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 */
44static 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, uid: i_uid);
64 i_gid_write(inode, gid: i_gid);
65 inode_set_mtime(inode, le32_to_cpu(sqsh_ino->mtime), nsec: 0);
66 inode_set_atime(inode, sec: inode_get_mtime_sec(inode), nsec: 0);
67 inode_set_ctime(inode, sec: inode_get_mtime_sec(inode), nsec: 0);
68 inode->i_mode = le16_to_cpu(sqsh_ino->mode);
69 inode->i_size = 0;
70
71 /* File type must not be set at this moment, for it will later be set by the caller. */
72 if (inode->i_mode & S_IFMT)
73 err = -EIO;
74
75 return err;
76}
77
78
79struct inode *squashfs_iget(struct super_block *sb, long long ino,
80 unsigned int ino_number)
81{
82 struct inode *inode = iget_locked(sb, ino_number);
83 int err;
84
85 TRACE("Entered squashfs_iget\n");
86
87 if (!inode)
88 return ERR_PTR(error: -ENOMEM);
89 if (!(inode_state_read_once(inode) & I_NEW))
90 return inode;
91
92 err = squashfs_read_inode(inode, ino);
93 if (err) {
94 iget_failed(inode);
95 return ERR_PTR(error: err);
96 }
97
98 unlock_new_inode(inode);
99 return inode;
100}
101
102
103/*
104 * Initialise VFS inode by reading inode from inode table (compressed
105 * metadata). The format and amount of data read depends on type.
106 */
107int squashfs_read_inode(struct inode *inode, long long ino)
108{
109 struct super_block *sb = inode->i_sb;
110 struct squashfs_sb_info *msblk = sb->s_fs_info;
111 u64 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
112 int err, type, offset = SQUASHFS_INODE_OFFSET(ino);
113 union squashfs_inode squashfs_ino;
114 struct squashfs_base_inode *sqshb_ino = &squashfs_ino.base;
115 int xattr_id = SQUASHFS_INVALID_XATTR;
116
117 TRACE("Entered squashfs_read_inode\n");
118
119 /*
120 * Read inode base common to all inode types.
121 */
122 err = squashfs_read_metadata(sb, sqshb_ino, &block,
123 &offset, sizeof(*sqshb_ino));
124 if (err < 0)
125 goto failed_read;
126
127 err = squashfs_new_inode(sb, inode, sqsh_ino: sqshb_ino);
128 if (err)
129 goto failed_read;
130
131 block = SQUASHFS_INODE_BLK(ino) + msblk->inode_table;
132 offset = SQUASHFS_INODE_OFFSET(ino);
133
134 type = le16_to_cpu(sqshb_ino->inode_type);
135 switch (type) {
136 case SQUASHFS_REG_TYPE: {
137 unsigned int frag_offset, frag;
138 int frag_size;
139 u64 frag_blk;
140 struct squashfs_reg_inode *sqsh_ino = &squashfs_ino.reg;
141
142 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
143 sizeof(*sqsh_ino));
144 if (err < 0)
145 goto failed_read;
146
147 inode->i_size = le32_to_cpu(sqsh_ino->file_size);
148 frag = le32_to_cpu(sqsh_ino->fragment);
149 if (frag != SQUASHFS_INVALID_FRAG) {
150 /*
151 * the file cannot have a fragment (tailend) and have a
152 * file size a multiple of the block size
153 */
154 if ((inode->i_size & (msblk->block_size - 1)) == 0) {
155 err = -EINVAL;
156 goto failed_read;
157 }
158 frag_offset = le32_to_cpu(sqsh_ino->offset);
159 frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
160 if (frag_size < 0) {
161 err = frag_size;
162 goto failed_read;
163 }
164 } else {
