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.starts_with(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 // SPIR-V format in little-endian mode. 76 if (startswith(Magic, "\x03\x02\x23\x07")) 77 return file_magic::spirv_object; 78 break; 79 80 case 0x07: // SPIR-V format in big-endian mode. 81 if (startswith(Magic, "\x07\x23\x02\x03")) 82 return file_magic::spirv_object; 83 break; 84 85 case 0x10: 86 if (startswith(Magic, "\x10\xFF\x10\xAD")) 87 return file_magic::offload_binary; 88 break; 89 90 case 0xDE: // 0x0B17C0DE = BC wraper 91 if (startswith(Magic, "\xDE\xC0\x17\x0B")) 92 return file_magic::bitcode; 93 break; 94 case 'B': 95 if (startswith(Magic, "BC\xC0\xDE")) 96 return file_magic::bitcode; 97 break; 98 case 'C': 99 if (startswith(Magic, "CCOB")) 100 return file_magic::offload_bundle_compressed; 101 break; 102 case '!': 103 if (startswith(Magic, "!<arch>\n") || startswith(Magic, "!<thin>\n")) 104 return file_magic::archive; 105 break; 106 case '<': 107 if (startswith(Magic, "<bigaf>\n")) 108 return file_magic::archive; 109 break; 110 case '\177': 111 if (startswith(Magic, "\177ELF") && Magic.size() >= 18) { 112 bool Data2MSB = Magic[5] == 2; 113 unsigned high = Data2MSB ? 16 : 17; 114 unsigned low = Data2MSB ? 17 : 16; 115 if (Magic[high] == 0) { 116 switch (Magic[low]) { 117 default: 118 return file_magic::elf; 119 case 1: 120 return file_magic::elf_relocatable; 121 case 2: 122 return file_magic::elf_executable; 123 case 3: 124 return file_magic::elf_shared_object; 125 case 4: 126 return file_magic::elf_core; 127 } 128 } 129 // It's still some type of ELF file. 130 return file_magic::elf; 131 } 132 break; 133 134 case 0xCA: 135 if (startswith(Magic, "\xCA\xFE\xBA\xBE") || 136 startswith(Magic, "\xCA\xFE\xBA\xBF")) { 137 // This is complicated by an overlap with Java class files. 138 // See the Mach-O section in /usr/share/file/magic for details. 139 if (Magic.size() >= 8 && Magic[7] < 43) 140 return file_magic::macho_universal_binary; 141 } 142 break; 143 144 // The two magic numbers for mach-o are: 145 // 0xfeedface - 32-bit mach-o 146 // 0xfeedfacf - 64-bit mach-o 147 case 0xFE: 148 case 0xCE: 149 case 0xCF: { 150 uint16_t type = 0; 151 if (startswith(Magic, "\xFE\xED\xFA\xCE") || 152 startswith(Magic, "\xFE\xED\xFA\xCF")) { 153 /* Native endian */ 154 size_t MinSize; 155 if (Magic[3] == char(0xCE)) 156 MinSize = sizeof(MachO::mach_header); 157 else 158 MinSize = sizeof(MachO::mach_header_64); 159 if (Magic.size() >= MinSize) 160 type = Magic[12] << 24 | Magic[13] << 12 | Magic[14] << 8 | Magic[15]; 161 } else if (startswith(Magic, "\xCE\xFA\xED\xFE") || 162 startswith(Magic, "\xCF\xFA\xED\xFE")) { 163 /* Reverse endian */ 164 size_t MinSize; 165 if (Magic[0] == char(0xCE)) 166 MinSize = sizeof(MachO::mach_header); 167 else 168 MinSize = sizeof(MachO::mach_header_64); 169 if (Magic.size() >= MinSize) 170 type = Magic[15] << 24 | Magic[14] << 12 | Magic[13] << 8 | Magic[12]; 171 } 172 switch (type) { 173 default: 174 break; 175 case 1: 176 return file_magic::macho_object; 177 case 2: 178 return file_magic::macho_executable; 179 case 3: 180 return file_magic::macho_fixed_virtual_memory_shared_lib; 