MachOUniversal.cpp revision 360784 
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
21using namespace llvm;
22using namespace object;
23
24static Error
25malformedError(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
31template<typename T>
32static 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
41MachOUniversalBinary::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
62Expected<std::unique_ptr<MachOObjectFile>>
63MachOUniversalBinary::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
83Expected<std::unique_ptr<Archive>>
84MachOUniversalBinary::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
100void MachOUniversalBinary::anchor() { }
101
102Expected<std::unique_ptr<MachOUniversalBinary>>
103MachOUniversalBinary::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
112MachOUniversalBinary::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() % (1ull << 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
213Expected<MachOUniversalBinary::ObjectForArch>
214MachOUniversalBinary::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  for (const auto &Obj : objects())
221    if (Obj.getArchFlagName() == ArchName)
222      return Obj;
223  return make_error<GenericBinaryError>("fat file does not "
224                                        "contain " +
225                                            ArchName,
226                                        object_error::arch_not_found);
227}
228
229Expected<std::unique_ptr<MachOObjectFile>>
230MachOUniversalBinary::getMachOObjectForArch(StringRef ArchName) const {
231  Expected<ObjectForArch> O = getObjectForArch(ArchName);
232  if (!O)
233    return O.takeError();
234  return O->getAsObjectFile();
235}
236
237Expected<std::unique_ptr<Archive>>
238MachOUniversalBinary::getArchiveForArch(StringRef ArchName) const {
239  Expected<ObjectForArch> O = getObjectForArch(ArchName);
240  if (!O)
241    return O.takeError();
242  return O->getAsArchive();
243}
244