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