lib/Object/MachOUniversal.cpp

   1 //===- MachOUniversal.cpp - Mach-O universal binary -------------*- 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 // This file defines the MachOUniversalBinary class.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "llvm/Object/MachOUniversal.h"
  14 #include "llvm/Object/Archive.h"
  15 #include "llvm/Object/MachO.h"
  16 #include "llvm/Object/ObjectFile.h"
  17 #include "llvm/Support/Casting.h"
  18 #include "llvm/Support/Host.h"
  19 #include "llvm/Support/MemoryBuffer.h"
  20
  21 using namespace llvm;
  22 using namespace object;
  23
  24 static Error
  25 malformedError(Twine Msg) {
  26   std::string StringMsg = "truncated or malformed fat file (" + Msg.str() + ")";
  27   return make_error<GenericBinaryError>(std::move(StringMsg),
  28                                         object_error::parse_failed);
  29 }
  30
  31 template<typename T>
  32 static T getUniversalBinaryStruct(const char *Ptr) {
  33   T Res;
  34   memcpy(&Res, Ptr, sizeof(T));
  35   // Universal binary headers have big-endian byte order.
  36   if (sys::IsLittleEndianHost)
  37     swapStruct(Res);
  38   return Res;
  39 }
  40
  41 MachOUniversalBinary::ObjectForArch::ObjectForArch(
  42     const MachOUniversalBinary *Parent, uint32_t Index)
  43     : Parent(Parent), Index(Index) {
  44   // The iterators use Parent as a nullptr and an Index+1 == NumberOfObjects.
  45   if (!Parent || Index >= Parent->getNumberOfObjects()) {
  46     clear();
  47   } else {
  48     // Parse object header.
  49     StringRef ParentData = Parent->getData();
  50     if (Parent->getMagic() == MachO::FAT_MAGIC) {
  51       const char *HeaderPos = ParentData.begin() + sizeof(MachO::fat_header) +
  52                               Index * sizeof(MachO::fat_arch);
  53       Header = getUniversalBinaryStruct<MachO::fat_arch>(HeaderPos);
  54     } else { // Parent->getMagic() == MachO::FAT_MAGIC_64
  55       const char *HeaderPos = ParentData.begin() + sizeof(MachO::fat_header) +
  56                               Index * sizeof(MachO::fat_arch_64);
  57       Header64 = getUniversalBinaryStruct<MachO::fat_arch_64>(HeaderPos);
  58     }
  59   }
  60 }
  61
  62 Expected<std::unique_ptr<MachOObjectFile>>
  63 MachOUniversalBinary::ObjectForArch::getAsObjectFile() const {
  64   if (!Parent)
  65     report_fatal_error("MachOUniversalBinary::ObjectForArch::getAsObjectFile() "
  66                        "called when Parent is a nullptr");
  67
  68   StringRef ParentData = Parent->getData();
  69   StringRef ObjectData;
  70   uint32_t cputype;
  71   if (Parent->getMagic() == MachO::FAT_MAGIC) {
  72     ObjectData = ParentData.substr(Header.offset, Header.size);
  73     cputype = Header.cputype;
  74   } else { // Parent->getMagic() == MachO::FAT_MAGIC_64
  75     ObjectData = ParentData.substr(Header64.offset, Header64.size);
  76     cputype = Header64.cputype;
  77   }
  78   StringRef ObjectName = Parent->getFileName();
  79   MemoryBufferRef ObjBuffer(ObjectData, ObjectName);
  80   return ObjectFile::createMachOObjectFile(ObjBuffer, cputype, Index);
  81 }
  82
  83 Expected<std::unique_ptr<Archive>>
  84 MachOUniversalBinary::ObjectForArch::getAsArchive() const {
  85   if (!Parent)
  86     report_fatal_error("MachOUniversalBinary::ObjectForArch::getAsArchive() "
  87                        "called when Parent is a nullptr");
  88
  89   StringRef ParentData = Parent->getData();
  90   StringRef ObjectData;
  91   if (Parent->getMagic() == MachO::FAT_MAGIC)
  92     ObjectData = ParentData.substr(Header.offset, Header.size);
  93   else // Parent->getMagic() == MachO::FAT_MAGIC_64
  94     ObjectData = ParentData.substr(Header64.offset, Header64.size);
  95   StringRef ObjectName = Parent->getFileName();
  96   MemoryBufferRef ObjBuffer(ObjectData, ObjectName);
  97   return Archive::create(ObjBuffer);
  98 }
  99
 100 void MachOUniversalBinary::anchor() { }
 101
 102 Expected<std::unique_ptr<MachOUniversalBinary>>
 103 MachOUniversalBinary::create(MemoryBufferRef Source) {
 104   Error Err = Error::success();
 105   std::unique_ptr<MachOUniversalBinary> Ret(
 106       new MachOUniversalBinary(Source, Err));
 107   if (Err)
 108     return std::move(Err);
 109   return std::move(Ret);
 110 }
 111
 112 MachOUniversalBinary::MachOUniversalBinary(MemoryBufferRef Source, Error &Err)
 113     : Binary(Binary::ID_MachOUniversalBinary, Source), Magic(0),
 114       NumberOfObjects(0) {
 115   ErrorAsOutParameter ErrAsOutParam(&Err);
 116   if (Data.getBufferSize() < sizeof(MachO::fat_header)) {
 117     Err = make_error<GenericBinaryError>("File too small to be a Mach-O "
 118                                          "universal file",
 119                                          object_error::invalid_file_type);
 120     return;
 121   }
 122   // Check for magic value and sufficient header size.