165 frag_blk = SQUASHFS_INVALID_BLK;
166 frag_size = 0;
167 frag_offset = 0;
168 }
169
170 set_nlink(inode, nlink: 1);
171 inode->i_fop = &squashfs_file_operations;
172 inode->i_mode |= S_IFREG;
173 inode->i_blocks = ((inode->i_size - 1) >> 9) + 1;
174 squashfs_i(inode)->fragment_block = frag_blk;
175 squashfs_i(inode)->fragment_size = frag_size;
176 squashfs_i(inode)->fragment_offset = frag_offset;
177 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
178 squashfs_i(inode)->block_list_start = block;
179 squashfs_i(inode)->offset = offset;
180 squashfs_i(inode)->parent = 0;
181 inode->i_data.a_ops = &squashfs_aops;
182
183 TRACE("File inode %x:%x, start_block %llx, block_list_start "
184 "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
185 offset, squashfs_i(inode)->start, block, offset);
186 break;
187 }
188 case SQUASHFS_LREG_TYPE: {
189 unsigned int frag_offset, frag;
190 int frag_size;
191 u64 frag_blk;
192 struct squashfs_lreg_inode *sqsh_ino = &squashfs_ino.lreg;
193
194 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
195 sizeof(*sqsh_ino));
196 if (err < 0)
197 goto failed_read;
198
199 inode->i_size = le64_to_cpu(sqsh_ino->file_size);
200 if (inode->i_size < 0) {
201 err = -EINVAL;
202 goto failed_read;
203 }
204 frag = le32_to_cpu(sqsh_ino->fragment);
205 if (frag != SQUASHFS_INVALID_FRAG) {
206 /*
207 * the file cannot have a fragment (tailend) and have a
208 * file size a multiple of the block size
209 */
210 if ((inode->i_size & (msblk->block_size - 1)) == 0) {
211 err = -EINVAL;
212 goto failed_read;
213 }
214 frag_offset = le32_to_cpu(sqsh_ino->offset);
215 frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
216 if (frag_size < 0) {
217 err = frag_size;
218 goto failed_read;
219 }
220 } else {
221 frag_blk = SQUASHFS_INVALID_BLK;
222 frag_size = 0;
223 frag_offset = 0;
224 }
225
226 xattr_id = le32_to_cpu(sqsh_ino->xattr);
227 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
228 inode->i_op = &squashfs_inode_ops;
229 inode->i_fop = &squashfs_file_operations;
230 inode->i_mode |= S_IFREG;
231 inode->i_blocks = (inode->i_size -
232 le64_to_cpu(sqsh_ino->sparse) + 511) >> 9;
233
234 squashfs_i(inode)->fragment_block = frag_blk;
235 squashfs_i(inode)->fragment_size = frag_size;
236 squashfs_i(inode)->fragment_offset = frag_offset;
237 squashfs_i(inode)->start = le64_to_cpu(sqsh_ino->start_block);
238 squashfs_i(inode)->block_list_start = block;
239 squashfs_i(inode)->offset = offset;
240 squashfs_i(inode)->parent = 0;
241 inode->i_data.a_ops = &squashfs_aops;
242
243 TRACE("File inode %x:%x, start_block %llx, block_list_start "
244 "%llx, offset %x\n", SQUASHFS_INODE_BLK(ino),
245 offset, squashfs_i(inode)->start, block, offset);
246 break;
247 }
248 case SQUASHFS_DIR_TYPE: {
249 struct squashfs_dir_inode *sqsh_ino = &squashfs_ino.dir;
250
251 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
252 sizeof(*sqsh_ino));
253 if (err < 0)
254 goto failed_read;
255
256 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
257 inode->i_size = le16_to_cpu(sqsh_ino->file_size);
258 inode->i_op = &squashfs_dir_inode_ops;
