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 <fcntl.h>
18 #include <arpa/inet.h>
19 #include <sys/ioctl.h>
20 #include <sys/stat.h>
21 #include <sys/types.h>
22 #include <string.h>
23
24 #if defined(__linux__)
25 #include <linux/fs.h>
26 #elif defined(__APPLE__) && defined(__MACH__)
27 #include <sys/disk.h>
28 #endif
29
30 #include "ext4_utils.h"
31 #include "output_file.h"
32 #include "backed_block.h"
33 #include "uuid.h"
34 #include "allocate.h"
35 #include "indirect.h"
36 #include "extent.h"
37
38 #include "ext4.h"
39 #include "jbd2.h"
40
41 int force = 0;
42 struct fs_info info;
43 struct fs_aux_info aux_info;
44
45 /* returns 1 if a is a power of b */
is_power_of(int a,int b)46 static int is_power_of(int a, int b)
47 {
48 while (a > b) {
49 if (a % b)
50 return 0;
51 a /= b;
52 }
53
54 return (a == b) ? 1 : 0;
55 }
56
57 /* Returns 1 if the bg contains a backup superblock. On filesystems with
58 the sparse_super feature, only block groups 0, 1, and powers of 3, 5,
59 and 7 have backup superblocks. Otherwise, all block groups have backup
60 superblocks */
ext4_bg_has_super_block(int bg)61 int ext4_bg_has_super_block(int bg)
62 {
63 /* Without sparse_super, every block group has a superblock */
64 if (!(info.feat_ro_compat & EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER))
65 return 1;
66
67 if (bg == 0 || bg == 1)
68 return 1;
69
70 if (is_power_of(bg, 3) || is_power_of(bg, 5) || is_power_of(bg, 7))
71 return 1;
72
73 return 0;
74 }
75
76 /* Write the filesystem image to a file */
write_ext4_image(const char * filename,int gz,int sparse)77 void write_ext4_image(const char *filename, int gz, int sparse)
78 {
79 int ret = 0;
80 struct output_file *out = open_output_file(filename, gz, sparse);
81 off_t off;
82
83 if (!out)
84 return;
85
86 /* The write_data* functions expect only block aligned calls.
87 * This is not an issue, except when we write out the super
88 * block on a system with a block size > 1K. So, we need to
89 * deal with that here.
90 */
91 if (info.block_size > 1024) {
92 u8 buf[4096] = { 0 }; /* The larget supported ext4 block size */
93 memcpy(buf + 1024, (u8*)aux_info.sb, 1024);
94 write_data_block(out, 0, buf, info.block_size);
95
96 } else {
97 write_data_block(out, 1024, (u8*)aux_info.sb, 1024);
98 }
99
100 write_data_block(out, (u64)(aux_info.first_data_block + 1) * info.block_size,
101 (u8*)aux_info.bg_desc,
102 aux_info.bg_desc_blocks * info.block_size);
103
104 for_each_data_block(write_data_block, write_data_file, out);
105
106 pad_output_file(out, info.len);
107
108 close_output_file(out);
109 }
110
111 /* Compute the rest of the parameters of the filesystem from the basic info */
ext4_create_fs_aux_info()112 void ext4_create_fs_aux_info()
113 {
114 aux_info.first_data_block = (info.block_size > 1024) ? 0 : 1;
115 aux_info.len_blocks = info.len / info.block_size;
116 aux_info.inode_table_blocks = DIV_ROUND_UP(info.inodes_per_group * info.inode_size,
117 info.block_size);
118 aux_info.groups = DIV_ROUND_UP(aux_info.len_blocks - aux_info.first_data_block,
119 info.blocks_per_group);
120 aux_info.blocks_per_ind = info.block_size / sizeof(u32);