181 case 4: 182 return file_magic::macho_core; 183 case 5: 184 return file_magic::macho_preload_executable; 185 case 6: 186 return file_magic::macho_dynamically_linked_shared_lib; 187 case 7: 188 return file_magic::macho_dynamic_linker; 189 case 8: 190 return file_magic::macho_bundle; 191 case 9: 192 return file_magic::macho_dynamically_linked_shared_lib_stub; 193 case 10: 194 return file_magic::macho_dsym_companion; 195 case 11: 196 return file_magic::macho_kext_bundle; 197 case 12: 198 return file_magic::macho_file_set; 199 } 200 break; 201 } 202 case 0xF0: // PowerPC Windows 203 case 0x83: // Alpha 32-bit 204 case 0x84: // Alpha 64-bit 205 case 0x66: // MPS R4000 Windows 206 case 0x50: // mc68K 207 if (startswith(Magic, "\x50\xed\x55\xba")) 208 return file_magic::cuda_fatbinary; 209 [[fallthrough]]; 210 211 case 0x4c: // 80386 Windows 212 case 0xc4: // ARMNT Windows 213 if (Magic[1] == 0x01) 214 return file_magic::coff_object; 215 [[fallthrough]]; 216 217 case 0x90: // PA-RISC Windows 218 case 0x68: // mc68K Windows 219 if (Magic[1] == 0x02) 220 return file_magic::coff_object; 221 break; 222 223 case 'M': // Possible MS-DOS stub on Windows PE file, MSF/PDB file or a 224 // Minidump file. 225 if (startswith(Magic, "MZ") && Magic.size() >= 0x3c + 4) { 226 uint32_t off = read32le(Magic.data() + 0x3c); 227 // PE/COFF file, either EXE or DLL. 228 if (Magic.substr(off).starts_with( 229 StringRef(COFF::PEMagic, sizeof(COFF::PEMagic)))) 230 return file_magic::pecoff_executable; 231 } 232 if (Magic.starts_with("Microsoft C/C++ MSF 7.00\r\n")) 233 return file_magic::pdb; 234 if (startswith(Magic, "MDMP")) 235 return file_magic::minidump; 236 break; 237 238 case 0x64: // x86-64 or ARM64 Windows. 239 if (Magic[1] == char(0x86) || Magic[1] == char(0xaa)) 240 return file_magic::coff_object; 241 break; 242 243 case 0x2d: // YAML '-' MachO TBD. 244 if (startswith(Magic, "--- !tapi") || startswith(Magic, "---\narchs:")) 245 return file_magic::tapi_file; 246 break; 247 case 0x7b: // JSON '{' MachO TBD. 248 return file_magic::tapi_file; 249 break; 250 251 case 'D': // DirectX container file - DXBC 252 if (startswith(Magic, "DXBC")) 253 return file_magic::dxcontainer_object; 254 break; 255 256 case 0x41: // ARM64EC windows 257 if (Magic[1] == char(0xA6)) 258 return file_magic::coff_object; 259 break; 260 261 case 0x4e: // ARM64X windows 262 if (Magic[1] == char(0xA6)) 263 return file_magic::coff_object; 264 break; 265 266 case '_': { 267 const char OBMagic[] = "__CLANG_OFFLOAD_BUNDLE__"; 268 if (Magic.size() >= sizeof(OBMagic) && startswith(Magic, OBMagic)) 269 return file_magic::offload_bundle; 270 break; 271 } 272 273 default: 274 break; 275 } 276 return file_magic::unknown; 277 } 278 279 std::error_code llvm::identify_magic(const Twine &Path, file_magic &Result) { 280 auto FileOrError = MemoryBuffer::getFile(Path, /*IsText=*/false, 281 /*RequiresNullTerminator=*/false); 282 if (!FileOrError) 283 return FileOrError.getError(); 284 285 std::unique_ptr<MemoryBuffer> FileBuffer = std::move(*FileOrError); 286 Result = identify_magic(FileBuffer->getBuffer()); 287 288 return std::error_code(); 289 } 290