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/ext4_utils.h"
18
19 #include <fcntl.h>
20 #include <inttypes.h>
21 #include <stddef.h>
22 #include <string.h>
23 #include <sys/stat.h>
24 #include <sys/types.h>
25
26 #ifdef _WIN32
27 #include <winsock2.h>
28 #else
29 #include <arpa/inet.h>
30 #include <sys/ioctl.h>
31 #endif
32
33 #if defined(__linux__)
34 #include <linux/fs.h>
35 #elif defined(__APPLE__) && defined(__MACH__)
36 #include <sys/disk.h>
37 #endif
38
39 int force = 0;
40 struct fs_info info;
41 struct fs_aux_info aux_info;
42
43 jmp_buf setjmp_env;
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
bitmap_get_bit(u8 * bitmap,u32 bit)57 int bitmap_get_bit(u8 *bitmap, u32 bit)
58 {
59 if (bitmap[bit / 8] & (1 << (bit % 8)))
60 return 1;
61
62 return 0;
63 }
64
bitmap_clear_bit(u8 * bitmap,u32 bit)65 void bitmap_clear_bit(u8 *bitmap, u32 bit)
66 {
67 bitmap[bit / 8] &= ~(1 << (bit % 8));
68
69 return;
70 }
71
72 /* Returns 1 if the bg contains a backup superblock. On filesystems with
73 the sparse_super feature, only block groups 0, 1, and powers of 3, 5,
74 and 7 have backup superblocks. Otherwise, all block groups have backup
75 superblocks */
ext4_bg_has_super_block(int bg)76 int ext4_bg_has_super_block(int bg)
77 {
78 /* Without sparse_super, every block group has a superblock */
79 if (!(info.feat_ro_compat & EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER))
80 return 1;
81
82 if (bg == 0 || bg == 1)
83 return 1;
84
85 if (is_power_of(bg, 3) || is_power_of(bg, 5) || is_power_of(bg, 7))
86 return 1;
87
88 return 0;
89 }
90
91 /* Function to read the primary superblock */
read_sb(int fd,struct ext4_super_block * sb)92 void read_sb(int fd, struct ext4_super_block *sb)
93 {
94 off64_t ret;
95
96 ret = lseek64(fd, 1024, SEEK_SET);
97 if (ret < 0)
98 critical_error_errno("failed to seek to superblock");
99
100 ret = read(fd, sb, sizeof(*sb));
101 if (ret < 0)
102 critical_error_errno("failed to read superblock");
103 if (ret != sizeof(*sb))
104 critical_error("failed to read all of superblock");
105 }
106
107 /* Compute the rest of the parameters of the filesystem from the basic info */
ext4_create_fs_aux_info()108 void ext4_create_fs_aux_info()
109 {
110 aux_info.first_data_block = (info.block_size > 1024) ? 0 : 1;
111 aux_info.len_blocks = info.len / info.block_size;
112 aux_info.inode_table_blocks = DIV_ROUND_UP(info.inodes_per_group * info.inode_size,
113 info.block_size);
114 aux_info.groups = DIV_ROUND_UP(aux_info.len_blocks - aux_info.first_data_block,
115 info.blocks_per_group);
116 aux_info.blocks_per_ind = info.block_size / sizeof(u32);
117 aux_info.blocks_per_dind = aux_info.blocks_per_ind * aux_info.blocks_per_ind;
118 aux_info.blocks_per_tind = aux_info.blocks_per_dind * aux_info.blocks_per_dind;
119
120 aux_info.bg_desc_blocks =
121 DIV_ROUND_UP(aux_info.groups * sizeof(struct ext2_group_desc),
122 info.block_size);
123
124 aux_info.default_i_flags = EXT4_NOATIME_FL;
125
126 u32 last_group_size = aux_info.len_blocks == info.blocks_per_group
127 ? aux_info.len_blocks : aux_info.len_blocks % info.blocks_per_group;
128 u32 last_header_size = 2 + aux_info.inode_table_blocks;
129 if (ext4_bg_has_super_block((int)aux_info.groups - 1))
130 last_header_size += 1 + aux_info.bg_desc_blocks +
131 info.bg_desc_reserve_blocks;
132 if (aux_info.groups <= 1 && last_group_size < last_header_size) {
133 critical_error("filesystem size too small");
134 }
135 if (last_group_size > 0 && last_group_size < last_header_size) {
136 aux_info.groups--;
137 aux_info.len_blocks -= last_group_size;
138 }
139
140 /* A zero-filled superblock to be written firstly to the block
141 * device to mark the file-system as invalid
142 */
143 aux_info.sb_zero = (struct ext4_super_block *)calloc(1, info.block_size);
144 if (!aux_info.sb_zero)
145 critical_error_errno("calloc");
146
147 /* The write_data* functions expect only block aligned calls.
148 * This is not an issue, except when we write out the super
149 * block on a system with a block size > 1K. So, we need to
150 * deal with that here.
