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
28void 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
49int 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
57struct 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
204struct 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
311corrupted:
312	free(dir->dirs);
313	free(dir);
314	return NULL;
315}
316
317
318int 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