Magic.cpp revision 344779
1227825Stheraven//===- llvm/BinaryFormat/Magic.cpp - File magic identification --*- C++ -*-===// 2227825Stheraven// 3227825Stheraven// The LLVM Compiler Infrastructure 4227825Stheraven// 5227825Stheraven// This file is distributed under the University of Illinois Open Source 6227825Stheraven// License. See LICENSE.TXT for details. 7227825Stheraven// 8227825Stheraven//===----------------------------------------------------------------------===// 9227825Stheraven 10227825Stheraven#include "llvm/BinaryFormat/Magic.h" 11227825Stheraven 12227825Stheraven#include "llvm/BinaryFormat/COFF.h" 13227825Stheraven#include "llvm/BinaryFormat/ELF.h" 14227825Stheraven#include "llvm/BinaryFormat/MachO.h" 15227825Stheraven#include "llvm/Support/Endian.h" 16227825Stheraven#include "llvm/Support/FileSystem.h" 17227825Stheraven#include "llvm/Support/MemoryBuffer.h" 18227825Stheraven 19227825Stheraven#if !defined(_MSC_VER) && !defined(__MINGW32__) 20227825Stheraven#include <unistd.h> 21227825Stheraven#else 22227825Stheraven#include <io.h> 23227825Stheraven#endif 24227825Stheraven 25227825Stheravenusing namespace llvm; 26227825Stheravenusing namespace llvm::support::endian; 27227825Stheravenusing namespace llvm::sys::fs; 28227825Stheraven 29227825Stheraventemplate <size_t N> 30227825Stheravenstatic bool startswith(StringRef Magic, const char (&S)[N]) { 31227825Stheraven return Magic.startswith(StringRef(S, N - 1)); 32227825Stheraven} 33227825Stheraven 34227825Stheraven/// Identify the magic in magic. 35227825Stheravenfile_magic llvm::identify_magic(StringRef Magic) { 36227825Stheraven if (Magic.size() < 4) 37227825Stheraven return file_magic::unknown; 38227825Stheraven switch ((unsigned char)Magic[0]) { 39227825Stheraven case 0x00: { 40227825Stheraven // COFF bigobj, CL.exe's LTO object file, or short import library file 41227825Stheraven if (startswith(Magic, "\0\0\xFF\xFF")) { 42227825Stheraven size_t MinSize = 43227825Stheraven offsetof(COFF::BigObjHeader, UUID) + sizeof(COFF::BigObjMagic); 44227825Stheraven if (Magic.size() < MinSize) 45227825Stheraven return file_magic::coff_import_library; 46227825Stheraven 47227825Stheraven const char *Start = Magic.data() + offsetof(COFF::BigObjHeader, UUID); 48227825Stheraven if (memcmp(Start, COFF::BigObjMagic, sizeof(COFF::BigObjMagic)) == 0) 49227825Stheraven return file_magic::coff_object; 50227825Stheraven if (memcmp(Start, COFF::ClGlObjMagic, sizeof(COFF::BigObjMagic)) == 0) 51227825Stheraven return file_magic::coff_cl_gl_object; 52227825Stheraven return file_magic::coff_import_library; 53227825Stheraven } 54227825Stheraven // Windows resource file 55227825Stheraven if (Magic.size() >= sizeof(COFF::WinResMagic) && 56227825Stheraven memcmp(Magic.data(), COFF::WinResMagic, sizeof(COFF::WinResMagic)) == 0) 57227825Stheraven return file_magic::windows_resource; 58227825Stheraven // 0x0000 = COFF unknown machine type 59227825Stheraven if (Magic[1] == 0) 60227825Stheraven return file_magic::coff_object; 61227825Stheraven if (startswith(Magic, "\0asm")) 62227825Stheraven return file_magic::wasm_object; 63227825Stheraven break; 64227825Stheraven } 65227825Stheraven case 0xDE: // 0x0B17C0DE = BC wraper 66227825Stheraven if (startswith(Magic, "\xDE\xC0\x17\x0B")) 67227825Stheraven return file_magic::bitcode; 68227825Stheraven break; 69227825Stheraven case 'B': 70227825Stheraven if (startswith(Magic, "BC\xC0\xDE")) 71227825Stheraven return file_magic::bitcode; 72227825Stheraven break; 73227825Stheraven case '!': 74227825Stheraven if (startswith(Magic, "!