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
22using namespace llvm;
23using namespace object;
24
25static Error
26malformedError(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
32template<typename T>
33static 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
42MachOUniversalBinary::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
63Expected<std::unique_ptr<MachOObjectFile>>
64MachOUniversalBinary::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
84Expected<std::unique_ptr<IRObjectFile>>
85MachOUniversalBinary::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
103Expected<std::unique_ptr<Archive>>
104MachOUniversalBinary::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
120void MachOUniversalBinary::anchor() { }
121
122Expected<std::unique_ptr<MachOUniversalBinary>>
123MachOUniversalBinary::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
132MachOUniversalBinary::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
233Expected<MachOUniversalBinary::ObjectForArch>
234MachOUniversalBinary::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
249Expected<std::unique_ptr<MachOObjectFile>>
250MachOUniversalBinary::getMachOObjectForArch(StringRef ArchName) const {
251  Expected<ObjectForArch> O = getObjectForArch(ArchName);
252  if (!O)
253    return O.takeError();
254  return O->getAsObjectFile();
255}
256
257Expected<std::unique_ptr<IRObjectFile>>
258MachOUniversalBinary::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
266Expected<std::unique_ptr<Archive>>
267MachOUniversalBinary::getArchiveForArch(StringRef ArchName) const {
268  Expected<ObjectForArch> O = getObjectForArch(ArchName);
269  if (!O)
270    return O.takeError();
271  return O->getAsArchive();
272}
273