1 //===- ArchiveWriter.cpp - ar File Format implementation --------*- 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 writeArchive function.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/Object/ArchiveWriter.h"
15 #include "llvm/ADT/ArrayRef.h"
16 #include "llvm/ADT/StringRef.h"
17 #include "llvm/IR/LLVMContext.h"
18 #include "llvm/Object/Archive.h"
19 #include "llvm/Object/ObjectFile.h"
20 #include "llvm/Object/SymbolicFile.h"
21 #include "llvm/Support/EndianStream.h"
22 #include "llvm/Support/Errc.h"
23 #include "llvm/Support/ErrorHandling.h"
24 #include "llvm/Support/Format.h"
25 #include "llvm/Support/Path.h"
26 #include "llvm/Support/ToolOutputFile.h"
27 #include "llvm/Support/raw_ostream.h"
28 
29 #if !defined(_MSC_VER) && !defined(__MINGW32__)
30 #include <unistd.h>
31 #else
32 #include <io.h>
33 #endif
34 
35 using namespace llvm;
36 
37 NewArchiveIterator::NewArchiveIterator() {}
38 
39 NewArchiveIterator::NewArchiveIterator(object::Archive::child_iterator I,
40                                        StringRef Name)
41     : IsNewMember(false), Name(Name), OldI(I) {}
42 
43 NewArchiveIterator::NewArchiveIterator(StringRef NewFilename, StringRef Name)
44     : IsNewMember(true), Name(Name), NewFilename(NewFilename) {}
45 
46 StringRef NewArchiveIterator::getName() const { return Name; }
47 
48 bool NewArchiveIterator::isNewMember() const { return IsNewMember; }
49 
50 object::Archive::child_iterator NewArchiveIterator::getOld() const {
51   assert(!IsNewMember);
52   return OldI;
53 }
54 
55 StringRef NewArchiveIterator::getNew() const {
56   assert(IsNewMember);
57   return NewFilename;
58 }
59 
60 llvm::ErrorOr<int>
61 NewArchiveIterator::getFD(sys::fs::file_status &NewStatus) const {
62   assert(IsNewMember);
63   int NewFD;
64   if (auto EC = sys::fs::openFileForRead(NewFilename, NewFD))
65     return EC;
66   assert(NewFD != -1);
67 
68   if (auto EC = sys::fs::status(NewFD, NewStatus))
69     return EC;
70 
71   // Opening a directory doesn't make sense. Let it fail.
72   // Linux cannot open directories with open(2), although
73   // cygwin and *bsd can.
74   if (NewStatus.type() == sys::fs::file_type::directory_file)
75     return make_error_code(errc::is_a_directory);
76 
77   return NewFD;
78 }
79 
80 template <typename T>
81 static void printWithSpacePadding(raw_fd_ostream &OS, T Data, unsigned Size,
82 				  bool MayTruncate = false) {
83   uint64_t OldPos = OS.tell();
84   OS << Data;
85   unsigned SizeSoFar = OS.tell() - OldPos;
86   if (Size > SizeSoFar) {
87     OS.indent(Size - SizeSoFar);
88   } else if (Size < SizeSoFar) {
89     assert(MayTruncate && "Data doesn't fit in Size");
90     // Some of the data this is used for (like UID) can be larger than the
91     // space available in the archive format. Truncate in that case.
92     OS.seek(OldPos + Size);
93   }
94 }
95 
96 static void print32BE(raw_ostream &Out, uint32_t Val) {
97   support::endian::Writer<support::big>(Out).write(Val);
98 }
99 
100 static void printRestOfMemberHeader(raw_fd_ostream &Out,
101                                     const sys::TimeValue &ModTime, unsigned UID,
102                                     unsigned GID, unsigned Perms,
103                                     unsigned Size) {
104   printWithSpacePadding(Out, ModTime.toEpochTime(), 12);
105   printWithSpacePadding(Out, UID, 6, true);
106   printWithSpacePadding(Out, GID, 6, true);
107   printWithSpacePadding(Out, format("%o", Perms), 8);
108   printWithSpacePadding(Out, Size, 10);
109   Out << "`\n";
110 }
111 
112 static void printMemberHeader(raw_fd_ostream &Out, StringRef Name,
113                               const sys::TimeValue &ModTime, unsigned UID,
114                               unsigned GID, unsigned Perms, unsigned Size) {
115   printWithSpacePadding(Out, Twine(Name) + "/", 16);
116   printRestOfMemberHeader(Out, ModTime, UID, GID, Perms, Size);
117 }
118 
119 static void printMemberHeader(raw_fd_ostream &Out, unsigned NameOffset,
120                               const sys::TimeValue &ModTime, unsigned UID,
121                               unsigned GID, unsigned Perms, unsigned Size) {
122   Out << '/';
123   printWithSpacePadding(Out, NameOffset, 15);
124   printRestOfMemberHeader(Out, ModTime, UID, GID, Perms, Size);
125 }
126 
127 static void writeStringTable(raw_fd_ostream &Out,
128                              ArrayRef<NewArchiveIterator> Members,
129                              std::vector<unsigned> &StringMapIndexes) {
130   unsigned StartOffset = 0;
131   for (ArrayRef<NewArchiveIterator>::iterator I = Members.begin(),
132                                               E = Members.end();
133        I != E; ++I) {
134     StringRef Name = I->getName();
135     if (Name.size() < 16)
136       continue;
137     if (StartOffset == 0) {
138       printWithSpacePadding(Out, "//", 58);
139       Out << "`\n";
140       StartOffset = Out.tell();
141     }
142     StringMapIndexes.push_back(Out.tell() - StartOffset);
143     Out << Name << "/\n";
144   }
145   if (StartOffset == 0)
146     return;
147   if (Out.tell() % 2)
148     Out << '\n';
149   int Pos = Out.tell();
150   Out.seek(StartOffset - 12);
151   printWithSpacePadding(Out, Pos - StartOffset, 10);
152   Out.seek(Pos);
153 }
154 
155 // Returns the offset of the first reference to a member offset.
