1 //===- llvm-objcopy.cpp ---------------------------------------------------===//
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 #include "llvm-objcopy.h"
10 #include "COFF/COFFObjcopy.h"
11 #include "CopyConfig.h"
12 #include "ELF/ELFObjcopy.h"
13 #include "MachO/MachOObjcopy.h"
14 #include "wasm/WasmObjcopy.h"
15 
16 #include "llvm/ADT/STLExtras.h"
17 #include "llvm/ADT/SmallVector.h"
18 #include "llvm/ADT/StringRef.h"
19 #include "llvm/ADT/Twine.h"
20 #include "llvm/BinaryFormat/ELF.h"
21 #include "llvm/Object/Archive.h"
22 #include "llvm/Object/ArchiveWriter.h"
23 #include "llvm/Object/Binary.h"
24 #include "llvm/Object/COFF.h"
25 #include "llvm/Object/ELFObjectFile.h"
26 #include "llvm/Object/ELFTypes.h"
27 #include "llvm/Object/Error.h"
28 #include "llvm/Object/MachO.h"
29 #include "llvm/Object/MachOUniversal.h"
30 #include "llvm/Object/Wasm.h"
31 #include "llvm/Option/Arg.h"
32 #include "llvm/Option/ArgList.h"
33 #include "llvm/Option/Option.h"
34 #include "llvm/Support/Casting.h"
35 #include "llvm/Support/CommandLine.h"
36 #include "llvm/Support/Errc.h"
37 #include "llvm/Support/Error.h"
38 #include "llvm/Support/ErrorHandling.h"
39 #include "llvm/Support/ErrorOr.h"
40 #include "llvm/Support/Host.h"
41 #include "llvm/Support/InitLLVM.h"
42 #include "llvm/Support/Memory.h"
43 #include "llvm/Support/Path.h"
44 #include "llvm/Support/Process.h"
45 #include "llvm/Support/SmallVectorMemoryBuffer.h"
46 #include "llvm/Support/StringSaver.h"
47 #include "llvm/Support/WithColor.h"
48 #include "llvm/Support/raw_ostream.h"
49 #include <algorithm>
50 #include <cassert>
51 #include <cstdlib>
52 #include <memory>
53 #include <string>
54 #include <system_error>
55 #include <utility>
56 
57 namespace llvm {
58 namespace objcopy {
59 
60 // The name this program was invoked as.
61 StringRef ToolName;
62 
63 ErrorSuccess reportWarning(Error E) {
64   assert(E);
65   WithColor::warning(errs(), ToolName) << toString(std::move(E)) << '\n';
66   return Error::success();
67 }
68 
69 static Expected<DriverConfig> getDriverConfig(ArrayRef<const char *> Args) {
70   StringRef Stem = sys::path::stem(ToolName);
71   auto Is = [=](StringRef Tool) {
72     // We need to recognize the following filenames:
73     //
74     // llvm-objcopy -> objcopy
75     // strip-10.exe -> strip
76     // powerpc64-unknown-freebsd13-objcopy -> objcopy
77     // llvm-install-name-tool -> install-name-tool
78     auto I = Stem.rfind_lower(Tool);
79     return I != StringRef::npos &&
80            (I + Tool.size() == Stem.size() || !isAlnum(Stem[I + Tool.size()]));
81   };
82 
83   if (Is("bitcode-strip") || Is("bitcode_strip"))
84     return parseBitcodeStripOptions(Args);
85   else if (Is("strip"))
86     return parseStripOptions(Args, reportWarning);
87   else if (Is("install-name-tool") || Is("install_name_tool"))
88     return parseInstallNameToolOptions(Args);
89   else
90     return parseObjcopyOptions(Args, reportWarning);
91 }
92 
93 } // end namespace objcopy
94 } // end namespace llvm
95 
96 using namespace llvm;
97 using namespace llvm::object;
98 using namespace llvm::objcopy;
99 
100 // For regular archives this function simply calls llvm::writeArchive,
101 // For thin archives it writes the archive file itself as well as its members.
102 static Error deepWriteArchive(StringRef ArcName,
103                               ArrayRef<NewArchiveMember> NewMembers,
104                               bool WriteSymtab, object::Archive::Kind Kind,
105                               bool Deterministic, bool Thin) {
106   if (Error E = writeArchive(ArcName, NewMembers, WriteSymtab, Kind,
107                              Deterministic, Thin))
108     return createFileError(ArcName, std::move(E));
109 
110   if (!Thin)
111     return Error::success();
112 
113   for (const NewArchiveMember &Member : NewMembers) {
114     // For regular files (as is the case for deepWriteArchive),
115     // FileOutputBuffer::create will return OnDiskBuffer.
