1 /*

     2  * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.

     3  *

     4  * Redistribution and use in source and binary forms, with or without

     5  * modification, are permitted provided that the following conditions

     6  * are met:

     7  *

     8  *   - Redistributions of source code must retain the above copyright

     9  *     notice, this list of conditions and the following disclaimer.

    10  *

    11  *   - Redistributions in binary form must reproduce the above copyright

    12  *     notice, this list of conditions and the following disclaimer in the

    13  *     documentation and/or other materials provided with the distribution.

    14  *

    15  *   - Neither the name of Oracle nor the names of its

    16  *     contributors may be used to endorse or promote products derived

    17  *     from this software without specific prior written permission.

    18  *

    19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS

    20  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

    21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

    22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR

    23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

    24  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

    25  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

    26  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

    27  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

    28  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

    29  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    30  */

    31 

    32 #ifndef LIBJIMAGE_IMAGEDECOMPRESSOR_HPP

    33 #define LIBJIMAGE_IMAGEDECOMPRESSOR_HPP

    34 

    35 #include <assert.h>

    36 #include <string.h>

    37 

    38 #include "imageFile.hpp"

    39 #include "inttypes.hpp"

    40 #include "jni.h"

    41 

    42 /*

    43  * Compressed resources located in image have an header.

    44  * This header contains:

    45  * - _magic: A magic u4, required to retrieved the header in the compressed content

    46  * - _size: The size of the compressed resource.

    47  * - _uncompressed_size: The uncompressed size of the compressed resource.

    48  * - _decompressor_name_offset: The ImageDecompressor instance name StringsTable offset.

    49  * - _decompressor_config_offset: StringsTable offset of configuration that could be needed by

    50  *   the decompressor in order to decompress.

    51  * - _is_terminal: 1: the compressed content is terminal. Uncompressing it would

    52  *   create the actual resource. 0: the compressed content is not terminal. Uncompressing it

    53  *   will result in a compressed content to be decompressed (This occurs when a stack of compressors

    54  *   have been used to compress the resource.

    55  */

    56 struct ResourceHeader {

    57     /* magic bytes that identifies a compressed resource header*/

    58     static const u4 resource_header_magic = 0xCAFEFAFA;

    59     u4 _magic; // Resource header

    60     u8 _size;    // Resource size

    61     u8 _uncompressed_size;  // Expected uncompressed size

    62     u4 _decompressor_name_offset;    // Strings table decompressor offset

    63     u4 _decompressor_config_offset; // Strings table config offset

    64     u1 _is_terminal; // Last decompressor 1, otherwise 0.

    65 };

    66 

    67 /*

    68  * Resources located in jimage file can be compressed. Compression occurs at

    69  * jimage file creation time. When compressed a resource is added an header that

    70  * contains the name of the compressor that compressed it.

    71  * Various compression strategies can be applied to compress a resource.

    72  * The same resource can even be compressed multiple time by a stack of compressors.

    73  * At runtime, a resource is decompressed in a loop until there is no more header

    74  * meaning that the resource is equivalent to the not compressed resource.

    75  * In each iteration, the name of the compressor located in the current header

    76  * is used to retrieve the associated instance of ImageDecompressor.

    77  * For example "zip" is the name of the compressor that compresses resources

    78  * using the zip algorithm. The ZipDecompressor class name is also "zip".

    79  * ImageDecompressor instances are retrieved from a static array in which

    80  * they are registered.

    81  */

    82 class ImageDecompressor {

    83 

    84 private:

    85     const char* _name;

    86 

    87     /*

    88      * Array of concrete decompressors. This array is used to retrieve the decompressor

    89      * that can handle resource decompression.

    90      */

    91     static ImageDecompressor** _decompressors;

    92     /**

    93      * Num of decompressors

    94      */

    95     static int _decompressors_num;

    96     /*

    97      * Identifier of a decompressor. This name is the identification key to retrieve

    98      * decompressor from a resource header.

    99      */

   100     inline const char* get_name() const { return _name; }

   101 

   102     static u8 getU8(u1* ptr, Endian *endian);

   103     static u4 getU4(u1* ptr, Endian *endian);

   104 

   105 protected:

   106     ImageDecompressor(const char* name) : _name(name) {

   107     }

   108     virtual void decompress_resource(u1* data, u1* uncompressed,

   109         ResourceHeader* header, const ImageStrings* strings) = 0;

   110 

   111 public:

   112     static void image_decompressor_init();

   113     static void image_decompressor_close();

   114     static ImageDecompressor* get_decompressor(const char * decompressor_name) ;

   115     static void decompress_resource(u1* compressed, u1* uncompressed,

   116         u8 uncompressed_size, const ImageStrings* strings, Endian* _endian);

   117 };

   118 

   119 /**

   120  * Zip decompressor.

   121  */

   122 class ZipDecompressor : public ImageDecompressor {

   123 public:

   124     ZipDecompressor(const char* sym) : ImageDecompressor(sym) { }

   125     void decompress_resource(u1* data, u1* uncompressed, ResourceHeader* header,

   126         const ImageStrings* strings);

   127     static jboolean decompress(void *in, u8 inSize, void *out, u8 outSize, char **pmsg);

   128 };

   129 

   130 /*

   131  * Shared Strings decompressor. This decompressor reconstruct the class

   132  * constant pool UTF_U entries by retrieving strings stored in jimage strings table.

   133  * In addition, if the UTF_8 entry is a descriptor, the descriptor has to be rebuilt,

   134  * all java type having been removed from the descriptor and added to the sting table.

   135  * eg: "(Ljava/lang/String;I)V" ==> "(L;I)V" and "java/lang", "String"

   136  * stored in string table. offsets to the 2 strings are compressed and stored in the

   137  * constantpool entry.

   138  */

   139 class SharedStringDecompressor : public ImageDecompressor {

   140 private:

   141     // the constant pool tag for UTF8 string located in strings table

   142     static const int externalized_string = 23;

   143     // the constant pool tag for UTF8 descriptors string located in strings table

   144     static const int externalized_string_descriptor = 25;

   145     // the constant pool tag for UTF8

   146     static const int constant_utf8 = 1;

   147     // the constant pool tag for long

   148     static const int constant_long = 5;

   149     // the constant pool tag for double

   150     static const int constant_double = 6;

   151     // array index is the constant pool tag. value is size.

   152     // eg: array[5]  = 8; means size of long is 8 bytes.

   153     static const u1 sizes[];

   154     // bit 5 and 6 are used to store the length of the compressed integer.

   155     // size can be 1 (01), 2 (10), 3 (11).

   156     // 0x60 ==> 0110000

   157     static const int compressed_index_size_mask = 0x60;

   158     /*

   159      * mask the length bits (5 and 6) and move to the right 5 bits.

   160      */

   161     inline static int get_compressed_length(char c) {

   162         return ((char) (c & compressed_index_size_mask) >> 5);

   163     }

   164     inline static bool is_compressed(signed char b1) { return b1 < 0; }

   165     static int decompress_int(unsigned char*& value);

   166 public:

   167     SharedStringDecompressor(const char* sym) : ImageDecompressor(sym){}

   168     void decompress_resource(u1* data, u1* uncompressed, ResourceHeader* header,

   169     const ImageStrings* strings);

   170 };

   171 #endif // LIBJIMAGE_IMAGEDECOMPRESSOR_HPP