/ioctl.h>
37 #endif
38
39 #if defined(__linux__)
40 #include <linux/fs.h>
41 #elif defined(__APPLE__) && defined(__MACH__)
42 #include <sys/disk.h>
43 #endif
44
45 int force = 0;
46 struct fs_info info;
47 struct fs_aux_info aux_info;
48 struct sparse_file *ext4_sparse_file;
49
50 jmp_buf setjmp_env;
51
52 /* returns 1 if a is a power of b */
is_power_of(int a,int b)53 static int is_power_of(int a, int b)
54 {
55 while (a > b) {
56 if (a % b)
57 return 0;
58 a /= b;
59 }
60
61 return (a == b) ? 1 : 0;
62 }
63
bitmap_get_bit(u8 * bitmap,u32 bit)64 int bitmap_get_bit(u8 *bitmap, u32 bit)
65 {
66 if (bitmap[bit / 8] & (1 << (bit % 8)))
67 return 1;
68
69 return 0;
70 }
71
bitmap_clear_bit(u8 * bitmap,u32 bit)72 void bitmap_clear_bit(u8 *bitmap, u32 bit)
73 {
74 bitmap[bit / 8] &= ~(1 << (bit % 8));
75
76 return;
77 }
78
79 /* Returns 1 if the bg contains a backup superblock. On filesystems with
80 the sparse_super feature, only block groups 0, 1, and powers of 3, 5,
81 and 7 have backup superblocks. Otherwise, all block groups have backup
82 superblocks */
ext4_bg_has_super_block(int bg)83 int ext4_bg_has_super_block(int bg)
84 {
85 /* Without sparse_super, every block group has a superblock */
86 if (!(info.feat_ro_compat & EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER))
87 return 1;
88
89 if (bg == 0 || bg == 1)
90 return 1;
91
92 if (is_power_of(bg, 3) || is_power_of(bg, 5) || is_power_of(bg, 7))
93 return 1;
94
95 return 0;
96 }
97
98 /* Function to read the primary superblock */
read_sb(int fd,struct ext4_super_block * sb)99 void read_sb(int fd, struct ext4_super_block *sb)
100 {
101 off64_t ret;
102
103 ret = lseek64(fd, 1024, SEEK_SET);
104 if (ret < 0)
105 critical_error_errno("failed to seek to superblock");
106
107 ret = read(fd, sb, sizeof(*sb));
108 if (ret < 0)
109 critical_error_errno("failed to read superblock");
110 if (ret != sizeof(*sb))
111 critical_error("failed to read all of superblock");
112 }
113
114 /* Function to write a primary or backup superblock at a given offset */
write_sb(int fd,unsigned long long offset,struct ext4_super_block * sb)115 void write_sb(int fd, unsigned long long offset, struct ext4_super_block *sb)
116 {
117 off64_t ret;
118
119 ret = lseek64(fd, offset, SEEK_SET);
120 if (ret < 0)
121 critical_error_errno("failed to seek to superblock");
122
123 ret = write(fd, sb, sizeof(*sb));
124 if (ret < 0)
125 critical_error_errno("failed to write superblock");
126 if (ret != sizeof(*sb))
127 critical_error("failed to write all of superblock");
128 }
129
130 /* Write the filesystem image to a file */
write_ext4_image(int fd,int gz,int sparse,int crc)131 void write_ext4_image(int fd, int gz, int sparse, int crc)
132 {
133 sparse_file_write(ext4_sparse_file, fd, gz, sparse, crc);
134 }
135
136 /* Compute the rest of the parameters of the filesystem from the basic info */
ext4_create_fs_aux_info()137 void ext4_create_fs_aux_info()
138 {
139 aux_info.first_data_block = (info.block_size > 1024) ? 0 : 1;
140 aux_info.len_blocks = info.len / info.block_size;
