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llvm-project/llvm/lib/Object/ArchiveWriter.cpp
Rafael Espindola a2ed0b0bab Start adding support for writing archives in BSD format. 
No support for the symbol table yet (but will hopefully add it today).
We always use the long filename format so that we can align the member,
which is an advantage of the BSD format.

llvm-svn: 241721
2015-07-08 20:47:32 +00:00

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//===- ArchiveWriter.cpp - ar File Format implementation --------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the writeArchive function.
//
//===----------------------------------------------------------------------===//
#include "llvm/Object/ArchiveWriter.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/Object/Archive.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Object/SymbolicFile.h"
#include "llvm/Support/EndianStream.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/ToolOutputFile.h"
#include "llvm/Support/raw_ostream.h"
#if !defined(_MSC_VER) && !defined(__MINGW32__)
#include <unistd.h>
#else
#include <io.h>
#endif
using namespace llvm;
NewArchiveIterator::NewArchiveIterator() {}
NewArchiveIterator::NewArchiveIterator(object::Archive::child_iterator I,
StringRef Name)
: IsNewMember(false), Name(Name), OldI(I) {}
NewArchiveIterator::NewArchiveIterator(StringRef NewFilename, StringRef Name)
: IsNewMember(true), Name(Name), NewFilename(NewFilename) {}
StringRef NewArchiveIterator::getName() const { return Name; }
bool NewArchiveIterator::isNewMember() const { return IsNewMember; }
object::Archive::child_iterator NewArchiveIterator::getOld() const {
assert(!IsNewMember);
return OldI;
}
StringRef NewArchiveIterator::getNew() const {
assert(IsNewMember);
return NewFilename;
}
llvm::ErrorOr<int>
NewArchiveIterator::getFD(sys::fs::file_status &NewStatus) const {
assert(IsNewMember);
int NewFD;
if (auto EC = sys::fs::openFileForRead(NewFilename, NewFD))
return EC;
assert(NewFD != -1);
if (auto EC = sys::fs::status(NewFD, NewStatus))
return EC;
// Opening a directory doesn't make sense. Let it fail.
// Linux cannot open directories with open(2), although
// cygwin and *bsd can.
if (NewStatus.type() == sys::fs::file_type::directory_file)
return make_error_code(errc::is_a_directory);
return NewFD;
}
template <typename T>
static void printWithSpacePadding(raw_fd_ostream &OS, T Data, unsigned Size,
bool MayTruncate = false) {
uint64_t OldPos = OS.tell();
OS << Data;
unsigned SizeSoFar = OS.tell() - OldPos;
if (Size > SizeSoFar) {
OS.indent(Size - SizeSoFar);
} else if (Size < SizeSoFar) {
assert(MayTruncate && "Data doesn't fit in Size");
// Some of the data this is used for (like UID) can be larger than the
// space available in the archive format. Truncate in that case.
OS.seek(OldPos + Size);
}
}
static void print32BE(raw_ostream &Out, uint32_t Val) {
support::endian::Writer<support::big>(Out).write(Val);
}
static void printRestOfMemberHeader(raw_fd_ostream &Out,
const sys::TimeValue &ModTime, unsigned UID,
unsigned GID, unsigned Perms,
unsigned Size) {
printWithSpacePadding(Out, ModTime.toEpochTime(), 12);
printWithSpacePadding(Out, UID, 6, true);
printWithSpacePadding(Out, GID, 6, true);
printWithSpacePadding(Out, format("%o", Perms), 8);
printWithSpacePadding(Out, Size, 10);
Out << "`\n";
}
static void printMemberHeader(raw_fd_ostream &Out, StringRef Name,
const sys::TimeValue &ModTime, unsigned UID,
unsigned GID, unsigned Perms, unsigned Size) {
printWithSpacePadding(Out, Twine(Name) + "/", 16);
printRestOfMemberHeader(Out, ModTime, UID, GID, Perms, Size);
}
static void
printMemberHeader(raw_fd_ostream &Out, object::Archive::Kind Kind,
StringRef Name,
std::vector<unsigned>::iterator &StringMapIndexIter,
const sys::TimeValue &ModTime, unsigned UID, unsigned GID,
unsigned Perms, unsigned Size) {
if (Kind == object::Archive::K_BSD) {
uint64_t PosAfterHeader = Out.tell() + 60 + Name.size();
// Pad so that even 64 bit object files are aligned.
