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//===- llvm/BinaryFormat/Magic.cpp - File magic identification --*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/BinaryFormat/Magic.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/BinaryFormat/MachO.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/FileSystem.h"
#if !defined(_MSC_VER) && !defined(__MINGW32__)
#include <unistd.h>
#else
#include <io.h>
#endif
using namespace llvm;
using namespace llvm::support::endian;
using namespace llvm::sys::fs;
template <size_t N>
static bool startswith(StringRef Magic, const char (&S)[N]) {
return Magic.startswith(StringRef(S, N - 1));
}
/// @brief Identify the magic in magic.
file_magic llvm::identify_magic(StringRef Magic) {
if (Magic.size() < 4)
return file_magic::unknown;
switch ((unsigned char)Magic[0]) {
case 0x00: {
// COFF bigobj, CL.exe's LTO object file, or short import library file
if (startswith(Magic, "\0\0\xFF\xFF")) {
size_t MinSize =
offsetof(COFF::BigObjHeader, UUID) + sizeof(COFF::BigObjMagic);
if (Magic.size() < MinSize)
return file_magic::coff_import_library;
const char *Start = Magic.data() + offsetof(COFF::BigObjHeader, UUID);
if (memcmp(Start, COFF::BigObjMagic, sizeof(COFF::BigObjMagic)) == 0)
return file_magic::coff_object;
if (memcmp(Start, COFF::ClGlObjMagic, sizeof(COFF::BigObjMagic)) == 0)
return file_magic::coff_cl_gl_object;
return file_magic::coff_import_library;
}
// Windows resource file
if (Magic.size() >= sizeof(COFF::WinResMagic) &&
memcmp(Magic.data(), COFF::WinResMagic, sizeof(COFF::WinResMagic)) == 0)
return file_magic::windows_resource;
// 0x0000 = COFF unknown machine type
if (Magic[1] == 0)
return file_magic::coff_object;
if (startswith(Magic, "\0asm"))
return file_magic::wasm_object;
break;
}
case 0xDE: // 0x0B17C0DE = BC wraper
if (startswith(Magic, "\xDE\xC0\x17\x0B"))
return file_magic::bitcode;
break;
case 'B':
if (startswith(Magic, "BC\xC0\xDE"))
return file_magic::bitcode;
break;
case '!':
if (startswith(Magic, "!<arch>\n") || startswith(Magic, "!<thin>\n"))
return file_magic::archive;
break;
case '\177':
if (startswith(Magic, "\177ELF") && Magic.size() >= 18) {
bool Data2MSB = Magic[5] == 2;
unsigned high = Data2MSB ? 16 : 17;
unsigned low = Data2MSB ? 17 : 16;
if (Magic[high] == 0) {
switch (Magic[low]) {
default:
return file_magic::elf;
case 1:
return file_magic::elf_relocatable;
case 2:
return file_magic::elf_executable;
case 3:
return file_magic::elf_shared_object;
case 4:
return file_magic::elf_core;
}
}
// It's still some type of ELF file.
return file_magic::elf;
}
break;
case 0xCA:
if (startswith(Magic, "\xCA\xFE\xBA\xBE") ||
startswith(Magic, "\xCA\xFE\xBA\xBF")) {
// This is complicated by an overlap with Java class files.
// See the Mach-O section in /usr/share/file/magic for details.
if (Magic.size() >= 8 && Magic[7] < 43)
return file_magic::macho_universal_binary;
}
break;
// The two magic numbers for mach-o are:
// 0xfeedface - 32-bit mach-o
// 0xfeedfacf - 64-bit mach-o
case 0xFE:
case 0xCE:
case 0xCF: {
uint16_t type = 0;
if (startswith(Magic, "\xFE\xED\xFA\xCE") ||
startswith(Magic, "\xFE\xED\xFA\xCF")) {
/* Native endian */
size_t MinSize;
if (Magic[3] == char(0xCE))
MinSize = sizeof(MachO::mach_header);
else
MinSize = sizeof(MachO::mach_header_64);
if (Magic.size() >= MinSize)
type = Magic[12] << 24 | Magic[13] << 12 | Magic[14] << 8 | Magic[15];
} else if (startswith(Magic, "\xCE\xFA\xED\xFE") ||
startswith(Magic, "\xCF\xFA\xED\xFE")) {
/* Reverse endian */
size_t MinSize;
if (Magic[0] == char(0xCE))
MinSize = sizeof(MachO::mach_header);
else
MinSize = sizeof(MachO::mach_header_64);
if (Magic.size() >= MinSize)
type = Magic[15] << 24 | Magic[14] << 12 | Magic[13] << 8 | Magic[12];
}
switch (type) {
default:
break;
case 1:
return file_magic::macho_object;
case 2:
return file_magic::macho_executable;
case 3:
return file_magic::macho_fixed_virtual_memory_shared_lib;
case 4:
return file_magic::macho_core;
case 5:
return file_magic::macho_preload_executable;
case 6:
return file_magic::macho_dynamically_linked_shared_lib;
case 7:
return file_magic::macho_dynamic_linker;
case 8:
return file_magic::macho_bundle;
case 9:
return file_magic::macho_dynamically_linked_shared_lib_stub;
case 10:
return file_magic::macho_dsym_companion;
case 11:
return file_magic::macho_kext_bundle;
}
break;
}
case 0xF0: // PowerPC Windows
case 0x83: // Alpha 32-bit
case 0x84: // Alpha 64-bit
case 0x66: // MPS R4000 Windows
case 0x50: // mc68K
case 0x4c: // 80386 Windows
case 0xc4: // ARMNT Windows
if (Magic[1] == 0x01)
return file_magic::coff_object;
LLVM_FALLTHROUGH;
case 0x90: // PA-RISC Windows
case 0x68: // mc68K Windows
if (Magic[1] == 0x02)
return file_magic::coff_object;
break;
case 'M': // Possible MS-DOS stub on Windows PE file
if (startswith(Magic, "MZ") && Magic.size() >= 0x3c + 4) {
uint32_t off = read32le(Magic.data() + 0x3c);
// PE/COFF file, either EXE or DLL.
if (Magic.substr(off).startswith(
StringRef(COFF::PEMagic, sizeof(COFF::PEMagic))))
return file_magic::pecoff_executable;
}
break;
case 0x64: // x86-64 or ARM64 Windows.
if (Magic[1] == char(0x86) || Magic[1] == char(0xaa))
return file_magic::coff_object;
break;
default:
break;
}
return file_magic::unknown;
}
std::error_code llvm::identify_magic(const Twine &Path, file_magic &Result) {
int FD;
if (std::error_code EC = openFileForRead(Path, FD))
return EC;
char Buffer[32];
int Length = read(FD, Buffer, sizeof(Buffer));
if (close(FD) != 0 || Length < 0)
return std::error_code(errno, std::generic_category());
Result = identify_magic(StringRef(Buffer, Length));
return std::error_code();
}
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