fs/ext2/ext2fs.c

   1 /*
   2  * (C) Copyright 2004
   3  *  esd gmbh <www.esd-electronics.com>
   4  *  Reinhard Arlt <reinhard.arlt@esd-electronics.com>
   5  *
   6  *  based on code from grub2 fs/ext2.c and fs/fshelp.c by
   7  *
   8  *  GRUB  --  GRand Unified Bootloader
   9  *  Copyright (C) 2003, 2004  Free Software Foundation, Inc.
  10  *
  11  *  This program is free software; you can redistribute it and/or modify
  12  *  it under the terms of the GNU General Public License as published by
  13  *  the Free Software Foundation; either version 2 of the License, or
  14  *  (at your option) any later version.
  15  *
  16  *  This program is distributed in the hope that it will be useful,
  17  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  *  GNU General Public License for more details.
  20  *
  21  *  You should have received a copy of the GNU General Public License
  22  *  along with this program; if not, write to the Free Software
  23  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  24  */
  25
  26 #include <common.h>
  27 #include <ext2fs.h>
  28 #include <malloc.h>
  29 #include <asm/byteorder.h>
  30
  31 extern int ext2fs_devread (int sector, int byte_offset, int byte_len,
  32                            char *buf);
  33
  34 /* Magic value used to identify an ext2 filesystem.  */
  35 #define EXT2_MAGIC              0xEF53
  36 /* Amount of indirect blocks in an inode.  */
  37 #define INDIRECT_BLOCKS         12
  38 /* Maximum lenght of a pathname.  */
  39 #define EXT2_PATH_MAX           4096
  40 /* Maximum nesting of symlinks, used to prevent a loop.  */
  41 #define EXT2_MAX_SYMLINKCNT     8
  42
  43 /* Filetype used in directory entry.  */
  44 #define FILETYPE_UNKNOWN        0
  45 #define FILETYPE_REG            1
  46 #define FILETYPE_DIRECTORY      2
  47 #define FILETYPE_SYMLINK        7
  48
  49 /* Filetype information as used in inodes.  */
  50 #define FILETYPE_INO_MASK       0170000
  51 #define FILETYPE_INO_REG        0100000
  52 #define FILETYPE_INO_DIRECTORY  0040000
  53 #define FILETYPE_INO_SYMLINK    0120000
  54
  55 /* Bits used as offset in sector */
  56 #define DISK_SECTOR_BITS        9
  57
  58 /* Log2 size of ext2 block in 512 blocks.  */
  59 #define LOG2_EXT2_BLOCK_SIZE(data) (__le32_to_cpu (data->sblock.log2_block_size) + 1)
  60
  61 /* Log2 size of ext2 block in bytes.  */
  62 #define LOG2_BLOCK_SIZE(data)      (__le32_to_cpu (data->sblock.log2_block_size) + 10)
  63
  64 /* The size of an ext2 block in bytes.  */
  65 #define EXT2_BLOCK_SIZE(data)      (1 << LOG2_BLOCK_SIZE(data))
  66
  67 /* The ext2 superblock.  */
  68 struct ext2_sblock {
  69         uint32_t total_inodes;
  70         uint32_t total_blocks;
  71         uint32_t reserved_blocks;
  72         uint32_t free_blocks;
  73         uint32_t free_inodes;
  74         uint32_t first_data_block;
  75         uint32_t log2_block_size;
  76         uint32_t log2_fragment_size;
  77         uint32_t blocks_per_group;
  78         uint32_t fragments_per_group;
  79         uint32_t inodes_per_group;
  80         uint32_t mtime;
  81         uint32_t utime;
  82         uint16_t mnt_count;
  83         uint16_t max_mnt_count;
  84         uint16_t magic;
  85         uint16_t fs_state;
  86         uint16_t error_handling;
  87         uint16_t minor_revision_level;
  88         uint32_t lastcheck;
  89         uint32_t checkinterval;
  90         uint32_t creator_os;
  91         uint32_t revision_level;
  92         uint16_t uid_reserved;
  93         uint16_t gid_reserved;
  94         uint32_t first_inode;
  95         uint16_t inode_size;
  96         uint16_t block_group_number;
  97         uint32_t feature_compatibility;
  98         uint32_t feature_incompat;
