Add Sony LZ4 compressed SIN image support

Makefile

@@ -38,7 +38,7 @@ LIB_SRCS = \
 LIB_OBJS = $(LIB_SRCS:%.cpp=%.o)
 LIB_INCS = -Iinclude -Iandroid-base/include
 
-LDFLAGS += -L. -l$(LIB_NAME) -lm -lz
+LDFLAGS += -L. -l$(LIB_NAME) -lm -lz -llz4
 
 BINS = simg2img simg2simg img2simg append2simg
 HEADERS = include/sparse/sparse.h

README.md

@@ -17,11 +17,16 @@ $ file /output/path/system.raw.img
 system.raw.img: Linux rev 1.0 ext4 filesystem data, UUID=57f8f4bc-abf4-655f-bf67-946fc0f9f25b (extents) (large files)
 ```
 
+Vendor extensions
+-----------------
+
+Sparse library was additionally patched to support Sony SIN images containing LZ4 compressed chunks of 0xCAC5 type.
+
 Windows
 -------
 
 If you want to build simg2img on Windows you'll need to [install MinGW](http://www.mingw.org/wiki/howto_install_the_mingw_gcc_compiler_suite)
-and also zlib and libasprintf (go to MinGW Libraries in the installer and check `mingw32-libz` and `mingw32-libasprintf`).
+and also zlib, liblz4, and libasprintf (go to MinGW Libraries in the installer and check `mingw32-libz`, `mingw32-lz4`, and `mingw32-libasprintf`).
 Once you've done that run the following command to build simg2img:
 
 ```
@@ -31,8 +36,8 @@ CFLAGS=-DUSE_MINGW LDFLAGS=-lasprintf mingw32-make
 Linux
 ------
 
-If zlib.h is missing then install it using
+If zlib.h and (or) lz4.h are missing then install them using
 
-Ubuntu: ```sudo apt-get install libz-dev```
+Ubuntu: ```sudo apt-get install libz-dev liblz4-dev```
 
-Fedora: ```sudo dnf install libz-devel```
+Fedora: ```sudo dnf install libz-devel lz4-devel```

sparse_format.h

@@ -42,6 +42,7 @@ typedef struct sparse_header {
 #define CHUNK_TYPE_FILL 0xCAC2
 #define CHUNK_TYPE_DONT_CARE 0xCAC3
 #define CHUNK_TYPE_CRC32 0xCAC4
+#define CHUNK_TYPE_SIN_LZ4 0xCAC5 /* Sony Xperia (SIN image) specific type */
 
 typedef struct chunk_header {
   __le16 chunk_type; /* 0xCAC1 -> raw; 0xCAC2 -> fill; 0xCAC3 -> don't care */

sparse_read.cpp

@@ -27,6 +27,7 @@
 #include <unistd.h>
 #include <algorithm>
 #include <string>
+#include <lz4.h>
 
 #include <sparse/sparse.h>
 
@@ -283,6 +284,55 @@ static int process_crc32_chunk(SparseFileSource* source, unsigned int chunk_size
   return 0;
 }
 
+static int process_sin_lz4_chunk(struct sparse_file* s, unsigned int chunk_size,
+                                 SparseFileSource* source, unsigned int blocks, unsigned int block,
+                                 uint32_t* crc32) {
+  int64_t len = blocks * s->block_size;
+  char* ibuf = (char*)malloc(chunk_size);
+  char* obuf = (char*)malloc(len);
+  int ret = 0;
+
+  if (!ibuf || !obuf) {
+    ret = -ENOMEM;
+    goto exit;
+  }
+
+  ret = source->ReadValue(ibuf, chunk_size);
+  if (ret < 0)
+    goto exit;
+
+  /* Chunk data is a huge (tens of megabytes) LZ4 block, so pass it directly
+   * to the LZ4 decompress.
+   *
+   * NB: there are 12 trailing bytes of unclear nature. LZ4 decompress code
+   * deals with them by properly stop at the final 5-literals sequence so it's
+   * safe to pass the whole blob as it is. Subject for future study.
+   */
+  ret = LZ4_decompress_safe(ibuf, obuf, chunk_size, len);
+  if (ret < 0 || ret != len) {
+    ret = -EINVAL;
+    goto exit;
+  }
+
+  free(ibuf); /* Release input memory ASAP */
+  ibuf = nullptr;
+
+  ret = sparse_file_add_data(s, obuf, len, block);
+  if (ret < 0)
+    goto exit;
+
+  if (crc32)
+    *crc32 = sparse_crc32(*crc32, obuf, len);
+
+  obuf = nullptr; /* Forget (prevent freeing of) delivered block */
+
+exit:
+  free(ibuf);
+  free(obuf);
+
+  return ret;
+}
+
 static int process_chunk(struct sparse_file* s, SparseFileSource* source, unsigned int chunk_hdr_sz,
                          chunk_header_t* chunk_header, unsigned int cur_block, uint32_t* crc_ptr) {
   int ret;
@@ -325,6 +375,14 @@ static int process_chunk(struct sparse_file* s, SparseFileSource* source, unsign
         return ret;
       }
       return 0;
+    case CHUNK_TYPE_SIN_LZ4:
+      ret = process_sin_lz4_chunk(s, chunk_data_size, source, chunk_header->chunk_sz, cur_block,
+                                  crc_ptr);
+      if (ret < 0) {
+        verbose_error(s->verbose, -EINVAL, "lz4 block at %" PRId64, offset);
+        return ret;
+      }
+      return chunk_header->chunk_sz;
     default:
       verbose_error(s->verbose, -EINVAL, "unknown block %04X at %" PRId64, chunk_header->chunk_type,
                     offset);