116     // OnDiskBuffer uses a temporary file and then renames it. So in reality
117     // there is no inefficiency / duplicated in-memory buffers in this case. For
118     // now in-memory buffers can not be completely avoided since
119     // NewArchiveMember still requires them even though writeArchive does not
120     // write them on disk.
121     Expected<std::unique_ptr<FileOutputBuffer>> FB =
122         FileOutputBuffer::create(Member.MemberName, Member.Buf->getBufferSize(),
123                                  FileOutputBuffer::F_executable);
124     if (!FB)
125       return FB.takeError();
126     std::copy(Member.Buf->getBufferStart(), Member.Buf->getBufferEnd(),
127               (*FB)->getBufferStart());
128     if (Error E = (*FB)->commit())
129       return E;
130   }
131   return Error::success();
132 }
133 
134 /// The function executeObjcopyOnIHex does the dispatch based on the format
135 /// of the output specified by the command line options.
136 static Error executeObjcopyOnIHex(CopyConfig &Config, MemoryBuffer &In,
137                                   raw_ostream &Out) {
138   // TODO: support output formats other than ELF.
139   if (Error E = Config.parseELFConfig())
140     return E;
141   return elf::executeObjcopyOnIHex(Config, In, Out);
142 }
143 
144 /// The function executeObjcopyOnRawBinary does the dispatch based on the format
145 /// of the output specified by the command line options.
146 static Error executeObjcopyOnRawBinary(CopyConfig &Config, MemoryBuffer &In,
147                                        raw_ostream &Out) {
148   switch (Config.OutputFormat) {
149   case FileFormat::ELF:
150   // FIXME: Currently, we call elf::executeObjcopyOnRawBinary even if the
151   // output format is binary/ihex or it's not given. This behavior differs from
152   // GNU objcopy. See https://bugs.llvm.org/show_bug.cgi?id=42171 for details.
153   case FileFormat::Binary:
154   case FileFormat::IHex:
155   case FileFormat::Unspecified:
156     if (Error E = Config.parseELFConfig())
157       return E;
158     return elf::executeObjcopyOnRawBinary(Config, In, Out);
159   }
160 
161   llvm_unreachable("unsupported output format");
162 }
163 
164 /// The function executeObjcopyOnBinary does the dispatch based on the format
165 /// of the input binary (ELF, MachO or COFF).
166 static Error executeObjcopyOnBinary(CopyConfig &Config, object::Binary &In,
167                                     raw_ostream &Out) {
168   if (auto *ELFBinary = dyn_cast<object::ELFObjectFileBase>(&In)) {
169     if (Error E = Config.parseELFConfig())
170       return E;
171     return elf::executeObjcopyOnBinary(Config, *ELFBinary, Out);
172   } else if (auto *COFFBinary = dyn_cast<object::COFFObjectFile>(&In))
173     return coff::executeObjcopyOnBinary(Config, *COFFBinary, Out);
174   else if (auto *MachOBinary = dyn_cast<object::MachOObjectFile>(&In))
175     return macho::executeObjcopyOnBinary(Config, *MachOBinary, Out);
176   else if (auto *MachOUniversalBinary =
177                dyn_cast<object::MachOUniversalBinary>(&In))
178     return macho::executeObjcopyOnMachOUniversalBinary(
179         Config, *MachOUniversalBinary, Out);
180   else if (auto *WasmBinary = dyn_cast<object::WasmObjectFile>(&In))
181     return objcopy::wasm::executeObjcopyOnBinary(Config, *WasmBinary, Out);
182   else
183     return createStringError(object_error::invalid_file_type,
184                              "unsupported object file format");
185 }
186 
187 namespace llvm {
188 namespace objcopy {
189 
190 Expected<std::vector<NewArchiveMember>>
191 createNewArchiveMembers(CopyConfig &Config, const Archive &Ar) {
192   std::vector<NewArchiveMember> NewArchiveMembers;
193   Error Err = Error::success();
194   for (const Archive::Child &Child : Ar.children(Err)) {
195     Expected<StringRef> ChildNameOrErr = Child.getName();
196     if (!ChildNameOrErr)
197       return createFileError(Ar.getFileName(), ChildNameOrErr.takeError());
198 
199     Expected<std::unique_ptr<Binary>> ChildOrErr = Child.getAsBinary();
200     if (!ChildOrErr)
201       return createFileError(Ar.getFileName() + "(" + *ChildNameOrErr + ")",
202                              ChildOrErr.takeError());
203 
204     SmallVector<char, 0> Buffer;
205     raw_svector_ostream MemStream(Buffer);
206 
207     if (Error E = executeObjcopyOnBinary(Config, *ChildOrErr->get(), MemStream))
