1 /* 2 * Squashfs - a compressed read only filesystem for Linux 3 * 4 * Copyright (c) 2010 5 * Phillip Lougher <phillip@lougher.demon.co.uk> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 2, 10 * or (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. 20 * 21 * xattr_id.c 22 */ 23 24 /* 25 * This file implements code to map the 32-bit xattr id stored in the inode 26 * into the on disk location of the xattr data. 27 */ 28 29 #include <linux/fs.h> 30 #include <linux/vfs.h> 31 #include <linux/slab.h> 32 33 #include "squashfs_fs.h" 34 #include "squashfs_fs_sb.h" 35 #include "squashfs.h" 36 #include "xattr.h" 37 38 /* 39 * Map xattr id using the xattr id look up table 40 */ 41 int squashfs_xattr_lookup(struct super_block *sb, unsigned int index, 42 int *count, unsigned int *size, unsigned long long *xattr) 43 { 44 struct squashfs_sb_info *msblk = sb->s_fs_info; 45 int block = SQUASHFS_XATTR_BLOCK(index); 46 int offset = SQUASHFS_XATTR_BLOCK_OFFSET(index); 47 u64 start_block = le64_to_cpu(msblk->xattr_id_table[block]); 48 struct squashfs_xattr_id id; 49 int err; 50 51 err = squashfs_read_metadata(sb, &id, &start_block, &offset, 52 sizeof(id)); 53 if (err < 0) 54 return err; 55 56 *xattr = le64_to_cpu(id.xattr); 57 *size = le32_to_cpu(id.size); 58 *count = le32_to_cpu(id.count); 59 return 0; 60 } 61 62 63 /* 64 * Read uncompressed xattr id lookup table indexes from disk into memory 65 */ 66 __le64 *squashfs_read_xattr_id_table(struct super_block *sb, u64 start, 67 u64 *xattr_table_start, int *xattr_ids) 68 { 69 unsigned int len; 70 __le64 *xid_table; 71 struct squashfs_xattr_id_table id_table; 72 int err; 73 74 err = squashfs_read_table(sb, &id_table, start, sizeof(id_table)); 75 if (err < 0) { 76 ERROR("unable to read xattr id table\n"); 77 return ERR_PTR(err); 78 } 79 *xattr_table_start = le64_to_cpu(id_table.xattr_table_start); 80 *xattr_ids = le32_to_cpu(id_table.xattr_ids); 81 len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids); 82 83 TRACE("In read_xattr_index_table, length %d\n", len); 84 85 /* Allocate xattr id lookup table indexes */ 86 xid_table = kmalloc(len, GFP_KERNEL); 87 if (xid_table == NULL) { 88 ERROR("Failed to allocate xattr id index table\n"); 89 return ERR_PTR(-ENOMEM); 90 } 91 92 err = squashfs_read_table(sb, xid_table, start + sizeof(id_table), len); 93 if (err < 0) { 94 ERROR("unable to read xattr id index table\n"); 95 kfree(xid_table); 96 return ERR_PTR(err); 97 } 98 99 return xid_table; 100 } 101