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>
150 lines
3.5 KiB
C
150 lines
3.5 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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* zlib_wrapper.c
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*/
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#include <linux/mutex.h>
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#include <linux/buffer_head.h>
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#include <linux/slab.h>
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#include <linux/zlib.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 "decompressor.h"
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static void *zlib_init(struct squashfs_sb_info *dummy, void *buff, int len)
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{
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z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL);
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if (stream == NULL)
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goto failed;
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stream->workspace = kmalloc(zlib_inflate_workspacesize(),
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GFP_KERNEL);
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if (stream->workspace == NULL)
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goto failed;
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return stream;
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failed:
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ERROR("Failed to allocate zlib workspace\n");
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kfree(stream);
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return ERR_PTR(-ENOMEM);
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}
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static void zlib_free(void *strm)
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{
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z_stream *stream = strm;
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if (stream)
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kfree(stream->workspace);
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kfree(stream);
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}
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static int zlib_uncompress(struct squashfs_sb_info *msblk, void **buffer,
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struct buffer_head **bh, int b, int offset, int length, int srclength,
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int pages)
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{
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int zlib_err, zlib_init = 0;
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int k = 0, page = 0;
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z_stream *stream = msblk->stream;
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mutex_lock(&msblk->read_data_mutex);
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stream->avail_out = 0;
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stream->avail_in = 0;
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do {
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if (stream->avail_in == 0 && k < b) {
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int avail = min(length, msblk->devblksize - offset);
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length -= avail;
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wait_on_buffer(bh[k]);
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if (!buffer_uptodate(bh[k]))
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goto release_mutex;
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stream->next_in = bh[k]->b_data + offset;
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stream->avail_in = avail;
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offset = 0;
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}
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if (stream->avail_out == 0 && page < pages) {
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stream->next_out = buffer[page++];
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stream->avail_out = PAGE_CACHE_SIZE;
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}
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if (!zlib_init) {
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zlib_err = zlib_inflateInit(stream);
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if (zlib_err != Z_OK) {
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ERROR("zlib_inflateInit returned unexpected "
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"result 0x%x, srclength %d\n",
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zlib_err, srclength);
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goto release_mutex;
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}
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zlib_init = 1;
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}
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zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH);
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if (stream->avail_in == 0 && k < b)
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put_bh(bh[k++]);
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} while (zlib_err == Z_OK);
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if (zlib_err != Z_STREAM_END) {
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ERROR("zlib_inflate error, data probably corrupt\n");
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goto release_mutex;
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}
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zlib_err = zlib_inflateEnd(stream);
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if (zlib_err != Z_OK) {
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ERROR("zlib_inflate error, data probably corrupt\n");
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goto release_mutex;
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}
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if (k < b) {
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ERROR("zlib_uncompress error, data remaining\n");
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goto release_mutex;
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}
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length = stream->total_out;
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mutex_unlock(&msblk->read_data_mutex);
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return length;
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release_mutex:
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mutex_unlock(&msblk->read_data_mutex);
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for (; k < b; k++)
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put_bh(bh[k]);
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return -EIO;
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}
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const struct squashfs_decompressor squashfs_zlib_comp_ops = {
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.init = zlib_init,
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.free = zlib_free,
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.decompress = zlib_uncompress,
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.id = ZLIB_COMPRESSION,
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.name = "zlib",
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.supported = 1
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};
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