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 template<typename T>
26 static void SwapStruct(T &Value);
27 
28 template<>
29 void SwapStruct(MachO::fat_header &H) {
30   sys::swapByteOrder(H.magic);
31   sys::swapByteOrder(H.nfat_arch);
32 }
33 
34 template<>
35 void SwapStruct(MachO::fat_arch &H) {
36   sys::swapByteOrder(H.cputype);
37   sys::swapByteOrder(H.cpusubtype);
38   sys::swapByteOrder(H.offset);
39   sys::swapByteOrder(H.size);
40   sys::swapByteOrder(H.align);
41 }
42 
43 template<>
44 void SwapStruct(MachO::fat_arch_64 &H) {
45   sys::swapByteOrder(H.cputype);
46   sys::swapByteOrder(H.cpusubtype);
47   sys::swapByteOrder(H.offset);
48   sys::swapByteOrder(H.size);
49   sys::swapByteOrder(H.align);
50   sys::swapByteOrder(H.reserved);
51 }
52 
53 template<typename T>
54 static T getUniversalBinaryStruct(const char *Ptr) {
55   T Res;
56   memcpy(&Res, Ptr, sizeof(T));
57   // Universal binary headers have big-endian byte order.
58   if (sys::IsLittleEndianHost)
59     SwapStruct(Res);
60   return Res;
61 }
62 
63 MachOUniversalBinary::ObjectForArch::ObjectForArch(
64     const MachOUniversalBinary *Parent, uint32_t Index)
65     : Parent(Parent), Index(Index) {
66   if (!Parent || Index >= Parent->getNumberOfObjects()) {
67     clear();
68   } else {
69     // Parse object header.
70     StringRef ParentData = Parent->getData();
71     if (Parent->getMagic() == MachO::FAT_MAGIC) {
72       const char *HeaderPos = ParentData.begin() + sizeof(MachO::fat_header) +
73                               Index * sizeof(MachO::fat_arch);
74       Header = getUniversalBinaryStruct<MachO::fat_arch>(HeaderPos);
75       if (ParentData.size() < Header.offset + Header.size) {
76         clear();
77       }
78     } else { // Parent->getMagic() == MachO::FAT_MAGIC_64
79       const char *HeaderPos = ParentData.begin() + sizeof(MachO::fat_header) +
80                               Index * sizeof(MachO::fat_arch_64);
81       Header64 = getUniversalBinaryStruct<MachO::fat_arch_64>(HeaderPos);
82       if (ParentData.size() < Header64.offset + Header64.size) {
83         clear();
84       }
85     }
86   }
87 }
88 
89 Expected<std::unique_ptr<MachOObjectFile>>
90 MachOUniversalBinary::ObjectForArch::getAsObjectFile() const {
91   if (!Parent)
92     return errorCodeToError(object_error::parse_failed);
93 
94   StringRef ParentData = Parent->getData();
95   StringRef ObjectData;
96   if (Parent->getMagic() == MachO::FAT_MAGIC)
97     ObjectData = ParentData.substr(Header.offset, Header.size);
98   else // Parent->getMagic() == MachO::FAT_MAGIC_64
99     ObjectData = ParentData.substr(Header64.offset, Header64.size);
100   StringRef ObjectName = Parent->getFileName();
101   MemoryBufferRef ObjBuffer(ObjectData, ObjectName);
102   return ObjectFile::createMachOObjectFile(ObjBuffer);
103 }
104 
105 ErrorOr<std::unique_ptr<Archive>>
106 MachOUniversalBinary::ObjectForArch::getAsArchive() const {
107   if (!Parent)
108     return object_error::parse_failed;
109 
110   StringRef ParentData = Parent->getData();
111   StringRef ObjectData;
112   if (Parent->getMagic() == MachO::FAT_MAGIC)
113     ObjectData = ParentData.substr(Header.offset, Header.size);
114   else // Parent->getMagic() == MachO::FAT_MAGIC_64
115     ObjectData = ParentData.substr(Header64.offset, Header64.size);
116   StringRef ObjectName = Parent->getFileName();
117   MemoryBufferRef ObjBuffer(ObjectData, ObjectName);
118   return Archive::create(ObjBuffer);
119 }
120 
121 void MachOUniversalBinary::anchor() { }
122 
123 ErrorOr<std::unique_ptr<MachOUniversalBinary>>
124 MachOUniversalBinary::create(MemoryBufferRef Source) {
125   std::error_code EC;
126   std::unique_ptr<MachOUniversalBinary> Ret(
127       new MachOUniversalBinary(Source, EC));
128   if (EC)
129     return EC;
130   return std::move(Ret);
131 }
132 
133 MachOUniversalBinary::MachOUniversalBinary(MemoryBufferRef Source,
134                                            std::error_code &ec)
135     : Binary(Binary::ID_MachOUniversalBinary, Source), Magic(0),
136       NumberOfObjects(0) {
137   if (Data.getBufferSize() < sizeof(MachO::fat_header)) {
138     ec = object_error::invalid_file_type;
139     return;
140   }
141   // Check for magic value and sufficient header size.
142   StringRef Buf = getData();
143   MachO::fat_header H= getUniversalBinaryStruct<MachO::fat_header>(Buf.begin());
144   Magic = H.magic;
145   NumberOfObjects = H.nfat_arch;
146   uint32_t MinSize = sizeof(MachO::fat_header);
147   if (Magic == MachO::FAT_MAGIC)
148     MinSize += sizeof(MachO::fat_arch) * NumberOfObjects;
149   else if (Magic == MachO::FAT_MAGIC_64)
150     MinSize += sizeof(MachO::fat_arch_64) * NumberOfObjects;
151   else {
152     ec = object_error::parse_failed;
153     return;
154   }
155   if (Buf.size() < MinSize) {
156     ec = object_error::parse_failed;
157     return;
158   }
159   ec = std::error_code();
160 }
161 
162 Expected<std::unique_ptr<MachOObjectFile>>
163 MachOUniversalBinary::getObjectForArch(StringRef ArchName) const {
164   if (Triple(ArchName).getArch() == Triple::ArchType::UnknownArch)
165     return errorCodeToError(object_error::arch_not_found);
166 
167   for (object_iterator I = begin_objects(), E = end_objects(); I != E; ++I) {
168     if (I->getArchTypeName() == ArchName)
169       return I->getAsObjectFile();
170   }
171   return errorCodeToError(object_error::arch_not_found);
172 }
173