  99         uint32_t feature_ro_compat;
 100         uint32_t unique_id[4];
 101         char volume_name[16];
 102         char last_mounted_on[64];
 103         uint32_t compression_info;
 104 };
 105
 106 /* The ext2 blockgroup.  */
 107 struct ext2_block_group {
 108         uint32_t block_id;
 109         uint32_t inode_id;
 110         uint32_t inode_table_id;
 111         uint16_t free_blocks;
 112         uint16_t free_inodes;
 113         uint16_t used_dir_cnt;
 114         uint32_t reserved[3];
 115 };
 116
 117 /* The ext2 inode.  */
 118 struct ext2_inode {
 119         uint16_t mode;
 120         uint16_t uid;
 121         uint32_t size;
 122         uint32_t atime;
 123         uint32_t ctime;
 124         uint32_t mtime;
 125         uint32_t dtime;
 126         uint16_t gid;
 127         uint16_t nlinks;
 128         uint32_t blockcnt;      /* Blocks of 512 bytes!! */
 129         uint32_t flags;
 130         uint32_t osd1;
 131         union {
 132                 struct datablocks {
 133                         uint32_t dir_blocks[INDIRECT_BLOCKS];
 134                         uint32_t indir_block;
 135                         uint32_t double_indir_block;
 136                         uint32_t tripple_indir_block;
 137                 } blocks;
 138                 char symlink[60];
 139         } b;
 140         uint32_t version;
 141         uint32_t acl;
 142         uint32_t dir_acl;
 143         uint32_t fragment_addr;
 144         uint32_t osd2[3];
 145 };
 146
 147 /* The header of an ext2 directory entry.  */
 148 struct ext2_dirent {
 149         uint32_t inode;
 150         uint16_t direntlen;
 151         uint8_t namelen;
 152         uint8_t filetype;
 153 };
 154
 155 struct ext2fs_node {
 156         struct ext2_data *data;
 157         struct ext2_inode inode;
 158         int ino;
 159         int inode_read;
 160 };
 161
 162 /* Information about a "mounted" ext2 filesystem.  */
 163 struct ext2_data {
 164         struct ext2_sblock sblock;
 165         struct ext2_inode *inode;
 166         struct ext2fs_node diropen;
 167 };
 168
 169
 170 typedef struct ext2fs_node *ext2fs_node_t;
 171
 172 struct ext2_data *ext2fs_root = NULL;
 173 ext2fs_node_t ext2fs_file = NULL;
 174 int symlinknest = 0;
 175 uint32_t *indir1_block = NULL;
 176 int indir1_size = 0;
 177 int indir1_blkno = -1;
 178 uint32_t *indir2_block = NULL;
 179 int indir2_size = 0;
 180 int indir2_blkno = -1;
 181 static unsigned int inode_size;
 182
 183
 184 static int ext2fs_blockgroup
 185         (struct ext2_data *data, int group, struct ext2_block_group *blkgrp) {
 186         unsigned int blkno;
 187         unsigned int blkoff;
 188         unsigned int desc_per_blk;
 189
 190         desc_per_blk = EXT2_BLOCK_SIZE(data) / sizeof(struct ext2_block_group);
 191
 192         blkno = __le32_to_cpu(data->sblock.first_data_block) + 1 +
 193         group / desc_per_blk;
 194         blkoff = (group % desc_per_blk) * sizeof(struct ext2_block_group);
 195 #ifdef DEBUG
 196         printf ("ext2fs read %d group descriptor (blkno %d blkoff %d)\n",
 197                 group, blkno, blkoff);
 198 #endif
 199         return (ext2fs_devread (blkno << LOG2_EXT2_BLOCK_SIZE(data),
 200                 blkoff, sizeof(struct ext2_block_group), (char *)blkgrp));
 201
 202 }
 203
 204
 205 static int ext2fs_read_inode
 206         (struct ext2_data *data, int ino, struct ext2_inode *inode) {
 207         struct ext2_block_group blkgrp;
 208         struct ext2_sblock *sblock = &data->sblock;
 209         int inodes_per_block;
 210         int status;
 211
 212         unsigned int blkno;
 213         unsigned int blkoff;
 214
 215 #ifdef DEBUG
 216         printf ("ext2fs read inode %d, inode_size %d\n", ino, inode_size);
