fs/cramfs/cramfs.c

   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
  30 #if (CONFIG_COMMANDS & CFG_CMD_JFFS2)
  31
  32 #include <asm/byteorder.h>
  33 #include <linux/stat.h>
  34 #include <jffs2/jffs2.h>
  35 #include <jffs2/load_kernel.h>
  36 #include <cramfs/cramfs_fs.h>
  37
  38 /* These two macros may change in future, to provide better st_ino
  39    semantics. */
  40 #define CRAMINO(x)      (CRAMFS_GET_OFFSET(x) ? CRAMFS_GET_OFFSET(x)<<2 : 1)
  41 #define OFFSET(x)       ((x)->i_ino)
  42
  43 struct cramfs_super super;
  44
  45 /* CPU address space offset calculation macro, struct part_info offset is
  46  * device address space offset, so we need to shift it by a device start address. */
  47 extern flash_info_t flash_info[];
  48 #define PART_OFFSET(x)  (x->offset + flash_info[x->dev->id->num].start[0])
  49
  50 static int cramfs_read_super (struct part_info *info)
  51 {
  52         unsigned long root_offset;
  53
  54         /* Read the first block and get the superblock from it */
  55         memcpy (&super, (void *) PART_OFFSET(info), sizeof (super));
  56
  57         /* Do sanity checks on the superblock */
  58         if (super.magic != CRAMFS_32 (CRAMFS_MAGIC)) {
  59                 /* check at 512 byte offset */
  60                 memcpy (&super, (void *) PART_OFFSET(info) + 512, sizeof (super));
  61                 if (super.magic != CRAMFS_32 (CRAMFS_MAGIC)) {
  62                         printf ("cramfs: wrong magic\n");
  63                         return -1;
  64                 }
  65         }
  66
  67         /* flags is reused several times, so swab it once */
  68         super.flags = CRAMFS_32 (super.flags);
  69         super.size = CRAMFS_32 (super.size);
  70
  71         /* get feature flags first */
  72         if (super.flags & ~CRAMFS_SUPPORTED_FLAGS) {
  73                 printf ("cramfs: unsupported filesystem features\n");
  74                 return -1;
  75         }
  76
  77         /* Check that the root inode is in a sane state */
  78         if (!S_ISDIR (CRAMFS_16 (super.root.mode))) {
  79                 printf ("cramfs: root is not a directory\n");
  80                 return -1;
  81         }
  82         root_offset = CRAMFS_GET_OFFSET (&(super.root)) << 2;
  83         if (root_offset == 0) {
  84                 printf ("cramfs: empty filesystem");
  85         } else if (!(super.flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET) &&
  86                    ((root_offset != sizeof (struct cramfs_super)) &&
  87                     (root_offset != 512 + sizeof (struct cramfs_super)))) {
  88                 printf ("cramfs: bad root offset %lu\n", root_offset);
  89                 return -1;
  90         }
  91
  92         return 0;
  93 }
  94
  95 static unsigned long cramfs_resolve (unsigned long begin, unsigned long offset,
  96                                      unsigned long size, int raw,
  97                                      char *filename)
  98 {
  99         unsigned long inodeoffset = 0, nextoffset;
 100
 101         while (inodeoffset < size) {
 102                 struct cramfs_inode *inode;
 103                 char *name;
 104                 int namelen;
 105
 106                 inode = (struct cramfs_inode *) (begin + offset +
 107                                                  inodeoffset);
 108
 109                 /*
 110                  * Namelengths on disk are shifted by two
 111                  * and the name padded out to 4-byte boundaries
 112                  * with zeroes.
