llvm/lib/BinaryFormat/Magic.cpp

   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     if (startswith(Magic, "CPCH"))
 102       return file_magic::clang_ast;
 103     break;
 104   case '!':
 105     if (startswith(Magic, "!<arch>\n") || startswith(Magic, "!<thin>\n"))
 106       return file_magic::archive;
 107     break;
 108   case '<':
 109     if (startswith(Magic, "<bigaf>\n"))
 110       return file_magic::archive;
 111     break;
 112   case '\177':
 113     if (startswith(Magic, "\177ELF") && Magic.size() >= 18) {
 114       bool Data2MSB = Magic[5] == 2;
 115       unsigned high = Data2MSB ? 16 : 17;
 116       unsigned low = Data2MSB ? 17 : 16;
 117       if (Magic[high] == 0) {
 118         switch (Magic[low]) {
 119         default:
 120           return file_magic::elf;
 121         case 1:
 122           return file_magic::elf_relocatable;
 123         case 2:
 124           return file_magic::elf_executable;
 125         case 3:
 126           return file_magic::elf_shared_object;
 127         case 4:
 128           return file_magic::elf_core;
 129         }
 130       }
 131       // It's still some type of ELF file.
 132       return file_magic::elf;
 133     }
 134     break;
 135
 136   case 0xCA:
 137     if (startswith(Magic, "\xCA\xFE\xBA\xBE") ||
 138         startswith(Magic, "\xCA\xFE\xBA\xBF")) {
 139       // This is complicated by an overlap with Java class files.
 140       // See the Mach-O section in /usr/share/file/magic for details.
 141       if (Magic.size() >= 8 && Magic[7] < 43)
 142         return file_magic::macho_universal_binary;
 143     }
 144     break;
 145
 146   // The two magic numbers for mach-o are:
 147   // 0xfeedface - 32-bit mach-o
 148   // 0xfeedfacf - 64-bit mach-o
 149   case 0xFE:
 150   case 0xCE:
 151   case 0xCF: {
 152     uint16_t type = 0;
 153     if (startswith(Magic, "\xFE\xED\xFA\xCE") ||
 154         startswith(Magic, "\xFE\xED\xFA\xCF")) {
 155       /* Native endian */
 156       size_t MinSize;
 157       if (Magic[3] == 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[12] << 24 | Magic[13] << 12 | Magic[14] << 8 | Magic[15];
 163     } else if (startswith(Magic, "\xCE\xFA\xED\xFE") ||
 164                startswith(Magic, "\xCF\xFA\xED\xFE")) {
 165       /* Reverse endian */
 166       size_t MinSize;
 167       if (Magic[0] == char(0xCE))
 168         MinSize = sizeof(MachO::mach_header);
 169       else
 170         MinSize = sizeof(MachO::mach_header_64);
 171       if (Magic.size() >= MinSize)
 172         type = Magic[15] << 24 | Magic[14] << 12 | Magic[13] << 8 | Magic[12];
 173     }
 174     switch (type) {
 175     default:
 176       break;
 177     case 1:
 178       return file_magic::macho_object;
 179     case 2:
 180       return file_magic::macho_executable;
 181     case 3:
 182       return file_magic::macho_fixed_virtual_memory_shared_lib;
 183     case 4:
 184       return file_magic::macho_core;
 185     case 5:
 186       return file_magic::macho_preload_executable;
 187     case 6:
 188       return file_magic::macho_dynamically_linked_shared_lib;
 189     case 7:
 190       return file_magic::macho_dynamic_linker;
 191     case 8:
 192       return file_magic::macho_bundle;
 193     case 9:
 194       return file_magic::macho_dynamically_linked_shared_lib_stub;
 195     case 10:
 196       return file_magic::macho_dsym_companion;
 197     case 11:
 198       return file_magic::macho_kext_bundle;
 199     case 12:
 200       return file_magic::macho_file_set;
 201     }
 202     break;
 203   }
 204   case 0xF0: // PowerPC Windows
 205   case 0x83: // Alpha 32-bit
 206   case 0x84: // Alpha 64-bit
 207   case 0x66: // MPS R4000 Windows
 208   case 0x50: // mc68K
 209     if (startswith(Magic, "\x50\xed\x55\xba"))
 210       return file_magic::cuda_fatbinary;
 211     [[fallthrough]];
 212
 213   case 0x4c: // 80386 Windows
 214   case 0xc4: // ARMNT Windows
 215     if (Magic[1] == 0x01)
 216       return file_magic::coff_object;
 217     [[fallthrough]];
 218
 219   case 0x90: // PA-RISC Windows
 220   case 0x68: // mc68K Windows
 221     if (Magic[1] == 0x02)
 222       return file_magic::coff_object;
 223     break;
 224
 225   case 'M': // Possible MS-DOS stub on Windows PE file, MSF/PDB file or a
 226             // Minidump file.
 227     if (startswith(Magic, "MZ") && Magic.size() >= 0x3c + 4) {
 228       uint32_t off = read32le(Magic.data() + 0x3c);
 229       // PE/COFF file, either EXE or DLL.
 230       if (Magic.substr(off).starts_with(
 231               StringRef(COFF::PEMagic, sizeof(COFF::PEMagic))))
 232         return file_magic::pecoff_executable;
 233     }
 234     if (Magic.starts_with("Microsoft C/C++ MSF 7.00\r\n"))
 235       return file_magic::pdb;
 236     if (startswith(Magic, "MDMP"))
 237       return file_magic::minidump;
 238     break;
 239
 240   case 0x64: // x86-64 or ARM64 Windows.
 241     if (Magic[1] == char(0x86) || Magic[1] == char(0xaa))
 242       return file_magic::coff_object;
 243     break;
 244
 245   case 0x2d: // YAML '-' MachO TBD.
 246     if (startswith(Magic, "--- !tapi") || startswith(Magic, "---\narchs:"))
 247       return file_magic::tapi_file;
 248     break;
 249   case 0x7b: // JSON '{' MachO TBD.
 250     return file_magic::tapi_file;
 251     break;
 252
 253   case 'D': // DirectX container file - DXBC
 254     if (startswith(Magic, "DXBC"))
 255       return file_magic::dxcontainer_object;
 256     break;
 257
 258   case 0x41: // ARM64EC windows
 259     if (Magic[1] == char(0xA6))
 260       return file_magic::coff_object;
 261     break;
 262
 263   case 0x4e: // ARM64X windows
 264     if (Magic[1] == char(0xA6))
 265       return file_magic::coff_object;
 266     break;
 267
 268   case '_': {
 269     const char OBMagic[] = "__CLANG_OFFLOAD_BUNDLE__";
 270     if (Magic.size() >= sizeof(OBMagic) && startswith(Magic, OBMagic))
 271       return file_magic::offload_bundle;
 272     break;
 273   }
 274
 275   default:
 276     break;
 277   }
 278   return file_magic::unknown;
 279 }
 280
 281 std::error_code llvm::identify_magic(const Twine &Path, file_magic &Result) {
 282   auto FileOrError = MemoryBuffer::getFile(Path, /*IsText=*/false,
 283                                            /*RequiresNullTerminator=*/false);
 284   if (!FileOrError)
 285     return FileOrError.getError();
 286
 287   std::unique_ptr<MemoryBuffer> FileBuffer = std::move(*FileOrError);
 288   Result = identify_magic(FileBuffer->getBuffer());
 289
 290   return std::error_code();
 291 }