<arch>\n") || startswith(Magic, "!<thin>\n")) 75227825Stheraven return file_magic::archive; 76227825Stheraven break; 77227825Stheraven 78227825Stheraven case '\177': 79227825Stheraven if (startswith(Magic, "\177ELF") && Magic.size() >= 18) { 80227825Stheraven bool Data2MSB = Magic[5] == 2; 81227825Stheraven unsigned high = Data2MSB ? 16 : 17; 82227825Stheraven unsigned low = Data2MSB ? 17 : 16; 83227825Stheraven if (Magic[high] == 0) { 84227825Stheraven switch (Magic[low]) { 85227825Stheraven default: 86227825Stheraven return file_magic::elf; 87227825Stheraven case 1: 88227825Stheraven return file_magic::elf_relocatable; 89227825Stheraven case 2: 90227825Stheraven return file_magic::elf_executable; 91227825Stheraven case 3: 92227825Stheraven return file_magic::elf_shared_object; 93227825Stheraven case 4: 94227825Stheraven return file_magic::elf_core; 95227825Stheraven } 96227825Stheraven } 97227825Stheraven // It's still some type of ELF file. 98227825Stheraven return file_magic::elf; 99227825Stheraven } 100227825Stheraven break; 101227825Stheraven 102227825Stheraven case 0xCA: 103227825Stheraven if (startswith(Magic, "\xCA\xFE\xBA\xBE") || 104227825Stheraven startswith(Magic, "\xCA\xFE\xBA\xBF")) { 105227825Stheraven // This is complicated by an overlap with Java class files. 106227825Stheraven // See the Mach-O section in /usr/share/file/magic for details. 107227825Stheraven if (Magic.size() >= 8 && Magic[7] < 43) 108227825Stheraven return file_magic::macho_universal_binary; 109227825Stheraven } 110227825Stheraven break; 111227825Stheraven 112227825Stheraven // The two magic numbers for mach-o are: 113227825Stheraven // 0xfeedface - 32-bit mach-o 114227825Stheraven // 0xfeedfacf - 64-bit mach-o 115227825Stheraven case 0xFE: 116227825Stheraven case 0xCE: 117227825Stheraven case 0xCF: { 118227825Stheraven uint16_t type = 0; 119227825Stheraven if (startswith(Magic, "\xFE\xED\xFA\xCE") || 120227825Stheraven startswith(Magic, "\xFE\xED\xFA\xCF")) { 121227825Stheraven /* Native endian */ 122227825Stheraven size_t MinSize; 123227825Stheraven if (Magic[3] == char(0xCE)) 124227825Stheraven MinSize = sizeof(MachO::mach_header); 125227825Stheraven else 126227825Stheraven MinSize = sizeof(MachO::mach_header_64); 127227825Stheraven if (Magic.size() >= MinSize) 128227825Stheraven type = Magic[12] << 24 | Magic[13] << 12 | Magic[14] << 8 | Magic[15]; 129227825Stheraven } else if (startswith(Magic, "\xCE\xFA\xED\xFE") || 130227825Stheraven startswith(Magic, "\xCF\xFA\xED\xFE")) { 131227825Stheraven /* Reverse endian */ 132227825Stheraven size_t MinSize; 133227825Stheraven if (Magic[0] == char(0xCE)) 134227825Stheraven MinSize = sizeof(MachO::mach_header); 135227825Stheraven else 136227825Stheraven MinSize = sizeof(MachO::mach_header_64); 137227825Stheraven if (Magic.size() >= MinSize) 138227825Stheraven type = Magic[15] << 24 | Magic[14] << 12 | Magic[13] << 8 | Magic[12]; 139227825Stheraven } 140227825Stheraven switch (type) { 141227825Stheraven default: 142227825Stheraven break; 143227825Stheraven