b7fc0ff09d
Extend decompressor framework to handle compression options stored in the filesystem. These options can be used by the relevant decompressor at initialisation time to over-ride defaults. The presence of compression options in the filesystem is indicated by the COMP_OPT filesystem flag. If present the data is read from the filesystem and passed to the decompressor init function. The decompressor init function signature has been extended to take this data. Also update the init function signature in the glib, lzo and xz decompressor wrappers. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
110 lines
2.8 KiB
C
110 lines
2.8 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@lougher.demon.co.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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/*
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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, LZMA_COMPRESSION, "lzma", 0
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};
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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, 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, XZ_COMPRESSION, "xz", 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, 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_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_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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void *squashfs_decompressor_init(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 *strm, *buffer = 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_CACHE_SIZE, GFP_KERNEL);
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if (buffer == NULL)
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return ERR_PTR(-ENOMEM);
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length = squashfs_read_data(sb, &buffer,
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sizeof(struct squashfs_super_block), 0, NULL,
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PAGE_CACHE_SIZE, 1);
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if (length < 0) {
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strm = ERR_PTR(length);
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goto finished;
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}
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}
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strm = msblk->decompressor->init(msblk, buffer, length);
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finished:
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kfree(buffer);
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return strm;
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}
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