1 /*
2 * cramfs.c
3 *
4 * Copyright (C) 1999 Linus Torvalds
5 *
6 * Copyright (C) 2000-2002 Transmeta Corporation
7 *
8 * Copyright (C) 2003 Kai-Uwe Bloem,
9 * Auerswald GmbH & Co KG, <linux-development@auerswald.de>
10 * - adapted from the www.tuxbox.org u-boot tree, added "ls" command
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License (Version 2) as
14 * published by the Free Software Foundation.
15 *
16 * Compressed ROM filesystem for Linux.
17 *
18 * TODO:
19 * add support for resolving symbolic links
20 */
21
22 /*
23 * These are the VFS interfaces to the compressed ROM filesystem.
24 * The actual compression is based on zlib, see the other files.
25 */
26
27 #include <common.h>
28 #include <malloc.h>
29 #include <asm/byteorder.h>
30 #include <linux/stat.h>
31 #include <jffs2/jffs2.h>
32 #include <jffs2/load_kernel.h>
33 #include <cramfs/cramfs_fs.h>
34
35 /* These two macros may change in future, to provide better st_ino
36 semantics. */
37 #define CRAMINO(x) (CRAMFS_GET_OFFSET(x) ? CRAMFS_GET_OFFSET(x)<<2 : 1)
38 #define OFFSET(x) ((x)->i_ino)
39
40 struct cramfs_super super;
41
42 /* CPU address space offset calculation macro, struct part_info offset is
43 * device address space offset, so we need to shift it by a device start address. */
44 #if defined(CONFIG_MTD_NOR_FLASH)
45 extern flash_info_t flash_info[];
46 #define PART_OFFSET(x) ((ulong)x->offset + \
47 flash_info[x->dev->id->num].start[0])
48 #else
49 #define PART_OFFSET(x) ((ulong)x->offset)
50 #endif
51
52 static int cramfs_uncompress (unsigned long begin, unsigned long offset,
53 unsigned long loadoffset);
54
cramfs_read_super(struct part_info * info)55 static int cramfs_read_super (struct part_info *info)
56 {
57 unsigned long root_offset;
58
59 /* Read the first block and get the superblock from it */
60 memcpy (&super, (void *) PART_OFFSET(info), sizeof (super));
61
62 /* Do sanity checks on the superblock */
63 if (super.magic != CRAMFS_32 (CRAMFS_MAGIC)) {
64 /* check at 512 byte offset */
65 memcpy (&super, (void *) PART_OFFSET(info) + 512, sizeof (super));
66 if (super.magic != CRAMFS_32 (CRAMFS_MAGIC)) {
67 printf ("cramfs: wrong magic\n");
68 return -1;
69 }
70 }
71
72 /* flags is reused several times, so swab it once */
73 super.flags = CRAMFS_32 (super.flags);
74 super.size = CRAMFS_32 (super.size);
75
76 /* get feature flags first */
77 if (super.flags & ~CRAMFS_SUPPORTED_FLAGS) {
78 printf ("cramfs: unsupported filesystem features\n");
79 return -1;
80 }
81
82 /* Check that the root inode is in a sane state */
83 if (!S_ISDIR (CRAMFS_16 (super.root.mode))) {
84 printf ("cramfs: root is not a directory\n");
85 return -1;
86 }
87 root_offset = CRAMFS_GET_OFFSET (&(super.root)) << 2;
88 if (root_offset == 0) {
89 printf ("cramfs: empty filesystem");
90 } else if (!(super.flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET) &&
91 ((root_offset != sizeof (struct cramfs_super)) &&
92 (root_offset != 512 + sizeof (struct cramfs_super)))) {
93 printf ("cramfs: bad root offset %lu\n", root_offset);
94 return -1;
95 }
96
97 return 0;
98 }
99
100 /* Unpack to an allocated buffer, trusting in the inode's size field. */
cramfs_uncompress_link(unsigned long begin,unsigned long offset)101 static char *cramfs_uncompress_link (unsigned long begin, unsigned long offset)
102 {
103 struct cramfs_inode *inode = (struct cramfs_inode *)(begin + offset);
104 unsigned long size = CRAMFS_24 (inode->size);
105 char *link = malloc (size + 1);
106
107 if (!link || cramfs_uncompress (begin, offset, (unsigned long)link) != size) {
108 free (link);
109 link = NULL;
110 } else {
111 link[size] = '\0';
112 }
113 return link;
114 }
115
cramfs_resolve(unsigned long begin,unsigned long offset,unsigned long size,int raw,char * filename)116 static unsigned long cramfs_resolve (unsigned long begin, unsigned long offset,
117 unsigned long size, int raw,
118 char *filename)
119 {
120 unsigned long inodeoffset = 0, nextoffset;
121
122 while (inodeoffset < size) {
123 struct cramfs_inode *inode;
124 char *name;
125 int namelen;
126
127 inode = (struct cramfs_inode *) (begin + offset +
128 inodeoffset);
129
130 /*
131 * Namelengths on disk are shifted by two
132 * and the name padded out to 4-byte boundaries
133 * with zeroes.
