1 /*
2 * Unsquash a squashfs filesystem. This is a highly compressed read only
3 * filesystem.
4 *
5 * Copyright (c) 2009, 2010, 2011, 2012
6 * Phillip Lougher <phillip@squashfs.org.uk>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version 2,
11 * or (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
21 *
22 * unsquash-1.c
23 */
24
25 #include "unsquashfs.h"
26 #include "squashfs_compat.h"
27
read_block_list_1(unsigned int * block_list,char * block_ptr,int blocks)28 void read_block_list_1(unsigned int *block_list, char *block_ptr, int blocks)
29 {
30 unsigned short block_size;
31 int i;
32
33 TRACE("read_block_list: blocks %d\n", blocks);
34
35 for(i = 0; i < blocks; i++, block_ptr += 2) {
36 if(swap) {
37 unsigned short sblock_size;
38 memcpy(&sblock_size, block_ptr, sizeof(unsigned short));
39 SQUASHFS_SWAP_SHORTS_3((&block_size), &sblock_size, 1);
40 } else
41 memcpy(&block_size, block_ptr, sizeof(unsigned short));
42 block_list[i] = SQUASHFS_COMPRESSED_SIZE(block_size) |
43 (SQUASHFS_COMPRESSED(block_size) ? 0 :
44 SQUASHFS_COMPRESSED_BIT_BLOCK);
45 }
46 }
47
48
read_fragment_table_1(long long * directory_table_end)49 int read_fragment_table_1(long long *directory_table_end)
50 {
51 TRACE("read_fragment_table\n");
52 *directory_table_end = sBlk.s.fragment_table_start;
53 return TRUE;
54 }
55
56
read_inode_1(unsigned int start_block,unsigned int offset)57 struct inode *read_inode_1(unsigned int start_block, unsigned int offset)
58 {
59 static union squashfs_inode_header_1 header;
60 long long start = sBlk.s.inode_table_start + start_block;
61 int bytes = lookup_entry(inode_table_hash, start);
62 char *block_ptr = inode_table + bytes + offset;
63 static struct inode i;
64
65 TRACE("read_inode: reading inode [%d:%d]\n", start_block, offset);
66
67 if(bytes == -1)
68 EXIT_UNSQUASH("read_inode: inode table block %lld not found\n",
69 start);
70
71 if(swap) {
72 squashfs_base_inode_header_1 sinode;
73 memcpy(&sinode, block_ptr, sizeof(header.base));
74 SQUASHFS_SWAP_BASE_INODE_HEADER_1(&header.base, &sinode,
75 sizeof(squashfs_base_inode_header_1));
76 } else
77 memcpy(&header.base, block_ptr, sizeof(header.base));
78
79 i.uid = (uid_t) uid_table[(header.base.inode_type - 1) /
80 SQUASHFS_TYPES * 16 + header.base.uid];
81 if(header.base.inode_type == SQUASHFS_IPC_TYPE) {
82 squashfs_ipc_inode_header_1 *inodep = &header.ipc;
83
84 if(swap) {
85 squashfs_ipc_inode_header_1 sinodep;
86 memcpy(&sinodep, block_ptr, sizeof(sinodep));
87 SQUASHFS_SWAP_IPC_INODE_HEADER_1(inodep, &sinodep);
88 } else
89 memcpy(inodep, block_ptr, sizeof(*inodep));
90
91 if(inodep->type == SQUASHFS_SOCKET_TYPE) {
92 i.mode = S_IFSOCK | header.base.mode;
93 i.type = SQUASHFS_SOCKET_TYPE;
94 } else {
95 i.mode = S_IFIFO | header.base.mode;
96 i.type = SQUASHFS_FIFO_TYPE;
97 }
98 i.uid = (uid_t) uid_table[inodep->offset * 16 + inodep->uid];
99 } else {
100 i.mode = lookup_type[(header.base.inode_type - 1) %
101 SQUASHFS_TYPES + 1] | header.base.mode;
102 i.type = (header.base.inode_type - 1) % SQUASHFS_TYPES + 1;
103 }
104
105 i.xattr = SQUASHFS_INVALID_XATTR;
106 i.gid = header.base.guid == 15 ? i.uid :
107 (uid_t) guid_table[header.base.guid];
108 i.time = sBlk.s.mkfs_time;
109 i.inode_number = inode_number ++;
110
111 switch(i.type) {
112 case SQUASHFS_DIR_TYPE: {
113 squashfs_dir_inode_header_1 *inode = &header.dir;
114
115 if(swap) {
