Thomas Gleixner | 68252eb | 2019-05-20 19:08:00 +0200 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
Phillip Lougher | 4b5397d | 2010-05-14 20:48:47 +0100 | [diff] [blame] | 2 | /* |
| 3 | * Squashfs - a compressed read only filesystem for Linux |
| 4 | * |
| 5 | * Copyright (c) 2010 |
Phillip Lougher | d7f2ff6 | 2011-05-26 10:39:56 +0100 | [diff] [blame] | 6 | * Phillip Lougher <phillip@squashfs.org.uk> |
Phillip Lougher | 4b5397d | 2010-05-14 20:48:47 +0100 | [diff] [blame] | 7 | * |
Phillip Lougher | 4b5397d | 2010-05-14 20:48:47 +0100 | [diff] [blame] | 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" |
Phillip Lougher | 4b5397d | 2010-05-14 20:48:47 +0100 | [diff] [blame] | 22 | #include "squashfs.h" |
Phillip Lougher | 5f3b321 | 2010-10-25 00:17:24 +0100 | [diff] [blame] | 23 | #include "xattr.h" |
Phillip Lougher | 4b5397d | 2010-05-14 20:48:47 +0100 | [diff] [blame] | 24 | |
| 25 | /* |
| 26 | * Map xattr id using the xattr id look up table |
| 27 | */ |
| 28 | int squashfs_xattr_lookup(struct super_block *sb, unsigned int index, |
Stephen Hemminger | aa5b189 | 2010-05-13 16:32:21 -0700 | [diff] [blame] | 29 | int *count, unsigned int *size, unsigned long long *xattr) |
Phillip Lougher | 4b5397d | 2010-05-14 20:48:47 +0100 | [diff] [blame] | 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; |
Phillip Lougher | 82de647 | 2011-05-20 02:26:43 +0100 | [diff] [blame] | 57 | struct squashfs_xattr_id_table *id_table; |
Phillip Lougher | 4b5397d | 2010-05-14 20:48:47 +0100 | [diff] [blame] | 58 | |
Phillip Lougher | 82de647 | 2011-05-20 02:26:43 +0100 | [diff] [blame] | 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); |
Phillip Lougher | 6f04864 | 2011-05-24 03:20:27 +0100 | [diff] [blame] | 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 | |
Phillip Lougher | 4b5397d | 2010-05-14 20:48:47 +0100 | [diff] [blame] | 77 | len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids); |
| 78 | |
| 79 | TRACE("In read_xattr_index_table, length %d\n", len); |
| 80 | |
Phillip Lougher | 82de647 | 2011-05-20 02:26:43 +0100 | [diff] [blame] | 81 | return squashfs_read_table(sb, start + sizeof(*id_table), len); |
Phillip Lougher | 4b5397d | 2010-05-14 20:48:47 +0100 | [diff] [blame] | 82 | } |