fs/squashfs/inode.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Squashfs - a compressed read only filesystem for Linux
   4  *
   5  * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
   6  * Phillip Lougher <phillip@squashfs.org.uk>
   7  *
   8  * inode.c
   9  */
  10
  11 /*
  12  * This file implements code to create and read inodes from disk.
  13  *
  14  * Inodes in Squashfs are identified by a 48-bit inode which encodes the
  15  * location of the compressed metadata block containing the inode, and the byte
  16  * offset into that block where the inode is placed (<block, offset>).
  17  *
  18  * To maximise compression there are different inodes for each file type
  19  * (regular file, directory, device, etc.), the inode contents and length
  20  * varying with the type.
  21  *
  22  * To further maximise compression, two types of regular file inode and
  23  * directory inode are defined: inodes optimised for frequently occurring
  24  * regular files and directories, and extended types where extra
  25  * information has to be stored.
  26  */
  27
  28 #include <linux/fs.h>
  29 #include <linux/vfs.h>
  30 #include <linux/xattr.h>
  31 #include <linux/pagemap.h>
  32
  33 #include "squashfs_fs.h"
  34 #include "squashfs_fs_sb.h"
  35 #include "squashfs_fs_i.h"
  36 #include "squashfs.h"
  37 #include "xattr.h"
  38
  39 /*
  40  * Initialise VFS inode with the base inode information common to all
  41  * Squashfs inode types.  Sqsh_ino contains the unswapped base inode
  42  * off disk.
  43  */
  44 static int squashfs_new_inode(struct super_block *sb, struct inode *inode,
  45                                 struct squashfs_base_inode *sqsh_ino)
  46 {
  47         uid_t i_uid;
  48         gid_t i_gid;
  49         int err;
  50
  51         inode->i_ino = le32_to_cpu(sqsh_ino->inode_number);
  52         if (inode->i_ino == 0)
  53                 return -EINVAL;
  54
  55         err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->uid), &i_uid);
  56         if (err)
  57                 return err;
  58
  59         err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->guid), &i_gid);
  60         if (err)
  61                 return err;
  62
  63         i_uid_write(inode, i_uid);
  64         i_gid_write(inode, i_gid);
  65         inode_set_mtime(inode, le32_to_cpu(sqsh_ino->mtime), 0);
  66         inode_set_atime(inode, inode_get_mtime_sec(inode), 0);
  67         inode_set_ctime(inode, inode_get_mtime_sec(inode), 0);
  68         inode->i_mode = le16_to_cpu(sqsh_ino->mode);
  69         inode->i_size = 0;
  70
  71         return err;
  72 }
  73
  74
  75 struct inode *squashfs_iget(struct super_block *sb, long long ino,
  76                                 unsigned int ino_number)
  77 {
  78         struct inode *inode = iget_locked(sb, ino_number);
  79         int err;
  80
  81         TRACE("Entered squashfs_iget\n");
  82
  83         if (!inode)
  84                 return ERR_PTR(-ENOMEM);
  85         if (!(inode->i_state & I_NEW))
  86                 return inode;
  87
  88         err = squashfs_read_inode(inode, ino);
  89         if (err) {
  90                 iget_failed(inode);
  91                 return ERR_PTR(err);
  92         }
  93
  94         unlock_new_inode(inode);
  95         return inode;
  96 }
  97
  98
  99 /*
 100  * Initialise VFS inode by reading inode from inode table (compressed
 101  * metadata).  The format and amount of data read depends on type.
 102  */
 103 int squashfs_read_inode(struct inode *inode, long long ino)
 104 {
 105         struct super_block *sb = inode->i_sb;
 106         struct squashfs_sb_info *msblk = sb->s_fs_info;
 107         u64 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
 108         int err, type, offset = SQUASHFS_INODE_OFFSET(ino);
 109         union squashfs_inode squashfs_ino;
 110         struct squashfs_base_inode *sqshb_ino = &squashfs_ino.base;
 111         int xattr_id = SQUASHFS_INVALID_XATTR;
 112
 113         TRACE("Entered squashfs_read_inode\n");
 114
 115         /*
 116          * Read inode base common to all inode types.