116 squashfs_dir_inode_header_1 sinode;
117 memcpy(&sinode, block_ptr, sizeof(header.dir));
118 SQUASHFS_SWAP_DIR_INODE_HEADER_1(inode,
119 &sinode);
120 } else
121 memcpy(inode, block_ptr, sizeof(header.dir));
122
123 i.data = inode->file_size;
124 i.offset = inode->offset;
125 i.start = inode->start_block;
126 i.time = inode->mtime;
127 break;
128 }
129 case SQUASHFS_FILE_TYPE: {
130 squashfs_reg_inode_header_1 *inode = &header.reg;
131
132 if(swap) {
133 squashfs_reg_inode_header_1 sinode;
134 memcpy(&sinode, block_ptr, sizeof(sinode));
135 SQUASHFS_SWAP_REG_INODE_HEADER_1(inode,
136 &sinode);
137 } else
138 memcpy(inode, block_ptr, sizeof(*inode));
139
140 i.data = inode->file_size;
141 i.time = inode->mtime;
142 i.blocks = (i.data + sBlk.s.block_size - 1) >>
143 sBlk.s.block_log;
144 i.start = inode->start_block;
145 i.block_ptr = block_ptr + sizeof(*inode);
146 i.fragment = 0;
147 i.frag_bytes = 0;
148 i.offset = 0;
149 i.sparse = 0;
150 break;
151 }
152 case SQUASHFS_SYMLINK_TYPE: {
153 squashfs_symlink_inode_header_1 *inodep =
154 &header.symlink;
155
156 if(swap) {
157 squashfs_symlink_inode_header_1 sinodep;
158 memcpy(&sinodep, block_ptr, sizeof(sinodep));
159 SQUASHFS_SWAP_SYMLINK_INODE_HEADER_1(inodep,
160 &sinodep);
161 } else
162 memcpy(inodep, block_ptr, sizeof(*inodep));
163
164 i.symlink = malloc(inodep->symlink_size + 1);
165 if(i.symlink == NULL)
166 EXIT_UNSQUASH("read_inode: failed to malloc "
167 "symlink data\n");
168 strncpy(i.symlink, block_ptr +
169 sizeof(squashfs_symlink_inode_header_1),
170 inodep->symlink_size);
171 i.symlink[inodep->symlink_size] = '\0';
172 i.data = inodep->symlink_size;
173 break;
174 }
175 case SQUASHFS_BLKDEV_TYPE:
176 case SQUASHFS_CHRDEV_TYPE: {
177 squashfs_dev_inode_header_1 *inodep = &header.dev;
178
179 if(swap) {
180 squashfs_dev_inode_header_1 sinodep;
181 memcpy(&sinodep, block_ptr, sizeof(sinodep));
182 SQUASHFS_SWAP_DEV_INODE_HEADER_1(inodep,
183 &sinodep);
184 } else
185 memcpy(inodep, block_ptr, sizeof(*inodep));
186
187 i.data = inodep->rdev;
188 break;
189 }
190 case SQUASHFS_FIFO_TYPE:
191 case SQUASHFS_SOCKET_TYPE: {
192 i.data = 0;
193 break;
194 }
195 default:
196 EXIT_UNSQUASH("Unknown inode type %d in "
197 " read_inode_header_1!\n",
198 header.base.inode_type);
199 }
200 return &i;
201 }
202
203
squashfs_opendir_1(unsigned int block_start,unsigned int offset,struct inode ** i)204 struct dir *squashfs_opendir_1(unsigned int block_start, unsigned int offset,
205 struct inode **i)
206 {
207 squashfs_dir_header_2 dirh;
208 char buffer[sizeof(squashfs_dir_entry_2) + SQUASHFS_NAME_LEN + 1]
209 __attribute__((aligned));
210 squashfs_dir_entry_2 *dire = (squashfs_dir_entry_2 *) buffer;
211 long long start;
212 int bytes;
213 int dir_count, size;
214 struct dir_ent *new_dir;
215 struct dir *dir;
216
217 TRACE("squashfs_opendir: inode start block %d, offset %d\n",
218 block_start, offset);
219
220 *i = s_ops.read_inode(block_start, offset);
221
222 dir = malloc(sizeof(struct dir));
223 if(dir == NULL)
224 EXIT_UNSQUASH("squashfs_opendir: malloc failed!\n");
225
226 dir->dir_count = 0;
227 dir->cur_entry = 0;
228 dir->mode = (*i)->mode;
229 dir->uid = (*i)->uid;
230 dir->guid = (*i)->gid;
231 dir->mtime = (*i)->time;
232 dir->xattr = (*i)->xattr;
233 dir->dirs = NULL;
234
235 if ((*i)->data == 0)
236 /*
237 * if the directory is empty, skip the unnecessary
238 * lookup_entry, this fixes the corner case with
