1 /*
2 * Unsquash a squashfs filesystem. This is a highly compressed read only
3 * filesystem.
4 *
5 * Copyright (c) 2009, 2010, 2011, 2012, 2013
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-3.c
23 */
24
25 #include "unsquashfs.h"
26 #include "squashfs_compat.h"
27
28 static squashfs_fragment_entry_3 *fragment_table;
29
read_fragment_table_3(long long * directory_table_end)30 int read_fragment_table_3(long long *directory_table_end)
31 {
32 int res, i;
33 int bytes = SQUASHFS_FRAGMENT_BYTES_3(sBlk.s.fragments);
34 int indexes = SQUASHFS_FRAGMENT_INDEXES_3(sBlk.s.fragments);
35 long long fragment_table_index[indexes];
36
37 TRACE("read_fragment_table: %d fragments, reading %d fragment indexes "
38 "from 0x%llx\n", sBlk.s.fragments, indexes,
39 sBlk.s.fragment_table_start);
40
41 if(sBlk.s.fragments == 0) {
42 *directory_table_end = sBlk.s.fragment_table_start;
43 return TRUE;
44 }
45
46 fragment_table = malloc(bytes);
47 if(fragment_table == NULL)
48 EXIT_UNSQUASH("read_fragment_table: failed to allocate "
49 "fragment table\n");
50
51 if(swap) {
52 long long sfragment_table_index[indexes];
53
54 res = read_fs_bytes(fd, sBlk.s.fragment_table_start,
55 SQUASHFS_FRAGMENT_INDEX_BYTES_3(sBlk.s.fragments),
56 sfragment_table_index);
57 if(res == FALSE) {
58 ERROR("read_fragment_table: failed to read fragment "
59 "table index\n");
60 return FALSE;
61 }
62 SQUASHFS_SWAP_FRAGMENT_INDEXES_3(fragment_table_index,
63 sfragment_table_index, indexes);
64 } else {
65 res = read_fs_bytes(fd, sBlk.s.fragment_table_start,
66 SQUASHFS_FRAGMENT_INDEX_BYTES_3(sBlk.s.fragments),
67 fragment_table_index);
68 if(res == FALSE) {
69 ERROR("read_fragment_table: failed to read fragment "
70 "table index\n");
71 return FALSE;
72 }
73 }
74
75 for(i = 0; i < indexes; i++) {
76 int expected = (i + 1) != indexes ? SQUASHFS_METADATA_SIZE :
77 bytes & (SQUASHFS_METADATA_SIZE - 1);
78 int length = read_block(fd, fragment_table_index[i], NULL,
79 expected, ((char *) fragment_table) + (i *
80 SQUASHFS_METADATA_SIZE));
81 TRACE("Read fragment table block %d, from 0x%llx, length %d\n",
82 i, fragment_table_index[i], length);
83 if(length == FALSE) {
84 ERROR("read_fragment_table: failed to read fragment "
85 "table block\n");
86 return FALSE;
87 }
88 }
89
90 if(swap) {
91 squashfs_fragment_entry_3 sfragment;
92 for(i = 0; i < sBlk.s.fragments; i++) {
93 SQUASHFS_SWAP_FRAGMENT_ENTRY_3((&sfragment),
94 (&fragment_table[i]));
95 memcpy((char *) &fragment_table[i], (char *) &sfragment,
96 sizeof(squashfs_fragment_entry_3));
97 }
98 }
99
100 *directory_table_end = fragment_table_index[0];
101 return TRUE;
102 }
103
104
read_fragment_3(unsigned int fragment,long long * start_block,int * size)105 void read_fragment_3(unsigned int fragment, long long *start_block, int *size)
106 {
107 TRACE("read_fragment: reading fragment %d\n", fragment);
108
