Torne (Richard Coles) | 5821806 | 2012-11-14 11:43:16 +0000 | [diff] [blame^] | 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_DISASSEMBLER_H_ |
| 6 | #define COURGETTE_DISASSEMBLER_H_ |
| 7 | |
| 8 | #include "base/basictypes.h" |
| 9 | |
| 10 | #include "courgette/courgette.h" |
| 11 | |
| 12 | namespace courgette { |
| 13 | |
| 14 | class AssemblyProgram; |
| 15 | |
| 16 | // A Relative Virtual Address is the address in the image file after it is |
| 17 | // loaded into memory relative to the image load address. |
| 18 | typedef uint32 RVA; |
| 19 | |
| 20 | class Disassembler { |
| 21 | public: |
| 22 | virtual ~Disassembler(); |
| 23 | |
| 24 | virtual ExecutableType kind() { return EXE_UNKNOWN; } |
| 25 | |
| 26 | // ok() may always be called but returns 'true' only after ParseHeader |
| 27 | // succeeds. |
| 28 | bool ok() const { return failure_reason_ == NULL; } |
| 29 | |
| 30 | // Returns 'true' if the buffer appears to be a valid executable of the |
| 31 | // expected type. It is not required that this be called before Disassemble. |
| 32 | virtual bool ParseHeader() = 0; |
| 33 | |
| 34 | // Disassembles the item passed to the factory method into the output |
| 35 | // parameter 'program'. |
| 36 | virtual bool Disassemble(AssemblyProgram* program) = 0; |
| 37 | |
| 38 | // Returns the length of the source executable. May reduce after ParseHeader. |
| 39 | size_t length() const { return length_; } |
| 40 | const uint8* start() const { return start_; } |
| 41 | const uint8* end() const { return end_; } |
| 42 | |
| 43 | // Returns a pointer into the memory copy of the file format. |
| 44 | // FileOffsetToPointer(0) returns a pointer to the start of the file format. |
| 45 | const uint8* OffsetToPointer(size_t offset) const; |
| 46 | |
| 47 | protected: |
| 48 | Disassembler(const void* start, size_t length); |
| 49 | |
| 50 | bool Good(); |
| 51 | bool Bad(const char *reason); |
| 52 | |
| 53 | // These helper functions avoid the need for casts in the main code. |
| 54 | uint16 ReadU16(const uint8* address, size_t offset) { |
| 55 | return *reinterpret_cast<const uint16*>(address + offset); |
| 56 | } |
| 57 | |
| 58 | uint32 ReadU32(const uint8* address, size_t offset) { |
| 59 | return *reinterpret_cast<const uint32*>(address + offset); |
| 60 | } |
| 61 | |
| 62 | uint64 ReadU64(const uint8* address, size_t offset) { |
| 63 | return *reinterpret_cast<const uint64*>(address + offset); |
| 64 | } |
| 65 | |
| 66 | static uint32 Read32LittleEndian(const void* address) { |
| 67 | return *reinterpret_cast<const uint32*>(address); |
| 68 | } |
| 69 | |
| 70 | // Reduce the length of the image in memory. Does not actually free |
| 71 | // (or realloc) any memory. Usually only called via ParseHeader() |
| 72 | void ReduceLength(size_t reduced_length); |
| 73 | |
| 74 | private: |
| 75 | const char* failure_reason_; |
| 76 | |
| 77 | // |
| 78 | // Basic information that is always valid after Construction, though |
| 79 | // ParseHeader may shorten the length if the executable is shorter than |
| 80 | // the total data. |
| 81 | // |
| 82 | size_t length_; // In current memory. |
| 83 | const uint8* start_; // In current memory, base for 'file offsets'. |
| 84 | const uint8* end_; // In current memory. |
| 85 | |
| 86 | DISALLOW_COPY_AND_ASSIGN(Disassembler); |
| 87 | }; |
| 88 | |
| 89 | } // namespace courgette |
| 90 | #endif // COURGETTE_DISASSEMBLER_H_ |