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         err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->uid), &i_uid);
  52         if (err)
  53                 return err;
  54
  55         err = squashfs_get_id(sb, le16_to_cpu(sqsh_ino->guid), &i_gid);
  56         if (err)
  57                 return err;
  58
  59         i_uid_write(inode, i_uid);
  60         i_gid_write(inode, i_gid);
  61         inode->i_ino = le32_to_cpu(sqsh_ino->inode_number);
  62         inode->i_mtime.tv_sec = le32_to_cpu(sqsh_ino->mtime);
  63         inode->i_atime.tv_sec = inode->i_mtime.tv_sec;
  64         inode->i_ctime.tv_sec = inode->i_mtime.tv_sec;
  65         inode->i_mode = le16_to_cpu(sqsh_ino->mode);
  66         inode->i_size = 0;
  67
  68         return err;
  69 }
  70
  71
  72 struct inode *squashfs_iget(struct super_block *sb, long long ino,
  73                                 unsigned int ino_number)
  74 {
  75         struct inode *inode = iget_locked(sb, ino_number);
  76         int err;
  77
  78         TRACE("Entered squashfs_iget\n");
  79
  80         if (!inode)
  81                 return ERR_PTR(-ENOMEM);
  82         if (!(inode->i_state & I_NEW))
  83                 return inode;
  84
  85         err = squashfs_read_inode(inode, ino);
  86         if (err) {
  87                 iget_failed(inode);
  88                 return ERR_PTR(err);
  89         }
  90
  91         unlock_new_inode(inode);
  92         return inode;
  93 }
  94
  95
  96 /*
  97  * Initialise VFS inode by reading inode from inode table (compressed
  98  * metadata).  The format and amount of data read depends on type.
  99  */
 100 int squashfs_read_inode(struct inode *inode, long long ino)
 101 {
 102         struct super_block *sb = inode->i_sb;
 103         struct squashfs_sb_info *msblk = sb->s_fs_info;
 104         u64 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
 105         int err, type, offset = SQUASHFS_INODE_OFFSET(ino);
 106         union squashfs_inode squashfs_ino;
 107         struct squashfs_base_inode *sqshb_ino = &squashfs_ino.base;
 108         int xattr_id = SQUASHFS_INVALID_XATTR;
 109
 110         TRACE("Entered squashfs_read_inode\n");
 111
 112         /*
 113          * Read inode base common to all inode types.
 114          */
 115         err = squashfs_read_metadata(sb, sqshb_ino, &block,
 116                                 &offset, sizeof(*sqshb_ino));
 117         if (err < 0)
 118                 goto failed_read;
 119
 120         err = squashfs_new_inode(sb, inode, sqshb_ino);
 121         if (err)
 122                 goto failed_read;
 123
 124         block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
 125         offset = SQUASHFS_INODE_OFFSET(ino);
 126
 127         type = le16_to_cpu(sqshb_ino->inode_type);
 128         switch (type) {
 129         case SQUASHFS_REG_TYPE: {
 130                 unsigned int frag_offset, frag;
 131                 int frag_size;
 132                 u64 frag_blk;
 133                 struct squashfs_reg_inode *sqsh_ino = &squashfs_ino.reg;
 134
 135                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 136                                                         sizeof(*sqsh_ino));
 137                 if (err < 0)
 138                         goto failed_read;
 139
 140                 frag = le32_to_cpu(sqsh_ino->fragment);
 141                 if (frag != SQUASHFS_INVALID_FRAG) {
 142                         frag_offset = le32_to_cpu(sqsh_ino->offset);
 143                         frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
 144                         if (frag_size < 0) {
 145                                 err = frag_size;
 146                                 goto failed_read;
 147                         }
 148                 } else {
 149                         frag_blk = SQUASHFS_INVALID_BLK;
 150                         frag_size = 0;
 151                         frag_offset = 0;
 152                 }
 153
 154                 set_nlink(inode, 1);
 155                 inode->i_size = le32_to_cpu(sqsh_ino->file_size);
 156                 inode->i_fop = &generic_ro_fops;
 157                 inode->i_mode |= S_IFREG;
 158                 inode->i_blocks = ((inode->i_size - 1) >> 9) + 1;
 159                 squashfs_i(inode)->fragment_block = frag_blk;
 160                 squashfs_i(inode)->fragment_size = frag_size;
 161                 squashfs_i(inode)->fragment_offset = frag_offset;
 162                 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
 163                 squashfs_i(inode)->block_list_start = block;
 164                 squashfs_i(inode)->offset = offset;
 165                 inode->i_data.a_ops = &squashfs_aops;
 166
 167                 TRACE("File inode %x:%x, start_block %llx, block_list_start "
 168                         "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
 169                         offset, squashfs_i(inode)->start, block, offset);
 170                 break;
 171         }
 172         case SQUASHFS_LREG_TYPE: {
 173                 unsigned int frag_offset, frag;
 174                 int frag_size;
 175                 u64 frag_blk;
 176                 struct squashfs_lreg_inode *sqsh_ino = &squashfs_ino.lreg;
 177
 178                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 179                                                         sizeof(*sqsh_ino));
 180                 if (err < 0)
 181                         goto failed_read;
 182
 183                 frag = le32_to_cpu(sqsh_ino->fragment);
 184                 if (frag != SQUASHFS_INVALID_FRAG) {