 217 #endif
 218         /* It is easier to calculate if the first inode is 0.  */
 219         ino--;
 220         status = ext2fs_blockgroup (data, ino / __le32_to_cpu
 221                                     (sblock->inodes_per_group), &blkgrp);
 222         if (status == 0) {
 223                 return (0);
 224         }
 225
 226         inodes_per_block = EXT2_BLOCK_SIZE(data) / inode_size;
 227
 228         blkno = __le32_to_cpu (blkgrp.inode_table_id) +
 229                 (ino % __le32_to_cpu (sblock->inodes_per_group))
 230                 / inodes_per_block;
 231         blkoff = (ino % inodes_per_block) * inode_size;
 232 #ifdef DEBUG
 233         printf ("ext2fs read inode blkno %d blkoff %d\n", blkno, blkoff);
 234 #endif
 235         /* Read the inode.  */
 236         status = ext2fs_devread (blkno << LOG2_EXT2_BLOCK_SIZE (data), blkoff,
 237                                  sizeof (struct ext2_inode), (char *) inode);
 238         if (status == 0) {
 239                 return (0);
 240         }
 241
 242         return (1);
 243 }
 244
 245
 246 void ext2fs_free_node (ext2fs_node_t node, ext2fs_node_t currroot) {
 247         if ((node != &ext2fs_root->diropen) && (node != currroot)) {
 248                 free (node);
 249         }
 250 }
 251
 252
 253 static int ext2fs_read_block (ext2fs_node_t node, int fileblock) {
 254         struct ext2_data *data = node->data;
 255         struct ext2_inode *inode = &node->inode;
 256         int blknr;
 257         int blksz = EXT2_BLOCK_SIZE (data);
 258         int log2_blksz = LOG2_EXT2_BLOCK_SIZE (data);
 259         int status;
 260
 261         /* Direct blocks.  */
 262         if (fileblock < INDIRECT_BLOCKS) {
 263                 blknr = __le32_to_cpu (inode->b.blocks.dir_blocks[fileblock]);
 264         }
 265         /* Indirect.  */
 266         else if (fileblock < (INDIRECT_BLOCKS + (blksz / 4))) {
 267                 if (indir1_block == NULL) {
 268                         indir1_block = (uint32_t *) malloc (blksz);
 269                         if (indir1_block == NULL) {
 270                                 printf ("** ext2fs read block (indir 1) malloc failed. **\n");
 271                                 return (-1);
 272                         }
 273                         indir1_size = blksz;
 274                         indir1_blkno = -1;
 275                 }
 276                 if (blksz != indir1_size) {
 277                         free (indir1_block);
 278                         indir1_block = NULL;
 279                         indir1_size = 0;
 280                         indir1_blkno = -1;
 281                         indir1_block = (uint32_t *) malloc (blksz);
 282                         if (indir1_block == NULL) {
 283                                 printf ("** ext2fs read block (indir 1) malloc failed. **\n");
 284                                 return (-1);
 285                         }
 286                         indir1_size = blksz;
 287                 }
 288                 if ((__le32_to_cpu (inode->b.blocks.indir_block) <<
 289                      log2_blksz) != indir1_blkno) {
 290                         status = ext2fs_devread (__le32_to_cpu(inode->b.blocks.indir_block) << log2_blksz,
 291                                                  0, blksz,
 292                                                  (char *) indir1_block);
 293                         if (status == 0) {
 294                                 printf ("** ext2fs read block (indir 1) failed. **\n");
 295                                 return (0);
 296                         }
 297                         indir1_blkno =
 298                                 __le32_to_cpu (inode->b.blocks.
