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Linux kernel mirror (for testing)
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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Squashfs - a compressed read only filesystem for Linux
4 *
5 * Copyright (c) 2010
6 * Phillip Lougher <phillip@squashfs.org.uk>
7 *
8 * xattr_id.c
9 */
10
11/*
12 * This file implements code to map the 32-bit xattr id stored in the inode
13 * into the on disk location of the xattr data.
14 */
15
16#include <linux/fs.h>
17#include <linux/vfs.h>
18#include <linux/slab.h>
19
20#include "squashfs_fs.h"
21#include "squashfs_fs_sb.h"
22#include "squashfs.h"
23#include "xattr.h"
24
25/*
26 * Map xattr id using the xattr id look up table
27 */
28int squashfs_xattr_lookup(struct super_block *sb, unsigned int index,
29 int *count, unsigned int *size, unsigned long long *xattr)
30{
31 struct squashfs_sb_info *msblk = sb->s_fs_info;
32 int block = SQUASHFS_XATTR_BLOCK(index);
33 int offset = SQUASHFS_XATTR_BLOCK_OFFSET(index);
34 u64 start_block = le64_to_cpu(msblk->xattr_id_table[block]);
35 struct squashfs_xattr_id id;
36 int err;
37
38 err = squashfs_read_metadata(sb, &id, &start_block, &offset,
39 sizeof(id));
40 if (err < 0)
41 return err;
42
43 *xattr = le64_to_cpu(id.xattr);
44 *size = le32_to_cpu(id.size);
45 *count = le32_to_cpu(id.count);
46 return 0;
47}
48
49
50/*
51 * Read uncompressed xattr id lookup table indexes from disk into memory
52 */
53__le64 *squashfs_read_xattr_id_table(struct super_block *sb, u64 start,
54 u64 *xattr_table_start, int *xattr_ids)
55{
56 unsigned int len;
57 struct squashfs_xattr_id_table *id_table;
58
59 id_table = squashfs_read_table(sb, start, sizeof(*id_table));
60 if (IS_ERR(id_table))
61 return (__le64 *) id_table;
62
63 *xattr_table_start = le64_to_cpu(id_table->xattr_table_start);
64 *xattr_ids = le32_to_cpu(id_table->xattr_ids);
65 kfree(id_table);
66
67 /* Sanity check values */
68
69 /* there is always at least one xattr id */
70 if (*xattr_ids == 0)
71 return ERR_PTR(-EINVAL);
72
73 /* xattr_table should be less than start */
74 if (*xattr_table_start >= start)
75 return ERR_PTR(-EINVAL);
76
77 len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids);
78
79 TRACE("In read_xattr_index_table, length %d\n", len);
80
81 return squashfs_read_table(sb, start + sizeof(*id_table), len);
82}