lib/Object/MachOUniversal.cpp

   1 //===- MachOUniversal.cpp - Mach-O universal binary -------------*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file defines the MachOUniversalBinary class.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Object/MachOUniversal.h"
  15 #include "llvm/Object/Archive.h"
  16 #include "llvm/Object/MachO.h"
  17 #include "llvm/Object/ObjectFile.h"
  18 #include "llvm/Support/Casting.h"
  19 #include "llvm/Support/Host.h"
  20 #include "llvm/Support/MemoryBuffer.h"
  21
  22 using namespace llvm;
  23 using namespace object;
  24
  25 static Error
  26 malformedError(Twine Msg) {
  27   std::string StringMsg = "truncated or malformed fat file (" + Msg.str() + ")";
  28   return make_error<GenericBinaryError>(std::move(StringMsg),
  29                                         object_error::parse_failed);
  30 }
  31
  32 template<typename T>
  33 static T getUniversalBinaryStruct(const char *Ptr) {
  34   T Res;
  35   memcpy(&Res, Ptr, sizeof(T));
  36   // Universal binary headers have big-endian byte order.
  37   if (sys::IsLittleEndianHost)
  38     swapStruct(Res);
  39   return Res;
  40 }
  41
  42 MachOUniversalBinary::ObjectForArch::ObjectForArch(
  43     const MachOUniversalBinary *Parent, uint32_t Index)
  44     : Parent(Parent), Index(Index) {
  45   // The iterators use Parent as a nullptr and an Index+1 == NumberOfObjects.
  46   if (!Parent || Index >= Parent->getNumberOfObjects()) {
  47     clear();
  48   } else {
  49     // Parse object header.
  50     StringRef ParentData = Parent->getData();
  51     if (Parent->getMagic() == MachO::FAT_MAGIC) {
  52       const char *HeaderPos = ParentData.begin() + sizeof(MachO::fat_header) +
  53                               Index * sizeof(MachO::fat_arch);
  54       Header = getUniversalBinaryStruct<MachO::fat_arch>(HeaderPos);
  55     } else { // Parent->getMagic() == MachO::FAT_MAGIC_64
  56       const char *HeaderPos = ParentData.begin() + sizeof(MachO::fat_header) +
  57                               Index * sizeof(MachO::fat_arch_64);
  58       Header64 = getUniversalBinaryStruct<MachO::fat_arch_64>(HeaderPos);
  59     }
  60   }
  61 }
  62
  63 Expected<std::unique_ptr<MachOObjectFile>>
  64 MachOUniversalBinary::ObjectForArch::getAsObjectFile() const {
  65   if (!Parent)
  66     report_fatal_error("MachOUniversalBinary::ObjectForArch::getAsObjectFile() "
  67                        "called when Parent is a nullptr");
  68
  69   StringRef ParentData = Parent->getData();
  70   StringRef ObjectData;
  71   uint32_t cputype;
  72   if (Parent->getMagic() == MachO::FAT_MAGIC) {
  73     ObjectData = ParentData.substr(Header.offset, Header.size);
  74     cputype = Header.cputype;
  75   } else { // Parent->getMagic() == MachO::FAT_MAGIC_64
  76     ObjectData = ParentData.substr(Header64.offset, Header64.size);
  77     cputype = Header64.cputype;
  78   }
  79   StringRef ObjectName = Parent->getFileName();
  80   MemoryBufferRef ObjBuffer(ObjectData, ObjectName);
  81   return ObjectFile::createMachOObjectFile(ObjBuffer, cputype, Index);
  82 }
  83
  84 Expected<std::unique_ptr<Archive>>
  85 MachOUniversalBinary::ObjectForArch::getAsArchive() const {
  86   if (!Parent)
  87     report_fatal_error("MachOUniversalBinary::ObjectForArch::getAsArchive() "
  88                        "called when Parent is a nullptr");
  89
  90   StringRef ParentData = Parent->getData();
  91   StringRef ObjectData;
  92   if (Parent->getMagic() == MachO::FAT_MAGIC)
  93     ObjectData = ParentData.substr(Header.offset, Header.size);
  94   else // Parent->getMagic() == MachO::FAT_MAGIC_64
  95     ObjectData = ParentData.substr(Header64.offset, Header64.size);
  96   StringRef ObjectName = Parent->getFileName();
  97   MemoryBufferRef ObjBuffer(ObjectData, ObjectName);
  98   return Archive::create(ObjBuffer);
  99 }
 100
 101 void MachOUniversalBinary::anchor() { }
 102
 103 Expected<std::unique_ptr<MachOUniversalBinary>>
 104 MachOUniversalBinary::create(MemoryBufferRef Source) {
 105   Error Err = Error::success();
 106   std::unique_ptr<MachOUniversalBinary> Ret(
 107       new MachOUniversalBinary(Source, Err));
 108   if (Err)
 109     return std::move(Err);
 110   return std::move(Ret);
 111 }
 112
 113 MachOUniversalBinary::MachOUniversalBinary(MemoryBufferRef Source, Error &Err)
 114     : Binary(Binary::ID_MachOUniversalBinary, Source), Magic(0),
 115       NumberOfObjects(0) {
 116   ErrorAsOutParameter ErrAsOutParam(&Err);
 117   if (Data.getBufferSize() < sizeof(MachO::fat_header)) {
 118     Err = make_error<GenericBinaryError>("File too small to be a Mach-O "
 119                                          "universal file",
 120                                          object_error::invalid_file_type);
 121     return;
 122   }
 123   // Check for magic value and sufficient header size.
 124   StringRef Buf = getData();
 125   MachO::fat_header H =
 126       getUniversalBinaryStruct<MachO::fat_header>(Buf.begin());
 127   Magic = H.magic;
 128   NumberOfObjects = H.nfat_arch;
 129   if (NumberOfObjects == 0) {
 130     Err = malformedError("contains zero architecture types");
 131     return;
 132   }
 133   uint32_t MinSize = sizeof(MachO::fat_header);
 134   if (Magic == MachO::FAT_MAGIC)
 135     MinSize += sizeof(MachO::fat_arch) * NumberOfObjects;
 136   else if (Magic == MachO::FAT_MAGIC_64)
 137     MinSize += sizeof(MachO::fat_arch_64) * NumberOfObjects;
 138   else {
 139     Err = malformedError("bad magic number");
 140     return;
 141   }
 142   if (Buf.size() < MinSize) {
 143     Err = malformedError("fat_arch" +
 144                          Twine(Magic == MachO::FAT_MAGIC ? "" : "_64") +
 145                          " structs would extend past the end of the file");
 146     return;
 147   }
 148   for (uint32_t i = 0; i < NumberOfObjects; i++) {
 149     ObjectForArch A(this, i);
 150     uint64_t bigSize = A.getOffset();
 151     bigSize += A.getSize();
 152     if (bigSize > Buf.size()) {
 153       Err = malformedError("offset plus size of cputype (" +
 154         Twine(A.getCPUType()) + ") cpusubtype (" +
 155         Twine(A.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK) +
 156         ") extends past the end of the file");
 157       return;
 158     }
 159 #define MAXSECTALIGN 15 /* 2**15 or 0x8000 */
 160     if (A.getAlign() > MAXSECTALIGN) {
 161       Err = malformedError("align (2^" + Twine(A.getAlign()) + ") too large "
 162         "for cputype (" + Twine(A.getCPUType()) + ") cpusubtype (" +
 163         Twine(A.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK) +
 164         ") (maximum 2^" + Twine(MAXSECTALIGN) + ")");
 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 }