 123   StringRef Buf = getData();
 124   MachO::fat_header H =
 125       getUniversalBinaryStruct<MachO::fat_header>(Buf.begin());
 126   Magic = H.magic;
 127   NumberOfObjects = H.nfat_arch;
 128   if (NumberOfObjects == 0) {
 129     Err = malformedError("contains zero architecture types");
 130     return;
 131   }
 132   uint32_t MinSize = sizeof(MachO::fat_header);
 133   if (Magic == MachO::FAT_MAGIC)
 134     MinSize += sizeof(MachO::fat_arch) * NumberOfObjects;
 135   else if (Magic == MachO::FAT_MAGIC_64)
 136     MinSize += sizeof(MachO::fat_arch_64) * NumberOfObjects;
 137   else {
 138     Err = malformedError("bad magic number");
 139     return;
 140   }
 141   if (Buf.size() < MinSize) {
 142     Err = malformedError("fat_arch" +
 143                          Twine(Magic == MachO::FAT_MAGIC ? "" : "_64") +
 144                          " structs would extend past the end of the file");
 145     return;
 146   }
 147   for (uint32_t i = 0; i < NumberOfObjects; i++) {
 148     ObjectForArch A(this, i);
 149     uint64_t bigSize = A.getOffset();
 150     bigSize += A.getSize();
 151     if (bigSize > Buf.size()) {
 152       Err = malformedError("offset plus size of cputype (" +
 153         Twine(A.getCPUType()) + ") cpusubtype (" +
 154         Twine(A.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK) +
 155         ") extends past the end of the file");
 156       return;
 157     }
 158
 159     if (A.getAlign() > MaxSectionAlignment) {
 160       Err = malformedError("align (2^" + Twine(A.getAlign()) +
 161                            ") too large for cputype (" + Twine(A.getCPUType()) +
 162                            ") cpusubtype (" +
 163                            Twine(A.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK) +
 164                            ") (maximum 2^" + Twine(MaxSectionAlignment) + ")");
 165       return;
 166     }
 167     if(A.getOffset() % (1 << A.getAlign()) != 0){
 168       Err = malformedError("offset: " + Twine(A.getOffset()) +
 169         " for cputype (" + Twine(A.getCPUType()) + ") cpusubtype (" +
 170         Twine(A.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK) +
 171         ") not aligned on it's alignment (2^" + Twine(A.getAlign()) + ")");
 172       return;
 173     }
 174     if (A.getOffset() < MinSize) {
 175       Err =  malformedError("cputype (" + Twine(A.getCPUType()) + ") "
 176         "cpusubtype (" + Twine(A.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK) +
 177         ") offset " + Twine(A.getOffset()) + " overlaps universal headers");
 178       return;
 179     }
 180   }
 181   for (uint32_t i = 0; i < NumberOfObjects; i++) {
 182     ObjectForArch A(this, i);
 183     for (uint32_t j = i + 1; j < NumberOfObjects; j++) {
 184       ObjectForArch B(this, j);
 185       if (A.getCPUType() == B.getCPUType() &&
 186           (A.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK) ==
 187           (B.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK)) {
 188         Err = malformedError("contains two of the same architecture (cputype "
 189           "(" + Twine(A.getCPUType()) + ") cpusubtype (" +
 190           Twine(A.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK) + "))");
 191         return;
 192       }
 193       if ((A.getOffset() >= B.getOffset() &&
 194            A.getOffset() < B.getOffset() + B.getSize()) ||
 195           (A.getOffset() + A.getSize() > B.getOffset() &&
 196            A.getOffset() + A.getSize() < B.getOffset() + B.getSize()) ||
 197           (A.getOffset() <= B.getOffset() &&
 198            A.getOffset() + A.getSize() >= B.getOffset() + B.getSize())) {
 199         Err =  malformedError("cputype (" + Twine(A.getCPUType()) + ") "
 200           "cpusubtype (" + Twine(A.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK) +
 201           ") at offset " + Twine(A.getOffset()) + " with a size of " +
 202           Twine(A.getSize()) + ", overlaps cputype (" + Twine(B.getCPUType()) +
 203           ") cpusubtype (" + Twine(B.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK)
 204           + ") at offset " + Twine(B.getOffset()) + " with a size of "
 205           + Twine(B.getSize()));
 206         return;
 207       }
 208     }
 209   }
 210   Err = Error::success();
 211 }
 212
 213 Expected<std::unique_ptr<MachOObjectFile>>
 214 MachOUniversalBinary::getObjectForArch(StringRef ArchName) const {
 215   if (Triple(ArchName).getArch() == Triple::ArchType::UnknownArch)
 216     return make_error<GenericBinaryError>("Unknown architecture "
 217                                           "named: " +
 218                                               ArchName,
 219                                           object_error::arch_not_found);
 220
 221   for (auto &Obj : objects())
 222     if (Obj.getArchFlagName() == ArchName)
 223       return Obj.getAsObjectFile();
 224   return make_error<GenericBinaryError>("fat file does not "
 225                                         "contain " +
 226                                             ArchName,
 227                                         object_error::arch_not_found);
 228 }