134 */
135 namelen = CRAMFS_GET_NAMELEN (inode) << 2;
136 name = (char *) inode + sizeof (struct cramfs_inode);
137
138 nextoffset =
139 inodeoffset + sizeof (struct cramfs_inode) + namelen;
140
141 for (;;) {
142 if (!namelen)
143 return -1;
144 if (name[namelen - 1])
145 break;
146 namelen--;
147 }
148
149 if (!strncmp(filename, name, namelen) &&
150 (namelen == strlen(filename))) {
151 char *p = strtok (NULL, "/");
152
153 if (raw && (p == NULL || *p == '\0'))
154 return offset + inodeoffset;
155
156 if (S_ISDIR (CRAMFS_16 (inode->mode))) {
157 return cramfs_resolve (begin,
158 CRAMFS_GET_OFFSET
159 (inode) << 2,
160 CRAMFS_24 (inode->
161 size), raw,
162 p);
163 } else if (S_ISREG (CRAMFS_16 (inode->mode))) {
164 return offset + inodeoffset;
165 } else if (S_ISLNK (CRAMFS_16 (inode->mode))) {
166 unsigned long ret;
167 char *link;
168 if (p && strlen(p)) {
169 printf ("unsupported symlink to \
170 non-terminal path\n");
171 return 0;
172 }
173 link = cramfs_uncompress_link (begin,
174 offset + inodeoffset);
175 if (!link) {
176 printf ("%*.*s: Error reading link\n",
177 namelen, namelen, name);
178 return 0;
179 } else if (link[0] == '/') {
180 printf ("unsupported symlink to \
181 absolute path\n");
182 free (link);
183 return 0;
184 }
185 ret = cramfs_resolve (begin,
186 offset,
187 size,
188 raw,
189 strtok(link, "/"));
190 free (link);
191 return ret;
192 } else {
193 printf ("%*.*s: unsupported file type (%x)\n",
194 namelen, namelen, name,
195 CRAMFS_16 (inode->mode));
196 return 0;
197 }
198 }
199
200 inodeoffset = nextoffset;
201 }
202
203 printf ("can't find corresponding entry\n");
204 return 0;
205 }
206
cramfs_uncompress(unsigned long begin,unsigned long offset,unsigned long loadoffset)207 static int cramfs_uncompress (unsigned long begin, unsigned long offset,
208 unsigned long loadoffset)
209 {
210 struct cramfs_inode *inode = (struct cramfs_inode *) (begin + offset);
211 u32 *block_ptrs = (u32 *)
212 (begin + (CRAMFS_GET_OFFSET (inode) << 2));
213 unsigned long curr_block = (CRAMFS_GET_OFFSET (inode) +
214 (((CRAMFS_24 (inode->size)) +
215 4095) >> 12)) << 2;
216 int size, total_size = 0;
217 int i;
218
219 cramfs_uncompress_init ();
220
221 for (i = 0; i < ((CRAMFS_24 (inode->size) + 4095) >> 12); i++) {
222 size = cramfs_uncompress_block ((void *) loadoffset,
223 (void *) (begin + curr_block),
224 (CRAMFS_32 (block_ptrs[i]) -
225 curr_block));
226 if (size < 0)
227 return size;
228 loadoffset += size;
229 total_size += size;
230 curr_block = CRAMFS_32 (block_ptrs[i]);
231 }
232
233 cramfs_uncompress_exit ();
234 return total_size;
235 }
236
cramfs_load(char * loadoffset,struct part_info * info,char * filename)237 int cramfs_load (char *loadoffset, struct part_info *info, char *filename)
238 {
239 unsigned long offset;
240
241 if (cramfs_read_super (info))
242 return -1;
243
244 offset = cramfs_resolve (PART_OFFSET(info),
245 CRAMFS_GET_OFFSET (&(super.root)) << 2,
246 CRAMFS_24 (super.root.size), 0,
247 strtok (filename, "/"));
248
249 if (offset <= 0)
250 return offset;
251
252 return cramfs_uncompress (PART_OFFSET(info), offset,
253 (unsigned long) loadoffset);
254 }
255
cramfs_list_inode(struct part_info * info,unsigned long offset)256 static int cramfs_list_inode (struct part_info *info, unsigned long offset)
257 {
258 struct cramfs_inode *inode = (struct cramfs_inode *)
259 (PART_OFFSET(info) + offset);
260 char *name, str[20];
261 int namelen, nextoff;
262
263 /*
264 * Namelengths on disk are shifted by two
265 * and the name padded out to 4-byte boundaries
266 * with zeroes.
