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/ErrorHandling.h"
22 #include "llvm/Support/Format.h"
23 #include "llvm/Support/Path.h"
24 #include "llvm/Support/ToolOutputFile.h"
25 #include "llvm/Support/raw_ostream.h"
26 
27 #if !defined(_MSC_VER) && !defined(__MINGW32__)
28 #include <unistd.h>
29 #else
30 #include <io.h>
31 #endif
32 
33 using namespace llvm;
34 
35 NewArchiveIterator::NewArchiveIterator() {}
36 
37 NewArchiveIterator::NewArchiveIterator(object::Archive::child_iterator I,
38                                        StringRef Name)
39     : IsNewMember(false), Name(Name), OldI(I) {}
40 
41 NewArchiveIterator::NewArchiveIterator(StringRef NewFilename, StringRef Name)
42     : IsNewMember(true), Name(Name), NewFilename(NewFilename) {}
43 
44 StringRef NewArchiveIterator::getName() const { return Name; }
45 
46 bool NewArchiveIterator::isNewMember() const { return IsNewMember; }
47 
48 object::Archive::child_iterator NewArchiveIterator::getOld() const {
49   assert(!IsNewMember);
50   return OldI;
51 }
52 
53 StringRef NewArchiveIterator::getNew() const {
54   assert(IsNewMember);
55   return NewFilename;
56 }
57 
58 llvm::ErrorOr<int>
59 NewArchiveIterator::getFD(sys::fs::file_status &NewStatus) const {
60   assert(IsNewMember);
61   int NewFD;
62   if (auto EC = sys::fs::openFileForRead(NewFilename, NewFD))
63     return EC;
64   assert(NewFD != -1);
65 
66   if (auto EC = sys::fs::status(NewFD, NewStatus))
67     return EC;
68 
69   // Opening a directory doesn't make sense. Let it fail.
70   // Linux cannot open directories with open(2), although
71   // cygwin and *bsd can.
72   if (NewStatus.type() == sys::fs::file_type::directory_file)
73     return make_error_code(std::errc::is_a_directory);
74 
75   return NewFD;
76 }
77 
78 template <typename T>
79 static void printWithSpacePadding(raw_fd_ostream &OS, T Data, unsigned Size,
80 				  bool MayTruncate = false) {
81   uint64_t OldPos = OS.tell();
82   OS << Data;
83   unsigned SizeSoFar = OS.tell() - OldPos;
84   if (Size > SizeSoFar) {
85     unsigned Remaining = Size - SizeSoFar;
86     for (unsigned I = 0; I < Remaining; ++I)
87       OS << ' ';
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_fd_ostream &Out, unsigned Val) {
97   // FIXME: Should use Endian.h here.
98   for (int I = 3; I >= 0; --I) {
99     char V = (Val >> (8 * I)) & 0xff;
100     Out << V;
101   }
102 }
103 
104 static void printRestOfMemberHeader(raw_fd_ostream &Out,
105                                     const sys::TimeValue &ModTime, unsigned UID,
106                                     unsigned GID, unsigned Perms,
107                                     unsigned Size) {
108   printWithSpacePadding(Out, ModTime.toEpochTime(), 12);
109   printWithSpacePadding(Out, UID, 6, true);
110   printWithSpacePadding(Out, GID, 6, true);
111   printWithSpacePadding(Out, format("%o", Perms), 8);
112   printWithSpacePadding(Out, Size, 10);
113   Out << "`\n";
114 }
115 
116 static void printMemberHeader(raw_fd_ostream &Out, StringRef Name,
117                               const sys::TimeValue &ModTime, unsigned UID,
118                               unsigned GID, unsigned Perms, unsigned Size) {
119   printWithSpacePadding(Out, Twine(Name) + "/", 16);
120   printRestOfMemberHeader(Out, ModTime, UID, GID, Perms, Size);
121 }
122 
123 static void printMemberHeader(raw_fd_ostream &Out, unsigned NameOffset,
124                               const sys::TimeValue &ModTime, unsigned UID,
125                               unsigned GID, unsigned Perms, unsigned Size) {
126   Out << '/';
127   printWithSpacePadding(Out, NameOffset, 15);
128   printRestOfMemberHeader(Out, ModTime, UID, GID, Perms, Size);
129 }
130 
131 static void writeStringTable(raw_fd_ostream &Out,
132                              ArrayRef<NewArchiveIterator> Members,
133                              std::vector<unsigned> &StringMapIndexes) {
134   unsigned StartOffset = 0;
135   for (ArrayRef<NewArchiveIterator>::iterator I = Members.begin(),
136                                               E = Members.end();
137        I != E; ++I) {
138     StringRef Name = I->getName();
139     if (Name.size() < 16)
140       continue;
141     if (StartOffset == 0) {
142       printWithSpacePadding(Out, "//", 58);
143       Out << "`\n";
144       StartOffset = Out.tell();
145     }
146     StringMapIndexes.push_back(Out.tell() - StartOffset);
147     Out << Name << "/\n";
148   }
149   if (StartOffset == 0)
150     return;
151   if (Out.tell() % 2)
152     Out << '\n';
153   int Pos = Out.tell();
154   Out.seek(StartOffset - 12);
155   printWithSpacePadding(Out, Pos - StartOffset, 10);
156   Out.seek(Pos);
157 }
158 
159 // Returns the offset of the first reference to a member offset.
