1 //===- llvm/BinaryFormat/Magic.cpp - File magic identification --*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "llvm/BinaryFormat/Magic.h" 10 #include "llvm/ADT/StringRef.h" 11 #include "llvm/ADT/Twine.h" 12 #include "llvm/BinaryFormat/COFF.h" 13 #include "llvm/BinaryFormat/MachO.h" 14 #include "llvm/Support/Endian.h" 15 #include "llvm/Support/MemoryBuffer.h" 16 17 #if !defined(_MSC_VER) && !defined(__MINGW32__) 18 #include <unistd.h> 19 #else 20 #include <io.h> 21 #endif 22 23 using namespace llvm; 24 using namespace llvm::support::endian; 25 using namespace llvm::sys::fs; 26 27 template <size_t N> 28 static bool startswith(StringRef Magic, const char (&S)[N]) { 29 return Magic.startswith(StringRef(S, N - 1)); 30 } 31 32 /// Identify the magic in magic. 33 file_magic llvm::identify_magic(StringRef Magic) { 34 if (Magic.size() < 4) 35 return file_magic::unknown; 36 switch ((unsigned char)Magic[0]) { 37 case 0x00: { 38 // COFF bigobj, CL.exe's LTO object file, or short import library file 39 if (startswith(Magic, "\0\0\xFF\xFF")) { 40 size_t MinSize = 41 offsetof(COFF::BigObjHeader, UUID) + sizeof(COFF::BigObjMagic); 42 if (Magic.size() < MinSize) 43 return file_magic::coff_import_library; 44 45 const char *Start = Magic.data() + offsetof(COFF::BigObjHeader, UUID); 46 if (memcmp(Start, COFF::BigObjMagic, sizeof(COFF::BigObjMagic)) == 0) 47 return file_magic::coff_object; 48 if (memcmp(Start, COFF::ClGlObjMagic, sizeof(COFF::BigObjMagic)) == 0) 49 return file_magic::coff_cl_gl_object; 50 return file_magic::coff_import_library; 51 } 52 // Windows resource file 53 if (Magic.size() >= sizeof(COFF::WinResMagic) && 54 memcmp(Magic.data(), COFF::WinResMagic, sizeof(COFF::WinResMagic)) == 0) 55 return file_magic::windows_resource; 56 // 0x0000 = COFF unknown machine type 57 if (Magic[1] == 0) 58 return file_magic::coff_object; 59 if (startswith(Magic, "\0asm")) 60 return file_magic::wasm_object; 61 break; 62 } 63 64 case 0x01: 65 // XCOFF format 66 if (startswith(Magic, "\x01\xDF")) 67 return file_magic::xcoff_object_32; 68 if (startswith(Magic, "\x01\xF7")) 69 return file_magic::xcoff_object_64; 70 break; 71 72 case 0x03: 73 if (startswith(Magic, "\x03\xF0\x00")) 74 return file_magic::goff_object; 75 break; 76 77 case 0x10: 78 if (startswith(Magic, "\x10\xFF\x10\xAD")) 79 return file_magic::offload_binary; 80 break; 81 82 case 0xDE: // 0x0B17C0DE = BC wraper 83 if (startswith(Magic, "\xDE\xC0\x17\x0B")) 84 return file_magic::bitcode; 85 break; 86 case 'B': 87 if (startswith(Magic, "BC\xC0\xDE")) 88 return file_magic::bitcode; 89 break; 90 case '!': 91 if (startswith(Magic, "!<arch>\n") || startswith(Magic, "!<thin>\n")) 92 return file_magic::archive; 93 break; 94 case '<': 95 if (startswith(Magic, "<bigaf>\n")) 96 return file_magic::archive; 97 break; 98 case '\177': 99 if (startswith(Magic, "\177ELF") && Magic.size() >= 18) { 100 bool Data2MSB = Magic[5] == 2; 101 unsigned high = Data2MSB ? 16 : 17; 102 unsigned low = Data2MSB ? 17 : 16; 103 if (Magic[high] == 0) { 104 switch (Magic[low]) { 105 default: 106 return file_magic::elf; 107 case 1: 108 return file_magic::elf_relocatable; 109 case 2: 110 return file_magic::elf_executable; 111 case 3: 112 return file_magic::elf_shared_object; 113 case 4: 114 return file_magic::elf_core; 115 } 116 } 117 // It's still some type of ELF file. 118 return file_magic::elf; 119 } 120 break; 121 122 case 0xCA: 123 if (startswith(Magic, "\xCA\xFE\xBA\xBE") || 124 startswith(Magic, "\xCA\xFE\xBA\xBF")) { 125 // This is complicated by an overlap with Java class files. 126 // See the Mach-O section in /usr/share/file/magic for details. 