 299                                                indir_block) << log2_blksz;
 300                 }
 301                 blknr = __le32_to_cpu (indir1_block
 302                                        [fileblock - INDIRECT_BLOCKS]);
 303         }
 304         /* Double indirect.  */
 305         else if (fileblock <
 306                  (INDIRECT_BLOCKS + (blksz / 4 * (blksz / 4 + 1)))) {
 307                 unsigned int perblock = blksz / 4;
 308                 unsigned int rblock = fileblock - (INDIRECT_BLOCKS
 309                                                    + blksz / 4);
 310
 311                 if (indir1_block == NULL) {
 312                         indir1_block = (uint32_t *) malloc (blksz);
 313                         if (indir1_block == NULL) {
 314                                 printf ("** ext2fs read block (indir 2 1) malloc failed. **\n");
 315                                 return (-1);
 316                         }
 317                         indir1_size = blksz;
 318                         indir1_blkno = -1;
 319                 }
 320                 if (blksz != indir1_size) {
 321                         free (indir1_block);
 322                         indir1_block = NULL;
 323                         indir1_size = 0;
 324                         indir1_blkno = -1;
 325                         indir1_block = (uint32_t *) malloc (blksz);
 326                         if (indir1_block == NULL) {
 327                                 printf ("** ext2fs read block (indir 2 1) malloc failed. **\n");
 328                                 return (-1);
 329                         }
 330                         indir1_size = blksz;
 331                 }
 332                 if ((__le32_to_cpu (inode->b.blocks.double_indir_block) <<
 333                      log2_blksz) != indir1_blkno) {
 334                         status = ext2fs_devread (__le32_to_cpu(inode->b.blocks.double_indir_block) << log2_blksz,
 335                                                 0, blksz,
 336                                                 (char *) indir1_block);
 337                         if (status == 0) {
 338                                 printf ("** ext2fs read block (indir 2 1) failed. **\n");
 339                                 return (-1);
 340                         }
 341                         indir1_blkno =
 342                                 __le32_to_cpu (inode->b.blocks.double_indir_block) << log2_blksz;
 343                 }
 344
 345                 if (indir2_block == NULL) {
 346                         indir2_block = (uint32_t *) malloc (blksz);
 347                         if (indir2_block == NULL) {
 348                                 printf ("** ext2fs read block (indir 2 2) malloc failed. **\n");
 349                                 return (-1);
 350                         }
 351                         indir2_size = blksz;
 352                         indir2_blkno = -1;
 353                 }
 354                 if (blksz != indir2_size) {
 355                         free (indir2_block);
 356                         indir2_block = NULL;
 357                         indir2_size = 0;
 358                         indir2_blkno = -1;
 359                         indir2_block = (uint32_t *) malloc (blksz);
 360                         if (indir2_block == NULL) {
 361                                 printf ("** ext2fs read block (indir 2 2) malloc failed. **\n");
 362                                 return (-1);
 363                         }
 364                         indir2_size = blksz;
 365                 }
 366                 if ((__le32_to_cpu (indir1_block[rblock / perblock]) <<
 367                      log2_blksz) != indir2_blkno) {
 368                         status = ext2fs_devread (__le32_to_cpu(indir1_block[rblock / perblock]) << log2_blksz,
 369                                                  0, blksz,
 370                                                  (char *) indir2_block);
 371                         if (status == 0) {
 372                                 printf ("** ext2fs read block (indir 2 2) failed. **\n");
 373                                 return (-1);
 374                         }
 375                         indir2_blkno =
 376                                 __le32_to_cpu (indir1_block[rblock / perblock]) << log2_blksz;
 377                 }
 378                 blknr = __le32_to_cpu (indir2_block[rblock % perblock]);
 379         }
 380         /* Tripple indirect.  */
 381         else {
 382                 printf ("** ext2fs doesn't support tripple indirect blocks. **\n");
 383                 return (-1);
 384         }
 385 #ifdef DEBUG
 386         printf ("ext2fs_read_block %08x\n", blknr);
 387 #endif
 388         return (blknr);
 389 }
 390
 391
 392 int ext2fs_read_file
 393         (ext2fs_node_t node, int pos, unsigned int len, char *buf) {
 394         int i;
 395         int blockcnt;
