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/*
* Squashfs - a compressed read only filesystem for Linux
*
* Copyright (c) 2010
* Phillip Lougher <phillip@lougher.demon.co.uk>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2,
* or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* xattr_id.c
*/
/*
* This file implements code to map the 32-bit xattr id stored in the inode
* into the on disk location of the xattr data.
*/
#include <linux/fs.h>
#include <linux/vfs.h>
#include <linux/slab.h>
#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "squashfs.h"
#include "xattr.h"
/*
* Map xattr id using the xattr id look up table
*/
int squashfs_xattr_lookup(struct super_block *sb, unsigned int index,
int *count, unsigned int *size, unsigned long long *xattr)
{
struct squashfs_sb_info *msblk = sb->s_fs_info;
int block = SQUASHFS_XATTR_BLOCK(index);
int offset = SQUASHFS_XATTR_BLOCK_OFFSET(index);
u64 start_block = le64_to_cpu(msblk->xattr_id_table[block]);
struct squashfs_xattr_id id;
int err;
err = squashfs_read_metadata(sb, &id, &start_block, &offset,
sizeof(id));
if (err < 0)
return err;
*xattr = le64_to_cpu(id.xattr);
*size = le32_to_cpu(id.size);
*count = le32_to_cpu(id.count);
return 0;
}
/*
* Read uncompressed xattr id lookup table indexes from disk into memory
*/
__le64 *squashfs_read_xattr_id_table(struct super_block *sb, u64 start,
u64 *xattr_table_start, int *xattr_ids)
{
unsigned int len;
__le64 *xid_table;
struct squashfs_xattr_id_table id_table;
int err;
err = squashfs_read_table(sb, &id_table, start, sizeof(id_table));
if (err < 0) {
ERROR("unable to read xattr id table\n");
return ERR_PTR(err);
}
*xattr_table_start = le64_to_cpu(id_table.xattr_table_start);
*xattr_ids = le32_to_cpu(id_table.xattr_ids);
len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids);
TRACE("In read_xattr_index_table, length %d\n", len);
/* Allocate xattr id lookup table indexes */
xid_table = kmalloc(len, GFP_KERNEL);
if (xid_table == NULL) {
ERROR("Failed to allocate xattr id index table\n");
return ERR_PTR(-ENOMEM);
}
err = squashfs_read_table(sb, xid_table, start + sizeof(id_table), len);
if (err < 0) {
ERROR("unable to read xattr id index table\n");
kfree(xid_table);
return ERR_PTR(err);
}
return xid_table;
}
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