 113                  */
 114                 namelen = CRAMFS_GET_NAMELEN (inode) << 2;
 115                 name = (char *) inode + sizeof (struct cramfs_inode);
 116
 117                 nextoffset =
 118                         inodeoffset + sizeof (struct cramfs_inode) + namelen;
 119
 120                 for (;;) {
 121                         if (!namelen)
 122                                 return -1;
 123                         if (name[namelen - 1])
 124                                 break;
 125                         namelen--;
 126                 }
 127
 128                 if (!strncmp (filename, name, namelen)) {
 129                         char *p = strtok (NULL, "/");
 130
 131                         if (raw && (p == NULL || *p == '\0'))
 132                                 return offset + inodeoffset;
 133
 134                         if (S_ISDIR (CRAMFS_16 (inode->mode))) {
 135                                 return cramfs_resolve (begin,
 136                                                        CRAMFS_GET_OFFSET
 137                                                        (inode) << 2,
 138                                                        CRAMFS_24 (inode->
 139                                                                   size), raw,
 140                                                        p);
 141                         } else if (S_ISREG (CRAMFS_16 (inode->mode))) {
 142                                 return offset + inodeoffset;
 143                         } else {
 144                                 printf ("%*.*s: unsupported file type (%x)\n",
 145                                         namelen, namelen, name,
 146                                         CRAMFS_16 (inode->mode));
 147                                 return 0;
 148                         }
 149                 }
 150
 151                 inodeoffset = nextoffset;
 152         }
 153
 154         printf ("can't find corresponding entry\n");
 155         return 0;
 156 }
 157
 158 static int cramfs_uncompress (unsigned long begin, unsigned long offset,
 159                               unsigned long loadoffset)
 160 {
 161         struct cramfs_inode *inode = (struct cramfs_inode *) (begin + offset);
 162         unsigned long *block_ptrs = (unsigned long *)
 163                 (begin + (CRAMFS_GET_OFFSET (inode) << 2));
 164         unsigned long curr_block = (CRAMFS_GET_OFFSET (inode) +
 165                                     (((CRAMFS_24 (inode->size)) +
 166                                       4095) >> 12)) << 2;
 167         int size, total_size = 0;
 168         int i;
 169
 170         cramfs_uncompress_init ();
 171
 172         for (i = 0; i < ((CRAMFS_24 (inode->size) + 4095) >> 12); i++) {
 173                 size = cramfs_uncompress_block ((void *) loadoffset,
 174                                                 (void *) (begin + curr_block),
 175                                                 (CRAMFS_32 (block_ptrs[i]) -
 176                                                  curr_block));
 177                 if (size < 0)
 178                         return size;
 179                 loadoffset += size;
 180                 total_size += size;
 181                 curr_block = CRAMFS_32 (block_ptrs[i]);
 182         }
 183
 184         cramfs_uncompress_exit ();
 185         return total_size;
 186 }
 187
 188 int cramfs_load (char *loadoffset, struct part_info *info, char *filename)
 189 {
 190         unsigned long offset;
 191
 192         if (cramfs_read_super (info))
 193                 return -1;
 194
 195         offset = cramfs_resolve (PART_OFFSET(info),
 196                                  CRAMFS_GET_OFFSET (&(super.root)) << 2,
 197                                  CRAMFS_24 (super.root.size), 0,
 198                                  strtok (filename, "/"));
 199
 200         if (offset <= 0)
 201                 return offset;
 202
 203         return cramfs_uncompress (PART_OFFSET(info), offset,
 204                                   (unsigned long) loadoffset);
 205 }
 206
 207 static int cramfs_list_inode (struct part_info *info, unsigned long offset)
 208 {
 209         struct cramfs_inode *inode = (struct cramfs_inode *)
 210                 (PART_OFFSET(info) + offset);
 211         char *name, str[20];
 212         int namelen, nextoff;
 213
 214         /*
 215          * Namelengths on disk are shifted by two
 216          * and the name padded out to 4-byte boundaries
 217          * with zeroes.
 218          */
 219         namelen = CRAMFS_GET_NAMELEN (inode) << 2;
 220         name = (char *) inode + sizeof (struct cramfs_inode);
 221         nextoff = namelen;
 222
 223         for (;;) {
 224                 if (!namelen)
 225                         return namelen;
 226                 if (name[namelen - 1])
 227                         break;
 228                 namelen--;
 229         }
 230
 231         printf (" %s %8d %*.*s", mkmodestr (CRAMFS_16 (inode->mode), str),
 232                 CRAMFS_24 (inode->size), namelen, namelen, name);
 233
 234         if ((CRAMFS_16 (inode->mode) & S_IFMT) == S_IFLNK) {
 235                 /* symbolic link.
 236                  * Unpack the link target, trusting in the inode's size field.