 396         int log2blocksize = LOG2_EXT2_BLOCK_SIZE (node->data);
 397         int blocksize = 1 << (log2blocksize + DISK_SECTOR_BITS);
 398         unsigned int filesize = __le32_to_cpu(node->inode.size);
 399
 400         /* Adjust len so it we can't read past the end of the file.  */
 401         if (len > filesize) {
 402                 len = filesize;
 403         }
 404         blockcnt = ((len + pos) + blocksize - 1) / blocksize;
 405
 406         for (i = pos / blocksize; i < blockcnt; i++) {
 407                 int blknr;
 408                 int blockoff = pos % blocksize;
 409                 int blockend = blocksize;
 410
 411                 int skipfirst = 0;
 412
 413                 blknr = ext2fs_read_block (node, i);
 414                 if (blknr < 0) {
 415                         return (-1);
 416                 }
 417                 blknr = blknr << log2blocksize;
 418
 419                 /* Last block.  */
 420                 if (i == blockcnt - 1) {
 421                         blockend = (len + pos) % blocksize;
 422
 423                         /* The last portion is exactly blocksize.  */
 424                         if (!blockend) {
 425                                 blockend = blocksize;
 426                         }
 427                 }
 428
 429                 /* First block.  */
 430                 if (i == pos / blocksize) {
 431                         skipfirst = blockoff;
 432                         blockend -= skipfirst;
 433                 }
 434
 435                 /* If the block number is 0 this block is not stored on disk but
 436                    is zero filled instead.  */
 437                 if (blknr) {
 438                         int status;
 439
 440                         status = ext2fs_devread (blknr, skipfirst, blockend, buf);
 441                         if (status == 0) {
 442                                 return (-1);
 443                         }
 444                 } else {
 445                         memset (buf, 0, blocksize - skipfirst);
 446                 }
 447                 buf += blocksize - skipfirst;
 448         }
 449         return (len);
 450 }
 451
 452
 453 static int ext2fs_iterate_dir (ext2fs_node_t dir, char *name, ext2fs_node_t * fnode, int *ftype)
 454 {
 455         unsigned int fpos = 0;
 456         int status;
 457         struct ext2fs_node *diro = (struct ext2fs_node *) dir;
 458
 459 #ifdef DEBUG
 460         if (name != NULL)
 461                 printf ("Iterate dir %s\n", name);
 462 #endif /* of DEBUG */
 463         if (!diro->inode_read) {
 464                 status = ext2fs_read_inode (diro->data, diro->ino,
 465                                             &diro->inode);
 466                 if (status == 0) {
 467                         return (0);
 468                 }
 469         }
 470         /* Search the file.  */
 471         while (fpos < __le32_to_cpu (diro->inode.size)) {
 472                 struct ext2_dirent dirent;
 473
 474                 status = ext2fs_read_file (diro, fpos,
 475                                            sizeof (struct ext2_dirent),
 476                                            (char *) &dirent);
 477                 if (status < 1) {
 478                         return (0);
 479                 }
 480                 if (dirent.namelen != 0) {
 481                         char filename[dirent.namelen + 1];
 482                         ext2fs_node_t fdiro;
 483                         int type = FILETYPE_UNKNOWN;
 484
 485                         status = ext2fs_read_file (diro,
 486                                                    fpos + sizeof (struct ext2_dirent),
 487                                                    dirent.namelen, filename);
 488                         if (status < 1) {
 489                                 return (0);
 490                         }
 491                         fdiro = malloc (sizeof (struct ext2fs_node));
 492                         if (!fdiro) {
 493                                 return (0);
 494                         }
 495
 496                         fdiro->data = diro->data;
 497                         fdiro->ino = __le32_to_cpu (dirent.inode);
 498
 499                         filename[dirent.namelen] = '\0';
 500
 501                         if (dirent.filetype != FILETYPE_UNKNOWN) {
 502                                 fdiro->inode_read = 0;
 503
 504                                 if (dirent.filetype == FILETYPE_DIRECTORY) {
 505                                         type = FILETYPE_DIRECTORY;
 506                                 } else if (dirent.filetype ==
 507                                            FILETYPE_SYMLINK) {
 508                                         type = FILETYPE_SYMLINK;
 509                                 } else if (dirent.filetype == FILETYPE_REG) {
 510                                         type = FILETYPE_REG;
 511                                 }
 512                         } else {