259 inode->i_fop = &squashfs_dir_ops;
260 inode->i_mode |= S_IFDIR;
261 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
262 squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
263 squashfs_i(inode)->dir_idx_cnt = 0;
264 squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
265
266 TRACE("Directory inode %x:%x, start_block %llx, offset %x\n",
267 SQUASHFS_INODE_BLK(ino), offset,
268 squashfs_i(inode)->start,
269 le16_to_cpu(sqsh_ino->offset));
270 break;
271 }
272 case SQUASHFS_LDIR_TYPE: {
273 struct squashfs_ldir_inode *sqsh_ino = &squashfs_ino.ldir;
274
275 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
276 sizeof(*sqsh_ino));
277 if (err < 0)
278 goto failed_read;
279
280 xattr_id = le32_to_cpu(sqsh_ino->xattr);
281 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
282 inode->i_size = le32_to_cpu(sqsh_ino->file_size);
283 inode->i_op = &squashfs_dir_inode_ops;
284 inode->i_fop = &squashfs_dir_ops;
285 inode->i_mode |= S_IFDIR;
286 squashfs_i(inode)->start = le32_to_cpu(sqsh_ino->start_block);
287 squashfs_i(inode)->offset = le16_to_cpu(sqsh_ino->offset);
288 squashfs_i(inode)->dir_idx_start = block;
289 squashfs_i(inode)->dir_idx_offset = offset;
290 squashfs_i(inode)->dir_idx_cnt = le16_to_cpu(sqsh_ino->i_count);
291 squashfs_i(inode)->parent = le32_to_cpu(sqsh_ino->parent_inode);
292
293 TRACE("Long directory inode %x:%x, start_block %llx, offset "
294 "%x\n", SQUASHFS_INODE_BLK(ino), offset,
295 squashfs_i(inode)->start,
296 le16_to_cpu(sqsh_ino->offset));
297 break;
298 }
299 case SQUASHFS_SYMLINK_TYPE:
300 case SQUASHFS_LSYMLINK_TYPE: {
301 struct squashfs_symlink_inode *sqsh_ino = &squashfs_ino.symlink;
302
303 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
304 sizeof(*sqsh_ino));
305 if (err < 0)
306 goto failed_read;
307
308 inode->i_size = le32_to_cpu(sqsh_ino->symlink_size);
309 if (inode->i_size > PAGE_SIZE) {
310 ERROR("Corrupted symlink\n");
311 return -EINVAL;
312 }
313
314 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
315 inode->i_op = &squashfs_symlink_inode_ops;
316 inode_nohighmem(inode);
317 inode->i_data.a_ops = &squashfs_symlink_aops;
318 inode->i_mode |= S_IFLNK;
319 squashfs_i(inode)->start = block;
320 squashfs_i(inode)->offset = offset;
321 squashfs_i(inode)->parent = 0;
322
323 if (type == SQUASHFS_LSYMLINK_TYPE) {
324 __le32 xattr;
325
326 err = squashfs_read_metadata(sb, NULL, &block,
327 &offset, inode->i_size);
328 if (err < 0)
329 goto failed_read;
330 err = squashfs_read_metadata(sb, &xattr, &block,
331 &offset, sizeof(xattr));
332 if (err < 0)
333 goto failed_read;
334 xattr_id = le32_to_cpu(xattr);
335 }
336
337 TRACE("Symbolic link inode %x:%x, start_block %llx, offset "
338 "%x\n", SQUASHFS_INODE_BLK(ino), offset,
339 block, offset);
340 break;
341 }
342 case SQUASHFS_BLKDEV_TYPE:
343 case SQUASHFS_CHRDEV_TYPE: {
344 struct squashfs_dev_inode *sqsh_ino = &squashfs_ino.dev;
345 unsigned int rdev;
346
347 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
348 sizeof(*sqsh_ino));
349 if (err < 0)
350 goto failed_read;
351