case 1: 144227825Stheraven return file_magic::macho_object; 145227825Stheraven case 2: 146227825Stheraven return file_magic::macho_executable; 147227825Stheraven case 3: 148227825Stheraven return file_magic::macho_fixed_virtual_memory_shared_lib; 149227825Stheraven case 4: 150227825Stheraven return file_magic::macho_core; 151227825Stheraven case 5: 152227825Stheraven return file_magic::macho_preload_executable; 153227825Stheraven case 6: 154227825Stheraven return file_magic::macho_dynamically_linked_shared_lib; 155227825Stheraven case 7: 156227825Stheraven return file_magic::macho_dynamic_linker; 157227825Stheraven case 8: 158227825Stheraven return file_magic::macho_bundle; 159227825Stheraven case 9: 160227825Stheraven return file_magic::macho_dynamically_linked_shared_lib_stub; 161227825Stheraven case 10: 162227825Stheraven return file_magic::macho_dsym_companion; 163227825Stheraven case 11: 164227825Stheraven return file_magic::macho_kext_bundle; 165227825Stheraven } 166227825Stheraven break; 167227825Stheraven } 168227825Stheraven case 0xF0: // PowerPC Windows 169227825Stheraven case 0x83: // Alpha 32-bit 170227825Stheraven case 0x84: // Alpha 64-bit 171227825Stheraven case 0x66: // MPS R4000 Windows 172227825Stheraven case 0x50: // mc68K 173227825Stheraven case 0x4c: // 80386 Windows 174227825Stheraven case 0xc4: // ARMNT Windows 175227825Stheraven if (Magic[1] == 0x01) 176227825Stheraven return file_magic::coff_object; 177227825Stheraven LLVM_FALLTHROUGH; 178227825Stheraven 179227825Stheraven case 0x90: // PA-RISC Windows 180227825Stheraven case 0x68: // mc68K Windows 181227825Stheraven if (Magic[1] == 0x02) 182227825Stheraven return file_magic::coff_object; 183227825Stheraven break; 184227825Stheraven 185227825Stheraven case 'M': // Possible MS-DOS stub on Windows PE file or MSF/PDB file. 186227825Stheraven if (startswith(Magic, "MZ") && Magic.size() >= 0x3c + 4) { 187227825Stheraven uint32_t off = read32le(Magic.data() + 0x3c); 188227825Stheraven // PE/COFF file, either EXE or DLL. 189227825Stheraven if (Magic.substr(off).startswith( 190227825Stheraven StringRef(COFF::PEMagic, sizeof(COFF::PEMagic)))) 191227825Stheraven return file_magic::pecoff_executable; 192227825Stheraven } 193227825Stheraven if (Magic.startswith("Microsoft C/C++ MSF 7.00\r\n")) 194227825Stheraven return file_magic::pdb; 195227825Stheraven break; 196227825Stheraven 197227825Stheraven case 0x64: // x86-64 or ARM64 Windows. 198227825Stheraven if (Magic[1] == char(0x86) || Magic[1] == char(0xaa)) 199227825Stheraven return file_magic::coff_object; 200227825Stheraven break; 201227825Stheraven 202227825Stheraven default: 203227825Stheraven break; 204227825Stheraven } 205227825Stheraven return file_magic::unknown; 206227825Stheraven} 207227825Stheraven 208227825Stheravenstd::error_code llvm::identify_magic(const Twine &Path, file_magic &Result) { 209262801Sdim auto FileOrError = MemoryBuffer::getFile(Path, -1LL, false); 210262801Sdim if (!FileOrError) 211262801Sdim return FileOrError.getError(); 212262801Sdim 213227825Stheraven std::unique_ptr<MemoryBuffer> FileBuffer = std::move(*FileOrError); 214262801Sdim Result = identify_magic(FileBuffer->getBuffer()); 215227825Stheraven 216227825Stheraven return std::error_code(); 217227825Stheraven} 218227825Stheraven