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 return err;
72}
73
74
75struct 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(error: -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(error: 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 */
103int 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, sqsh_ino: 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, nlink: 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(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(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
416failed_read:
417 ERROR("Unable to read inode 0x%llx\n", ino);
418 return err;
419}
420
421
422const struct inode_operations squashfs_inode_ops = {
423 .listxattr = squashfs_listxattr
424};
425
426

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