 513                                 /* The filetype can not be read from the dirent, get it from inode */
 514
 515                                 status = ext2fs_read_inode (diro->data,
 516                                                             __le32_to_cpu(dirent.inode),
 517                                                             &fdiro->inode);
 518                                 if (status == 0) {
 519                                         free (fdiro);
 520                                         return (0);
 521                                 }
 522                                 fdiro->inode_read = 1;
 523
 524                                 if ((__le16_to_cpu (fdiro->inode.mode) &
 525                                      FILETYPE_INO_MASK) ==
 526                                     FILETYPE_INO_DIRECTORY) {
 527                                         type = FILETYPE_DIRECTORY;
 528                                 } else if ((__le16_to_cpu (fdiro->inode.mode)
 529                                             & FILETYPE_INO_MASK) ==
 530                                            FILETYPE_INO_SYMLINK) {
 531                                         type = FILETYPE_SYMLINK;
 532                                 } else if ((__le16_to_cpu (fdiro->inode.mode)
 533                                             & FILETYPE_INO_MASK) ==
 534                                            FILETYPE_INO_REG) {
 535                                         type = FILETYPE_REG;
 536                                 }
 537                         }
 538 #ifdef DEBUG
 539                         printf ("iterate >%s<\n", filename);
 540 #endif /* of DEBUG */
 541                         if ((name != NULL) && (fnode != NULL)
 542                             && (ftype != NULL)) {
 543                                 if (strcmp (filename, name) == 0) {
 544                                         *ftype = type;
 545                                         *fnode = fdiro;
 546                                         return (1);
 547                                 }
 548                         } else {
 549                                 if (fdiro->inode_read == 0) {
 550                                         status = ext2fs_read_inode (diro->data,
 551                                                             __le32_to_cpu (dirent.inode),
 552                                                             &fdiro->inode);
 553                                         if (status == 0) {
 554                                                 free (fdiro);
 555                                                 return (0);
 556                                         }
 557                                         fdiro->inode_read = 1;
 558                                 }
 559                                 switch (type) {
 560                                 case FILETYPE_DIRECTORY:
 561                                         printf ("<DIR> ");
 562                                         break;
 563                                 case FILETYPE_SYMLINK:
 564                                         printf ("<SYM> ");
 565                                         break;
 566                                 case FILETYPE_REG:
 567                                         printf ("      ");
 568                                         break;
 569                                 default:
 570                                         printf ("< ? > ");
 571                                         break;
 572                                 }
 573                                 printf ("%10d %s\n",
 574                                         __le32_to_cpu (fdiro->inode.size),
 575                                         filename);
 576                         }
 577                         free (fdiro);
 578                 }
 579                 fpos += __le16_to_cpu (dirent.direntlen);
 580         }
 581         return (0);
 582 }
 583
 584
 585 static char *ext2fs_read_symlink (ext2fs_node_t node) {
 586         char *symlink;
 587         struct ext2fs_node *diro = node;
 588         int status;
 589
 590         if (!diro->inode_read) {
 591                 status = ext2fs_read_inode (diro->data, diro->ino,
 592                                             &diro->inode);
 593                 if (status == 0) {
 594                         return (0);
 595                 }
 596         }
 597         symlink = malloc (__le32_to_cpu (diro->inode.size) + 1);
 598         if (!symlink) {
 599                 return (0);
 600         }
 601         /* If the filesize of the symlink is bigger than
 602            60 the symlink is stored in a separate block,
 603            otherwise it is stored in the inode.  */
 604         if (__le32_to_cpu (diro->inode.size) <= 60) {
 605                 strncpy (symlink, diro->inode.b.symlink,
 606                          __le32_to_cpu (diro->inode.size));
 607         } else {
