b6bec26cea
Rename the source file to match the function name and thereby also make room for a possible future even slightly faster "non-safe" decompressor version. Signed-off-by: Markus F.X.J. Oberhumer <markus@oberhumer.com>
290 lines
6.8 KiB
C
290 lines
6.8 KiB
C
/*
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* LZO decompressor for the Linux kernel. Code borrowed from the lzo
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* implementation by Markus Franz Xaver Johannes Oberhumer.
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*
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* Linux kernel adaptation:
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* Copyright (C) 2009
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* Albin Tonnerre, Free Electrons <albin.tonnerre@free-electrons.com>
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*
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* Original code:
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* Copyright (C) 1996-2005 Markus Franz Xaver Johannes Oberhumer
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* All Rights Reserved.
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*
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* lzop and the LZO library are free software; you can redistribute them
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* and/or modify them under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, 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; see the file COPYING.
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* If not, write to the Free Software Foundation, Inc.,
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* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* Markus F.X.J. Oberhumer
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* <markus@oberhumer.com>
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* http://www.oberhumer.com/opensource/lzop/
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*/
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#ifdef STATIC
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#include "lzo/lzo1x_decompress_safe.c"
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#else
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#include <linux/decompress/unlzo.h>
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#endif
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#include <linux/types.h>
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#include <linux/lzo.h>
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#include <linux/decompress/mm.h>
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#include <linux/compiler.h>
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#include <asm/unaligned.h>
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static const unsigned char lzop_magic[] = {
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0x89, 0x4c, 0x5a, 0x4f, 0x00, 0x0d, 0x0a, 0x1a, 0x0a };
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#define LZO_BLOCK_SIZE (256*1024l)
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#define HEADER_HAS_FILTER 0x00000800L
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#define HEADER_SIZE_MIN (9 + 7 + 4 + 8 + 1 + 4)
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#define HEADER_SIZE_MAX (9 + 7 + 1 + 8 + 8 + 4 + 1 + 255 + 4)
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STATIC inline int INIT parse_header(u8 *input, int *skip, int in_len)
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{
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int l;
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u8 *parse = input;
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u8 *end = input + in_len;
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u8 level = 0;
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u16 version;
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/*
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* Check that there's enough input to possibly have a valid header.
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* Then it is possible to parse several fields until the minimum
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* size may have been used.
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*/
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if (in_len < HEADER_SIZE_MIN)
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return 0;
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/* read magic: 9 first bits */
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for (l = 0; l < 9; l++) {
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if (*parse++ != lzop_magic[l])
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return 0;
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}
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/* get version (2bytes), skip library version (2),
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* 'need to be extracted' version (2) and
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* method (1) */
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version = get_unaligned_be16(parse);
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parse += 7;
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if (version >= 0x0940)
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level = *parse++;
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if (get_unaligned_be32(parse) & HEADER_HAS_FILTER)
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parse += 8; /* flags + filter info */
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else
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parse += 4; /* flags */
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/*
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* At least mode, mtime_low, filename length, and checksum must
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* be left to be parsed. If also mtime_high is present, it's OK
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* because the next input buffer check is after reading the
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* filename length.
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*/
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if (end - parse < 8 + 1 + 4)
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return 0;
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/* skip mode and mtime_low */
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parse += 8;
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if (version >= 0x0940)
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parse += 4; /* skip mtime_high */
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l = *parse++;
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/* don't care about the file name, and skip checksum */
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if (end - parse < l + 4)
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return 0;
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parse += l + 4;
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*skip = parse - input;
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return 1;
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}
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STATIC inline int INIT unlzo(u8 *input, int in_len,
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int (*fill) (void *, unsigned int),
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int (*flush) (void *, unsigned int),
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u8 *output, int *posp,
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void (*error) (char *x))
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{
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u8 r = 0;
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int skip = 0;
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u32 src_len, dst_len;
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size_t tmp;
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u8 *in_buf, *in_buf_save, *out_buf;
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int ret = -1;
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if (output) {
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out_buf = output;
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} else if (!flush) {
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error("NULL output pointer and no flush function provided");
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goto exit;
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} else {
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out_buf = malloc(LZO_BLOCK_SIZE);
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if (!out_buf) {
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error("Could not allocate output buffer");
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goto exit;
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}
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}
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if (input && fill) {
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error("Both input pointer and fill function provided, don't know what to do");
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goto exit_1;
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} else if (input) {
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in_buf = input;
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} else if (!fill) {
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error("NULL input pointer and missing fill function");
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goto exit_1;
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} else {
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in_buf = malloc(lzo1x_worst_compress(LZO_BLOCK_SIZE));
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if (!in_buf) {
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error("Could not allocate input buffer");
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goto exit_1;
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}
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}
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in_buf_save = in_buf;
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if (posp)
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*posp = 0;
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if (fill) {
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/*
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* Start from in_buf + HEADER_SIZE_MAX to make it possible
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* to use memcpy() to copy the unused data to the beginning
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* of the buffer. This way memmove() isn't needed which
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* is missing from pre-boot environments of most archs.