267 */
268 namelen = CRAMFS_GET_NAMELEN (inode) << 2;
269 name = (char *) inode + sizeof (struct cramfs_inode);
270 nextoff = namelen;
271
272 for (;;) {
273 if (!namelen)
274 return namelen;
275 if (name[namelen - 1])
276 break;
277 namelen--;
278 }
279
280 printf (" %s %8d %*.*s", mkmodestr (CRAMFS_16 (inode->mode), str),
281 CRAMFS_24 (inode->size), namelen, namelen, name);
282
283 if ((CRAMFS_16 (inode->mode) & S_IFMT) == S_IFLNK) {
284 char *link = cramfs_uncompress_link (PART_OFFSET(info), offset);
285 if (link)
286 printf (" -> %s\n", link);
287 else
288 printf (" [Error reading link]\n");
289 free (link);
290 } else
291 printf ("\n");
292
293 return nextoff;
294 }
295
cramfs_ls(struct part_info * info,char * filename)296 int cramfs_ls (struct part_info *info, char *filename)
297 {
298 struct cramfs_inode *inode;
299 unsigned long inodeoffset = 0, nextoffset;
300 unsigned long offset, size;
301
302 if (cramfs_read_super (info))
303 return -1;
304
305 if (strlen (filename) == 0 || !strcmp (filename, "/")) {
306 /* Root directory. Use root inode in super block */
307 offset = CRAMFS_GET_OFFSET (&(super.root)) << 2;
308 size = CRAMFS_24 (super.root.size);
309 } else {
310 /* Resolve the path */
311 offset = cramfs_resolve (PART_OFFSET(info),
312 CRAMFS_GET_OFFSET (&(super.root)) <<
313 2, CRAMFS_24 (super.root.size), 1,
314 strtok (filename, "/"));
315
316 if (offset <= 0)
317 return offset;
318
319 /* Resolving was successful. Examine the inode */
320 inode = (struct cramfs_inode *) (PART_OFFSET(info) + offset);
321 if (!S_ISDIR (CRAMFS_16 (inode->mode))) {
322 /* It's not a directory - list it, and that's that */
323 return (cramfs_list_inode (info, offset) > 0);
324 }
325
326 /* It's a directory. List files within */
327 offset = CRAMFS_GET_OFFSET (inode) << 2;
328 size = CRAMFS_24 (inode->size);
329 }
330
331 /* List the given directory */
332 while (inodeoffset < size) {
333 inode = (struct cramfs_inode *) (PART_OFFSET(info) + offset +
334 inodeoffset);
335
336 nextoffset = cramfs_list_inode (info, offset + inodeoffset);
337 if (nextoffset == 0)
338 break;
339 inodeoffset += sizeof (struct cramfs_inode) + nextoffset;
340 }
341
342 return 1;
343 }
344
cramfs_info(struct part_info * info)345 int cramfs_info (struct part_info *info)
346 {
347 if (cramfs_read_super (info))
348 return 0;
349
350 printf ("size: 0x%x (%u)\n", super.size, super.size);
351
352 if (super.flags != 0) {
353 printf ("flags:\n");
354 if (super.flags & CRAMFS_FLAG_FSID_VERSION_2)
355 printf ("\tFSID version 2\n");
356 if (super.flags & CRAMFS_FLAG_SORTED_DIRS)
357 printf ("\tsorted dirs\n");
358 if (super.flags & CRAMFS_FLAG_HOLES)
359 printf ("\tholes\n");
360 if (super.flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET)
361 printf ("\tshifted root offset\n");
362 }
363
364 printf ("fsid:\n\tcrc: 0x%x\n\tedition: 0x%x\n",
365 super.fsid.crc, super.fsid.edition);
366 printf ("name: %16s\n", super.name);
367
368 return 1;
369 }
370
cramfs_check(struct part_info * info)371 int cramfs_check (struct part_info *info)
372 {
373 struct cramfs_super *sb;
374
375 if (info->dev->id->type != MTD_DEV_TYPE_NOR)
376 return 0;
377
378 sb = (struct cramfs_super *) PART_OFFSET(info);
379 if (sb->magic != CRAMFS_32 (CRAMFS_MAGIC)) {
380 /* check at 512 byte offset */
381 sb = (struct cramfs_super *) (PART_OFFSET(info) + 512);
382 if (sb->magic != CRAMFS_32 (CRAMFS_MAGIC))
383 return 0;
384 }
385 return 1;
386 }
387