156 static ErrorOr<unsigned>
157 writeSymbolTable(raw_fd_ostream &Out, ArrayRef<NewArchiveIterator> Members,
158                  ArrayRef<MemoryBufferRef> Buffers,
159                  std::vector<unsigned> &MemberOffsetRefs) {
160   unsigned StartOffset = 0;
161   unsigned MemberNum = 0;
162   std::string NameBuf;
163   raw_string_ostream NameOS(NameBuf);
164   unsigned NumSyms = 0;
165   LLVMContext Context;
166   for (ArrayRef<NewArchiveIterator>::iterator I = Members.begin(),
167                                               E = Members.end();
168        I != E; ++I, ++MemberNum) {
169     MemoryBufferRef MemberBuffer = Buffers[MemberNum];
170     ErrorOr<std::unique_ptr<object::SymbolicFile>> ObjOrErr =
171         object::SymbolicFile::createSymbolicFile(
172             MemberBuffer, sys::fs::file_magic::unknown, &Context);
173     if (!ObjOrErr)
174       continue;  // FIXME: check only for "not an object file" errors.
175     object::SymbolicFile &Obj = *ObjOrErr.get();
176 
177     if (!StartOffset) {
178       printMemberHeader(Out, "", sys::TimeValue::now(), 0, 0, 0, 0);
179       StartOffset = Out.tell();
180       print32BE(Out, 0);
181     }
182 
183     for (const object::BasicSymbolRef &S : Obj.symbols()) {
184       uint32_t Symflags = S.getFlags();
185       if (Symflags & object::SymbolRef::SF_FormatSpecific)
186         continue;
187       if (!(Symflags & object::SymbolRef::SF_Global))
188         continue;
189       if (Symflags & object::SymbolRef::SF_Undefined)
190         continue;
191       if (auto EC = S.printName(NameOS))
192         return EC;
193       NameOS << '\0';
194       ++NumSyms;
195       MemberOffsetRefs.push_back(MemberNum);
196       print32BE(Out, 0);
197     }
198   }
199   Out << NameOS.str();
200 
201   if (StartOffset == 0)
202     return 0;
203 
204   if (Out.tell() % 2)
205     Out << '\0';
206 
207   unsigned Pos = Out.tell();
208   Out.seek(StartOffset - 12);
209   printWithSpacePadding(Out, Pos - StartOffset, 10);
210   Out.seek(StartOffset);
211   print32BE(Out, NumSyms);
212   Out.seek(Pos);
213   return StartOffset + 4;
214 }
215 
216 std::pair<StringRef, std::error_code>
217 llvm::writeArchive(StringRef ArcName,
218                    std::vector<NewArchiveIterator> &NewMembers,
219                    bool WriteSymtab) {
220   SmallString<128> TmpArchive;
221   int TmpArchiveFD;
222   if (auto EC = sys::fs::createUniqueFile(ArcName + ".temp-archive-%%%%%%%.a",
223                                           TmpArchiveFD, TmpArchive))
224     return std::make_pair(ArcName, EC);
225 
226   tool_output_file Output(TmpArchive, TmpArchiveFD);
227   raw_fd_ostream &Out = Output.os();
228   Out << "!<arch>\n";
229 
230   std::vector<unsigned> MemberOffsetRefs;
231 
232   std::vector<std::unique_ptr<MemoryBuffer>> Buffers;
233   std::vector<MemoryBufferRef> Members;
234   std::vector<sys::fs::file_status> NewMemberStatus;
235 
236   for (unsigned I = 0, N = NewMembers.size(); I < N; ++I) {
237     NewArchiveIterator &Member = NewMembers[I];
238     MemoryBufferRef MemberRef;
239 
240     if (Member.isNewMember()) {
241       StringRef Filename = Member.getNew();
242       NewMemberStatus.resize(NewMemberStatus.size() + 1);
243       sys::fs::file_status &Status = NewMemberStatus.back();
244       ErrorOr<int> FD = Member.getFD(Status);
245       if (auto EC = FD.getError())
246         return std::make_pair(Filename, EC);
247       ErrorOr<std::unique_ptr<MemoryBuffer>> MemberBufferOrErr =
248           MemoryBuffer::getOpenFile(FD.get(), Filename, Status.getSize(),
249                                     false);
