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