109 squashfs_fragment_entry_3 *fragment_entry = &fragment_table[fragment];
110 *start_block = fragment_entry->start_block;
111 *size = fragment_entry->size;
112 }
113
114
read_inode_3(unsigned int start_block,unsigned int offset)115 struct inode *read_inode_3(unsigned int start_block, unsigned int offset)
116 {
117 static union squashfs_inode_header_3 header;
118 long long start = sBlk.s.inode_table_start + start_block;
119 int bytes = lookup_entry(inode_table_hash, start);
120 char *block_ptr = inode_table + bytes + offset;
121 static struct inode i;
122
123 TRACE("read_inode: reading inode [%d:%d]\n", start_block, offset);
124
125 if(bytes == -1)
126 EXIT_UNSQUASH("read_inode: inode table block %lld not found\n",
127 start);
128
129 if(swap) {
130 squashfs_base_inode_header_3 sinode;
131 memcpy(&sinode, block_ptr, sizeof(header.base));
132 SQUASHFS_SWAP_BASE_INODE_HEADER_3(&header.base, &sinode,
133 sizeof(squashfs_base_inode_header_3));
134 } else
135 memcpy(&header.base, block_ptr, sizeof(header.base));
136
137 i.xattr = SQUASHFS_INVALID_XATTR;
138 i.uid = (uid_t) uid_table[header.base.uid];
139 i.gid = header.base.guid == SQUASHFS_GUIDS ? i.uid :
140 (uid_t) guid_table[header.base.guid];
141 i.mode = lookup_type[header.base.inode_type] | header.base.mode;
142 i.type = header.base.inode_type;
143 i.time = header.base.mtime;
144 i.inode_number = header.base.inode_number;
145
146 switch(header.base.inode_type) {
147 case SQUASHFS_DIR_TYPE: {
148 squashfs_dir_inode_header_3 *inode = &header.dir;
149
150 if(swap) {
151 squashfs_dir_inode_header_3 sinode;
152 memcpy(&sinode, block_ptr, sizeof(header.dir));
153 SQUASHFS_SWAP_DIR_INODE_HEADER_3(&header.dir,
154 &sinode);
155 } else
156 memcpy(&header.dir, block_ptr,
157 sizeof(header.dir));
158
159 i.data = inode->file_size;
160 i.offset = inode->offset;
161 i.start = inode->start_block;
162 break;
163 }
164 case SQUASHFS_LDIR_TYPE: {
165 squashfs_ldir_inode_header_3 *inode = &header.ldir;
166
167 if(swap) {
168 squashfs_ldir_inode_header_3 sinode;
169 memcpy(&sinode, block_ptr, sizeof(header.ldir));
170 SQUASHFS_SWAP_LDIR_INODE_HEADER_3(&header.ldir,
171 &sinode);
172 } else
173 memcpy(&header.ldir, block_ptr,
174 sizeof(header.ldir));
175
176 i.data = inode->file_size;
177 i.offset = inode->offset;
178 i.start = inode->start_block;
179 break;
180 }
181 case SQUASHFS_FILE_TYPE: {
182 squashfs_reg_inode_header_3 *inode = &header.reg;
183
184 if(swap) {
185 squashfs_reg_inode_header_3 sinode;
186 memcpy(&sinode, block_ptr, sizeof(sinode));
187 SQUASHFS_SWAP_REG_INODE_HEADER_3(inode,
188 &sinode);
189 } else
190 memcpy(inode, block_ptr, sizeof(*inode));
191
192 i.data = inode->file_size;
193 i.frag_bytes = inode->fragment == SQUASHFS_INVALID_FRAG
194 ? 0 : inode->file_size % sBlk.s.block_size;
195 i.fragment = inode->fragment;
196 i.offset = inode->offset;
197 i.blocks = inode->fragment == SQUASHFS_INVALID_FRAG ?
