lib: add support for LZO-compressed kernels

[mirror_ubuntu-artful-kernel.git] / lib / decompress_unlzo.c

diff --git a/lib/decompress_unlzo.c b/lib/decompress_unlzo.c
new file mode 100644 (file)
index 0000000..db521f4
--- /dev/null
+++ b/lib/decompress_unlzo.c
@@ -0,0 +1,209 @@
+/*
+ * 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 obytes_processed = 0;
+
+       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;
+               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;
+               }
+
+               obytes_processed += dst_len;
+               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;
+       }
+
+exit_2:
+       if (!input)
+               free(in_buf);
+exit_1:
+       if (!output)
+               free(out_buf);
+exit:
+       return obytes_processed;
+}
+
+#define decompress unlzo