153 строки
3.5 KiB
C
153 строки
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_fs_i.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)
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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 NULL;
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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 = 0, zlib_init = 0;
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int avail, bytes, 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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bytes = length;
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do {
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if (stream->avail_in == 0 && k < b) {
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avail = min(bytes, msblk->devblksize - offset);
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bytes -= 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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if (avail == 0) {
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offset = 0;
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put_bh(bh[k++]);
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continue;
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}
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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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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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