unsigned Pad = OffsetToAlignment(PosAfterHeader, 8);
unsigned NameWithPadding = Name.size() + Pad;
printWithSpacePadding(Out, Twine("#1/") + Twine(NameWithPadding), 16);
printRestOfMemberHeader(Out, ModTime, UID, GID, Perms,
NameWithPadding + Size);
Out << Name;
assert(PosAfterHeader == Out.tell());
while (Pad--)
Out.write(uint8_t(0));
return;
}
if (Name.size() < 16) {
printMemberHeader(Out, Name, ModTime, UID, GID, Perms, Size);
return;
}
Out << '/';
printWithSpacePadding(Out, *StringMapIndexIter++, 15);
printRestOfMemberHeader(Out, ModTime, UID, GID, Perms, Size);
}
static void writeStringTable(raw_fd_ostream &Out,
ArrayRef<NewArchiveIterator> Members,
std::vector<unsigned> &StringMapIndexes) {
unsigned StartOffset = 0;
for (ArrayRef<NewArchiveIterator>::iterator I = Members.begin(),
E = Members.end();
I != E; ++I) {
StringRef Name = I->getName();
if (Name.size() < 16)
continue;
if (StartOffset == 0) {
printWithSpacePadding(Out, "//", 58);
Out << "`\n";
StartOffset = Out.tell();
}
StringMapIndexes.push_back(Out.tell() - StartOffset);
Out << Name << "/\n";
}
if (StartOffset == 0)
return;
if (Out.tell() % 2)
Out << '\n';
int Pos = Out.tell();
Out.seek(StartOffset - 12);
printWithSpacePadding(Out, Pos - StartOffset, 10);
Out.seek(Pos);
}
// Returns the offset of the first reference to a member offset.
static ErrorOr<unsigned>
writeSymbolTable(raw_fd_ostream &Out, object::Archive::Kind Kind,
ArrayRef<NewArchiveIterator> Members,
ArrayRef<MemoryBufferRef> Buffers,
std::vector<unsigned> &MemberOffsetRefs) {
if (Kind != object::Archive::K_GNU)
return 0;
unsigned StartOffset = 0;
unsigned MemberNum = 0;
std::string NameBuf;
raw_string_ostream NameOS(NameBuf);
unsigned NumSyms = 0;
LLVMContext Context;
for (ArrayRef<NewArchiveIterator>::iterator I = Members.begin(),
E = Members.end();
I != E; ++I, ++MemberNum) {
MemoryBufferRef MemberBuffer = Buffers[MemberNum];
ErrorOr<std::unique_ptr<object::SymbolicFile>> ObjOrErr =
object::SymbolicFile::createSymbolicFile(
MemberBuffer, sys::fs::file_magic::unknown, &Context);
if (!ObjOrErr)
continue; // FIXME: check only for "not an object file" errors.
object::SymbolicFile &Obj = *ObjOrErr.get();
if (!StartOffset) {
printMemberHeader(Out, "", sys::TimeValue::now(), 0, 0, 0, 0);
StartOffset = Out.tell();
print32BE(Out, 0);
}
for (const object::BasicSymbolRef &S : Obj.symbols()) {
uint32_t Symflags = S.getFlags();
if (Symflags & object::SymbolRef::SF_FormatSpecific)
continue;
if (!(Symflags & object::SymbolRef::SF_Global))
continue;
if (Symflags & object::SymbolRef::SF_Undefined)
continue;
if (auto EC = S.printName(NameOS))
return EC;
NameOS << '\0';
++NumSyms;
MemberOffsetRefs.push_back(MemberNum);
print32BE(Out, 0);
}
}
Out << NameOS.str();
if (StartOffset == 0)
return 0;
if (Out.tell() % 2)
Out << '\0';
unsigned Pos = Out.tell();
Out.seek(StartOffset - 12);
printWithSpacePadding(Out, Pos - StartOffset, 10);
Out.seek(StartOffset);
print32BE(Out, NumSyms);
Out.seek(Pos);
return StartOffset + 4;
}
std::pair<StringRef, std::error_code>
llvm::writeArchive(StringRef ArcName,
std::vector<NewArchiveIterator> &NewMembers,
bool WriteSymtab, object::Archive::Kind Kind) {
SmallString<128> TmpArchive;
int TmpArchiveFD;