141 aux_info.inode_table_blocks = DIV_ROUND_UP(info.inodes_per_group * info.inode_size,
142 info.block_size);
143 aux_info.groups = DIV_ROUND_UP(aux_info.len_blocks - aux_info.first_data_block,
144 info.blocks_per_group);
145 aux_info.blocks_per_ind = info.block_size / sizeof(u32);
146 aux_info.blocks_per_dind = aux_info.blocks_per_ind * aux_info.blocks_per_ind;
147 aux_info.blocks_per_tind = aux_info.blocks_per_dind * aux_info.blocks_per_dind;
148
149 aux_info.bg_desc_blocks =
150 DIV_ROUND_UP(aux_info.groups * sizeof(struct ext2_group_desc),
151 info.block_size);
152
153 aux_info.default_i_flags = EXT4_NOATIME_FL;
154
155 u32 last_group_size = aux_info.len_blocks % info.blocks_per_group;
156 u32 last_header_size = 2 + aux_info.inode_table_blocks;
157 if (ext4_bg_has_super_block(aux_info.groups - 1))
158 last_header_size += 1 + aux_info.bg_desc_blocks +
159 info.bg_desc_reserve_blocks;
160 if (last_group_size > 0 && last_group_size < last_header_size) {
161 aux_info.groups--;
162 aux_info.len_blocks -= last_group_size;
163 }
164
165 aux_info.sb = calloc(info.block_size, 1);
166 /* Alloc an array to hold the pointers to the backup superblocks */
167 aux_info.backup_sb = calloc(aux_info.groups, sizeof(char *));
168
169 if (!aux_info.sb)
170 critical_error_errno("calloc");
171
172 aux_info.bg_desc = calloc(info.block_size, aux_info.bg_desc_blocks);
173 if (!aux_info.bg_desc)
174 critical_error_errno("calloc");
175 aux_info.xattrs = NULL;
176 }
177
ext4_free_fs_aux_info()178 void ext4_free_fs_aux_info()
179 {
180 unsigned int i;
181
182 for (i=0; i<aux_info.groups; i++) {
183 if (aux_info.backup_sb[i])
184 free(aux_info.backup_sb[i]);
185 }
186 free(aux_info.sb);
187 free(aux_info.bg_desc);
188 }
189
190 /* Fill in the superblock memory buffer based on the filesystem parameters */
ext4_fill_in_sb()191 void ext4_fill_in_sb()
192 {
193 unsigned int i;
194 struct ext4_super_block *sb = aux_info.sb;
195
196 sb->s_inodes_count = info.inodes_per_group * aux_info.groups;
197 sb->s_blocks_count_lo = aux_info.len_blocks;
198 sb->s_r_blocks_count_lo = 0;
199 sb->s_free_blocks_count_lo = 0;
200 sb->s_free_inodes_count = 0;
201 sb->s_first_data_block = aux_info.first_data_block;
202 sb->s_log_block_size = log_2(info.block_size / 1024);
203 sb->s_obso_log_frag_size = log_2(info.block_size / 1024);
204 sb->s_blocks_per_group = info.blocks_per_group;
205 sb->s_obso_frags_per_group = info.blocks_per_group;
206 sb->s_inodes_per_group = info.inodes_per_group;
207 sb->s_mtime = 0;
208 sb->s_wtime = 0;
209 sb->s_mnt_count = 0;
210 sb->s_max_mnt_count = 0xFFFF;
211 sb->s_magic = EXT4_SUPER_MAGIC;
212 sb->s_state = EXT4_VALID_FS;
213 sb->s_errors = EXT4_ERRORS_RO;
214 sb->s_minor_rev_level = 0;
215 sb->s_lastcheck = 0;
216 sb->s_checkinterval = 0;
217 sb->s_creator_os = EXT4_OS_LINUX;
218 sb->s_rev_level = EXT4_DYNAMIC_REV;
219 sb->s_def_resuid = EXT4_DEF_RESUID;
220 sb->s_def_resgid = EXT4_DEF_RESGID;
221
222 sb->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
223 sb->s_inode_size = info.inode_size;
224 sb->s_block_group_nr = 0;
225 sb->s_feature_compat = info.feat_compat;