 237                  */
 238                 unsigned long size = CRAMFS_24 (inode->size);
 239                 char *link = malloc (size);
 240
 241                 if (link != NULL && cramfs_uncompress (PART_OFFSET(info), offset,
 242                                                        (unsigned long) link)
 243                     == size)
 244                         printf (" -> %*.*s\n", (int) size, (int) size, link);
 245                 else
 246                         printf (" [Error reading link]\n");
 247                 if (link)
 248                         free (link);
 249         } else
 250                 printf ("\n");
 251
 252         return nextoff;
 253 }
 254
 255 int cramfs_ls (struct part_info *info, char *filename)
 256 {
 257         struct cramfs_inode *inode;
 258         unsigned long inodeoffset = 0, nextoffset;
 259         unsigned long offset, size;
 260
 261         if (cramfs_read_super (info))
 262                 return -1;
 263
 264         if (strlen (filename) == 0 || !strcmp (filename, "/")) {
 265                 /* Root directory. Use root inode in super block */
 266                 offset = CRAMFS_GET_OFFSET (&(super.root)) << 2;
 267                 size = CRAMFS_24 (super.root.size);
 268         } else {
 269                 /* Resolve the path */
 270                 offset = cramfs_resolve (PART_OFFSET(info),
 271                                          CRAMFS_GET_OFFSET (&(super.root)) <<
 272                                          2, CRAMFS_24 (super.root.size), 1,
 273                                          strtok (filename, "/"));
 274
 275                 if (offset <= 0)
 276                         return offset;
 277
 278                 /* Resolving was successful. Examine the inode */
 279                 inode = (struct cramfs_inode *) (PART_OFFSET(info) + offset);
 280                 if (!S_ISDIR (CRAMFS_16 (inode->mode))) {
 281                         /* It's not a directory - list it, and that's that */
 282                         return (cramfs_list_inode (info, offset) > 0);
 283                 }
 284
 285                 /* It's a directory. List files within */
 286                 offset = CRAMFS_GET_OFFSET (inode) << 2;
 287                 size = CRAMFS_24 (inode->size);
 288         }
 289
 290         /* List the given directory */
 291         while (inodeoffset < size) {
 292                 inode = (struct cramfs_inode *) (PART_OFFSET(info) + offset +
 293                                                  inodeoffset);
 294
 295                 nextoffset = cramfs_list_inode (info, offset + inodeoffset);
 296                 if (nextoffset == 0)
 297                         break;
 298                 inodeoffset += sizeof (struct cramfs_inode) + nextoffset;
 299         }
 300
 301         return 1;
 302 }
 303
 304 int cramfs_info (struct part_info *info)
 305 {
 306         if (cramfs_read_super (info))
 307                 return 0;
 308
 309         printf ("size: 0x%x (%u)\n", super.size, super.size);
 310
 311         if (super.flags != 0) {
 312                 printf ("flags:\n");
 313                 if (super.flags & CRAMFS_FLAG_FSID_VERSION_2)
 314                         printf ("\tFSID version 2\n");
 315                 if (super.flags & CRAMFS_FLAG_SORTED_DIRS)
 316                         printf ("\tsorted dirs\n");
 317                 if (super.flags & CRAMFS_FLAG_HOLES)
 318                         printf ("\tholes\n");
 319                 if (super.flags & CRAMFS_FLAG_SHIFTED_ROOT_OFFSET)
 320                         printf ("\tshifted root offset\n");
 321         }
 322
 323         printf ("fsid:\n\tcrc: 0x%x\n\tedition: 0x%x\n",
 324                 super.fsid.crc, super.fsid.edition);
 325         printf ("name: %16s\n", super.name);
 326
 327         return 1;
 328 }
 329
 330 int cramfs_check (struct part_info *info)
 331 {
 332         struct cramfs_super *sb;
 333
 334         if (info->dev->id->type != MTD_DEV_TYPE_NOR)
 335                 return 0;
 336
 337         sb = (struct cramfs_super *) PART_OFFSET(info);
 338         if (sb->magic != CRAMFS_32 (CRAMFS_MAGIC)) {
 339                 /* check at 512 byte offset */
 340                 sb = (struct cramfs_super *) (PART_OFFSET(info) + 512);
 341                 if (sb->magic != CRAMFS_32 (CRAMFS_MAGIC))
 342                         return 0;
 343         }
 344         return 1;
 345 }
 346
 347 #endif /* CFG_FS_CRAMFS */