1 // Copyright (c) 2006, Google Inc. 2 // 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 are 6 // met: 7 // 8 // * Redistributions of source code must retain the above copyright 9 // notice, this list of conditions and the following disclaimer. 10 // * Redistributions in binary form must reproduce the above 11 // copyright notice, this list of conditions and the following disclaimer 12 // in the documentation and/or other materials provided with the 13 // distribution. 14 // * Neither the name of Google Inc. nor the names of its 15 // contributors may be used to endorse or promote products derived from 16 // this software without specific prior written permission. 17 // 18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 30 // macho_walker.h: Iterate over the load commands in a mach-o file 31 // 32 // Author: Dan Waylonis 33 34 #ifndef COMMON_MAC_MACHO_WALKER_H__ 35 #define COMMON_MAC_MACHO_WALKER_H__ 36 37 #include <mach/machine.h> 38 #include <mach-o/loader.h> 39 #include <sys/types.h> 40 41 namespace MacFileUtilities { 42 43 class MachoWalker { 44 public: 45 // A callback function executed when a new load command is read. If no 46 // further processing of load commands is desired, return false. Otherwise, 47 // return true. 48 // |cmd| is the current command, and |offset| is the location relative to the 49 // beginning of the file (not header) where the command was read. If |swap| 50 // is set, then any command data (other than the returned load_command) should 51 // be swapped when read 52 typedef bool (*LoadCommandCallback)(MachoWalker *walker, load_command *cmd, 53 off_t offset, bool swap, void *context); 54 55 MachoWalker(const char *path, LoadCommandCallback callback, void *context); 56 MachoWalker(void *memory, size_t size, LoadCommandCallback callback, 57 void *context); 58 ~MachoWalker(); 59 60 // Begin walking the header for |cpu_type| and |cpu_subtype|. If |cpu_type| 61 // is 0, then the native cpu type is used. Otherwise, accepted values are 62 // listed in /usr/include/mach/machine.h (e.g., CPU_TYPE_X86 or 63 // CPU_TYPE_POWERPC). If |cpu_subtype| is CPU_SUBTYPE_MULTIPLE, the match is 64 // only done on |cpu_type|. 65 // Returns false if opening the file failed or if the |cpu_type|/|cpu_subtype| 66 // is not present in the file. 67 bool WalkHeader(cpu_type_t cpu_type, cpu_subtype_t cpu_subtype); 68 69 // Read |size| bytes from the opened file at |offset| into |buffer| 70 bool ReadBytes(void *buffer, size_t size, off_t offset); 71 72 // Return the current header and header offset 73 bool CurrentHeader(struct mach_header_64 *header, off_t *offset); 74 75 private: 76 // Locate (if any) the header offset for |cpu_type| and return in |offset|. 77 // Return true if found, false otherwise. 78 bool FindHeader(cpu_type_t cpu_type, 79 cpu_subtype_t cpu_subtype, 80 off_t &offset); 81 82 // Process an individual header starting at |offset| from the start of the 83 // file. Return true if successful, false otherwise. 84 bool WalkHeaderAtOffset(off_t offset); 85 bool WalkHeader64AtOffset(off_t offset); 86 87 // Bottleneck for walking the load commands 88 bool WalkHeaderCore(off_t offset, uint32_t number_of_commands, bool swap); 89 90 // File descriptor to the opened file 91 int file_; 92 93 // Memory location to read from. 94 void *memory_; 95 96 // Size of the memory segment we can read from. 97 size_t memory_size_; 98 99 // User specified callback & context 100 LoadCommandCallback callback_; 101 void *callback_context_; 102 103 // Current header, size, and offset. The mach_header_64 is used for both 104 // 32-bit and 64-bit headers because they only differ in their last field 105 // (reserved). By adding the |current_header_size_| and the 106 // |current_header_offset_|, you can determine the offset in the file just 107 // after the header. 108 struct mach_header_64 *current_header_; 109 unsigned long current_header_size_; 110 off_t current_header_offset_; 111 112 private: 113 MachoWalker(const MachoWalker &); 114 MachoWalker &operator=(const MachoWalker &); 115 }; 116 117 } // namespace MacFileUtilities 118 119 #endif // COMMON_MAC_MACHO_WALKER_H__ 120