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 }; 425 426