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Based on 1 normalized pattern(s): 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 23 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520170857.458548087@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
90 lines
2.6 KiB
C
90 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Squashfs - a compressed read only filesystem for Linux
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*
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* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
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* Phillip Lougher <phillip@squashfs.org.uk>
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*
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* fragment.c
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*/
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/*
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* This file implements code to handle compressed fragments (tail-end packed
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* datablocks).
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*
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* Regular files contain a fragment index which is mapped to a fragment
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* location on disk and compressed size using a fragment lookup table.
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* Like everything in Squashfs this fragment lookup table is itself stored
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* compressed into metadata blocks. A second index table is used to locate
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* these. This second index table for speed of access (and because it
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* is small) is read at mount time and cached in memory.
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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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/*
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* Look-up fragment using the fragment index table. Return the on disk
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* location of the fragment and its compressed size
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*/
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int squashfs_frag_lookup(struct super_block *sb, unsigned int fragment,
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u64 *fragment_block)
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{
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struct squashfs_sb_info *msblk = sb->s_fs_info;
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int block, offset, size;
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struct squashfs_fragment_entry fragment_entry;
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u64 start_block;
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if (fragment >= msblk->fragments)
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return -EIO;
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block = SQUASHFS_FRAGMENT_INDEX(fragment);
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offset = SQUASHFS_FRAGMENT_INDEX_OFFSET(fragment);
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start_block = le64_to_cpu(msblk->fragment_index[block]);
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size = squashfs_read_metadata(sb, &fragment_entry, &start_block,
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&offset, sizeof(fragment_entry));
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if (size < 0)
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return size;
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*fragment_block = le64_to_cpu(fragment_entry.start_block);
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return squashfs_block_size(fragment_entry.size);
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}
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/*
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* Read the uncompressed fragment lookup table indexes off disk into memory
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*/
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__le64 *squashfs_read_fragment_index_table(struct super_block *sb,
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u64 fragment_table_start, u64 next_table, unsigned int fragments)
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{
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unsigned int length = SQUASHFS_FRAGMENT_INDEX_BYTES(fragments);
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__le64 *table;
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/*
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* Sanity check, length bytes should not extend into the next table -
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* this check also traps instances where fragment_table_start is
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* incorrectly larger than the next table start
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*/
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if (fragment_table_start + length > next_table)
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return ERR_PTR(-EINVAL);
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table = squashfs_read_table(sb, fragment_table_start, length);
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/*
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* table[0] points to the first fragment table metadata block, this
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* should be less than fragment_table_start
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*/
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if (!IS_ERR(table) && le64_to_cpu(table[0]) >= fragment_table_start) {
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kfree(table);
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return ERR_PTR(-EINVAL);
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}
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return table;
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}
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