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/IRObjectFile.h"
16 #include "llvm/Object/MachO.h"
17 #include "llvm/Object/ObjectFile.h"
18 #include "llvm/Support/ErrorHandling.h"
19 #include "llvm/Support/SwapByteOrder.h"
20 #include "llvm/Support/type_traits.h"
21 
22 using namespace llvm;
23 using namespace object;
24 
25 static Error
malformedError(Twine Msg)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>
getUniversalBinaryStruct(const char * Ptr)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 
ObjectForArch(const MachOUniversalBinary * Parent,uint32_t Index)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>>
getAsObjectFile() const64 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<IRObjectFile>>
getAsIRObject(LLVMContext & Ctx) const85 MachOUniversalBinary::ObjectForArch::getAsIRObject(LLVMContext &Ctx) const {
86   if (!Parent)
87     report_fatal_error("MachOUniversalBinary::ObjectForArch::getAsIRObject() "
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   }
97   StringRef ObjectName = Parent->getFileName();
98   MemoryBufferRef ObjBuffer(ObjectData, ObjectName);
99 
100   return IRObjectFile::create(ObjBuffer, Ctx);
101 }
102 
103 Expected<std::unique_ptr<Archive>>
getAsArchive() const104 MachOUniversalBinary::ObjectForArch::getAsArchive() const {
105   if (!Parent)
106     report_fatal_error("MachOUniversalBinary::ObjectForArch::getAsArchive() "
107                        "called when Parent is a nullptr");
108 
109   StringRef ParentData = Parent->getData();
110   StringRef ObjectData;
111   if (Parent->getMagic() == MachO::FAT_MAGIC)
112     ObjectData = ParentData.substr(Header.offset, Header.size);
113   else // Parent->getMagic() == MachO::FAT_MAGIC_64
114     ObjectData = ParentData.substr(Header64.offset, Header64.size);
115   StringRef ObjectName = Parent->getFileName();
116   MemoryBufferRef ObjBuffer(ObjectData, ObjectName);
117   return Archive::create(ObjBuffer);
118 }
119 
anchor()120 void MachOUniversalBinary::anchor() { }
121 
122 Expected<std::unique_ptr<MachOUniversalBinary>>
create(MemoryBufferRef Source)123 MachOUniversalBinary::create(MemoryBufferRef Source) {
124   Error Err = Error::success();
125   std::unique_ptr<MachOUniversalBinary> Ret(
126       new MachOUniversalBinary(Source, Err));
127   if (Err)
128     return std::move(Err);
129   return std::move(Ret);
130 }
131 
MachOUniversalBinary(MemoryBufferRef Source,Error & Err)132 MachOUniversalBinary::MachOUniversalBinary(MemoryBufferRef Source, Error &Err)
133     : Binary(Binary::ID_MachOUniversalBinary, Source), Magic(0),
134       NumberOfObjects(0) {
135   ErrorAsOutParameter ErrAsOutParam(&Err);
136   if (Data.getBufferSize() < sizeof(MachO::fat_header)) {
137     Err = make_error<GenericBinaryError>("File too small to be a Mach-O "
138                                          "universal file",
139                                          object_error::invalid_file_type);
140     return;
141   }
142   // Check for magic value and sufficient header size.
143   StringRef Buf = getData();
144   MachO::fat_header H =
145       getUniversalBinaryStruct<MachO::fat_header>(Buf.begin());
146   Magic = H.magic;
147   NumberOfObjects = H.nfat_arch;
148   if (NumberOfObjects == 0) {
149     Err = malformedError("contains zero architecture types");
150     return;
151   }
152   uint32_t MinSize = sizeof(MachO::fat_header);
153   if (Magic == MachO::FAT_MAGIC)
154     MinSize += sizeof(MachO::fat_arch) * NumberOfObjects;
155   else if (Magic == MachO::FAT_MAGIC_64)
156     MinSize += sizeof(MachO::fat_arch_64) * NumberOfObjects;
157   else {
158     Err = malformedError("bad magic number");
159     return;
160   }
161   if (Buf.size() < MinSize) {
162     Err = malformedError("fat_arch" +
163                          Twine(Magic == MachO::FAT_MAGIC ? "" : "_64") +
164                          " structs would extend past the end of the file");
165     return;
166   }
167   for (uint32_t i = 0; i < NumberOfObjects; i++) {
168     ObjectForArch A(this, i);
169     uint64_t bigSize = A.getOffset();
170     bigSize += A.getSize();
171     if (bigSize > Buf.size()) {
172       Err = malformedError("offset plus size of cputype (" +
173         Twine(A.getCPUType()) + ") cpusubtype (" +
174         Twine(A.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK) +
175         ") extends past the end of the file");
176       return;
177     }
178 
179     if (A.getAlign() > MaxSectionAlignment) {
180       Err = malformedError("align (2^" + Twine(A.getAlign()) +