226 sb->s_feature_incompat = info.feat_incompat;
227 sb->s_feature_ro_compat = info.feat_ro_compat;
228 generate_uuid("extandroid/make_ext4fs", info.label, sb->s_uuid);
229 memset(sb->s_volume_name, 0, sizeof(sb->s_volume_name));
230 strncpy(sb->s_volume_name, info.label, sizeof(sb->s_volume_name));
231 memset(sb->s_last_mounted, 0, sizeof(sb->s_last_mounted));
232 sb->s_algorithm_usage_bitmap = 0;
233
234 sb->s_reserved_gdt_blocks = info.bg_desc_reserve_blocks;
235 sb->s_prealloc_blocks = 0;
236 sb->s_prealloc_dir_blocks = 0;
237
238 //memcpy(sb->s_journal_uuid, sb->s_uuid, sizeof(sb->s_journal_uuid));
239 if (info.feat_compat & EXT4_FEATURE_COMPAT_HAS_JOURNAL)
240 sb->s_journal_inum = EXT4_JOURNAL_INO;
241 sb->s_journal_dev = 0;
242 sb->s_last_orphan = 0;
243 sb->s_hash_seed[0] = 0; /* FIXME */
244 sb->s_def_hash_version = DX_HASH_TEA;
245 sb->s_reserved_char_pad = EXT4_JNL_BACKUP_BLOCKS;
246 sb->s_desc_size = sizeof(struct ext2_group_desc);
247 sb->s_default_mount_opts = 0; /* FIXME */
248 sb->s_first_meta_bg = 0;
249 sb->s_mkfs_time = 0;
250 //sb->s_jnl_blocks[17]; /* FIXME */
251
252 sb->s_blocks_count_hi = aux_info.len_blocks >> 32;
253 sb->s_r_blocks_count_hi = 0;
254 sb->s_free_blocks_count_hi = 0;
255 sb->s_min_extra_isize = sizeof(struct ext4_inode) -
256 EXT4_GOOD_OLD_INODE_SIZE;
257 sb->s_want_extra_isize = sizeof(struct ext4_inode) -
258 EXT4_GOOD_OLD_INODE_SIZE;
259 sb->s_flags = 2;
260 sb->s_raid_stride = 0;
261 sb->s_mmp_interval = 0;
262 sb->s_mmp_block = 0;
263 sb->s_raid_stripe_width = 0;
264 sb->s_log_groups_per_flex = 0;
265 sb->s_kbytes_written = 0;
266
267 for (i = 0; i < aux_info.groups; i++) {
268 u64 group_start_block = aux_info.first_data_block + i *
269 info.blocks_per_group;
270 u32 header_size = 0;
271 if (ext4_bg_has_super_block(i)) {
272 if (i != 0) {
273 aux_info.backup_sb[i] = calloc(info.block_size, 1);
274 memcpy(aux_info.backup_sb[i], sb, info.block_size);
275 /* Update the block group nr of this backup superblock */
276 aux_info.backup_sb[i]->s_block_group_nr = i;
277 sparse_file_add_data(ext4_sparse_file, aux_info.backup_sb[i],
278 info.block_size, group_start_block);
279 }
280 sparse_file_add_data(ext4_sparse_file, aux_info.bg_desc,
281 aux_info.bg_desc_blocks * info.block_size,
282 group_start_block + 1);
283 header_size = 1 + aux_info.bg_desc_blocks + info.bg_desc_reserve_blocks;
284 }
285
286 aux_info.bg_desc[i].bg_block_bitmap = group_start_block + header_size;
287 aux_info.bg_desc[i].bg_inode_bitmap = group_start_block + header_size + 1;
288 aux_info.bg_desc[i].bg_inode_table = group_start_block + header_size + 2;
289
290 aux_info.bg_desc[i].bg_free_blocks_count = sb->s_blocks_per_group;
291 aux_info.bg_desc[i].bg_free_inodes_count = sb->s_inodes_per_group;
292 aux_info.bg_desc[i].bg_used_dirs_count = 0;
293 }
294 }
295
ext4_queue_sb(void)296 void ext4_queue_sb(void)
297 {
298 /* The write_data* functions expect only block aligned calls.
299 * This is not an issue, except when we write out the super
300 * block on a system with a block size > 1K. So, we need to
301 * deal with that here.