121 aux_info.blocks_per_dind = aux_info.blocks_per_ind * aux_info.blocks_per_ind;
122 aux_info.blocks_per_tind = aux_info.blocks_per_dind * aux_info.blocks_per_dind;
123
124 aux_info.bg_desc_blocks =
125 DIV_ROUND_UP(aux_info.groups * sizeof(struct ext2_group_desc),
126 info.block_size);
127
128 aux_info.bg_desc_reserve_blocks =
129 DIV_ROUND_UP(aux_info.groups * 1024 * sizeof(struct ext2_group_desc),
130 info.block_size) - aux_info.bg_desc_blocks;
131
132 if (aux_info.bg_desc_reserve_blocks > aux_info.blocks_per_ind)
133 aux_info.bg_desc_reserve_blocks = aux_info.blocks_per_ind;
134
135 aux_info.default_i_flags = EXT4_NOATIME_FL;
136
137 u32 last_group_size = aux_info.len_blocks % info.blocks_per_group;
138 u32 last_header_size = 2 + aux_info.inode_table_blocks;
139 if (ext4_bg_has_super_block(aux_info.groups - 1))
140 last_header_size += 1 + aux_info.bg_desc_blocks +
141 aux_info.bg_desc_reserve_blocks;
142 if (last_group_size > 0 && last_group_size < last_header_size) {
143 aux_info.groups--;
144 aux_info.len_blocks -= last_group_size;
145 }
146
147 aux_info.sb = calloc(info.block_size, 1);
148 if (!aux_info.sb)
149 critical_error_errno("calloc");
150
151 aux_info.bg_desc = calloc(info.block_size, aux_info.bg_desc_blocks);
152 if (!aux_info.bg_desc)
153 critical_error_errno("calloc");
154 }
155
ext4_free_fs_aux_info()156 void ext4_free_fs_aux_info()
157 {
158 free(aux_info.sb);
159 free(aux_info.bg_desc);
160 }
161
162 /* Fill in the superblock memory buffer based on the filesystem parameters */
ext4_fill_in_sb()163 void ext4_fill_in_sb()
164 {
165 unsigned int i;
166 struct ext4_super_block *sb = aux_info.sb;
167
168 sb->s_inodes_count = info.inodes_per_group * aux_info.groups;
169 sb->s_blocks_count_lo = aux_info.len_blocks;
170 sb->s_r_blocks_count_lo = 0;
171 sb->s_free_blocks_count_lo = 0;
172 sb->s_free_inodes_count = 0;
173 sb->s_first_data_block = aux_info.first_data_block;
174 sb->s_log_block_size = log_2(info.block_size / 1024);
175 sb->s_obso_log_frag_size = log_2(info.block_size / 1024);
176 sb->s_blocks_per_group = info.blocks_per_group;
177 sb->s_obso_frags_per_group = info.blocks_per_group;
178 sb->s_inodes_per_group = info.inodes_per_group;
179 sb->s_mtime = 0;
180 sb->s_wtime = 0;
181 sb->s_mnt_count = 0;
182 sb->s_max_mnt_count = 0xFFFF;
183 sb->s_magic = EXT4_SUPER_MAGIC;
184 sb->s_state = EXT4_VALID_FS;
185 sb->s_errors = EXT4_ERRORS_RO;
186 sb->s_minor_rev_level = 0;
187 sb->s_lastcheck = 0;
188 sb->s_checkinterval = 0;
189 sb->s_creator_os = EXT4_OS_LINUX;
190 sb->s_rev_level = EXT4_DYNAMIC_REV;
191 sb->s_def_resuid = EXT4_DEF_RESUID;
192 sb->s_def_resgid = EXT4_DEF_RESGID;
193
194 sb->s_first_ino = EXT4_GOOD_OLD_FIRST_INO;
195 sb->s_inode_size = info.inode_size;
196 sb->s_block_group_nr = 0;
197 sb->s_feature_compat = info.feat_compat;
198 sb->s_feature_incompat = info.feat_incompat;
199 sb->s_feature_ro_compat = info.feat_ro_compat;
200 generate_uuid("extandroid/make_ext4fs", info.label, sb->s_uuid);
201 memset(sb->s_volume_name, 0, sizeof(sb->s_volume_name));
202 strncpy(sb->s_volume_name, info.label, sizeof(sb->s_volume_name));