 117          */
 118         err = squashfs_read_metadata(sb, sqshb_ino, &block,
 119                                 &offset, sizeof(*sqshb_ino));
 120         if (err < 0)
 121                 goto failed_read;
 122
 123         err = squashfs_new_inode(sb, inode, sqshb_ino);
 124         if (err)
 125                 goto failed_read;
 126
 127         block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
 128         offset = SQUASHFS_INODE_OFFSET(ino);
 129
 130         type = le16_to_cpu(sqshb_ino->inode_type);
 131         switch (type) {
 132         case SQUASHFS_REG_TYPE: {
 133                 unsigned int frag_offset, frag;
 134                 int frag_size;
 135                 u64 frag_blk;
 136                 struct squashfs_reg_inode *sqsh_ino = &squashfs_ino.reg;
 137
 138                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 139                                                         sizeof(*sqsh_ino));
 140                 if (err < 0)
 141                         goto failed_read;
 142
 143                 frag = le32_to_cpu(sqsh_ino->fragment);
 144                 if (frag != SQUASHFS_INVALID_FRAG) {
 145                         frag_offset = le32_to_cpu(sqsh_ino->offset);
 146                         frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
 147                         if (frag_size < 0) {
 148                                 err = frag_size;
 149                                 goto failed_read;
 150                         }
 151                 } else {
 152                         frag_blk = SQUASHFS_INVALID_BLK;
 153                         frag_size = 0;
 154                         frag_offset = 0;
 155                 }
 156
 157                 set_nlink(inode, 1);
 158                 inode->i_size = le32_to_cpu(sqsh_ino->file_size);
 159                 inode->i_fop = &generic_ro_fops;
 160                 inode->i_mode |= S_IFREG;
 161                 inode->i_blocks = ((inode->i_size - 1) >> 9) + 1;
 162                 squashfs_i(inode)->fragment_block = frag_blk;
 163                 squashfs_i(inode)->fragment_size = frag_size;
 164                 squashfs_i(inode)->fragment_offset = frag_offset;
 165                 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
 166                 squashfs_i(inode)->block_list_start = block;
 167                 squashfs_i(inode)->offset = offset;
 168                 inode->i_data.a_ops = &squashfs_aops;
 169
 170                 TRACE("File inode %x:%x, start_block %llx, block_list_start "
 171                         "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
 172                         offset, squashfs_i(inode)->start, block, offset);
 173                 break;
 174         }
 175         case SQUASHFS_LREG_TYPE: {
 176                 unsigned int frag_offset, frag;
 177                 int frag_size;
 178                 u64 frag_blk;
 179                 struct squashfs_lreg_inode *sqsh_ino = &squashfs_ino.lreg;
 180
 181                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 182                                                         sizeof(*sqsh_ino));
 183                 if (err < 0)
 184                         goto failed_read;
 185
 186                 frag = le32_to_cpu(sqsh_ino->fragment);
 187                 if (frag != SQUASHFS_INVALID_FRAG) {
 188                         frag_offset = le32_to_cpu(sqsh_ino->offset);
 189                         frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
 190                         if (frag_size < 0) {
 191                                 err = frag_size;
 192                                 goto failed_read;
 193                         }
 194                 } else {
 195                         frag_blk = SQUASHFS_INVALID_BLK;
 196                         frag_size = 0;
 197                         frag_offset = 0;
 198                 }
 199
 200                 xattr_id = le32_to_cpu(sqsh_ino->xattr);
 201                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 202                 inode->i_size = le64_to_cpu(sqsh_ino->file_size);
 203                 inode->i_op = &squashfs_inode_ops;
 204                 inode->i_fop = &generic_ro_fops;
 205                 inode->i_mode |= S_IFREG;
 206                 inode->i_blocks = (inode->i_size -
 207                                 le64_to_cpu(sqsh_ino->sparse) + 511) >> 9;
 208
 209                 squashfs_i(inode)->fragment_block = frag_blk;
 210                 squashfs_i(inode)->fragment_size = frag_size;
 211                 squashfs_i(inode)->fragment_offset = frag_offset;
 212                 squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block);
 213                 squashfs_i(inode)->block_list_start = block;
 214                 squashfs_i(inode)->offset = offset;
 215                 inode->i_data.a_ops = &squashfs_aops;
 216