302 */
303 if (info.block_size > 1024) {
304 u8 *buf = calloc(info.block_size, 1);
305 memcpy(buf + 1024, (u8*)aux_info.sb, 1024);
306 sparse_file_add_data(ext4_sparse_file, buf, info.block_size, 0);
307 } else {
308 sparse_file_add_data(ext4_sparse_file, aux_info.sb, 1024, 1);
309 }
310 }
311
ext4_parse_sb_info(struct ext4_super_block * sb)312 void ext4_parse_sb_info(struct ext4_super_block *sb)
313 {
314 if (sb->s_magic != EXT4_SUPER_MAGIC)
315 error("superblock magic incorrect");
316
317 if ((sb->s_state & EXT4_VALID_FS) != EXT4_VALID_FS)
318 error("filesystem state not valid");
319
320 ext4_parse_sb(sb, &info);
321
322 ext4_create_fs_aux_info();
323
324 memcpy(aux_info.sb, sb, sizeof(*sb));
325
326 if (aux_info.first_data_block != sb->s_first_data_block)
327 critical_error("first data block does not match");
328 }
329
ext4_create_resize_inode()330 void ext4_create_resize_inode()
331 {
332 struct block_allocation *reserve_inode_alloc = create_allocation();
333 u32 reserve_inode_len = 0;
334 unsigned int i;
335
336 struct ext4_inode *inode = get_inode(EXT4_RESIZE_INO);
337 if (inode == NULL) {
338 error("failed to get resize inode");
339 return;
340 }
341
342 for (i = 0; i < aux_info.groups; i++) {
343 if (ext4_bg_has_super_block(i)) {
344 u64 group_start_block = aux_info.first_data_block + i *
345 info.blocks_per_group;
346 u32 reserved_block_start = group_start_block + 1 +
347 aux_info.bg_desc_blocks;
348 u32 reserved_block_len = info.bg_desc_reserve_blocks;
349 append_region(reserve_inode_alloc, reserved_block_start,
350 reserved_block_len, i);
351 reserve_inode_len += reserved_block_len;
352 }
353 }
354
355 inode_attach_resize(inode, reserve_inode_alloc);
356
357 inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR;
358 inode->i_links_count = 1;
359
360 free_alloc(reserve_inode_alloc);
361 }
362
363 /* Allocate the blocks to hold a journal inode and connect them to the
364 reserved journal inode */
ext4_create_journal_inode()365 void ext4_create_journal_inode()
366 {
367 struct ext4_inode *inode = get_inode(EXT4_JOURNAL_INO);
368 if (inode == NULL) {
369 error("failed to get journal inode");
370 return;
371 }
372
373 u8 *journal_data = inode_allocate_data_extents(inode,
374 info.journal_blocks * info.block_size,
375 info.journal_blocks * info.block_size);
376 if (!journal_data) {
377 error("failed to allocate extents for journal data");
378 return;
379 }
380
381 inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR;
382 inode->i_links_count = 1;
383
384 journal_superblock_t *jsb = (journal_superblock_t *)journal_data;
385 jsb->s_header.h_magic = htonl(JBD2_MAGIC_NUMBER);
386 jsb->s_header.h_blocktype = htonl(JBD2_SUPERBLOCK_V2);
387 jsb->s_blocksize = htonl(info.block_size);
388 jsb->s_maxlen = htonl(info.journal_blocks);
389 jsb->s_nr_users = htonl(1);
390 jsb->s_first = htonl(1);
391 jsb->s_sequence = htonl(1);
392
393 memcpy(aux_info.sb->s_jnl_blocks, &inode->i_block, sizeof(inode->i_block));
394 }
395
396 /* Update the number of free blocks and inodes in the filesystem and in each
397 block group */
ext4_update_free()398 void ext4_update_free()
399 {
400 u32 i;
401
402 for (i = 0; i < aux_info.groups; i++) {
403 u32 bg_free_blocks = get_free_blocks(i);
404 u32 bg_free_inodes = get_free_inodes(i);
405 u16 crc;
406
407 aux_info.bg_desc[i].bg_free_blocks_count = bg_free_blocks;
408 aux_info.sb->s_free_blocks_count_lo += bg_free_blocks;
409
410 aux_info.bg_desc[i].bg_free_inodes_count = bg_free_inodes;
411 aux_info.sb->s_free_inodes_count += bg_free_inodes;
412
413 aux_info.bg_desc[i].bg_used_dirs_count += get_directories(i);
414