 185                         frag_offset = le32_to_cpu(sqsh_ino->offset);
 186                         frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
 187                         if (frag_size < 0) {
 188                                 err = frag_size;
 189                                 goto failed_read;
 190                         }
 191                 } else {
 192                         frag_blk = SQUASHFS_INVALID_BLK;
 193                         frag_size = 0;
 194                         frag_offset = 0;
 195                 }
 196
 197                 xattr_id = le32_to_cpu(sqsh_ino->xattr);
 198                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 199                 inode->i_size = le64_to_cpu(sqsh_ino->file_size);
 200                 inode->i_op = &squashfs_inode_ops;
 201                 inode->i_fop = &generic_ro_fops;
 202                 inode->i_mode |= S_IFREG;
 203                 inode->i_blocks = (inode->i_size -
 204                                 le64_to_cpu(sqsh_ino->sparse) + 511) >> 9;
 205
 206                 squashfs_i(inode)->fragment_block = frag_blk;
 207                 squashfs_i(inode)->fragment_size = frag_size;
 208                 squashfs_i(inode)->fragment_offset = frag_offset;
 209                 squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block);
 210                 squashfs_i(inode)->block_list_start = block;
 211                 squashfs_i(inode)->offset = offset;
 212                 inode->i_data.a_ops = &squashfs_aops;
 213
 214                 TRACE("File inode %x:%x, start_block %llx, block_list_start "
 215                         "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
 216                         offset, squashfs_i(inode)->start, block, offset);
 217                 break;
 218         }
 219         case SQUASHFS_DIR_TYPE: {
 220                 struct squashfs_dir_inode *sqsh_ino = &squashfs_ino.dir;
 221
 222                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 223                                 sizeof(*sqsh_ino));
 224                 if (err < 0)
 225                         goto failed_read;
 226
 227                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 228                 inode->i_size = le16_to_cpu(sqsh_ino->file_size);
 229                 inode->i_op = &squashfs_dir_inode_ops;
 230                 inode->i_fop = &squashfs_dir_ops;
 231                 inode->i_mode |= S_IFDIR;
 232                 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
 233                 squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
 234                 squashfs_i(inode)->dir_idx_cnt = 0;
 235                 squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
 236
 237                 TRACE("Directory inode %x:%x, start_block %llx, offset %x\n",
 238                                 SQUASHFS_INODE_BLK(ino), offset,
 239                                 squashfs_i(inode)->start,
 240                                 le16_to_cpu(sqsh_ino->offset));
 241                 break;
 242         }
 243         case SQUASHFS_LDIR_TYPE: {
 244                 struct squashfs_ldir_inode *sqsh_ino = &squashfs_ino.ldir;
 245
 246                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 247                                 sizeof(*sqsh_ino));
 248                 if (err < 0)
 249                         goto failed_read;
 250
 251                 xattr_id = le32_to_cpu(sqsh_ino->xattr);
 252                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 253                 inode->i_size = le32_to_cpu(sqsh_ino->file_size);
 254                 inode->i_op = &squashfs_dir_inode_ops;
 255                 inode->i_fop = &squashfs_dir_ops;
 256                 inode->i_mode |= S_IFDIR;
 257                 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
 258                 squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
 259                 squashfs_i(inode)->dir_idx_start = block;
 260                 squashfs_i(inode)->dir_idx_offset = offset;
 261                 squashfs_i(inode)->dir_idx_cnt = le16_to_cpu(sqsh_ino->i_count);
 262                 squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
 263
 264                 TRACE("Long directory inode %x:%x, start_block %llx, offset "
 265                                 "%x\n", SQUASHFS_INODE_BLK(ino), offset,
 266                                 squashfs_i(inode)->start,
 267                                 le16_to_cpu(sqsh_ino->offset));
 268                 break;
 269         }
 270         case SQUASHFS_SYMLINK_TYPE:
 271         case SQUASHFS_LSYMLINK_TYPE: {
 272                 struct squashfs_symlink_inode *sqsh_ino = &squashfs_ino.symlink;
 273
 274                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 275                                 sizeof(*sqsh_ino));
 276                 if (err < 0)
 277                         goto failed_read;
 278
 279                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 280                 inode->i_size = le32_to_cpu(sqsh_ino->symlink_size);
 281                 inode->i_op = &squashfs_symlink_inode_ops;
 282                 inode_nohighmem(inode);
 283                 inode->i_data.a_ops = &squashfs_symlink_aops;
 284                 inode->i_mode |= S_IFLNK;
 285                 squashfs_i(inode)->start = block;
 286                 squashfs_i(inode)->offset = offset;
 287
 288                 if (type == SQUASHFS_LSYMLINK_TYPE) {
 289                         __le32 xattr;
 290
 291                         err = squashfs_read_metadata(sb, NULL, &block,