if (auto EC = sys::fs::createUniqueFile(ArcName + ".temp-archive-%%%%%%%.a",
TmpArchiveFD, TmpArchive))
return std::make_pair(ArcName, EC);
tool_output_file Output(TmpArchive, TmpArchiveFD);
raw_fd_ostream &Out = Output.os();
Out << "!<arch>\n";
std::vector<unsigned> MemberOffsetRefs;
std::vector<std::unique_ptr<MemoryBuffer>> Buffers;
std::vector<MemoryBufferRef> Members;
std::vector<sys::fs::file_status> NewMemberStatus;
for (unsigned I = 0, N = NewMembers.size(); I < N; ++I) {
NewArchiveIterator &Member = NewMembers[I];
MemoryBufferRef MemberRef;
if (Member.isNewMember()) {
StringRef Filename = Member.getNew();
NewMemberStatus.resize(NewMemberStatus.size() + 1);
sys::fs::file_status &Status = NewMemberStatus.back();
ErrorOr<int> FD = Member.getFD(Status);
if (auto EC = FD.getError())
return std::make_pair(Filename, EC);
ErrorOr<std::unique_ptr<MemoryBuffer>> MemberBufferOrErr =
MemoryBuffer::getOpenFile(FD.get(), Filename, Status.getSize(),
false);
if (auto EC = MemberBufferOrErr.getError())
return std::make_pair(Filename, EC);
if (close(FD.get()) != 0)
return std::make_pair(Filename,
std::error_code(errno, std::generic_category()));
Buffers.push_back(std::move(MemberBufferOrErr.get()));
MemberRef = Buffers.back()->getMemBufferRef();
} else {
object::Archive::child_iterator OldMember = Member.getOld();
ErrorOr<MemoryBufferRef> MemberBufferOrErr =
OldMember->getMemoryBufferRef();
if (auto EC = MemberBufferOrErr.getError())
return std::make_pair("", EC);
MemberRef = MemberBufferOrErr.get();
}
Members.push_back(MemberRef);
}
unsigned MemberReferenceOffset = 0;
if (WriteSymtab) {
ErrorOr<unsigned> MemberReferenceOffsetOrErr =
writeSymbolTable(Out, Kind, NewMembers, Members, MemberOffsetRefs);
if (auto EC = MemberReferenceOffsetOrErr.getError())
return std::make_pair(ArcName, EC);
MemberReferenceOffset = MemberReferenceOffsetOrErr.get();
}
std::vector<unsigned> StringMapIndexes;
if (Kind != object::Archive::K_BSD)
writeStringTable(Out, NewMembers, StringMapIndexes);
unsigned MemberNum = 0;
unsigned NewMemberNum = 0;
std::vector<unsigned>::iterator StringMapIndexIter = StringMapIndexes.begin();
std::vector<unsigned> MemberOffset;
for (const NewArchiveIterator &I : NewMembers) {
MemoryBufferRef File = Members[MemberNum++];
unsigned Pos = Out.tell();
MemberOffset.push_back(Pos);
if (I.isNewMember()) {
StringRef FileName = I.getNew();
const sys::fs::file_status &Status = NewMemberStatus[NewMemberNum++];
printMemberHeader(Out, Kind, sys::path::filename(FileName),
StringMapIndexIter, Status.getLastModificationTime(),
Status.getUser(), Status.getGroup(),
Status.permissions(), Status.getSize());
} else {
object::Archive::child_iterator OldMember = I.getOld();
printMemberHeader(Out, Kind, I.getName(), StringMapIndexIter,
OldMember->getLastModified(), OldMember->getUID(),
OldMember->getGID(), OldMember->getAccessMode(),
OldMember->getSize());
}
Out << File.getBuffer();
if (Out.tell() % 2)
Out << '\n';
}
if (MemberReferenceOffset) {
Out.seek(MemberReferenceOffset);
for (unsigned MemberNum : MemberOffsetRefs)
print32BE(Out, MemberOffset[MemberNum]);
}
Output.keep();
Out.close();
sys::fs::rename(TmpArchive, ArcName);
return std::make_pair("", std::error_code());
}
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