352 if (type == SQUASHFS_CHRDEV_TYPE)
353 inode->i_mode |= S_IFCHR;
354 else
355 inode->i_mode |= S_IFBLK;
356 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
357 rdev = le32_to_cpu(sqsh_ino->rdev);
358 init_special_inode(inode, inode->i_mode, new_decode_dev(dev: rdev));
359 squashfs_i(inode)->parent = 0;
360
361 TRACE("Device inode %x:%x, rdev %x\n",
362 SQUASHFS_INODE_BLK(ino), offset, rdev);
363 break;
364 }
365 case SQUASHFS_LBLKDEV_TYPE:
366 case SQUASHFS_LCHRDEV_TYPE: {
367 struct squashfs_ldev_inode *sqsh_ino = &squashfs_ino.ldev;
368 unsigned int rdev;
369
370 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
371 sizeof(*sqsh_ino));
372 if (err < 0)
373 goto failed_read;
374
375 if (type == SQUASHFS_LCHRDEV_TYPE)
376 inode->i_mode |= S_IFCHR;
377 else
378 inode->i_mode |= S_IFBLK;
379 xattr_id = le32_to_cpu(sqsh_ino->xattr);
380 inode->i_op = &squashfs_inode_ops;
381 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
382 rdev = le32_to_cpu(sqsh_ino->rdev);
383 init_special_inode(inode, inode->i_mode, new_decode_dev(dev: rdev));
384 squashfs_i(inode)->parent = 0;
385
386 TRACE("Device inode %x:%x, rdev %x\n",
387 SQUASHFS_INODE_BLK(ino), offset, rdev);
388 break;
389 }
390 case SQUASHFS_FIFO_TYPE:
391 case SQUASHFS_SOCKET_TYPE: {
392 struct squashfs_ipc_inode *sqsh_ino = &squashfs_ino.ipc;
393
394 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
395 sizeof(*sqsh_ino));
396 if (err < 0)
397 goto failed_read;
398
399 if (type == SQUASHFS_FIFO_TYPE)
400 inode->i_mode |= S_IFIFO;
401 else
402 inode->i_mode |= S_IFSOCK;
403 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
404 init_special_inode(inode, inode->i_mode, 0);
405 squashfs_i(inode)->parent = 0;
406 break;
407 }
408 case SQUASHFS_LFIFO_TYPE:
409 case SQUASHFS_LSOCKET_TYPE: {
410 struct squashfs_lipc_inode *sqsh_ino = &squashfs_ino.lipc;
411
412 err = squashfs_read_metadata(sb, sqsh_ino, &block, &offset,
413 sizeof(*sqsh_ino));
414 if (err < 0)
415 goto failed_read;
416
417 if (type == SQUASHFS_LFIFO_TYPE)
418 inode->i_mode |= S_IFIFO;
419 else
420 inode->i_mode |= S_IFSOCK;
421 xattr_id = le32_to_cpu(sqsh_ino->xattr);
422 inode->i_op = &squashfs_inode_ops;
423 set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
424 init_special_inode(inode, inode->i_mode, 0);
425 squashfs_i(inode)->parent = 0;
426 break;
427 }
428 default:
429 ERROR("Unknown inode type %d in squashfs_iget!\n", type);
430 return -EINVAL;
431 }
432
433 if (xattr_id != SQUASHFS_INVALID_XATTR && msblk->xattr_id_table) {
434 err = squashfs_xattr_lookup(sb, xattr_id,
435 &squashfs_i(inode)->xattr_count,
436 &squashfs_i(inode)->xattr_size,
437 &squashfs_i(inode)->xattr);
438 if (err < 0)
439 goto failed_read;
440 inode->i_blocks += ((squashfs_i(inode)->xattr_size - 1) >> 9)
441 + 1;
442 } else
443 squashfs_i(inode)->xattr_count = 0;
444
445 return 0;
446
447failed_read:
448 ERROR("Unable to read inode 0x%llx\n", ino);
449 return err;
450}
451
452
453const struct inode_operations squashfs_inode_ops = {
454 .listxattr = squashfs_listxattr
455};
456
457

source code of linux/fs/squashfs/inode.c