 608                 status = ext2fs_read_file (diro, 0,
 609                                            __le32_to_cpu (diro->inode.size),
 610                                            symlink);
 611                 if (status == 0) {
 612                         free (symlink);
 613                         return (0);
 614                 }
 615         }
 616         symlink[__le32_to_cpu (diro->inode.size)] = '\0';
 617         return (symlink);
 618 }
 619
 620
 621 int ext2fs_find_file1
 622         (const char *currpath,
 623          ext2fs_node_t currroot, ext2fs_node_t * currfound, int *foundtype) {
 624         char fpath[strlen (currpath) + 1];
 625         char *name = fpath;
 626         char *next;
 627         int status;
 628         int type = FILETYPE_DIRECTORY;
 629         ext2fs_node_t currnode = currroot;
 630         ext2fs_node_t oldnode = currroot;
 631
 632         strncpy (fpath, currpath, strlen (currpath) + 1);
 633
 634         /* Remove all leading slashes.  */
 635         while (*name == '/') {
 636                 name++;
 637         }
 638         if (!*name) {
 639                 *currfound = currnode;
 640                 return (1);
 641         }
 642
 643         for (;;) {
 644                 int found;
 645
 646                 /* Extract the actual part from the pathname.  */
 647                 next = strchr (name, '/');
 648                 if (next) {
 649                         /* Remove all leading slashes.  */
 650                         while (*next == '/') {
 651                                 *(next++) = '\0';
 652                         }
 653                 }
 654
 655                 /* At this point it is expected that the current node is a directory, check if this is true.  */
 656                 if (type != FILETYPE_DIRECTORY) {
 657                         ext2fs_free_node (currnode, currroot);
 658                         return (0);
 659                 }
 660
 661                 oldnode = currnode;
 662
 663                 /* Iterate over the directory.  */
 664                 found = ext2fs_iterate_dir (currnode, name, &currnode, &type);
 665                 if (found == 0) {
 666                         return (0);
 667                 }
 668                 if (found == -1) {
 669                         break;
 670                 }
 671
 672                 /* Read in the symlink and follow it.  */
 673                 if (type == FILETYPE_SYMLINK) {
 674                         char *symlink;
 675
 676                         /* Test if the symlink does not loop.  */
 677                         if (++symlinknest == 8) {
 678                                 ext2fs_free_node (currnode, currroot);
 679                                 ext2fs_free_node (oldnode, currroot);
 680                                 return (0);
 681                         }
 682
 683                         symlink = ext2fs_read_symlink (currnode);
 684                         ext2fs_free_node (currnode, currroot);
 685
 686                         if (!symlink) {
 687                                 ext2fs_free_node (oldnode, currroot);
 688                                 return (0);
 689                         }
 690 #ifdef DEBUG
 691                         printf ("Got symlink >%s<\n", symlink);
 692 #endif /* of DEBUG */
 693                         /* The symlink is an absolute path, go back to the root inode.  */
 694                         if (symlink[0] == '/') {
 695                                 ext2fs_free_node (oldnode, currroot);
 696                                 oldnode = &ext2fs_root->diropen;
 697                         }
 698
 699                         /* Lookup the node the symlink points to.  */
 700                         status = ext2fs_find_file1 (symlink, oldnode,
 701                                                     &currnode, &type);
 702
 703                         free (symlink);
 704
 705                         if (status == 0) {
 706                                 ext2fs_free_node (oldnode, currroot);
 707                                 return (0);
 708                         }
 709                 }
 710
 711                 ext2fs_free_node (oldnode, currroot);
 712
 713                 /* Found the node!  */
 714                 if (!next || *next == '\0') {
 715                         *currfound = currnode;
 716                         *foundtype = type;
 717                         return (1);
 718                 }
 719                 name = next;
 720         }
 721         return (-1);
 722 }
 723
 724
 725 int ext2fs_find_file
 726         (const char *path,
 727          ext2fs_node_t rootnode, ext2fs_node_t * foundnode, int expecttype) {
 728         int status;
 729         int foundtype = FILETYPE_DIRECTORY;
 730
 731
 732         symlinknest = 0;
 733         if (!path) {
 734                 return (0);
 735         }
 736
 737         status = ext2fs_find_file1 (path, rootnode, foundnode, &foundtype);
