diff options
Diffstat (limited to 'lib/decompress_unlzo.c')
| -rw-r--r-- | lib/decompress_unlzo.c | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/lib/decompress_unlzo.c b/lib/decompress_unlzo.c new file mode 100644 index 00000000..bcb3a4bd --- /dev/null +++ b/lib/decompress_unlzo.c @@ -0,0 +1,217 @@ +/* + * LZO decompressor for the Linux kernel. Code borrowed from the lzo + * implementation by Markus Franz Xaver Johannes Oberhumer. + * + * Linux kernel adaptation: + * Copyright (C) 2009 + * Albin Tonnerre, Free Electrons <albin.tonnerre@free-electrons.com> + * + * Original code: + * Copyright (C) 1996-2005 Markus Franz Xaver Johannes Oberhumer + * All Rights Reserved. + * + * lzop and the LZO library are free software; you can redistribute them + * and/or modify them under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; see the file COPYING. + * If not, write to the Free Software Foundation, Inc., + * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Markus F.X.J. Oberhumer + * <markus@oberhumer.com> + * http://www.oberhumer.com/opensource/lzop/ + */ + +#ifdef STATIC +#include "lzo/lzo1x_decompress.c" +#else +#include <linux/slab.h> +#include <linux/decompress/unlzo.h> +#endif + +#include <linux/types.h> +#include <linux/lzo.h> +#include <linux/decompress/mm.h> + +#include <linux/compiler.h> +#include <asm/unaligned.h> + +static const unsigned char lzop_magic[] = { + 0x89, 0x4c, 0x5a, 0x4f, 0x00, 0x0d, 0x0a, 0x1a, 0x0a }; + +#define LZO_BLOCK_SIZE (256*1024l) +#define HEADER_HAS_FILTER 0x00000800L + +STATIC inline int INIT parse_header(u8 *input, u8 *skip) +{ + int l; + u8 *parse = input; + u8 level = 0; + u16 version; + + /* read magic: 9 first bits */ + for (l = 0; l < 9; l++) { + if (*parse++ != lzop_magic[l]) + return 0; + } + /* get version (2bytes), skip library version (2), + * 'need to be extracted' version (2) and + * method (1) */ + version = get_unaligned_be16(parse); + parse += 7; + if (version >= 0x0940) + level = *parse++; + if (get_unaligned_be32(parse) & HEADER_HAS_FILTER) + parse += 8; /* flags + filter info */ + else + parse += 4; /* flags */ + + /* skip mode and mtime_low */ + parse += 8; + if (version >= 0x0940) + parse += 4; /* skip mtime_high */ + + l = *parse++; + /* don't care about the file name, and skip checksum */ + parse += l + 4; + + *skip = parse - input; + return 1; +} + +STATIC inline int INIT unlzo(u8 *input, int in_len, + int (*fill) (void *, unsigned int), + int (*flush) (void *, unsigned int), + u8 *output, int *posp, + void (*error_fn) (char *x)) +{ + u8 skip = 0, r = 0; + u32 src_len, dst_len; + size_t tmp; + u8 *in_buf, *in_buf_save, *out_buf; + int ret = -1; + + set_error_fn(error_fn); + + if (output) { + out_buf = output; + } else if (!flush) { + error("NULL output pointer and no flush function provided"); + goto exit; + } else { + out_buf = malloc(LZO_BLOCK_SIZE); + if (!out_buf) { + error("Could not allocate output buffer"); + goto exit; + } + } + + if (input && fill) { + error("Both input pointer and fill function provided, don't know what to do"); + goto exit_1; + } else if (input) { + in_buf = input; + } else if (!fill || !posp) { + error("NULL input pointer and missing position pointer or fill function"); + goto exit_1; + } else { + in_buf = malloc(lzo1x_worst_compress(LZO_BLOCK_SIZE)); + if (!in_buf) { + error("Could not allocate input buffer"); + goto exit_1; + } + } + in_buf_save = in_buf; + + if (posp) + *posp = 0; + + if (fill) + fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE)); + + if (!parse_header(input, &skip)) { + error("invalid header"); + goto exit_2; + } + in_buf += skip; + + if (posp) + *posp = skip; + + for (;;) { + /* read uncompressed block size */ + dst_len = get_unaligned_be32(in_buf); + in_buf += 4; + + /* exit if last block */ + if (dst_len == 0) { + if (posp) + *posp += 4; + break; + } + + if (dst_len > LZO_BLOCK_SIZE) { + error("dest len longer than block size"); + goto exit_2; + } + + /* read compressed block size, and skip block checksum info */ + src_len = get_unaligned_be32(in_buf); + in_buf += 8; + + if (src_len <= 0 || src_len > dst_len) { + error("file corrupted"); + goto exit_2; + } + + /* decompress */ + tmp = dst_len; + + /* When the input data is not compressed at all, + * lzo1x_decompress_safe will fail, so call memcpy() + * instead */ + if (unlikely(dst_len == src_len)) + memcpy(out_buf, in_buf, src_len); + else { + r = lzo1x_decompress_safe((u8 *) in_buf, src_len, + out_buf, &tmp); + + if (r != LZO_E_OK || dst_len != tmp) { + error("Compressed data violation"); + goto exit_2; + } + } + + if (flush) + flush(out_buf, dst_len); + if (output) + out_buf += dst_len; + if (posp) + *posp += src_len + 12; + if (fill) { + in_buf = in_buf_save; + fill(in_buf, lzo1x_worst_compress(LZO_BLOCK_SIZE)); + } else + in_buf += src_len; + } + + ret = 0; +exit_2: + if (!input) + free(in_buf); +exit_1: + if (!output) + free(out_buf); +exit: + return ret; +} + +#define decompress unlzo |