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      1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef COURGETTE_COURGETTE_H_
      6 #define COURGETTE_COURGETTE_H_
      7 
      8 #include <stddef.h>   // Required to define size_t on GCC
      9 
     10 #include "base/files/file_path.h"
     11 
     12 namespace courgette {
     13 
     14 // Status codes for Courgette APIs.
     15 //
     16 // Client code should only rely on the distintion between C_OK and the other
     17 // status codes.
     18 //
     19 enum Status {
     20   C_OK = 1,                       // Successful operation.
     21 
     22   C_GENERAL_ERROR = 2,            // Error other than listed below.
     23 
     24   C_READ_OPEN_ERROR = 3,          // Could not open input file for reading.
     25   C_READ_ERROR = 4,               // Could not read from opened input file.
     26 
     27   C_WRITE_OPEN_ERROR = 3,         // Could not open output file for writing.
     28   C_WRITE_ERROR = 4,              // Could not write to opened output file.
     29 
     30   C_BAD_ENSEMBLE_MAGIC = 5,       // Ensemble patch has bad magic.
     31   C_BAD_ENSEMBLE_VERSION = 6,     // Ensemble patch has wrong version.
     32   C_BAD_ENSEMBLE_HEADER = 7,      // Ensemble patch has corrupt header.
     33   C_BAD_ENSEMBLE_CRC = 8,         // Ensemble patch has corrupt data.
     34 
     35   C_BAD_TRANSFORM = 12,           // Transform mis-specified.
     36   C_BAD_BASE = 13,                // Base for transform malformed.
     37 
     38   C_BINARY_DIFF_CRC_ERROR = 14,   // Internal diff input doesn't have expected
     39                                   // CRC.
     40 
     41   // Internal errors.
     42   C_STREAM_ERROR = 20,            // Unexpected error from streams.h.
     43   C_STREAM_NOT_CONSUMED = 21,     // Stream has extra data, is expected to be
     44                                   // used up.
     45   C_SERIALIZATION_FAILED = 22,    //
     46   C_DESERIALIZATION_FAILED = 23,  //
     47   C_INPUT_NOT_RECOGNIZED = 24,    // Unrecognized input (not an executable).
     48   C_DISASSEMBLY_FAILED = 25,      //
     49   C_ASSEMBLY_FAILED = 26,         //
     50   C_ADJUSTMENT_FAILED = 27,       //
     51   C_TRIM_FAILED = 28,             // TrimLabels failed
     52 };
     53 
     54 // What type of executable is something
     55 // This is part of the patch format. Never reuse an id number.
     56 enum ExecutableType {
     57   EXE_UNKNOWN = 0,
     58   EXE_WIN_32_X86 = 1,
     59   EXE_ELF_32_X86 = 2,
     60   EXE_ELF_32_ARM = 3,
     61   EXE_WIN_32_X64 = 4,
     62 };
     63 
     64 class SinkStream;
     65 class SinkStreamSet;
     66 class SourceStream;
     67 class SourceStreamSet;
     68 
     69 class AssemblyProgram;
     70 class EncodedProgram;
     71 
     72 // Applies the patch to the bytes in |old| and writes the transformed ensemble
     73 // to |output|.
     74 // Returns C_OK unless something went wrong.
     75 Status ApplyEnsemblePatch(SourceStream* old, SourceStream* patch,
     76                           SinkStream* output);
     77 
     78 // Applies the patch in |patch_file_name| to the bytes in |old_file_name| and
     79 // writes the transformed ensemble to |new_file_name|.
     80 // Returns C_OK unless something went wrong.
     81 // This function first validates that the patch file has a proper header, so the
     82 // function can be used to 'try' a patch.
     83 Status ApplyEnsemblePatch(const base::FilePath::CharType* old_file_name,
     84                           const base::FilePath::CharType* patch_file_name,
     85                           const base::FilePath::CharType* new_file_name);
     86 
     87 // Generates a patch that will transform the bytes in |old| into the bytes in
     88 // |target|.
     89 // Returns C_OK unless something when wrong (unexpected).
     90 Status GenerateEnsemblePatch(SourceStream* old, SourceStream* target,
     91                              SinkStream* patch);
     92 
     93 // Detects the type of an executable file, and it's length. The length
     94 // may be slightly smaller than some executables (like ELF), but will include
     95 // all bytes the courgette algorithm has special benefit for.
     96 // On sucess:
     97 //   Fill in type and detected_length, and return C_OK.
     98 // On failure:
     99 //   Fill in type with UNKNOWN, detected_length with 0, and
    100 //   return C_INPUT_NOT_RECOGNIZED
    101 Status DetectExecutableType(const void* buffer, size_t length,
    102                             ExecutableType* type,
    103                             size_t* detected_length);
    104 
    105 // Attempts to detect the type of executable, and parse it with the
    106 // appropriate tools, storing the pointer to the AssemblyProgram in |*output|.
    107 // Returns C_OK if successful, otherwise returns an error status and sets
    108 // |*output| to NULL.
    109 Status ParseDetectedExecutable(const void* buffer, size_t length,
    110                                AssemblyProgram** output);
    111 
    112 // Trims labels used fewer than a given number of times from an
    113 // assembly program in-place.
    114 Status TrimLabels(AssemblyProgram* program);
    115 
    116 // Converts |program| into encoded form, returning it as |*output|.
    117 // Returns C_OK if succeeded, otherwise returns an error status and
    118 // sets |*output| to NULL
    119 Status Encode(AssemblyProgram* program, EncodedProgram** output);
    120 
    121 // Serializes |encoded| into the stream set.
    122 // Returns C_OK if succeeded, otherwise returns an error status.
    123 Status WriteEncodedProgram(EncodedProgram* encoded, SinkStreamSet* sink);
    124 
    125 // Assembles |encoded|, emitting the bytes into |buffer|.
    126 // Returns C_OK if succeeded, otherwise returns an error status and leaves
    127 // |buffer| in an undefined state.
    128 Status Assemble(EncodedProgram* encoded, SinkStream* buffer);
    129 
    130 // Deserializes program from the stream set.
    131 // Returns C_OK if succeeded, otherwise returns an error status and
    132 // sets |*output| to NULL
    133 Status ReadEncodedProgram(SourceStreamSet* source, EncodedProgram** output);
    134 
    135 // Used to free an AssemblyProgram returned by other APIs.
    136 void DeleteAssemblyProgram(AssemblyProgram* program);
    137 
    138 // Used to free an EncodedProgram returned by other APIs.
    139 void DeleteEncodedProgram(EncodedProgram* encoded);
    140 
    141 // Adjusts |program| to look more like |model|.
    142 //
    143 Status Adjust(const AssemblyProgram& model, AssemblyProgram *program);
    144 
    145 }  // namespace courgette
    146 #endif  // COURGETTE_COURGETTE_H_
    147