1 //===- ArchiveWriter.cpp - ar File Format implementation --------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the writeArchive function.
12 //===----------------------------------------------------------------------===//
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"
29 #if !defined(_MSC_VER) && !defined(__MINGW32__)
37 NewArchiveMember::NewArchiveMember(MemoryBufferRef BufRef)
38 : Buf(MemoryBuffer::getMemBuffer(BufRef, false)) {}
40 Expected<NewArchiveMember>
41 NewArchiveMember::getOldMember(const object::Archive::Child &OldMember,
43 Expected<llvm::MemoryBufferRef> BufOrErr = OldMember.getMemoryBufferRef();
45 return BufOrErr.takeError();
48 assert(M.IsNew == false);
49 M.Buf = MemoryBuffer::getMemBuffer(*BufOrErr, false);
51 auto ModTimeOrErr = OldMember.getLastModified();
53 return ModTimeOrErr.takeError();
54 M.ModTime = ModTimeOrErr.get();
55 Expected<unsigned> UIDOrErr = OldMember.getUID();
57 return UIDOrErr.takeError();
58 M.UID = UIDOrErr.get();
59 Expected<unsigned> GIDOrErr = OldMember.getGID();
61 return GIDOrErr.takeError();
62 M.GID = GIDOrErr.get();
63 Expected<sys::fs::perms> AccessModeOrErr = OldMember.getAccessMode();
65 return AccessModeOrErr.takeError();
66 M.Perms = AccessModeOrErr.get();
71 Expected<NewArchiveMember> NewArchiveMember::getFile(StringRef FileName,
73 sys::fs::file_status Status;
75 if (auto EC = sys::fs::openFileForRead(FileName, FD))
76 return errorCodeToError(EC);
79 if (auto EC = sys::fs::status(FD, Status))
80 return errorCodeToError(EC);
82 // Opening a directory doesn't make sense. Let it fail.
83 // Linux cannot open directories with open(2), although
84 // cygwin and *bsd can.
85 if (Status.type() == sys::fs::file_type::directory_file)
86 return errorCodeToError(make_error_code(errc::is_a_directory));
88 ErrorOr<std::unique_ptr<MemoryBuffer>> MemberBufferOrErr =
89 MemoryBuffer::getOpenFile(FD, FileName, Status.getSize(), false);
90 if (!MemberBufferOrErr)
91 return errorCodeToError(MemberBufferOrErr.getError());
94 return errorCodeToError(std::error_code(errno, std::generic_category()));
98 M.Buf = std::move(*MemberBufferOrErr);
100 M.ModTime = std::chrono::time_point_cast<std::chrono::seconds>(
101 Status.getLastModificationTime());
102 M.UID = Status.getUser();
103 M.GID = Status.getGroup();
104 M.Perms = Status.permissions();
109 template <typename T>
110 static void printWithSpacePadding(raw_fd_ostream &OS, T Data, unsigned Size,
111 bool MayTruncate = false) {
112 uint64_t OldPos = OS.tell();
114 unsigned SizeSoFar = OS.tell() - OldPos;
115 if (Size > SizeSoFar) {
116 OS.indent(Size - SizeSoFar);
117 } else if (Size < SizeSoFar) {
118 assert(MayTruncate && "Data doesn't fit in Size");
119 // Some of the data this is used for (like UID) can be larger than the
120 // space available in the archive format. Truncate in that case.
