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_ENCODED_PROGRAM_H_
6#define COURGETTE_ENCODED_PROGRAM_H_
7
8#include <vector>
9
10#include "base/basictypes.h"
11#include "courgette/disassembler.h"
12#include "courgette/memory_allocator.h"
13#include "courgette/types_elf.h"
14
15namespace courgette {
16
17class SinkStream;
18class SinkStreamSet;
19class SourceStreamSet;
20
21// An EncodedProgram is a set of tables that contain a simple 'binary assembly
22// language' that can be assembled to produce a sequence of bytes, for example,
23// a Windows 32-bit executable.
24//
25class EncodedProgram {
26 public:
27  EncodedProgram();
28  ~EncodedProgram();
29
30  // Generating an EncodedProgram:
31  //
32  // (1) The image base can be specified at any time.
33  void set_image_base(uint64 base) { image_base_ = base; }
34
35  // (2) Address tables and indexes defined first.
36  CheckBool DefineRel32Label(int index, RVA address) WARN_UNUSED_RESULT;
37  CheckBool DefineAbs32Label(int index, RVA address) WARN_UNUSED_RESULT;
38  void EndLabels();
39
40  // (3) Add instructions in the order needed to generate bytes of file.
41  // NOTE: If any of these methods ever fail, the EncodedProgram instance
42  // has failed and should be discarded.
43  CheckBool AddOrigin(RVA rva) WARN_UNUSED_RESULT;
44  CheckBool AddCopy(uint32 count, const void* bytes) WARN_UNUSED_RESULT;
45  CheckBool AddRel32(int label_index) WARN_UNUSED_RESULT;
46  CheckBool AddRel32ARM(uint16 op, int label_index) WARN_UNUSED_RESULT;
47  CheckBool AddAbs32(int label_index) WARN_UNUSED_RESULT;
48  CheckBool AddPeMakeRelocs(ExecutableType kind) WARN_UNUSED_RESULT;
49  CheckBool AddElfMakeRelocs() WARN_UNUSED_RESULT;
50  CheckBool AddElfARMMakeRelocs() WARN_UNUSED_RESULT;
51
52  // (3) Serialize binary assembly language tables to a set of streams.
53  CheckBool WriteTo(SinkStreamSet* streams) WARN_UNUSED_RESULT;
54
55  // Using an EncodedProgram to generate a byte stream:
56  //
57  // (4) Deserializes a fresh EncodedProgram from a set of streams.
58  bool ReadFrom(SourceStreamSet* streams);
59
60  // (5) Assembles the 'binary assembly language' into final file.
61  CheckBool AssembleTo(SinkStream* buffer) WARN_UNUSED_RESULT;
62
63 private:
64  // Binary assembly language operations.
65  // These are part of the patch format. Reusing an existing value will
66  // break backwards compatibility.
67  enum OP {
68    ORIGIN = 0,    // ORIGIN <rva> - set address for subsequent assembly.
69    COPY = 1,      // COPY <count> <bytes> - copy bytes to output.
70    COPY1 = 2,     // COPY1 <byte> - same as COPY 1 <byte>.
71    REL32 = 3,     // REL32 <index> - emit rel32 encoded reference to address at
72                   // address table offset <index>
73    ABS32 = 4,     // ABS32 <index> - emit abs32 encoded reference to address at
74                   // address table offset <index>
75    MAKE_PE_RELOCATION_TABLE = 5,  // Emit PE base relocation table blocks.
76    MAKE_ELF_RELOCATION_TABLE = 6, // Emit Elf relocation table for X86
77    MAKE_ELF_ARM_RELOCATION_TABLE = 7, // Emit Elf relocation table for ARM
78    MAKE_PE64_RELOCATION_TABLE = 8, // Emit PE64 base relocation table blocks.
79    // ARM reserves 0x1000-LAST_ARM, bits 13-16 define the opcode
80    // subset, and 1-12 are the compressed ARM op.
81    REL32ARM8   = 0x1000,
82    REL32ARM11  = 0x2000,
83    REL32ARM24  = 0x3000,
84    REL32ARM25  = 0x4000,
85    REL32ARM21  = 0x5000,
86    LAST_ARM    = 0x5FFF,
87  };
88
89  typedef NoThrowBuffer<RVA> RvaVector;
90  typedef NoThrowBuffer<uint32> UInt32Vector;
91  typedef NoThrowBuffer<uint8> UInt8Vector;
92  typedef NoThrowBuffer<OP> OPVector;
93
94  void DebuggingSummary();
95  CheckBool GeneratePeRelocations(SinkStream *buffer,
96                                  uint8 type) WARN_UNUSED_RESULT;
97  CheckBool GenerateElfRelocations(Elf32_Word pending_elf_relocation_table,
98                                   SinkStream *buffer) WARN_UNUSED_RESULT;
99  CheckBool DefineLabelCommon(RvaVector*, int, RVA) WARN_UNUSED_RESULT;
100  void FinishLabelsCommon(RvaVector* addresses);
101
102  // Decodes and evaluates courgette ops for ARM rel32 addresses.
103  CheckBool EvaluateRel32ARM(OP op, size_t& ix_rel32_ix, RVA& current_rva,
104                             SinkStream* output);
105
106  // Binary assembly language tables.
107  uint64 image_base_;
108  RvaVector rel32_rva_;
109  RvaVector abs32_rva_;
110  OPVector ops_;
111  RvaVector origins_;
112  UInt32Vector copy_counts_;
113  UInt8Vector copy_bytes_;
114  UInt32Vector rel32_ix_;
115  UInt32Vector abs32_ix_;
116
117  // Table of the addresses containing abs32 relocations; computed during
118  // assembly, used to generate base relocation table.
119  UInt32Vector abs32_relocs_;
120
121  DISALLOW_COPY_AND_ASSIGN(EncodedProgram);
122};
123
124}  // namespace courgette
125#endif  // COURGETTE_ENCODED_PROGRAM_H_
126