198 (i.data + sBlk.s.block_size - 1) >>
199 sBlk.s.block_log :
200 i.data >> sBlk.s.block_log;
201 i.start = inode->start_block;
202 i.sparse = 1;
203 i.block_ptr = block_ptr + sizeof(*inode);
204 break;
205 }
206 case SQUASHFS_LREG_TYPE: {
207 squashfs_lreg_inode_header_3 *inode = &header.lreg;
208
209 if(swap) {
210 squashfs_lreg_inode_header_3 sinode;
211 memcpy(&sinode, block_ptr, sizeof(sinode));
212 SQUASHFS_SWAP_LREG_INODE_HEADER_3(inode,
213 &sinode);
214 } else
215 memcpy(inode, block_ptr, sizeof(*inode));
216
217 i.data = inode->file_size;
218 i.frag_bytes = inode->fragment == SQUASHFS_INVALID_FRAG
219 ? 0 : inode->file_size % sBlk.s.block_size;
220 i.fragment = inode->fragment;
221 i.offset = inode->offset;
222 i.blocks = inode->fragment == SQUASHFS_INVALID_FRAG ?
223 (inode->file_size + sBlk.s.block_size - 1) >>
224 sBlk.s.block_log :
225 inode->file_size >> sBlk.s.block_log;
226 i.start = inode->start_block;
227 i.sparse = 1;
228 i.block_ptr = block_ptr + sizeof(*inode);
229 break;
230 }
231 case SQUASHFS_SYMLINK_TYPE: {
232 squashfs_symlink_inode_header_3 *inodep =
233 &header.symlink;
234
235 if(swap) {
236 squashfs_symlink_inode_header_3 sinodep;
237 memcpy(&sinodep, block_ptr, sizeof(sinodep));
238 SQUASHFS_SWAP_SYMLINK_INODE_HEADER_3(inodep,
239 &sinodep);
240 } else
241 memcpy(inodep, block_ptr, sizeof(*inodep));
242
243 i.symlink = malloc(inodep->symlink_size + 1);
244 if(i.symlink == NULL)
245 EXIT_UNSQUASH("read_inode: failed to malloc "
246 "symlink data\n");
247 strncpy(i.symlink, block_ptr +
248 sizeof(squashfs_symlink_inode_header_3),
249 inodep->symlink_size);
250 i.symlink[inodep->symlink_size] = '\0';
251 i.data = inodep->symlink_size;
252 break;
253 }
254 case SQUASHFS_BLKDEV_TYPE:
255 case SQUASHFS_CHRDEV_TYPE: {
256 squashfs_dev_inode_header_3 *inodep = &header.dev;
257
258 if(swap) {
259 squashfs_dev_inode_header_3 sinodep;
260 memcpy(&sinodep, block_ptr, sizeof(sinodep));
261 SQUASHFS_SWAP_DEV_INODE_HEADER_3(inodep,
262 &sinodep);
263 } else
264 memcpy(inodep, block_ptr, sizeof(*inodep));
265
266 i.data = inodep->rdev;
267 break;
268 }
269 case SQUASHFS_FIFO_TYPE:
270 case SQUASHFS_SOCKET_TYPE:
271 i.data = 0;
272 break;
273 default:
274 EXIT_UNSQUASH("Unknown inode type %d in read_inode!\n",
275 header.base.inode_type);
276 }
277 return &i;
278 }
279
280
squashfs_opendir_3(unsigned int block_start,unsigned int offset,struct inode ** i)281 struct dir *squashfs_opendir_3(unsigned int block_start, unsigned int offset,
282 struct inode **i)
283 {
284 squashfs_dir_header_3 dirh;
285 char buffer[sizeof(squashfs_dir_entry_3) + SQUASHFS_NAME_LEN + 1]
286 __attribute__((aligned));
287 squashfs_dir_entry_3 *dire = (squashfs_dir_entry_3 *) buffer;
288 long long start;
289 int bytes;
290 int dir_count, size;
291 struct dir_ent *new_dir;
292 struct dir *dir;
293
294 TRACE("squashfs_opendir: inode start block %d, offset %d\n",
