courgette/courgette.h

   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 };
  62
  63 class SinkStream;
  64 class SinkStreamSet;
  65 class SourceStream;
  66 class SourceStreamSet;
  67
  68 class AssemblyProgram;
  69 class EncodedProgram;
  70
  71 // Applies the patch to the bytes in |old| and writes the transformed ensemble
  72 // to |output|.
  73 // Returns C_OK unless something went wrong.
  74 Status ApplyEnsemblePatch(SourceStream* old, SourceStream* patch,
  75                           SinkStream* output);
  76
  77 // Applies the patch in |patch_file_name| to the bytes in |old_file_name| and
  78 // writes the transformed ensemble to |new_file_name|.
  79 // Returns C_OK unless something went wrong.
  80 // This function first validates that the patch file has a proper header, so the
  81 // function can be used to 'try' a patch.
  82 Status ApplyEnsemblePatch(const base::FilePath::CharType* old_file_name,
  83                           const base::FilePath::CharType* patch_file_name,
  84                           const base::FilePath::CharType* new_file_name);
  85
  86 // Generates a patch that will transform the bytes in |old| into the bytes in
  87 // |target|.
  88 // Returns C_OK unless something when wrong (unexpected).
  89 Status GenerateEnsemblePatch(SourceStream* old, SourceStream* target,
  90                              SinkStream* patch);
  91
  92 // Detects the type of an executable file, and it's length. The length
  93 // may be slightly smaller than some executables (like ELF), but will include
  94 // all bytes the courgette algorithm has special benefit for.
  95 // On sucess:
  96 //   Fill in type and detected_length, and return C_OK.
  97 // On failure:
  98 //   Fill in type with UNKNOWN, detected_length with 0, and
  99 //   return C_INPUT_NOT_RECOGNIZED
 100 Status DetectExecutableType(const void* buffer, size_t length,
 101                             ExecutableType* type,
 102                             size_t* detected_length);
 103
 104 // Attempts to detect the type of executable, and parse it with the
 105 // appropriate tools, storing the pointer to the AssemblyProgram in |*output|.
 106 // Returns C_OK if successful, otherwise returns an error status and sets
 107 // |*output| to NULL.
 108 Status ParseDetectedExecutable(const void* buffer, size_t length,
 109                                AssemblyProgram** output);
 110
 111 // Trims labels used fewer than a given number of times from an
 112 // assembly program in-place.
 113 Status TrimLabels(AssemblyProgram* program);
 114
 115 // Converts |program| into encoded form, returning it as |*output|.
 116 // Returns C_OK if succeeded, otherwise returns an error status and
 117 // sets |*output| to NULL
 118 Status Encode(AssemblyProgram* program, EncodedProgram** output);
 119
 120 // Serializes |encoded| into the stream set.
 121 // Returns C_OK if succeeded, otherwise returns an error status.
 122 Status WriteEncodedProgram(EncodedProgram* encoded, SinkStreamSet* sink);
 123
 124 // Assembles |encoded|, emitting the bytes into |buffer|.
 125 // Returns C_OK if succeeded, otherwise returns an error status and leaves
 126 // |buffer| in an undefined state.
 127 Status Assemble(EncodedProgram* encoded, SinkStream* buffer);
 128
 129 // Deserializes program from the stream set.
 130 // Returns C_OK if succeeded, otherwise returns an error status and
 131 // sets |*output| to NULL
 132 Status ReadEncodedProgram(SourceStreamSet* source, EncodedProgram** output);
 133
 134 // Used to free an AssemblyProgram returned by other APIs.
 135 void DeleteAssemblyProgram(AssemblyProgram* program);
 136
 137 // Used to free an EncodedProgram returned by other APIs.
 138 void DeleteEncodedProgram(EncodedProgram* encoded);
 139
 140 // Adjusts |program| to look more like |model|.
 141 //
 142 Status Adjust(const AssemblyProgram& model, AssemblyProgram *program);
 143
 144 }  // namespace courgette
 145 #endif  // COURGETTE_COURGETTE_H_