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Diffstat (limited to 'lib/BinaryFormat/Magic.cpp')
| -rw-r--r-- | lib/BinaryFormat/Magic.cpp | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/lib/BinaryFormat/Magic.cpp b/lib/BinaryFormat/Magic.cpp new file mode 100644 index 000000000000..ca4d93f99d92 --- /dev/null +++ b/lib/BinaryFormat/Magic.cpp @@ -0,0 +1,216 @@ +//===- 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 (startswith(Magic, "\0\0\0\0\x20\0\0\0\xFF")) + 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")) { + uint32_t off = read32le(Magic.data() + 0x3c); + // PE/COFF file, either EXE or DLL. + if (off < Magic.size() && + memcmp(Magic.data() + off, COFF::PEMagic, sizeof(COFF::PEMagic)) == 0) + return file_magic::pecoff_executable; + } + break; + + case 0x64: // x86-64 Windows. + if (Magic[1] == char(0x86)) + 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(); +} |