 217                 TRACE("File inode %x:%x, start_block %llx, block_list_start "
 218                         "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
 219                         offset, squashfs_i(inode)->start, block, offset);
 220                 break;
 221         }
 222         case SQUASHFS_DIR_TYPE: {
 223                 struct squashfs_dir_inode *sqsh_ino = &squashfs_ino.dir;
 224
 225                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 226                                 sizeof(*sqsh_ino));
 227                 if (err < 0)
 228                         goto failed_read;
 229
 230                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 231                 inode->i_size = le16_to_cpu(sqsh_ino->file_size);
 232                 inode->i_op = &squashfs_dir_inode_ops;
 233                 inode->i_fop = &squashfs_dir_ops;
 234                 inode->i_mode |= S_IFDIR;
 235                 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
 236                 squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
 237                 squashfs_i(inode)->dir_idx_cnt = 0;
 238                 squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
 239
 240                 TRACE("Directory inode %x:%x, start_block %llx, offset %x\n",
 241                                 SQUASHFS_INODE_BLK(ino), offset,
 242                                 squashfs_i(inode)->start,
 243                                 le16_to_cpu(sqsh_ino->offset));
 244                 break;
 245         }
 246         case SQUASHFS_LDIR_TYPE: {
 247                 struct squashfs_ldir_inode *sqsh_ino = &squashfs_ino.ldir;
 248
 249                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 250                                 sizeof(*sqsh_ino));
 251                 if (err < 0)
 252                         goto failed_read;
 253
 254                 xattr_id = le32_to_cpu(sqsh_ino->xattr);
 255                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 256                 inode->i_size = le32_to_cpu(sqsh_ino->file_size);
 257                 inode->i_op = &squashfs_dir_inode_ops;
 258                 inode->i_fop = &squashfs_dir_ops;
 259                 inode->i_mode |= S_IFDIR;
 260                 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
 261                 squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
 262                 squashfs_i(inode)->dir_idx_start = block;
 263                 squashfs_i(inode)->dir_idx_offset = offset;
 264                 squashfs_i(inode)->dir_idx_cnt = le16_to_cpu(sqsh_ino->i_count);
 265                 squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
 266
 267                 TRACE("Long directory inode %x:%x, start_block %llx, offset "
 268                                 "%x\n", SQUASHFS_INODE_BLK(ino), offset,
 269                                 squashfs_i(inode)->start,
 270                                 le16_to_cpu(sqsh_ino->offset));
 271                 break;
 272         }
 273         case SQUASHFS_SYMLINK_TYPE:
 274         case SQUASHFS_LSYMLINK_TYPE: {
 275                 struct squashfs_symlink_inode *sqsh_ino = &squashfs_ino.symlink;
 276
 277                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 278                                 sizeof(*sqsh_ino));
 279                 if (err < 0)
 280                         goto failed_read;
 281
 282                 inode->i_size = le32_to_cpu(sqsh_ino->symlink_size);
 283                 if (inode->i_size > PAGE_SIZE) {
 284                         ERROR("Corrupted symlink\n");
 285                         return -EINVAL;
 286                 }
 287
 288                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 289                 inode->i_op = &squashfs_symlink_inode_ops;
 290                 inode_nohighmem(inode);
 291                 inode->i_data.a_ops = &squashfs_symlink_aops;
 292                 inode->i_mode |= S_IFLNK;
 293                 squashfs_i(inode)->start = block;
 294                 squashfs_i(inode)->offset = offset;
 295
 296                 if (type == SQUASHFS_LSYMLINK_TYPE) {
 297                         __le32 xattr;
 298
 299                         err = squashfs_read_metadata(sb, NULL, &block,
 300                                                 &offset, inode->i_size);
 301                         if (err < 0)
 302                                 goto failed_read;
 303                         err = squashfs_read_metadata(sb, &xattr, &block,
 304                                                 &offset, sizeof(xattr));
 305                         if (err < 0)
 306                                 goto failed_read;
 307                         xattr_id = le32_to_cpu(xattr);
 308                 }
 309
 310                 TRACE("Symbolic link inode %x:%x, start_block %llx, offset "
 311                                 "%x\n", SQUASHFS_INODE_BLK(ino), offset,