415 aux_info.bg_desc[i].bg_flags = get_bg_flags(i);
416
417 crc = ext4_crc16(~0, aux_info.sb->s_uuid, sizeof(aux_info.sb->s_uuid));
418 crc = ext4_crc16(crc, &i, sizeof(i));
419 crc = ext4_crc16(crc, &aux_info.bg_desc[i], offsetof(struct ext2_group_desc, bg_checksum));
420 aux_info.bg_desc[i].bg_checksum = crc;
421 }
422 }
423
get_block_device_size(int fd)424 u64 get_block_device_size(int fd)
425 {
426 u64 size = 0;
427 int ret;
428
429 #if defined(__linux__)
430 ret = ioctl(fd, BLKGETSIZE64, &size);
431 #elif defined(__APPLE__) && defined(__MACH__)
432 ret = ioctl(fd, DKIOCGETBLOCKCOUNT, &size);
433 #else
434 close(fd);
435 return 0;
436 #endif
437
438 if (ret)
439 return 0;
440
441 return size;
442 }
443
is_block_device_fd(int fd)444 int is_block_device_fd(int fd)
445 {
446 #ifdef USE_MINGW
447 return 0;
448 #else
449 struct stat st;
450 int ret = fstat(fd, &st);
451 if (ret < 0)
452 return 0;
453
454 return S_ISBLK(st.st_mode);
455 #endif
456 }
457
get_file_size(int fd)458 u64 get_file_size(int fd)
459 {
460 struct stat buf;
461 int ret;
462 u64 reserve_len = 0;
463 s64 computed_size;
464
465 ret = fstat(fd, &buf);
466 if (ret)
467 return 0;
468
469 if (info.len < 0)
470 reserve_len = -info.len;
471
472 if (S_ISREG(buf.st_mode))
473 computed_size = buf.st_size - reserve_len;
474 else if (S_ISBLK(buf.st_mode))
475 computed_size = get_block_device_size(fd) - reserve_len;
476 else
477 computed_size = 0;
478
479 if (computed_size < 0) {
480 warn("Computed filesystem size less than 0");
481 computed_size = 0;
482 }
483
484 return computed_size;
485 }
486
parse_num(const char * arg)487 u64 parse_num(const char *arg)
488 {
489 char *endptr;
490 u64 num = strtoull(arg, &endptr, 10);
491 if (*endptr == 'k' || *endptr == 'K')
492 num *= 1024LL;
493 else if (*endptr == 'm' || *endptr == 'M')
494 num *= 1024LL * 1024LL;
495 else if (*endptr == 'g' || *endptr == 'G')
496 num *= 1024LL * 1024LL * 1024LL;
497
498 return num;
499 }
500
read_ext(int fd,int verbose)501 int read_ext(int fd, int verbose)
502 {
503 off64_t ret;
504 struct ext4_super_block sb;
505
506 read_sb(fd, &sb);
507
508 ext4_parse_sb_info(&sb);
509
510 ret = lseek64(fd, info.len, SEEK_SET);
511 if (ret < 0)
512 critical_error_errno("failed to seek to end of input image");
513
514 ret = lseek64(fd, info.block_size * (aux_info.first_data_block + 1), SEEK_SET);
515 if (ret < 0)
516 critical_error_errno("failed to seek to block group descriptors");
517
518 ret = read(fd, aux_info.bg_desc, info.block_size * aux_info.bg_desc_blocks);
519 if (ret < 0)
520 critical_error_errno("failed to read block group descriptors");
521 if (ret != (int)info.block_size * (int)aux_info.bg_desc_blocks)
522 critical_error("failed to read all of block group descriptors");
523
524 if (verbose) {
525 printf("Found filesystem with parameters:\n");
526 printf(" Size: %"PRIu64"\n", info.len);
527 printf(" Block size: %d\n", info.block_size);
528 printf(" Blocks per group: %d\n", info.blocks_per_group);
529 printf(" Inodes per group: %d\n", info.inodes_per_group);
530 printf(" Inode size: %d\n", info.inode_size);
531 printf(" Label: %s\n", info.label);
532 printf(" Blocks: %"PRIu64"\n", aux_info.len_blocks);
533 printf(" Block groups: %d\n", aux_info.groups);
534 printf(" Reserved block group size: %d\n", info.bg_desc_reserve_blocks);
535 printf(" Used %d/%d inodes and %d/%d blocks\n",
536 aux_info.sb->s_inodes_count - aux_info.sb->s_free_inodes_count,
537 aux_info.sb->s_inodes_count,
538 aux_info.sb->s_blocks_count_lo - aux_info.sb->s_free_blocks_count_lo,
539 aux_info.sb->s_blocks_count_lo);
540 }
541
542 return 0;
543 }
544
545