1 // SPDX-License-Identifier: GPL-2.0-or-later 1
2 /*
3 * Squashfs - a compressed read only filesyste
4 *
5 * Copyright (c) 2002, 2003, 2004, 2005, 2006,
6 * Phillip Lougher <phillip@squashfs.org.uk>
7 *
8 * fragment.c
9 */
10
11 /*
12 * This file implements code to handle compres
13 * datablocks).
14 *
15 * Regular files contain a fragment index whic
16 * location on disk and compressed size using
17 * Like everything in Squashfs this fragment l
18 * compressed into metadata blocks. A second
19 * these. This second index table for speed o
20 * is small) is read at mount time and cached
21 */
22
23 #include <linux/fs.h>
24 #include <linux/vfs.h>
25 #include <linux/slab.h>
26
27 #include "squashfs_fs.h"
28 #include "squashfs_fs_sb.h"
29 #include "squashfs.h"
30
31 /*
32 * Look-up fragment using the fragment index t
33 * location of the fragment and its compressed
34 */
35 int squashfs_frag_lookup(struct super_block *s
36 u64 *fragment_
37 {
38 struct squashfs_sb_info *msblk = sb->s
39 int block, offset, size;
40 struct squashfs_fragment_entry fragmen
41 u64 start_block;
42
43 if (fragment >= msblk->fragments)
44 return -EIO;
45 block = SQUASHFS_FRAGMENT_INDEX(fragme
46 offset = SQUASHFS_FRAGMENT_INDEX_OFFSE
47
48 start_block = le64_to_cpu(msblk->fragm
49
50 size = squashfs_read_metadata(sb, &fra
51 &offse
52 if (size < 0)
53 return size;
54
55 *fragment_block = le64_to_cpu(fragment
56 return squashfs_block_size(fragment_en
57 }
58
59
60 /*
61 * Read the uncompressed fragment lookup table
62 */
63 __le64 *squashfs_read_fragment_index_table(str
64 u64 fragment_table_start, u64 next_tab
65 {
66 unsigned int length = SQUASHFS_FRAGMEN
67 __le64 *table;
68
69 /*
70 * Sanity check, length bytes should n
71 * this check also traps instances whe
72 * incorrectly larger than the next ta
73 */
74 if (fragment_table_start + length > ne
75 return ERR_PTR(-EINVAL);
76
77 table = squashfs_read_table(sb, fragme
78
79 /*
80 * table[0] points to the first fragme
81 * should be less than fragment_table_
82 */
83 if (!IS_ERR(table) && le64_to_cpu(tabl
84 kfree(table);
85 return ERR_PTR(-EINVAL);
86 }
87
88 return table;
89 }
90
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