156 lines
3.9 KiB
C
156 lines
3.9 KiB
C
/*
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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, 2009
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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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* decompressor.c
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*/
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#include <linux/types.h>
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#include <linux/mutex.h>
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#include <linux/slab.h>
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#include <linux/buffer_head.h>
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#include "squashfs_fs.h"
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#include "squashfs_fs_sb.h"
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#include "decompressor.h"
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#include "squashfs.h"
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#include "page_actor.h"
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/*
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* This file (and decompressor.h) implements a decompressor framework for
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* Squashfs, allowing multiple decompressors to be easily supported
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*/
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static const struct squashfs_decompressor squashfs_lzma_unsupported_comp_ops = {
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NULL, NULL, NULL, NULL, LZMA_COMPRESSION, "lzma", 0
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};
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#ifndef CONFIG_SQUASHFS_LZ4
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static const struct squashfs_decompressor squashfs_lz4_comp_ops = {
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NULL, NULL, NULL, NULL, LZ4_COMPRESSION, "lz4", 0
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};
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#endif
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#ifndef CONFIG_SQUASHFS_LZO
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static const struct squashfs_decompressor squashfs_lzo_comp_ops = {
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NULL, NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 0
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};
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#endif
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#ifndef CONFIG_SQUASHFS_XZ
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static const struct squashfs_decompressor squashfs_xz_comp_ops = {
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NULL, NULL, NULL, NULL, XZ_COMPRESSION, "xz", 0
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};
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#endif
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#ifndef CONFIG_SQUASHFS_ZLIB
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static const struct squashfs_decompressor squashfs_zlib_comp_ops = {
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NULL, NULL, NULL, NULL, ZLIB_COMPRESSION, "zlib", 0
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};
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#endif
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#ifndef CONFIG_SQUASHFS_ZSTD
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static const struct squashfs_decompressor squashfs_zstd_comp_ops = {
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NULL, NULL, NULL, NULL, ZSTD_COMPRESSION, "zstd", 0
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};
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#endif
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static const struct squashfs_decompressor squashfs_unknown_comp_ops = {
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NULL, NULL, NULL, NULL, 0, "unknown", 0
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};
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static const struct squashfs_decompressor *decompressor[] = {
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&squashfs_zlib_comp_ops,
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&squashfs_lz4_comp_ops,
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&squashfs_lzo_comp_ops,
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&squashfs_xz_comp_ops,
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&squashfs_lzma_unsupported_comp_ops,
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&squashfs_zstd_comp_ops,
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&squashfs_unknown_comp_ops
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};
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const struct squashfs_decompressor *squashfs_lookup_decompressor(int id)
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{
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int i;
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for (i = 0; decompressor[i]->id; i++)
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if (id == decompressor[i]->id)
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break;
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return decompressor[i];
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}
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static void *get_comp_opts(struct super_block *sb, unsigned short flags)
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{
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struct squashfs_sb_info *msblk = sb->s_fs_info;
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void *buffer = NULL, *comp_opts;
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struct squashfs_page_actor *actor = NULL;
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int length = 0;
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/*
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* Read decompressor specific options from file system if present
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*/
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if (SQUASHFS_COMP_OPTS(flags)) {
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buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
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if (buffer == NULL) {
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comp_opts = ERR_PTR(-ENOMEM);
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goto out;
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}
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actor = squashfs_page_actor_init(&buffer, 1, 0);
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if (actor == NULL) {
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comp_opts = ERR_PTR(-ENOMEM);
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goto out;
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}
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length = squashfs_read_data(sb,
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sizeof(struct squashfs_super_block), 0, NULL, actor);
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if (length < 0) {
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comp_opts = ERR_PTR(length);
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goto out;
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}
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}
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comp_opts = squashfs_comp_opts(msblk, buffer, length);
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out:
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kfree(actor);
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kfree(buffer);
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return comp_opts;
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}
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void *squashfs_decompressor_setup(struct super_block *sb, unsigned short flags)
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{
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struct squashfs_sb_info *msblk = sb->s_fs_info;
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void *stream, *comp_opts = get_comp_opts(sb, flags);
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if (IS_ERR(comp_opts))
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return comp_opts;
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stream = squashfs_decompressor_create(msblk, comp_opts);
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if (IS_ERR(stream))
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kfree(comp_opts);
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return stream;
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}
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