127 if (Magic.size() >= 8 && Magic[7] < 43) 128 return file_magic::macho_universal_binary; 129 } 130 break; 131 132 // The two magic numbers for mach-o are: 133 // 0xfeedface - 32-bit mach-o 134 // 0xfeedfacf - 64-bit mach-o 135 case 0xFE: 136 case 0xCE: 137 case 0xCF: { 138 uint16_t type = 0; 139 if (startswith(Magic, "\xFE\xED\xFA\xCE") || 140 startswith(Magic, "\xFE\xED\xFA\xCF")) { 141 /* Native endian */ 142 size_t MinSize; 143 if (Magic[3] == char(0xCE)) 144 MinSize = sizeof(MachO::mach_header); 145 else 146 MinSize = sizeof(MachO::mach_header_64); 147 if (Magic.size() >= MinSize) 148 type = Magic[12] << 24 | Magic[13] << 12 | Magic[14] << 8 | Magic[15]; 149 } else if (startswith(Magic, "\xCE\xFA\xED\xFE") || 150 startswith(Magic, "\xCF\xFA\xED\xFE")) { 151 /* Reverse endian */ 152 size_t MinSize; 153 if (Magic[0] == char(0xCE)) 154 MinSize = sizeof(MachO::mach_header); 155 else 156 MinSize = sizeof(MachO::mach_header_64); 157 if (Magic.size() >= MinSize) 158 type = Magic[15] << 24 | Magic[14] << 12 | Magic[13] << 8 | Magic[12]; 159 } 160 switch (type) { 161 default: 162 break; 163 case 1: 164 return file_magic::macho_object; 165 case 2: 166 return file_magic::macho_executable; 167 case 3: 168 return file_magic::macho_fixed_virtual_memory_shared_lib; 169 case 4: 170 return file_magic::macho_core; 171 case 5: 172 return file_magic::macho_preload_executable; 173 case 6: 174 return file_magic::macho_dynamically_linked_shared_lib; 175 case 7: 176 return file_magic::macho_dynamic_linker; 177 case 8: 178 return file_magic::macho_bundle; 179 case 9: 180 return file_magic::macho_dynamically_linked_shared_lib_stub; 181 case 10: 182 return file_magic::macho_dsym_companion; 183 case 11: 184 return file_magic::macho_kext_bundle; 185 } 186 break; 187 } 188 case 0xF0: // PowerPC Windows 189 case 0x83: // Alpha 32-bit 190 case 0x84: // Alpha 64-bit 191 case 0x66: // MPS R4000 Windows 192 case 0x50: // mc68K 193 if (startswith(Magic, "\x50\xed\x55\xba")) 194 return file_magic::cuda_fatbinary; 195 LLVM_FALLTHROUGH; 196 197 case 0x4c: // 80386 Windows 198 case 0xc4: // ARMNT Windows 199 if (Magic[1] == 0x01) 200 return file_magic::coff_object; 201 LLVM_FALLTHROUGH; 202 203 case 0x90: // PA-RISC Windows 204 case 0x68: // mc68K Windows 205 if (Magic[1] == 0x02) 206 return file_magic::coff_object; 207 break; 208 209 case 'M': // Possible MS-DOS stub on Windows PE file, MSF/PDB file or a 210 // Minidump file. 211 if (startswith(Magic, "MZ") && Magic.size() >= 0x3c + 4) { 212 uint32_t off = read32le(Magic.data() + 0x3c); 213 // PE/COFF file, either EXE or DLL. 214 if (Magic.substr(off).startswith( 215 StringRef(COFF::PEMagic, sizeof(COFF::PEMagic)))) 216 return file_magic::pecoff_executable; 217 } 218 if (Magic.startswith("Microsoft C/C++ MSF 7.00\r\n")) 219 return file_magic::pdb; 220 if (startswith(Magic, "MDMP")) 221 return file_magic::minidump; 222 break; 223 224 case 0x64: // x86-64 or ARM64 Windows. 225 if (Magic[1] == char(0x86) || Magic[1] == char(0xaa)) 226 return file_magic::coff_object; 227 break; 228 229 case 0x2d: // YAML '-' 230 if (startswith(Magic, "--- !tapi") || startswith(Magic, "---\narchs:")) 231 return file_magic::tapi_file; 232 break; 233 234 case 'D': // DirectX container file - DXBC 235 if (startswith(Magic, "DXBC")) 236 return file_magic::dxcontainer_object; 237 break; 238 239 default: 240 break; 241 } 242 return file_magic::unknown; 243 } 244 245 std::error_code llvm::identify_magic(const Twine &Path, file_magic &Result) { 246 auto FileOrError = MemoryBuffer::getFile(Path, /*IsText=*/false, 247 /*RequiresNullTerminator=*/false); 248 if (!FileOrError) 249 return FileOrError.getError(); 250 251 std::unique_ptr<MemoryBuffer> FileBuffer = std::move(*FileOrError); 252 Result = identify_magic(FileBuffer->getBuffer()); 253 254 return std::error_code(); 255 } 256