181                            ") too large for cputype (" + Twine(A.getCPUType()) +
182                            ") cpusubtype (" +
183                            Twine(A.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK) +
184                            ") (maximum 2^" + Twine(MaxSectionAlignment) + ")");
185       return;
186     }
187     if(A.getOffset() % (1ull << A.getAlign()) != 0){
188       Err = malformedError("offset: " + Twine(A.getOffset()) +
189         " for cputype (" + Twine(A.getCPUType()) + ") cpusubtype (" +
190         Twine(A.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK) +
191         ") not aligned on it's alignment (2^" + Twine(A.getAlign()) + ")");
192       return;
193     }
194     if (A.getOffset() < MinSize) {
195       Err =  malformedError("cputype (" + Twine(A.getCPUType()) + ") "
196         "cpusubtype (" + Twine(A.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK) +
197         ") offset " + Twine(A.getOffset()) + " overlaps universal headers");
198       return;
199     }
200   }
201   for (uint32_t i = 0; i < NumberOfObjects; i++) {
202     ObjectForArch A(this, i);
203     for (uint32_t j = i + 1; j < NumberOfObjects; j++) {
204       ObjectForArch B(this, j);
205       if (A.getCPUType() == B.getCPUType() &&
206           (A.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK) ==
207           (B.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK)) {
208         Err = malformedError("contains two of the same architecture (cputype "
209           "(" + Twine(A.getCPUType()) + ") cpusubtype (" +
210           Twine(A.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK) + "))");
211         return;
212       }
213       if ((A.getOffset() >= B.getOffset() &&
214            A.getOffset() < B.getOffset() + B.getSize()) ||
215           (A.getOffset() + A.getSize() > B.getOffset() &&
216            A.getOffset() + A.getSize() < B.getOffset() + B.getSize()) ||
217           (A.getOffset() <= B.getOffset() &&
218            A.getOffset() + A.getSize() >= B.getOffset() + B.getSize())) {
219         Err =  malformedError("cputype (" + Twine(A.getCPUType()) + ") "
220           "cpusubtype (" + Twine(A.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK) +
221           ") at offset " + Twine(A.getOffset()) + " with a size of " +
222           Twine(A.getSize()) + ", overlaps cputype (" + Twine(B.getCPUType()) +
223           ") cpusubtype (" + Twine(B.getCPUSubType() & ~MachO::CPU_SUBTYPE_MASK)
224           + ") at offset " + Twine(B.getOffset()) + " with a size of "
225           + Twine(B.getSize()));
226         return;
227       }
228     }
229   }
230   Err = Error::success();
231 }
232 
233 Expected<MachOUniversalBinary::ObjectForArch>
getObjectForArch(StringRef ArchName) const234 MachOUniversalBinary::getObjectForArch(StringRef ArchName) const {
235   if (Triple(ArchName).getArch() == Triple::ArchType::UnknownArch)
236     return make_error<GenericBinaryError>("Unknown architecture "
237                                           "named: " +
238                                               ArchName,
239                                           object_error::arch_not_found);
240   for (const auto &Obj : objects())
241     if (Obj.getArchFlagName() == ArchName)
242       return Obj;
243   return make_error<GenericBinaryError>("fat file does not "
244                                         "contain " +
245                                             ArchName,
246                                         object_error::arch_not_found);
247 }
248 
249 Expected<std::unique_ptr<MachOObjectFile>>
getMachOObjectForArch(StringRef ArchName) const250 MachOUniversalBinary::getMachOObjectForArch(StringRef ArchName) const {
251   Expected<ObjectForArch> O = getObjectForArch(ArchName);
252   if (!O)
253     return O.takeError();
254   return O->getAsObjectFile();
255 }
256 
257 Expected<std::unique_ptr<IRObjectFile>>
getIRObjectForArch(StringRef ArchName,LLVMContext & Ctx) const258 MachOUniversalBinary::getIRObjectForArch(StringRef ArchName,
259                                          LLVMContext &Ctx) const {
260   Expected<ObjectForArch> O = getObjectForArch(ArchName);
261   if (!O)
262     return O.takeError();
263   return O->getAsIRObject(Ctx);
264 }
265 
266 Expected<std::unique_ptr<Archive>>
getArchiveForArch(StringRef ArchName) const267 MachOUniversalBinary::getArchiveForArch(StringRef ArchName) const {
268   Expected<ObjectForArch> O = getObjectForArch(ArchName);
269   if (!O)
270     return O.takeError();
271   return O->getAsArchive();
272 }
273