 312                                 block, offset);
 313                 break;
 314         }
 315         case SQUASHFS_BLKDEV_TYPE:
 316         case SQUASHFS_CHRDEV_TYPE: {
 317                 struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev;
 318                 unsigned int rdev;
 319
 320                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 321                                 sizeof(*sqsh_ino));
 322                 if (err < 0)
 323                         goto failed_read;
 324
 325                 if (type == SQUASHFS_CHRDEV_TYPE)
 326                         inode->i_mode |= S_IFCHR;
 327                 else
 328                         inode->i_mode |= S_IFBLK;
 329                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 330                 rdev = le32_to_cpu(sqsh_ino->rdev);
 331                 init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
 332
 333                 TRACE("Device inode %x:%x, rdev %x\n",
 334                                 SQUASHFS_INODE_BLK(ino), offset, rdev);
 335                 break;
 336         }
 337         case SQUASHFS_LBLKDEV_TYPE:
 338         case SQUASHFS_LCHRDEV_TYPE: {
 339                 struct squashfs_ldev_inode *sqsh_ino = &squashfs_ino.ldev;
 340                 unsigned int rdev;
 341
 342                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 343                                 sizeof(*sqsh_ino));
 344                 if (err < 0)
 345                         goto failed_read;
 346
 347                 if (type == SQUASHFS_LCHRDEV_TYPE)
 348                         inode->i_mode |= S_IFCHR;
 349                 else
 350                         inode->i_mode |= S_IFBLK;
 351                 xattr_id = le32_to_cpu(sqsh_ino->xattr);
 352                 inode->i_op = &squashfs_inode_ops;
 353                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 354                 rdev = le32_to_cpu(sqsh_ino->rdev);
 355                 init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
 356
 357                 TRACE("Device inode %x:%x, rdev %x\n",
 358                                 SQUASHFS_INODE_BLK(ino), offset, rdev);
 359                 break;
 360         }
 361         case SQUASHFS_FIFO_TYPE:
 362         case SQUASHFS_SOCKET_TYPE: {
 363                 struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc;
 364
 365                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 366                                 sizeof(*sqsh_ino));
 367                 if (err < 0)
 368                         goto failed_read;
 369
 370                 if (type == SQUASHFS_FIFO_TYPE)
 371                         inode->i_mode |= S_IFIFO;
 372                 else
 373                         inode->i_mode |= S_IFSOCK;
 374                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 375                 init_special_inode(inode, inode->i_mode, 0);
 376                 break;
 377         }
 378         case SQUASHFS_LFIFO_TYPE:
 379         case SQUASHFS_LSOCKET_TYPE: {
 380                 struct squashfs_lipc_inode *sqsh_ino = &squashfs_ino.lipc;
 381
 382                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 383                                 sizeof(*sqsh_ino));
 384                 if (err < 0)
 385                         goto failed_read;
 386
 387                 if (type == SQUASHFS_LFIFO_TYPE)
 388                         inode->i_mode |= S_IFIFO;
 389                 else
 390                         inode->i_mode |= S_IFSOCK;
 391                 xattr_id = le32_to_cpu(sqsh_ino->xattr);
 392                 inode->i_op = &squashfs_inode_ops;
 393                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 394                 init_special_inode(inode, inode->i_mode, 0);
 395                 break;
 396         }
 397         default:
 398                 ERROR("Unknown inode type %d in squashfs_iget!\n", type);
 399                 return -EINVAL;
 400         }
 401
 402         if (xattr_id != SQUASHFS_INVALID_XATTR && msblk->xattr_id_table) {
 403                 err = squashfs_xattr_lookup(sb, xattr_id,
 404                                         &squashfs_i(inode)->xattr_count,
 405                                         &squashfs_i(inode)->xattr_size,
 406                                         &squashfs_i(inode)->xattr);
 407                 if (err < 0)
 408                         goto failed_read;
 409                 inode->i_blocks += ((squashfs_i(inode)->xattr_size - 1) >> 9)
 410                                 + 1;
 411         } else
 412                 squashfs_i(inode)->xattr_count = 0;
 413
 414         return 0;
 415
 416 failed_read:
 417         ERROR("Unable to read inode 0x%llx\n", ino);
 418         return err;
 419 }
 420
 421
 422 const struct inode_operations squashfs_inode_ops = {
 423         .listxattr = squashfs_listxattr
 424 };
 425