 738         if (status == 0) {
 739                 return (0);
 740         }
 741         /* Check if the node that was found was of the expected type.  */
 742         if ((expecttype == FILETYPE_REG) && (foundtype != expecttype)) {
 743                 return (0);
 744         } else if ((expecttype == FILETYPE_DIRECTORY)
 745                    && (foundtype != expecttype)) {
 746                 return (0);
 747         }
 748         return (1);
 749 }
 750
 751
 752 int ext2fs_ls (char *dirname) {
 753         ext2fs_node_t dirnode;
 754         int status;
 755
 756         if (ext2fs_root == NULL) {
 757                 return (0);
 758         }
 759
 760         status = ext2fs_find_file (dirname, &ext2fs_root->diropen, &dirnode,
 761                                    FILETYPE_DIRECTORY);
 762         if (status != 1) {
 763                 printf ("** Can not find directory. **\n");
 764                 return (1);
 765         }
 766         ext2fs_iterate_dir (dirnode, NULL, NULL, NULL);
 767         ext2fs_free_node (dirnode, &ext2fs_root->diropen);
 768         return (0);
 769 }
 770
 771
 772 int ext2fs_open (char *filename) {
 773         ext2fs_node_t fdiro = NULL;
 774         int status;
 775         int len;
 776
 777         if (ext2fs_root == NULL) {
 778                 return (-1);
 779         }
 780         ext2fs_file = NULL;
 781         status = ext2fs_find_file (filename, &ext2fs_root->diropen, &fdiro,
 782                                    FILETYPE_REG);
 783         if (status == 0) {
 784                 goto fail;
 785         }
 786         if (!fdiro->inode_read) {
 787                 status = ext2fs_read_inode (fdiro->data, fdiro->ino,
 788                                             &fdiro->inode);
 789                 if (status == 0) {
 790                         goto fail;
 791                 }
 792         }
 793         len = __le32_to_cpu (fdiro->inode.size);
 794         ext2fs_file = fdiro;
 795         return (len);
 796
 797 fail:
 798         ext2fs_free_node (fdiro, &ext2fs_root->diropen);
 799         return (-1);
 800 }
 801
 802
 803 int ext2fs_close (void
 804         ) {
 805         if ((ext2fs_file != NULL) && (ext2fs_root != NULL)) {
 806                 ext2fs_free_node (ext2fs_file, &ext2fs_root->diropen);
 807                 ext2fs_file = NULL;
 808         }
 809         if (ext2fs_root != NULL) {
 810                 free (ext2fs_root);
 811                 ext2fs_root = NULL;
 812         }
 813         if (indir1_block != NULL) {
 814                 free (indir1_block);
 815                 indir1_block = NULL;
 816                 indir1_size = 0;
 817                 indir1_blkno = -1;
 818         }
 819         if (indir2_block != NULL) {
 820                 free (indir2_block);
 821                 indir2_block = NULL;
 822                 indir2_size = 0;
 823                 indir2_blkno = -1;
 824         }
 825         return (0);
 826 }
 827
 828
 829 int ext2fs_read (char *buf, unsigned len) {
 830         int status;
 831
 832         if (ext2fs_root == NULL) {
 833                 return (0);
 834         }
 835
 836         if (ext2fs_file == NULL) {
 837                 return (0);
 838         }
 839
 840         status = ext2fs_read_file (ext2fs_file, 0, len, buf);
 841         return (status);
 842 }
 843
 844
 845 int ext2fs_mount (unsigned part_length) {
 846         struct ext2_data *data;
 847         int status;
 848
 849         data = malloc (sizeof (struct ext2_data));
 850         if (!data) {
 851                 return (0);
 852         }
 853         /* Read the superblock.  */
 854         status = ext2fs_devread (1 * 2, 0, sizeof (struct ext2_sblock),
 855                                  (char *) &data->sblock);
 856         if (status == 0) {
 857                 goto fail;
 858         }
 859         /* Make sure this is an ext2 filesystem.  */
 860         if (__le16_to_cpu (data->sblock.magic) != EXT2_MAGIC) {
 861                 goto fail;
 862         }
 863         if (__le32_to_cpu(data->sblock.revision_level == 0)) {
 864                 inode_size = 128;
 865         } else {
 866                 inode_size = __le16_to_cpu(data->sblock.inode_size);
 867         }
 868 #ifdef DEBUG
 869         printf("EXT2 rev %d, inode_size %d\n",
 870                         __le32_to_cpu(data->sblock.revision_level), inode_size);
 871 #endif
 872         data->diropen.data = data;
 873         data->diropen.ino = 2;
 874         data->diropen.inode_read = 1;
 875         data->inode = &data->diropen.inode;
 876
 877         status = ext2fs_read_inode (data, 2, data->inode);
 878         if (status == 0) {
 879                 goto fail;
 880         }
 881
 882         ext2fs_root = data;
 883
 884         return (1);
 885
 886 fail:
 887         printf ("Failed to mount ext2 filesystem...\n");
 888         free (data);
 889         ext2fs_root = NULL;
 890         return (0);
 891 }