203 memset(sb->s_last_mounted, 0, sizeof(sb->s_last_mounted));
204 sb->s_algorithm_usage_bitmap = 0;
205
206 sb->s_reserved_gdt_blocks = aux_info.bg_desc_reserve_blocks;
207 sb->s_prealloc_blocks = 0;
208 sb->s_prealloc_dir_blocks = 0;
209
210 //memcpy(sb->s_journal_uuid, sb->s_uuid, sizeof(sb->s_journal_uuid));
211 if (info.feat_compat & EXT4_FEATURE_COMPAT_HAS_JOURNAL)
212 sb->s_journal_inum = EXT4_JOURNAL_INO;
213 sb->s_journal_dev = 0;
214 sb->s_last_orphan = 0;
215 sb->s_hash_seed[0] = 0; /* FIXME */
216 sb->s_def_hash_version = DX_HASH_TEA;
217 sb->s_reserved_char_pad = EXT4_JNL_BACKUP_BLOCKS;
218 sb->s_desc_size = sizeof(struct ext2_group_desc);
219 sb->s_default_mount_opts = 0; /* FIXME */
220 sb->s_first_meta_bg = 0;
221 sb->s_mkfs_time = 0;
222 //sb->s_jnl_blocks[17]; /* FIXME */
223
224 sb->s_blocks_count_hi = aux_info.len_blocks >> 32;
225 sb->s_r_blocks_count_hi = 0;
226 sb->s_free_blocks_count_hi = 0;
227 sb->s_min_extra_isize = sizeof(struct ext4_inode) -
228 EXT4_GOOD_OLD_INODE_SIZE;
229 sb->s_want_extra_isize = sizeof(struct ext4_inode) -
230 EXT4_GOOD_OLD_INODE_SIZE;
231 sb->s_flags = 0;
232 sb->s_raid_stride = 0;
233 sb->s_mmp_interval = 0;
234 sb->s_mmp_block = 0;
235 sb->s_raid_stripe_width = 0;
236 sb->s_log_groups_per_flex = 0;
237 sb->s_kbytes_written = 0;
238
239 for (i = 0; i < aux_info.groups; i++) {
240 u64 group_start_block = aux_info.first_data_block + i *
241 info.blocks_per_group;
242 u32 header_size = 0;
243 if (ext4_bg_has_super_block(i)) {
244 if (i != 0) {
245 queue_data_block((u8 *)sb, info.block_size, group_start_block);
246 queue_data_block((u8 *)aux_info.bg_desc,
247 aux_info.bg_desc_blocks * info.block_size,
248 group_start_block + 1);
249 }
250 header_size = 1 + aux_info.bg_desc_blocks + aux_info.bg_desc_reserve_blocks;
251 }
252
253 aux_info.bg_desc[i].bg_block_bitmap = group_start_block + header_size;
254 aux_info.bg_desc[i].bg_inode_bitmap = group_start_block + header_size + 1;
255 aux_info.bg_desc[i].bg_inode_table = group_start_block + header_size + 2;
256
257 aux_info.bg_desc[i].bg_free_blocks_count = sb->s_blocks_per_group;
258 aux_info.bg_desc[i].bg_free_inodes_count = sb->s_inodes_per_group;
259 aux_info.bg_desc[i].bg_used_dirs_count = 0;
260 }
261 }
262
ext4_create_resize_inode()263 void ext4_create_resize_inode()
264 {
265 struct block_allocation *reserve_inode_alloc = create_allocation();
266 u32 reserve_inode_len = 0;
267 unsigned int i;
268
269 struct ext4_inode *inode = get_inode(EXT4_RESIZE_INO);
270 if (inode == NULL) {
271 error("failed to get resize inode");
272 return;
273 }
274
275 for (i = 0; i < aux_info.groups; i++) {
276 if (ext4_bg_has_super_block(i)) {
277 u64 group_start_block = aux_info.first_data_block + i *
278 info.blocks_per_group;
279 u32 reserved_block_start = group_start_block + 1 +
280 aux_info.bg_desc_blocks;
281 u32 reserved_block_len = aux_info.bg_desc_reserve_blocks;
282 append_region(reserve_inode_alloc, reserved_block_start,
283 reserved_block_len, i);
284 reserve_inode_len += reserved_block_len;
285 }
286 }
287
288 inode_attach_resize(inode, reserve_inode_alloc);
289