208       return std::move(E);
209 
210     Expected<NewArchiveMember> Member =
211         NewArchiveMember::getOldMember(Child, Config.DeterministicArchives);
212     if (!Member)
213       return createFileError(Ar.getFileName(), Member.takeError());
214 
215     Member->Buf = std::make_unique<SmallVectorMemoryBuffer>(
216         std::move(Buffer), ChildNameOrErr.get());
217     Member->MemberName = Member->Buf->getBufferIdentifier();
218     NewArchiveMembers.push_back(std::move(*Member));
219   }
220   if (Err)
221     return createFileError(Config.InputFilename, std::move(Err));
222   return std::move(NewArchiveMembers);
223 }
224 
225 } // end namespace objcopy
226 } // end namespace llvm
227 
228 static Error executeObjcopyOnArchive(CopyConfig &Config,
229                                      const object::Archive &Ar) {
230   Expected<std::vector<NewArchiveMember>> NewArchiveMembersOrErr =
231       createNewArchiveMembers(Config, Ar);
232   if (!NewArchiveMembersOrErr)
233     return NewArchiveMembersOrErr.takeError();
234   return deepWriteArchive(Config.OutputFilename, *NewArchiveMembersOrErr,
235                           Ar.hasSymbolTable(), Ar.kind(),
236                           Config.DeterministicArchives, Ar.isThin());
237 }
238 
239 static Error restoreStatOnFile(StringRef Filename,
240                                const sys::fs::file_status &Stat,
241                                const CopyConfig &Config) {
242   int FD;
243 
244   // Writing to stdout should not be treated as an error here, just
245   // do not set access/modification times or permissions.
246   if (Filename == "-")
247     return Error::success();
248 
249   if (auto EC =
250           sys::fs::openFileForWrite(Filename, FD, sys::fs::CD_OpenExisting))
251     return createFileError(Filename, EC);
252 
253   if (Config.PreserveDates)
254     if (auto EC = sys::fs::setLastAccessAndModificationTime(
255             FD, Stat.getLastAccessedTime(), Stat.getLastModificationTime()))
256       return createFileError(Filename, EC);
257 
258   sys::fs::file_status OStat;
259   if (std::error_code EC = sys::fs::status(FD, OStat))
260     return createFileError(Filename, EC);
261   if (OStat.type() == sys::fs::file_type::regular_file) {
262 #ifndef _WIN32
263     // Keep ownership if llvm-objcopy is called under root.
264     if (Config.InputFilename == Config.OutputFilename && OStat.getUser() == 0)
265       sys::fs::changeFileOwnership(FD, Stat.getUser(), Stat.getGroup());
266 #endif
267 
268     sys::fs::perms Perm = Stat.permissions();
269     if (Config.InputFilename != Config.OutputFilename)
270       Perm = static_cast<sys::fs::perms>(Perm & ~sys::fs::getUmask() & ~06000);
271 #ifdef _WIN32
272     if (auto EC = sys::fs::setPermissions(Filename, Perm))
273 #else
274     if (auto EC = sys::fs::setPermissions(FD, Perm))
275 #endif
276       return createFileError(Filename, EC);
277   }
278 
279   if (auto EC = sys::Process::SafelyCloseFileDescriptor(FD))
280     return createFileError(Filename, EC);
281 
282   return Error::success();
283 }
284 
285 /// The function executeObjcopy does the higher level dispatch based on the type
286 /// of input (raw binary, archive or single object file) and takes care of the
287 /// format-agnostic modifications, i.e. preserving dates.
288 static Error executeObjcopy(CopyConfig &Config) {
289   sys::fs::file_status Stat;
290   if (Config.InputFilename != "-") {
291     if (auto EC = sys::fs::status(Config.InputFilename, Stat))
292       return createFileError(Config.InputFilename, EC);
293   } else {
294     Stat.permissions(static_cast<sys::fs::perms>(0777));
295   }
296 
297   std::function<Error(raw_ostream & OutFile)> ObjcopyFunc;
298 
299   OwningBinary<llvm::object::Binary> BinaryHolder;
300   std::unique_ptr<MemoryBuffer> MemoryBufferHolder;
301 
302   if (Config.InputFormat == FileFormat::Binary ||
303       Config.InputFormat == FileFormat::IHex) {
304     ErrorOr<std::unique_ptr<MemoryBuffer>> BufOrErr =
305         MemoryBuffer::getFileOrSTDIN(Config.InputFilename);
306     if (!BufOrErr)
307       return createFileError(Config.InputFilename, BufOrErr.getError());
308     MemoryBufferHolder = std::move(*BufOrErr);
309 
310     if (Config.InputFormat == FileFormat::Binary)
311       ObjcopyFunc = [&](raw_ostream &OutFile) -> Error {
312         // Handle FileFormat::Binary.