151 */
152 aux_info.sb_block = (struct ext4_super_block *)calloc(1, info.block_size);
153 if (!aux_info.sb_block)
154 critical_error_errno("calloc");
155
156 if (info.block_size > 1024)
157 aux_info.sb = (struct ext4_super_block *)((char *)aux_info.sb_block + 1024);
158 else
159 aux_info.sb = aux_info.sb_block;
160
161 /* Alloc an array to hold the pointers to the backup superblocks */
162 aux_info.backup_sb = (struct ext4_super_block **)calloc(aux_info.groups, sizeof(char *));
163
164 if (!aux_info.sb)
165 critical_error_errno("calloc");
166
167 aux_info.bg_desc = (struct ext2_group_desc *)calloc(info.block_size, aux_info.bg_desc_blocks);
168 if (!aux_info.bg_desc)
169 critical_error_errno("calloc");
170 aux_info.xattrs = NULL;
171 }
172
ext4_free_fs_aux_info()173 void ext4_free_fs_aux_info()
174 {
175 unsigned int i;
176
177 for (i=0; i<aux_info.groups; i++) {
178 if (aux_info.backup_sb[i])
179 free(aux_info.backup_sb[i]);
180 }
181 free(aux_info.sb_block);
182 free(aux_info.sb_zero);
183 free(aux_info.bg_desc);
184 }
185
ext4_parse_sb_info(struct ext4_super_block * sb)186 void ext4_parse_sb_info(struct ext4_super_block *sb)
187 {
188 if (sb->s_magic != EXT4_SUPER_MAGIC)
189 error("superblock magic incorrect");
190
191 if ((sb->s_state & EXT4_VALID_FS) != EXT4_VALID_FS)
192 error("filesystem state not valid");
193
194 ext4_parse_sb(sb, &info);
195
196 ext4_create_fs_aux_info();
197
198 memcpy(aux_info.sb, sb, sizeof(*sb));
199
200 if (aux_info.first_data_block != sb->s_first_data_block)
201 critical_error("first data block does not match");
202 }
203
get_block_device_size(int fd)204 u64 get_block_device_size(int fd)
205 {
206 u64 size = 0;
207 int ret;
208
209 #if defined(__linux__)
210 ret = ioctl(fd, BLKGETSIZE64, &size);
211 #elif defined(__APPLE__) && defined(__MACH__)
212 ret = ioctl(fd, DKIOCGETBLOCKCOUNT, &size);
213 #else
214 close(fd);
215 return 0;
216 #endif
217
218 if (ret)
219 return 0;
220
221 return size;
222 }
223
is_block_device_fd(int fd)224 int is_block_device_fd(int fd __attribute__((unused)))
225 {
226 #ifdef _WIN32
227 return 0;
228 #else
229 struct stat st;
230 int ret = fstat(fd, &st);
231 if (ret < 0)
232 return 0;
233
234 return S_ISBLK(st.st_mode);
235 #endif
236 }
237
get_file_size(int fd)238 u64 get_file_size(int fd)
239 {
240 struct stat buf;
241 int ret;
242 u64 reserve_len = 0;
243 s64 computed_size;
244
245 ret = fstat(fd, &buf);
246 if (ret)
247 return 0;
248
249 if (info.len < 0)
250 reserve_len = -info.len;
251
252 if (S_ISREG(buf.st_mode))
253 computed_size = buf.st_size - reserve_len;
254 else if (S_ISBLK(buf.st_mode))
255 computed_size = get_block_device_size(fd) - reserve_len;
256 else
257 computed_size = 0;
258
259 if (computed_size < 0) {
260 warn("Computed filesystem size less than 0");
261 computed_size = 0;
262 }
263
264 return computed_size;
265 }
266
read_ext(int fd,int verbose)267 int read_ext(int fd, int verbose)
268 {
269 off64_t ret;
270 struct ext4_super_block sb;
271
272 read_sb(fd, &sb);
273
274 ext4_parse_sb_info(&sb);
275
276 ret = lseek64(fd, info.len, SEEK_SET);
277 if (ret < 0)
278 critical_error_errno("failed to seek to end of input image");
279
280 ret = lseek64(fd, info.block_size * (aux_info.first_data_block + 1), SEEK_SET);
281 if (ret < 0)
282 critical_error_errno("failed to seek to block group descriptors");
283
284 ret = read(fd, aux_info.bg_desc, info.block_size * aux_info.bg_desc_blocks);
285 if (ret < 0)
286 critical_error_errno("failed to read block group descriptors");
287 if (ret != (int)info.block_size * (int)aux_info.bg_desc_blocks)
288 critical_error("failed to read all of block group descriptors");
289
290 if (verbose) {
291 printf("Found filesystem with parameters:\n");
292 printf(" Size: %" PRIu64 "\n", info.len);
293 printf(" Block size: %d\n", info.block_size);
294 printf(" Blocks per group: %d\n", info.blocks_per_group);
295 printf(" Inodes per group: %d\n", info.inodes_per_group);
296 printf(" Inode size: %d\n", info.inode_size);
297 printf(" Label: %s\n", info.label);
298 printf(" Blocks: %" PRIext4u64 "\n", aux_info.len_blocks);
299 printf(" Block groups: %d\n", aux_info.groups);
300 printf(" Reserved block group size: %d\n", info.bg_desc_reserve_blocks);
301 printf(" Used %d/%d inodes and %d/%d blocks\n",
302 aux_info.sb->s_inodes_count - aux_info.sb->s_free_inodes_count,
303 aux_info.sb->s_inodes_count,
304 aux_info.sb->s_blocks_count_lo - aux_info.sb->s_free_blocks_count_lo,
305 aux_info.sb->s_blocks_count_lo);
306 }
307
308 return 0;
309 }
310
311