160 static ErrorOr<unsigned>
161 writeSymbolTable(raw_fd_ostream &Out, ArrayRef<NewArchiveIterator> Members,
162                  ArrayRef<MemoryBufferRef> Buffers,
163                  std::vector<unsigned> &MemberOffsetRefs) {
164   unsigned StartOffset = 0;
165   unsigned MemberNum = 0;
166   std::string NameBuf;
167   raw_string_ostream NameOS(NameBuf);
168   unsigned NumSyms = 0;
169   LLVMContext Context;
170   for (ArrayRef<NewArchiveIterator>::iterator I = Members.begin(),
171                                               E = Members.end();
172        I != E; ++I, ++MemberNum) {
173     MemoryBufferRef MemberBuffer = Buffers[MemberNum];
174     ErrorOr<std::unique_ptr<object::SymbolicFile>> ObjOrErr =
175         object::SymbolicFile::createSymbolicFile(
176             MemberBuffer, sys::fs::file_magic::unknown, &Context);
177     if (!ObjOrErr)
178       continue;  // FIXME: check only for "not an object file" errors.
179     object::SymbolicFile &Obj = *ObjOrErr.get();
180 
181     if (!StartOffset) {
182       printMemberHeader(Out, "", sys::TimeValue::now(), 0, 0, 0, 0);
183       StartOffset = Out.tell();
184       print32BE(Out, 0);
185     }
186 
187     for (const object::BasicSymbolRef &S : Obj.symbols()) {
188       uint32_t Symflags = S.getFlags();
189       if (Symflags & object::SymbolRef::SF_FormatSpecific)
190         continue;
191       if (!(Symflags & object::SymbolRef::SF_Global))
192         continue;
193       if (Symflags & object::SymbolRef::SF_Undefined)
194         continue;
195       if (auto EC = S.printName(NameOS))
196         return EC;
197       NameOS << '\0';
198       ++NumSyms;
199       MemberOffsetRefs.push_back(MemberNum);
200       print32BE(Out, 0);
201     }
202   }
203   Out << NameOS.str();
204 
205   if (StartOffset == 0)
206     return 0;
207 
208   if (Out.tell() % 2)
209     Out << '\0';
210 
211   unsigned Pos = Out.tell();
212   Out.seek(StartOffset - 12);
213   printWithSpacePadding(Out, Pos - StartOffset, 10);
214   Out.seek(StartOffset);
215   print32BE(Out, NumSyms);
216   Out.seek(Pos);
217   return StartOffset + 4;
218 }
219 
220 std::pair<StringRef, std::error_code>
221 llvm::writeArchive(StringRef ArcName,
222                    std::vector<NewArchiveIterator> &NewMembers,
223                    bool WriteSymtab) {
224   SmallString<128> TmpArchive;
225   int TmpArchiveFD;
226   if (auto EC = sys::fs::createUniqueFile(ArcName + ".temp-archive-%%%%%%%.a",
227                                           TmpArchiveFD, TmpArchive))
228     return std::make_pair(ArcName, EC);
229 
230   tool_output_file Output(TmpArchive, TmpArchiveFD);
231   raw_fd_ostream &Out = Output.os();
232   Out << "!<arch>\n";
233 
234   std::vector<unsigned> MemberOffsetRefs;
235 
236   std::vector<std::unique_ptr<MemoryBuffer>> Buffers;
237   std::vector<MemoryBufferRef> Members;
238   std::vector<sys::fs::file_status> NewMemberStatus;
239 
240   for (unsigned I = 0, N = NewMembers.size(); I < N; ++I) {
241     NewArchiveIterator &Member = NewMembers[I];
242     MemoryBufferRef MemberRef;
243 
244     if (Member.isNewMember()) {
245       StringRef Filename = Member.getNew();
246       NewMemberStatus.resize(NewMemberStatus.size() + 1);
247       sys::fs::file_status &Status = NewMemberStatus.back();
248       ErrorOr<int> FD = Member.getFD(Status);
249       if (auto EC = FD.getError())
250         return std::make_pair(Filename, EC);
251       ErrorOr<std::unique_ptr<MemoryBuffer>> MemberBufferOrErr =
252           MemoryBuffer::getOpenFile(FD.get(), Filename, Status.getSize(),
253                                     false);