290 inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR;
291 inode->i_links_count = 1;
292
293 free_alloc(reserve_inode_alloc);
294 }
295
296 /* Allocate the blocks to hold a journal inode and connect them to the
297 reserved journal inode */
ext4_create_journal_inode()298 void ext4_create_journal_inode()
299 {
300 struct ext4_inode *inode = get_inode(EXT4_JOURNAL_INO);
301 if (inode == NULL) {
302 error("failed to get journal inode");
303 return;
304 }
305
306 u8 *journal_data = inode_allocate_data_extents(inode,
307 info.journal_blocks * info.block_size,
308 info.journal_blocks * info.block_size);
309 if (!journal_data) {
310 error("failed to allocate extents for journal data");
311 return;
312 }
313
314 inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR;
315 inode->i_links_count = 1;
316
317 journal_superblock_t *jsb = (journal_superblock_t *)journal_data;
318 jsb->s_header.h_magic = htonl(JBD2_MAGIC_NUMBER);
319 jsb->s_header.h_blocktype = htonl(JBD2_SUPERBLOCK_V2);
320 jsb->s_blocksize = htonl(info.block_size);
321 jsb->s_maxlen = htonl(info.journal_blocks);
322 jsb->s_nr_users = htonl(1);
323 jsb->s_first = htonl(1);
324 jsb->s_sequence = htonl(1);
325
326 memcpy(aux_info.sb->s_jnl_blocks, &inode->i_block, sizeof(inode->i_block));
327 }
328
329 /* Update the number of free blocks and inodes in the filesystem and in each
330 block group */
ext4_update_free()331 void ext4_update_free()
332 {
333 unsigned int i;
334
335 for (i = 0; i < aux_info.groups; i++) {
336 u32 bg_free_blocks = get_free_blocks(i);
337 u32 bg_free_inodes = get_free_inodes(i);
338
339 aux_info.bg_desc[i].bg_free_blocks_count = bg_free_blocks;
340 aux_info.sb->s_free_blocks_count_lo += bg_free_blocks;
341
342 aux_info.bg_desc[i].bg_free_inodes_count = bg_free_inodes;
343 aux_info.sb->s_free_inodes_count += bg_free_inodes;
344
345 aux_info.bg_desc[i].bg_used_dirs_count += get_directories(i);
346 }
347 }
348
get_block_device_size(const char * filename)349 static u64 get_block_device_size(const char *filename)
350 {
351 int fd = open(filename, O_RDONLY);
352 u64 size = 0;
353 int ret;
354
355 if (fd < 0)
356 return 0;
357
358 #if defined(__linux__)
359 ret = ioctl(fd, BLKGETSIZE64, &size);
360 #elif defined(__APPLE__) && defined(__MACH__)
361 ret = ioctl(fd, DKIOCGETBLOCKCOUNT, &size);
362 #else
363 return 0;
364 #endif
365
366 close(fd);
367
368 if (ret)
369 return 0;
370
371 return size;
372 }
373
get_file_size(const char * filename)374 u64 get_file_size(const char *filename)
375 {
376 struct stat buf;
377 int ret;
378
379 ret = stat(filename, &buf);
380 if (ret)
381 return 0;
382
383 if (S_ISREG(buf.st_mode))
384 return buf.st_size;
385 else if (S_ISBLK(buf.st_mode))
386 return get_block_device_size(filename);
387 else
388 return 0;
389 }
390
parse_num(const char * arg)391 u64 parse_num(const char *arg)
392 {
393 char *endptr;
394 u64 num = strtoull(arg, &endptr, 10);
395 if (*endptr == 'k' || *endptr == 'K')
396 num *= 1024LL;
397 else if (*endptr == 'm' || *endptr == 'M')
398 num *= 1024LL * 1024LL;
399 else if (*endptr == 'g' || *endptr == 'G')
400 num *= 1024LL * 1024LL * 1024LL;
401
402 return num;
403 }
404
405