 292                                                 &offset, inode->i_size);
 293                         if (err < 0)
 294                                 goto failed_read;
 295                         err = squashfs_read_metadata(sb, &xattr, &block,
 296                                                 &offset, sizeof(xattr));
 297                         if (err < 0)
 298                                 goto failed_read;
 299                         xattr_id = le32_to_cpu(xattr);
 300                 }
 301
 302                 TRACE("Symbolic link inode %x:%x, start_block %llx, offset "
 303                                 "%x\n", SQUASHFS_INODE_BLK(ino), offset,
 304                                 block, offset);
 305                 break;
 306         }
 307         case SQUASHFS_BLKDEV_TYPE:
 308         case SQUASHFS_CHRDEV_TYPE: {
 309                 struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev;
 310                 unsigned int rdev;
 311
 312                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 313                                 sizeof(*sqsh_ino));
 314                 if (err < 0)
 315                         goto failed_read;
 316
 317                 if (type == SQUASHFS_CHRDEV_TYPE)
 318                         inode->i_mode |= S_IFCHR;
 319                 else
 320                         inode->i_mode |= S_IFBLK;
 321                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 322                 rdev = le32_to_cpu(sqsh_ino->rdev);
 323                 init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
 324
 325                 TRACE("Device inode %x:%x, rdev %x\n",
 326                                 SQUASHFS_INODE_BLK(ino), offset, rdev);
 327                 break;
 328         }
 329         case SQUASHFS_LBLKDEV_TYPE:
 330         case SQUASHFS_LCHRDEV_TYPE: {
 331                 struct squashfs_ldev_inode *sqsh_ino = &squashfs_ino.ldev;
 332                 unsigned int rdev;
 333
 334                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 335                                 sizeof(*sqsh_ino));
 336                 if (err < 0)
 337                         goto failed_read;
 338
 339                 if (type == SQUASHFS_LCHRDEV_TYPE)
 340                         inode->i_mode |= S_IFCHR;
 341                 else
 342                         inode->i_mode |= S_IFBLK;
 343                 xattr_id = le32_to_cpu(sqsh_ino->xattr);
 344                 inode->i_op = &squashfs_inode_ops;
 345                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 346                 rdev = le32_to_cpu(sqsh_ino->rdev);
 347                 init_special_inode(inode, inode->i_mode, new_decode_dev(rdev));
 348
 349                 TRACE("Device inode %x:%x, rdev %x\n",
 350                                 SQUASHFS_INODE_BLK(ino), offset, rdev);
 351                 break;
 352         }
 353         case SQUASHFS_FIFO_TYPE:
 354         case SQUASHFS_SOCKET_TYPE: {
 355                 struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc;
 356
 357                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 358                                 sizeof(*sqsh_ino));
 359                 if (err < 0)
 360                         goto failed_read;
 361
 362                 if (type == SQUASHFS_FIFO_TYPE)
 363                         inode->i_mode |= S_IFIFO;
 364                 else
 365                         inode->i_mode |= S_IFSOCK;
 366                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 367                 init_special_inode(inode, inode->i_mode, 0);
 368                 break;
 369         }
 370         case SQUASHFS_LFIFO_TYPE:
 371         case SQUASHFS_LSOCKET_TYPE: {
 372                 struct squashfs_lipc_inode *sqsh_ino = &squashfs_ino.lipc;
 373
 374                 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
 375                                 sizeof(*sqsh_ino));
 376                 if (err < 0)
 377                         goto failed_read;
 378
 379                 if (type == SQUASHFS_LFIFO_TYPE)
 380                         inode->i_mode |= S_IFIFO;
 381                 else
 382                         inode->i_mode |= S_IFSOCK;
 383                 xattr_id = le32_to_cpu(sqsh_ino->xattr);
 384                 inode->i_op = &squashfs_inode_ops;
 385                 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 386                 init_special_inode(inode, inode->i_mode, 0);
 387                 break;
 388         }
 389         default:
 390                 ERROR("Unknown inode type %d in squashfs_iget!\n", type);
 391                 return -EINVAL;
 392         }
 393
 394         if (xattr_id != SQUASHFS_INVALID_XATTR && msblk->xattr_id_table) {
 395                 err = squashfs_xattr_lookup(sb, xattr_id,
 396                                         &squashfs_i(inode)->xattr_count,
 397                                         &squashfs_i(inode)->xattr_size,
 398                                         &squashfs_i(inode)->xattr);
 399                 if (err < 0)
 400                         goto failed_read;
 401                 inode->i_blocks += ((squashfs_i(inode)->xattr_size - 1) >> 9)
 402                                 + 1;
 403         } else
 404                 squashfs_i(inode)->xattr_count = 0;
 405
 406         return 0;
 407
 408 failed_read:
 409         ERROR("Unable to read inode 0x%llx\n", ino);
 410         return err;
 411 }
 412
 413
 414 const struct inode_operations squashfs_inode_ops = {
 415         .listxattr = squashfs_listxattr
 416 };
 417