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![Phillip Lougher](/assets/img/avatar_default.png)
My existing email address may stop working in a month or two, so update email to one that will continue working. Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
180 lines
4.1 KiB
C
180 lines
4.1 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, 2010
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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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* xz_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/xz.h>
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#include <linux/bitops.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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struct squashfs_xz {
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struct xz_dec *state;
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struct xz_buf buf;
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};
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struct comp_opts {
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__le32 dictionary_size;
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__le32 flags;
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};
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static void *squashfs_xz_init(struct squashfs_sb_info *msblk, void *buff,
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int len)
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{
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struct comp_opts *comp_opts = buff;
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struct squashfs_xz *stream;
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int dict_size = msblk->block_size;
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int err, n;
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if (comp_opts) {
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/* check compressor options are the expected length */
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if (len < sizeof(*comp_opts)) {
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err = -EIO;
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goto failed;
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}
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dict_size = le32_to_cpu(comp_opts->dictionary_size);
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/* the dictionary size should be 2^n or 2^n+2^(n+1) */
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n = ffs(dict_size) - 1;
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if (dict_size != (1 << n) && dict_size != (1 << n) +
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(1 << (n + 1))) {
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err = -EIO;
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goto failed;
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}
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}
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dict_size = max_t(int, dict_size, SQUASHFS_METADATA_SIZE);
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stream = kmalloc(sizeof(*stream), GFP_KERNEL);
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if (stream == NULL) {
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err = -ENOMEM;
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goto failed;
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}
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stream->state = xz_dec_init(XZ_PREALLOC, dict_size);
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if (stream->state == NULL) {
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kfree(stream);
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err = -ENOMEM;
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goto failed;
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}
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return stream;
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failed:
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ERROR("Failed to initialise xz decompressor\n");
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return ERR_PTR(err);
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}
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static void squashfs_xz_free(void *strm)
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{
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struct squashfs_xz *stream = strm;
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if (stream) {
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xz_dec_end(stream->state);
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kfree(stream);
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}
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}
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static int squashfs_xz_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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enum xz_ret xz_err;
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int avail, total = 0, k = 0, page = 0;
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struct squashfs_xz *stream = msblk->stream;
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mutex_lock(&msblk->read_data_mutex);
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xz_dec_reset(stream->state);
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stream->buf.in_pos = 0;
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stream->buf.in_size = 0;
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stream->buf.out_pos = 0;
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stream->buf.out_size = PAGE_CACHE_SIZE;
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stream->buf.out = buffer[page++];
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do {
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if (stream->buf.in_pos == stream->buf.in_size && k < b) {
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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->buf.in = bh[k]->b_data + offset;
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stream->buf.in_size = avail;
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stream->buf.in_pos = 0;
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offset = 0;
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}
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if (stream->buf.out_pos == stream->buf.out_size
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&& page < pages) {
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stream->buf.out = buffer[page++];
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stream->buf.out_pos = 0;
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total += PAGE_CACHE_SIZE;
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}
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xz_err = xz_dec_run(stream->state, &stream->buf);
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if (stream->buf.in_pos == stream->buf.in_size && k < b)
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put_bh(bh[k++]);
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} while (xz_err == XZ_OK);
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if (xz_err != XZ_STREAM_END) {
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ERROR("xz_dec_run 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("xz_uncompress error, input remaining\n");
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goto release_mutex;
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}
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total += stream->buf.out_pos;
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mutex_unlock(&msblk->read_data_mutex);
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return total;
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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_xz_comp_ops = {
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.init = squashfs_xz_init,
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.free = squashfs_xz_free,
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.decompress = squashfs_xz_uncompress,
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.id = XZ_COMPRESSION,
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.name = "xz",
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.supported = 1
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};
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