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