121 OS.seek(OldPos + Size);
125 static bool isBSDLike(object::Archive::Kind Kind) {
127 case object::Archive::K_GNU:
129 case object::Archive::K_BSD:
130 case object::Archive::K_DARWIN:
132 case object::Archive::K_MIPS64:
133 case object::Archive::K_DARWIN64:
134 case object::Archive::K_COFF:
137 llvm_unreachable("not supported for writting");
140 static void print32(raw_ostream &Out, object::Archive::Kind Kind,
143 support::endian::Writer<support::little>(Out).write(Val);
145 support::endian::Writer<support::big>(Out).write(Val);
148 static void printRestOfMemberHeader(
149 raw_fd_ostream &Out, const sys::TimePoint<std::chrono::seconds> &ModTime,
150 unsigned UID, unsigned GID, unsigned Perms, unsigned Size) {
151 printWithSpacePadding(Out, sys::toTimeT(ModTime), 12);
152 printWithSpacePadding(Out, UID, 6, true);
153 printWithSpacePadding(Out, GID, 6, true);
154 printWithSpacePadding(Out, format("%o", Perms), 8);
155 printWithSpacePadding(Out, Size, 10);
160 printGNUSmallMemberHeader(raw_fd_ostream &Out, StringRef Name,
161 const sys::TimePoint<std::chrono::seconds> &ModTime,
162 unsigned UID, unsigned GID, unsigned Perms,
164 printWithSpacePadding(Out, Twine(Name) + "/", 16);
165 printRestOfMemberHeader(Out, ModTime, UID, GID, Perms, Size);
169 printBSDMemberHeader(raw_fd_ostream &Out, StringRef Name,
170 const sys::TimePoint<std::chrono::seconds> &ModTime,
171 unsigned UID, unsigned GID, unsigned Perms,
173 uint64_t PosAfterHeader = Out.tell() + 60 + Name.size();
174 // Pad so that even 64 bit object files are aligned.
175 unsigned Pad = OffsetToAlignment(PosAfterHeader, 8);
176 unsigned NameWithPadding = Name.size() + Pad;
177 printWithSpacePadding(Out, Twine("#1/") + Twine(NameWithPadding), 16);
178 printRestOfMemberHeader(Out, ModTime, UID, GID, Perms,
179 NameWithPadding + Size);
181 assert(PosAfterHeader == Out.tell());
183 Out.write(uint8_t(0));
186 static bool useStringTable(bool Thin, StringRef Name) {
187 return Thin || Name.size() >= 16;
191 printMemberHeader(raw_fd_ostream &Out, object::Archive::Kind Kind, bool Thin,
193 std::vector<unsigned>::iterator &StringMapIndexIter,
194 const sys::TimePoint<std::chrono::seconds> &ModTime,
195 unsigned UID, unsigned GID, unsigned Perms, unsigned Size) {
197 return printBSDMemberHeader(Out, Name, ModTime, UID, GID, Perms, Size);
198 if (!useStringTable(Thin, Name))
199 return printGNUSmallMemberHeader(Out, Name, ModTime, UID, GID, Perms, Size);
201 printWithSpacePadding(Out, *StringMapIndexIter++, 15);
202 printRestOfMemberHeader(Out, ModTime, UID, GID, Perms, Size);
205 // Compute the relative path from From to To.
206 static std::string computeRelativePath(StringRef From, StringRef To) {
207 if (sys::path::is_absolute(From) || sys::path::is_absolute(To))
210 StringRef DirFrom = sys::path::parent_path(From);
211 auto FromI = sys::path::begin(DirFrom);
212 auto ToI = sys::path::begin(To);
213 while (*FromI == *ToI) {
218 SmallString<128> Relative;
219 for (auto FromE = sys::path::end(DirFrom); FromI != FromE; ++FromI)
220 sys::path::append(Relative, "..");
222 for (auto ToE = sys::path::end(To); ToI != ToE; ++ToI)
223 sys::path::append(Relative, *ToI);
226 // Replace backslashes with slashes so that the path is portable between *nix
228 std::replace(Relative.begin(), Relative.end(), '\\', '/');
231 return Relative.str();
234 static void writeStringTable(raw_fd_ostream &Out, StringRef ArcName,
235 ArrayRef<NewArchiveMember> Members,
236 std::vector<unsigned> &StringMapIndexes,
238 unsigned StartOffset = 0;
239 for (const NewArchiveMember &M : Members) {
240 StringRef Path = M.Buf->getBufferIdentifier();
241 StringRef Name = sys::path::filename(Path);
242 if (!useStringTable(Thin, Name))
244 if (StartOffset == 0) {
245 printWithSpacePadding(Out, "//", 58);
247 StartOffset = Out.tell();
249 StringMapIndexes.push_back(Out.tell() - StartOffset);
253 Out << computeRelativePath(ArcName, Path);
255 Out << M.Buf->getBufferIdentifier();
261 if (StartOffset == 0)
265 int Pos = Out.tell();
266 Out.seek(StartOffset - 12);
267 printWithSpacePadding(Out, Pos - StartOffset, 10);
271 static sys::TimePoint<std::chrono::seconds> now(bool Deterministic) {
272 using namespace std::chrono;
275 return time_point_cast<seconds>(system_clock::now());
276 return sys::TimePoint<seconds>();
279 // Returns the offset of the first reference to a member offset.