313         return executeObjcopyOnRawBinary(Config, *MemoryBufferHolder, OutFile);
314       };
315     else
316       ObjcopyFunc = [&](raw_ostream &OutFile) -> Error {
317         // Handle FileFormat::IHex.
318         return executeObjcopyOnIHex(Config, *MemoryBufferHolder, OutFile);
319       };
320   } else {
321     Expected<OwningBinary<llvm::object::Binary>> BinaryOrErr =
322         createBinary(Config.InputFilename);
323     if (!BinaryOrErr)
324       return createFileError(Config.InputFilename, BinaryOrErr.takeError());
325     BinaryHolder = std::move(*BinaryOrErr);
326 
327     if (Archive *Ar = dyn_cast<Archive>(BinaryHolder.getBinary())) {
328       // Handle Archive.
329       if (Error E = executeObjcopyOnArchive(Config, *Ar))
330         return E;
331     } else {
332       // Handle llvm::object::Binary.
333       ObjcopyFunc = [&](raw_ostream &OutFile) -> Error {
334         return executeObjcopyOnBinary(Config, *BinaryHolder.getBinary(),
335                                       OutFile);
336       };
337     }
338   }
339 
340   if (ObjcopyFunc) {
341     if (Config.SplitDWO.empty()) {
342       // Apply transformations described by Config and store result into
343       // Config.OutputFilename using specified ObjcopyFunc function.
344       if (Error E = writeToOutput(Config.OutputFilename, ObjcopyFunc))
345         return E;
346     } else {
347       Config.ExtractDWO = true;
348       Config.StripDWO = false;
349       // Copy .dwo tables from the Config.InputFilename into Config.SplitDWO
350       // file using specified ObjcopyFunc function.
351       if (Error E = writeToOutput(Config.SplitDWO, ObjcopyFunc))
352         return E;
353       Config.ExtractDWO = false;
354       Config.StripDWO = true;
355       // Apply transformations described by Config, remove .dwo tables and
356       // store result into Config.OutputFilename using specified ObjcopyFunc
357       // function.
358       if (Error E = writeToOutput(Config.OutputFilename, ObjcopyFunc))
359         return E;
360     }
361   }
362 
363   if (Error E = restoreStatOnFile(Config.OutputFilename, Stat, Config))
364     return E;
365 
366   if (!Config.SplitDWO.empty()) {
367     Stat.permissions(static_cast<sys::fs::perms>(0666));
368     if (Error E = restoreStatOnFile(Config.SplitDWO, Stat, Config))
369       return E;
370   }
371 
372   return Error::success();
373 }
374 
375 namespace {
376 
377 } // anonymous namespace
378 
379 int main(int argc, char **argv) {
380   InitLLVM X(argc, argv);
381   ToolName = argv[0];
382 
383   // Expand response files.
384   // TODO: Move these lines, which are copied from lib/Support/CommandLine.cpp,
385   // into a separate function in the CommandLine library and call that function
386   // here. This is duplicated code.
387   SmallVector<const char *, 20> NewArgv(argv, argv + argc);
388   BumpPtrAllocator A;
389   StringSaver Saver(A);
390   cl::ExpandResponseFiles(Saver,
391                           Triple(sys::getProcessTriple()).isOSWindows()
392                               ? cl::TokenizeWindowsCommandLine
393                               : cl::TokenizeGNUCommandLine,
394                           NewArgv);
395 
396   auto Args = makeArrayRef(NewArgv).drop_front();
397   Expected<DriverConfig> DriverConfig = getDriverConfig(Args);
398 
399   if (!DriverConfig) {
400     logAllUnhandledErrors(DriverConfig.takeError(),
401                           WithColor::error(errs(), ToolName));
402     return 1;
403   }
404   for (CopyConfig &CopyConfig : DriverConfig->CopyConfigs) {
405     if (Error E = executeObjcopy(CopyConfig)) {
406       logAllUnhandledErrors(std::move(E), WithColor::error(errs(), ToolName));
407       return 1;
408     }
409   }
410 
411   return 0;
412 }
413