250       if (auto EC = MemberBufferOrErr.getError())
251         return std::make_pair(Filename, EC);
252       if (close(FD.get()) != 0)
253         return std::make_pair(Filename,
254                               std::error_code(errno, std::generic_category()));
255       Buffers.push_back(std::move(MemberBufferOrErr.get()));
256       MemberRef = Buffers.back()->getMemBufferRef();
257     } else {
258       object::Archive::child_iterator OldMember = Member.getOld();
259       ErrorOr<MemoryBufferRef> MemberBufferOrErr =
260           OldMember->getMemoryBufferRef();
261       if (auto EC = MemberBufferOrErr.getError())
262         return std::make_pair("", EC);
263       MemberRef = MemberBufferOrErr.get();
264     }
265     Members.push_back(MemberRef);
266   }
267 
268   unsigned MemberReferenceOffset = 0;
269   if (WriteSymtab) {
270     ErrorOr<unsigned> MemberReferenceOffsetOrErr =
271         writeSymbolTable(Out, NewMembers, Members, MemberOffsetRefs);
272     if (auto EC = MemberReferenceOffsetOrErr.getError())
273       return std::make_pair(ArcName, EC);
274     MemberReferenceOffset = MemberReferenceOffsetOrErr.get();
275   }
276 
277   std::vector<unsigned> StringMapIndexes;
278   writeStringTable(Out, NewMembers, StringMapIndexes);
279 
280   unsigned MemberNum = 0;
281   unsigned LongNameMemberNum = 0;
282   unsigned NewMemberNum = 0;
283   std::vector<unsigned> MemberOffset;
284   for (std::vector<NewArchiveIterator>::iterator I = NewMembers.begin(),
285                                                  E = NewMembers.end();
286        I != E; ++I, ++MemberNum) {
287 
288     unsigned Pos = Out.tell();
289     MemberOffset.push_back(Pos);
290 
291     MemoryBufferRef File = Members[MemberNum];
292     if (I->isNewMember()) {
293       StringRef FileName = I->getNew();
294       const sys::fs::file_status &Status = NewMemberStatus[NewMemberNum];
295       NewMemberNum++;
296 
297       StringRef Name = sys::path::filename(FileName);
298       if (Name.size() < 16)
299         printMemberHeader(Out, Name, Status.getLastModificationTime(),
300                           Status.getUser(), Status.getGroup(),
301                           Status.permissions(), Status.getSize());
302       else
303         printMemberHeader(Out, StringMapIndexes[LongNameMemberNum++],
304                           Status.getLastModificationTime(), Status.getUser(),
305                           Status.getGroup(), Status.permissions(),
306                           Status.getSize());
307     } else {
308       object::Archive::child_iterator OldMember = I->getOld();
309       StringRef Name = I->getName();
310 
311       if (Name.size() < 16)
312         printMemberHeader(Out, Name, OldMember->getLastModified(),
313                           OldMember->getUID(), OldMember->getGID(),
314                           OldMember->getAccessMode(), OldMember->getSize());
315       else
316         printMemberHeader(Out, StringMapIndexes[LongNameMemberNum++],
317                           OldMember->getLastModified(), OldMember->getUID(),
318                           OldMember->getGID(), OldMember->getAccessMode(),
319                           OldMember->getSize());
320     }
321 
322     Out << File.getBuffer();
323 
324     if (Out.tell() % 2)
325       Out << '\n';
326   }
327 
328   if (MemberReferenceOffset) {
329     Out.seek(MemberReferenceOffset);
330     for (unsigned MemberNum : MemberOffsetRefs)
331       print32BE(Out, MemberOffset[MemberNum]);
332   }
333 
334   Output.keep();
335   Out.close();
336   sys::fs::rename(TmpArchive, ArcName);
337   return std::make_pair("", std::error_code());
338 }
339