280 static ErrorOr<unsigned>
281 writeSymbolTable(raw_fd_ostream &Out, object::Archive::Kind Kind,
282 ArrayRef<NewArchiveMember> Members,
283 std::vector<unsigned> &MemberOffsetRefs, bool Deterministic) {
284 unsigned HeaderStartOffset = 0;
285 unsigned BodyStartOffset = 0;
286 SmallString<128> NameBuf;
287 raw_svector_ostream NameOS(NameBuf);
289 for (unsigned MemberNum = 0, N = Members.size(); MemberNum < N; ++MemberNum) {
290 MemoryBufferRef MemberBuffer = Members[MemberNum].Buf->getMemBufferRef();
291 Expected<std::unique_ptr<object::SymbolicFile>> ObjOrErr =
292 object::SymbolicFile::createSymbolicFile(
293 MemberBuffer, sys::fs::file_magic::unknown, &Context);
295 // FIXME: check only for "not an object file" errors.
296 consumeError(ObjOrErr.takeError());
299 object::SymbolicFile &Obj = *ObjOrErr.get();
301 if (!HeaderStartOffset) {
302 HeaderStartOffset = Out.tell();
304 printBSDMemberHeader(Out, "__.SYMDEF", now(Deterministic), 0, 0, 0, 0);
306 printGNUSmallMemberHeader(Out, "", now(Deterministic), 0, 0, 0, 0);
307 BodyStartOffset = Out.tell();
308 print32(Out, Kind, 0); // number of entries or bytes
311 for (const object::BasicSymbolRef &S : Obj.symbols()) {
312 uint32_t Symflags = S.getFlags();
313 if (Symflags & object::SymbolRef::SF_FormatSpecific)
315 if (!(Symflags & object::SymbolRef::SF_Global))
317 if (Symflags & object::SymbolRef::SF_Undefined)
320 unsigned NameOffset = NameOS.tell();
321 if (auto EC = S.printName(NameOS))
324 MemberOffsetRefs.push_back(MemberNum);
326 print32(Out, Kind, NameOffset);
327 print32(Out, Kind, 0); // member offset
331 if (HeaderStartOffset == 0)
334 // ld64 prefers the cctools type archive which pads its string table to a
335 // boundary of sizeof(int32_t).
337 for (unsigned P = OffsetToAlignment(NameOS.tell(), sizeof(int32_t)); P--;)
340 StringRef StringTable = NameOS.str();
342 print32(Out, Kind, StringTable.size()); // byte count of the string table
344 // If there are no symbols, emit an empty symbol table, to satisfy Solaris
345 // tools, older versions of which expect a symbol table in a non-empty
346 // archive, regardless of whether there are any symbols in it.
347 if (StringTable.size() == 0)
348 print32(Out, Kind, 0);
350 // ld64 requires the next member header to start at an offset that is
352 unsigned Pad = OffsetToAlignment(Out.tell(), 4);
354 Out.write(uint8_t(0));
356 // Patch up the size of the symbol table now that we know how big it is.
357 unsigned Pos = Out.tell();
358 const unsigned MemberHeaderSize = 60;
359 Out.seek(HeaderStartOffset + 48); // offset of the size field.
360 printWithSpacePadding(Out, Pos - MemberHeaderSize - HeaderStartOffset, 10);
362 // Patch up the number of symbols.