239 * completely empty filesystems where lookup_entry correctly
240 * returning -1 is incorrectly treated as an error
241 */
242 return dir;
243
244 start = sBlk.s.directory_table_start + (*i)->start;
245 bytes = lookup_entry(directory_table_hash, start);
246 if(bytes == -1)
247 EXIT_UNSQUASH("squashfs_opendir: directory block %d not "
248 "found!\n", block_start);
249
250 bytes += (*i)->offset;
251 size = (*i)->data + bytes;
252
253 while(bytes < size) {
254 if(swap) {
255 squashfs_dir_header_2 sdirh;
256 memcpy(&sdirh, directory_table + bytes, sizeof(sdirh));
257 SQUASHFS_SWAP_DIR_HEADER_2(&dirh, &sdirh);
258 } else
259 memcpy(&dirh, directory_table + bytes, sizeof(dirh));
260
261 dir_count = dirh.count + 1;
262 TRACE("squashfs_opendir: Read directory header @ byte position "
263 "%d, %d directory entries\n", bytes, dir_count);
264 bytes += sizeof(dirh);
265
266 /* dir_count should never be larger than 256 */
267 if(dir_count > 256)
268 goto corrupted;
269
270 while(dir_count--) {
271 if(swap) {
272 squashfs_dir_entry_2 sdire;
273 memcpy(&sdire, directory_table + bytes,
274 sizeof(sdire));
275 SQUASHFS_SWAP_DIR_ENTRY_2(dire, &sdire);
276 } else
277 memcpy(dire, directory_table + bytes,
278 sizeof(*dire));
279 bytes += sizeof(*dire);
280
281 /* size should never be larger than SQUASHFS_NAME_LEN */
282 if(dire->size > SQUASHFS_NAME_LEN)
283 goto corrupted;
284
285 memcpy(dire->name, directory_table + bytes,
286 dire->size + 1);
287 dire->name[dire->size + 1] = '\0';
288 TRACE("squashfs_opendir: directory entry %s, inode "
289 "%d:%d, type %d\n", dire->name,
290 dirh.start_block, dire->offset, dire->type);
291 if((dir->dir_count % DIR_ENT_SIZE) == 0) {
292 new_dir = realloc(dir->dirs, (dir->dir_count +
293 DIR_ENT_SIZE) * sizeof(struct dir_ent));
294 if(new_dir == NULL)
295 EXIT_UNSQUASH("squashfs_opendir: "
296 "realloc failed!\n");
297 dir->dirs = new_dir;
298 }
299 strcpy(dir->dirs[dir->dir_count].name, dire->name);
300 dir->dirs[dir->dir_count].start_block =
301 dirh.start_block;
302 dir->dirs[dir->dir_count].offset = dire->offset;
303 dir->dirs[dir->dir_count].type = dire->type;
304 dir->dir_count ++;
305 bytes += dire->size + 1;
306 }
307 }
308
309 return dir;
310
311 corrupted:
312 free(dir->dirs);
313 free(dir);
314 return NULL;
315 }
316
317
read_uids_guids_1()318 int read_uids_guids_1()
319 {
320 int res;
321
322 TRACE("read_uids_guids: no_uids %d, no_guids %d\n", sBlk.no_uids,
323 sBlk.no_guids);
324
325 uid_table = malloc((sBlk.no_uids + sBlk.no_guids) *
326 sizeof(unsigned int));
327 if(uid_table == NULL) {
328 ERROR("read_uids_guids: failed to allocate uid/gid table\n");
329 return FALSE;
330 }
331
332 guid_table = uid_table + sBlk.no_uids;
333
334 if(swap) {
335 unsigned int suid_table[sBlk.no_uids + sBlk.no_guids];
336
337 res = read_fs_bytes(fd, sBlk.uid_start, (sBlk.no_uids +
338 sBlk.no_guids) * sizeof(unsigned int), suid_table);
339 if(res == FALSE) {
340 ERROR("read_uids_guids: failed to read uid/gid table"
341 "\n");
342 return FALSE;
343 }
344 SQUASHFS_SWAP_INTS_3(uid_table, suid_table,
345 sBlk.no_uids + sBlk.no_guids);
346 } else {
347 res = read_fs_bytes(fd, sBlk.uid_start, (sBlk.no_uids +
348 sBlk.no_guids) * sizeof(unsigned int), uid_table);
349 if(res == FALSE) {
350 ERROR("read_uids_guids: failed to read uid/gid table"
351 "\n");
352 return FALSE;
353 }
354 }
355
356 return TRUE;
357 }
358