1 // Copyright 2006 Google LLC 2 // 3 // Redistribution and use in source and binary forms, with or without 4 // modification, are permitted provided that the following conditions are 5 // met: 6 // 7 // * Redistributions of source code must retain the above copyright 8 // notice, this list of conditions and the following disclaimer. 9 // * Redistributions in binary form must reproduce the above 10 // copyright notice, this list of conditions and the following disclaimer 11 // in the documentation and/or other materials provided with the 12 // distribution. 13 // * Neither the name of Google LLC nor the names of its 14 // contributors may be used to endorse or promote products derived from 15 // this software without specific prior written permission. 16 // 17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 18 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 19 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 20 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 21 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 22 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 23 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 27 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 29 // macho_walker.h: Iterate over the load commands in a mach-o file 30 // 31 // Author: Dan Waylonis 32 33 #ifndef COMMON_MAC_MACHO_WALKER_H__ 34 #define COMMON_MAC_MACHO_WALKER_H__ 35 36 #include <mach/machine.h> 37 #include <mach-o/loader.h> 38 #include <sys/types.h> 39 40 namespace MacFileUtilities { 41 42 class MachoWalker { 43 public: 44 // A callback function executed when a new load command is read. If no 45 // further processing of load commands is desired, return false. Otherwise, 46 // return true. 47 // |cmd| is the current command, and |offset| is the location relative to the 48 // beginning of the file (not header) where the command was read. If |swap| 49 // is set, then any command data (other than the returned load_command) should 50 // be swapped when read 51 typedef bool (*LoadCommandCallback)(MachoWalker* walker, load_command* cmd, 52 off_t offset, bool swap, void* context); 53 54 MachoWalker(const char* path, LoadCommandCallback callback, void* context); 55 MachoWalker(void* memory, size_t size, LoadCommandCallback callback, 56 void* context); 57 ~MachoWalker(); 58 59 // Begin walking the header for |cpu_type| and |cpu_subtype|. If |cpu_type| 60 // is 0, then the native cpu type is used. Otherwise, accepted values are 61 // listed in /usr/include/mach/machine.h (e.g., CPU_TYPE_X86 or 62 // CPU_TYPE_POWERPC). If |cpu_subtype| is CPU_SUBTYPE_MULTIPLE, the match is 63 // only done on |cpu_type|. 64 // Returns false if opening the file failed or if the |cpu_type|/|cpu_subtype| 65 // is not present in the file. 66 bool WalkHeader(cpu_type_t cpu_type, cpu_subtype_t cpu_subtype); 67 68 // Read |size| bytes from the opened file at |offset| into |buffer| 69 bool ReadBytes(void* buffer, size_t size, off_t offset); 70 71 // Return the current header and header offset 72 bool CurrentHeader(struct mach_header_64* header, off_t* offset); 73 74 private: 75 // Locate (if any) the header offset for |cpu_type| and return in |offset|. 76 // Return true if found, false otherwise. 77 bool FindHeader(cpu_type_t cpu_type, 78 cpu_subtype_t cpu_subtype, 79 off_t& offset); 80 81 // Process an individual header starting at |offset| from the start of the 82 // file. Return true if successful, false otherwise. 83 bool WalkHeaderAtOffset(off_t offset); 84 bool WalkHeader64AtOffset(off_t offset); 85 86 // Bottleneck for walking the load commands 87 bool WalkHeaderCore(off_t offset, uint32_t number_of_commands, bool swap); 88 89 // File descriptor to the opened file 90 int file_; 91 92 // Memory location to read from. 93 void* memory_; 94 95 // Size of the memory segment we can read from. 96 size_t memory_size_; 97 98 // User specified callback & context 99 LoadCommandCallback callback_; 100 void* callback_context_; 101 102 // Current header, size, and offset. The mach_header_64 is used for both 103 // 32-bit and 64-bit headers because they only differ in their last field 104 // (reserved). By adding the |current_header_size_| and the 105 // |current_header_offset_|, you can determine the offset in the file just 106 // after the header. 107 struct mach_header_64* current_header_; 108 unsigned long current_header_size_; 109 off_t current_header_offset_; 110 111 private: 112 MachoWalker(const MachoWalker&); 113 MachoWalker& operator=(const MachoWalker&); 114 }; 115 116 } // namespace MacFileUtilities 117 118 #endif // COMMON_MAC_MACHO_WALKER_H__ 119