254       if (auto EC = MemberBufferOrErr.getError())
255         return std::make_pair(Filename, EC);
256       if (close(FD.get()) != 0)
257         return std::make_pair(Filename,
258                               std::error_code(errno, std::generic_category()));
259       Buffers.push_back(std::move(MemberBufferOrErr.get()));
260       MemberRef = Buffers.back()->getMemBufferRef();
261     } else {
262       object::Archive::child_iterator OldMember = Member.getOld();
263       ErrorOr<MemoryBufferRef> MemberBufferOrErr =
264           OldMember->getMemoryBufferRef();
265       if (auto EC = MemberBufferOrErr.getError())
266         return std::make_pair("", EC);
267       MemberRef = MemberBufferOrErr.get();
268     }
269     Members.push_back(MemberRef);
270   }
271 
272   unsigned MemberReferenceOffset = 0;
273   if (WriteSymtab) {
274     ErrorOr<unsigned> MemberReferenceOffsetOrErr =
275         writeSymbolTable(Out, NewMembers, Members, MemberOffsetRefs);
276     if (auto EC = MemberReferenceOffsetOrErr.getError())
277       return std::make_pair(ArcName, EC);
278     MemberReferenceOffset = MemberReferenceOffsetOrErr.get();
279   }
280 
281   std::vector<unsigned> StringMapIndexes;
282   writeStringTable(Out, NewMembers, StringMapIndexes);
283 
284   unsigned MemberNum = 0;
285   unsigned LongNameMemberNum = 0;
286   unsigned NewMemberNum = 0;
287   std::vector<unsigned> MemberOffset;
288   for (std::vector<NewArchiveIterator>::iterator I = NewMembers.begin(),
289                                                  E = NewMembers.end();
290        I != E; ++I, ++MemberNum) {
291 
292     unsigned Pos = Out.tell();
293     MemberOffset.push_back(Pos);
294 
295     MemoryBufferRef File = Members[MemberNum];
296     if (I->isNewMember()) {
297       StringRef FileName = I->getNew();
298       const sys::fs::file_status &Status = NewMemberStatus[NewMemberNum];
299       NewMemberNum++;
300 
301       StringRef Name = sys::path::filename(FileName);
302       if (Name.size() < 16)
303         printMemberHeader(Out, Name, Status.getLastModificationTime(),
304                           Status.getUser(), Status.getGroup(),
305                           Status.permissions(), Status.getSize());
306       else
307         printMemberHeader(Out, StringMapIndexes[LongNameMemberNum++],
308                           Status.getLastModificationTime(), Status.getUser(),
309                           Status.getGroup(), Status.permissions(),
310                           Status.getSize());
311     } else {
312       object::Archive::child_iterator OldMember = I->getOld();
313       StringRef Name = I->getName();
314 
315       if (Name.size() < 16)
316         printMemberHeader(Out, Name, OldMember->getLastModified(),
317                           OldMember->getUID(), OldMember->getGID(),
318                           OldMember->getAccessMode(), OldMember->getSize());
319       else
320         printMemberHeader(Out, StringMapIndexes[LongNameMemberNum++],
321                           OldMember->getLastModified(), OldMember->getUID(),
322                           OldMember->getGID(), OldMember->getAccessMode(),
323                           OldMember->getSize());
324     }
325 
326     Out << File.getBuffer();
327 
328     if (Out.tell() % 2)
329       Out << '\n';
330   }
331 
332   if (MemberReferenceOffset) {
333     Out.seek(MemberReferenceOffset);
334     for (unsigned MemberNum : MemberOffsetRefs)
335       print32BE(Out, MemberOffset[MemberNum]);
336   }
337 
338   Output.keep();
339   Out.close();
340   sys::fs::rename(TmpArchive, ArcName);
341   return std::make_pair("", std::error_code());
342 }
343