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*/
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in_buf += HEADER_SIZE_MAX;
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in_len = fill(in_buf, HEADER_SIZE_MAX);
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}
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if (!parse_header(in_buf, &skip, in_len)) {
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error("invalid header");
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goto exit_2;
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}
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in_buf += skip;
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in_len -= skip;
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if (fill) {
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/* Move the unused data to the beginning of the buffer. */
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memcpy(in_buf_save, in_buf, in_len);
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in_buf = in_buf_save;
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}
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if (posp)
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*posp = skip;
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for (;;) {
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/* read uncompressed block size */
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if (fill && in_len < 4) {
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skip = fill(in_buf + in_len, 4 - in_len);
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if (skip > 0)
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in_len += skip;
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}
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if (in_len < 4) {
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error("file corrupted");
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goto exit_2;
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}
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dst_len = get_unaligned_be32(in_buf);
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in_buf += 4;
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in_len -= 4;
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/* exit if last block */
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if (dst_len == 0) {
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if (posp)
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*posp += 4;
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break;
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}
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if (dst_len > LZO_BLOCK_SIZE) {
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error("dest len longer than block size");
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goto exit_2;
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}
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/* read compressed block size, and skip block checksum info */
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if (fill && in_len < 8) {
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skip = fill(in_buf + in_len, 8 - in_len);
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if (skip > 0)
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in_len += skip;
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}
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if (in_len < 8) {
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error("file corrupted");
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goto exit_2;
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}
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src_len = get_unaligned_be32(in_buf);
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in_buf += 8;
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in_len -= 8;
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if (src_len <= 0 || src_len > dst_len) {
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error("file corrupted");
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goto exit_2;
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}
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/* decompress */
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if (fill && in_len < src_len) {
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skip = fill(in_buf + in_len, src_len - in_len);
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if (skip > 0)
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in_len += skip;
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}
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if (in_len < src_len) {
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error("file corrupted");
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goto exit_2;
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}
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tmp = dst_len;
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/* When the input data is not compressed at all,
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* lzo1x_decompress_safe will fail, so call memcpy()
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* instead */
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if (unlikely(dst_len == src_len))
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memcpy(out_buf, in_buf, src_len);
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else {
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r = lzo1x_decompress_safe((u8 *) in_buf, src_len,
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out_buf, &tmp);
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if (r != LZO_E_OK || dst_len != tmp) {
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error("Compressed data violation");
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goto exit_2;
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}
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}
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if (flush && flush(out_buf, dst_len) != dst_len)
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goto exit_2;
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if (output)
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out_buf += dst_len;
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if (posp)
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*posp += src_len + 12;
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in_buf += src_len;
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in_len -= src_len;
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if (fill) {
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/*
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* If there happens to still be unused data left in
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* in_buf, move it to the beginning of the buffer.
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* Use a loop to avoid memmove() dependency.
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*/
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if (in_len > 0)
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for (skip = 0; skip < in_len; ++skip)
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in_buf_save[skip] = in_buf[skip];
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in_buf = in_buf_save;
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}
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}
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ret = 0;
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exit_2:
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if (!input)
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free(in_buf_save);
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exit_1:
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if (!output)
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free(out_buf);
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exit:
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return ret;
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}
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#define decompress unlzo
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