295 block_start, offset);
296
297 *i = s_ops.read_inode(block_start, offset);
298
299 dir = malloc(sizeof(struct dir));
300 if(dir == NULL)
301 EXIT_UNSQUASH("squashfs_opendir: malloc failed!\n");
302
303 dir->dir_count = 0;
304 dir->cur_entry = 0;
305 dir->mode = (*i)->mode;
306 dir->uid = (*i)->uid;
307 dir->guid = (*i)->gid;
308 dir->mtime = (*i)->time;
309 dir->xattr = (*i)->xattr;
310 dir->dirs = NULL;
311
312 if ((*i)->data == 3)
313 /*
314 * if the directory is empty, skip the unnecessary
315 * lookup_entry, this fixes the corner case with
316 * completely empty filesystems where lookup_entry correctly
317 * returning -1 is incorrectly treated as an error
318 */
319 return dir;
320
321 start = sBlk.s.directory_table_start + (*i)->start;
322 bytes = lookup_entry(directory_table_hash, start);
323
324 if(bytes == -1)
325 EXIT_UNSQUASH("squashfs_opendir: directory block %d not "
326 "found!\n", block_start);
327
328 bytes += (*i)->offset;
329 size = (*i)->data + bytes - 3;
330
331 while(bytes < size) {
332 if(swap) {
333 squashfs_dir_header_3 sdirh;
334 memcpy(&sdirh, directory_table + bytes, sizeof(sdirh));
335 SQUASHFS_SWAP_DIR_HEADER_3(&dirh, &sdirh);
336 } else
337 memcpy(&dirh, directory_table + bytes, sizeof(dirh));
338
339 dir_count = dirh.count + 1;
340 TRACE("squashfs_opendir: Read directory header @ byte position "
341 "%d, %d directory entries\n", bytes, dir_count);
342 bytes += sizeof(dirh);
343
344 /* dir_count should never be larger than 256 */
345 if(dir_count > 256)
346 goto corrupted;
347
348 while(dir_count--) {
349 if(swap) {
350 squashfs_dir_entry_3 sdire;
351 memcpy(&sdire, directory_table + bytes,
352 sizeof(sdire));
353 SQUASHFS_SWAP_DIR_ENTRY_3(dire, &sdire);
354 } else
355 memcpy(dire, directory_table + bytes,
356 sizeof(*dire));
357 bytes += sizeof(*dire);
358
359 /* size should never be larger than SQUASHFS_NAME_LEN */
360 if(dire->size > SQUASHFS_NAME_LEN)
361 goto corrupted;
362
363 memcpy(dire->name, directory_table + bytes,
364 dire->size + 1);
365 dire->name[dire->size + 1] = '\0';
366 TRACE("squashfs_opendir: directory entry %s, inode "
367 "%d:%d, type %d\n", dire->name,
368 dirh.start_block, dire->offset, dire->type);
369 if((dir->dir_count % DIR_ENT_SIZE) == 0) {
370 new_dir = realloc(dir->dirs, (dir->dir_count +
371 DIR_ENT_SIZE) * sizeof(struct dir_ent));
372 if(new_dir == NULL)
373 EXIT_UNSQUASH("squashfs_opendir: "
374 "realloc failed!\n");
375 dir->dirs = new_dir;
376 }
377 strcpy(dir->dirs[dir->dir_count].name, dire->name);
378 dir->dirs[dir->dir_count].start_block =
379 dirh.start_block;
380 dir->dirs[dir->dir_count].offset = dire->offset;
381 dir->dirs[dir->dir_count].type = dire->type;
382 dir->dir_count ++;
383 bytes += dire->size + 1;
384 }
385 }
386
387 return dir;
388
389 corrupted:
390 free(dir->dirs);
391 free(dir);
392 return NULL;
393 }
394