363 Out.seek(BodyStartOffset);
364 unsigned NumSyms = MemberOffsetRefs.size();
366 print32(Out, Kind, NumSyms * 8);
368 print32(Out, Kind, NumSyms);
371 return BodyStartOffset + 4;
374 std::pair<StringRef, std::error_code>
375 llvm::writeArchive(StringRef ArcName,
376 std::vector<NewArchiveMember> &NewMembers,
377 bool WriteSymtab, object::Archive::Kind Kind,
378 bool Deterministic, bool Thin,
379 std::unique_ptr<MemoryBuffer> OldArchiveBuf) {
380 assert((!Thin || !isBSDLike(Kind)) && "Only the gnu format has a thin mode");
381 SmallString<128> TmpArchive;
383 if (auto EC = sys::fs::createUniqueFile(ArcName + ".temp-archive-%%%%%%%.a",
384 TmpArchiveFD, TmpArchive))
385 return std::make_pair(ArcName, EC);
387 tool_output_file Output(TmpArchive, TmpArchiveFD);
388 raw_fd_ostream &Out = Output.os();
394 std::vector<unsigned> MemberOffsetRefs;
396 unsigned MemberReferenceOffset = 0;
398 ErrorOr<unsigned> MemberReferenceOffsetOrErr = writeSymbolTable(
399 Out, Kind, NewMembers, MemberOffsetRefs, Deterministic);
400 if (auto EC = MemberReferenceOffsetOrErr.getError())
401 return std::make_pair(ArcName, EC);
402 MemberReferenceOffset = MemberReferenceOffsetOrErr.get();
405 std::vector<unsigned> StringMapIndexes;
406 if (!isBSDLike(Kind))
407 writeStringTable(Out, ArcName, NewMembers, StringMapIndexes, Thin);
409 std::vector<unsigned>::iterator StringMapIndexIter = StringMapIndexes.begin();
410 std::vector<unsigned> MemberOffset;
411 for (const NewArchiveMember &M : NewMembers) {
412 MemoryBufferRef File = M.Buf->getMemBufferRef();
413 unsigned Padding = 0;
415 unsigned Pos = Out.tell();
416 MemberOffset.push_back(Pos);
418 // ld64 expects the members to be 8-byte aligned for 64-bit content and at
419 // least 4-byte aligned for 32-bit content. Opt for the larger encoding
420 // uniformly. This matches the behaviour with cctools and ensures that ld64
421 // is happy with archives that we generate.
422 if (Kind == object::Archive::K_DARWIN)
423 Padding = OffsetToAlignment(M.Buf->getBufferSize(), 8);
425 printMemberHeader(Out, Kind, Thin,
426 sys::path::filename(M.Buf->getBufferIdentifier()),
427 StringMapIndexIter, M.ModTime, M.UID, M.GID, M.Perms,
428 M.Buf->getBufferSize() + Padding);
431 Out << File.getBuffer();
439 if (MemberReferenceOffset) {
440 Out.seek(MemberReferenceOffset);
441 for (unsigned MemberNum : MemberOffsetRefs) {
443 Out.seek(Out.tell() + 4); // skip over the string offset
444 print32(Out, Kind, MemberOffset[MemberNum]);
451 // At this point, we no longer need whatever backing memory
452 // was used to generate the NewMembers. On Windows, this buffer
453 // could be a mapped view of the file we want to replace (if
454 // we're updating an existing archive, say). In that case, the
455 // rename would still succeed, but it would leave behind a
456 // temporary file (actually the original file renamed) because
457 // a file cannot be deleted while there's a handle open on it,
458 // only renamed. So by freeing this buffer, this ensures that
459 // the last open handle on the destination file, if any, is
460 // closed before we attempt to rename.
461 OldArchiveBuf.reset();
463 sys::fs::rename(TmpArchive, ArcName);
464 return std::make_pair("", std::error_code());