llvm/lib/Support/FileCollector.cpp

   1 //===-- FileCollector.cpp ---------------------------------------*- C++ -*-===//
   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/Support/FileCollector.h"
  10 #include "llvm/ADT/SmallString.h"
  11 #include "llvm/ADT/Twine.h"
  12 #include "llvm/Support/FileSystem.h"
  13 #include "llvm/Support/Path.h"
  14 #include "llvm/Support/Process.h"
  15
  16 using namespace llvm;
  17
  18 FileCollectorBase::FileCollectorBase() = default;
  19 FileCollectorBase::~FileCollectorBase() = default;
  20
  21 void FileCollectorBase::addFile(const Twine &File) {
  22   std::lock_guard<std::mutex> lock(Mutex);
  23   std::string FileStr = File.str();
  24   if (markAsSeen(FileStr))
  25     addFileImpl(FileStr);
  26 }
  27
  28 void FileCollectorBase::addDirectory(const Twine &Dir) {
  29   assert(sys::fs::is_directory(Dir));
  30   std::error_code EC;
  31   addDirectoryImpl(Dir, vfs::getRealFileSystem(), EC);
  32 }
  33
  34 static bool isCaseSensitivePath(StringRef Path) {
  35   SmallString<256> TmpDest = Path, UpperDest, RealDest;
  36
  37   // Remove component traversals, links, etc.
  38   if (sys::fs::real_path(Path, TmpDest))
  39     return true; // Current default value in vfs.yaml
  40   Path = TmpDest;
  41
  42   // Change path to all upper case and ask for its real path, if the latter
  43   // exists and is equal to path, it's not case sensitive. Default to case
  44   // sensitive in the absence of real_path, since this is the YAMLVFSWriter
  45   // default.
  46   UpperDest = Path.upper();
  47   if (!sys::fs::real_path(UpperDest, RealDest) && Path.equals(RealDest))
  48     return false;
  49   return true;
  50 }
  51
  52 FileCollector::FileCollector(std::string Root, std::string OverlayRoot)
  53     : Root(std::move(Root)), OverlayRoot(std::move(OverlayRoot)) {
  54 }
  55
  56 void FileCollector::PathCanonicalizer::updateWithRealPath(
  57     SmallVectorImpl<char> &Path) {
  58   StringRef SrcPath(Path.begin(), Path.size());
  59   StringRef Filename = sys::path::filename(SrcPath);
  60   StringRef Directory = sys::path::parent_path(SrcPath);
  61
  62   // Use real_path to fix any symbolic link component present in the directory
  63   // part of the path, caching the search because computing the real path is
  64   // expensive.
  65   SmallString<256> RealPath;
  66   auto DirWithSymlink = CachedDirs.find(Directory);
  67   if (DirWithSymlink == CachedDirs.end()) {
  68     // FIXME: Should this be a call to FileSystem::getRealpath(), in some
  69     // cases? What if there is nothing on disk?
  70     if (sys::fs::real_path(Directory, RealPath))
  71       return;
  72     CachedDirs[Directory] = std::string(RealPath.str());
  73   } else {
  74     RealPath = DirWithSymlink->second;
  75   }
  76
  77   // Finish recreating the path by appending the original filename, since we
  78   // don't need to resolve symlinks in the filename.
  79   //
  80   // FIXME: If we can cope with this, maybe we can cope without calling
  81   // getRealPath() at all when there's no ".." component.
  82   sys::path::append(RealPath, Filename);
  83
  84   // Swap to create the output.
  85   Path.swap(RealPath);
  86 }
  87
  88 /// Make Path absolute.
  89 static void makeAbsolute(SmallVectorImpl<char> &Path) {
  90   // We need an absolute src path to append to the root.
  91   sys::fs::make_absolute(Path);
  92
  93   // Canonicalize src to a native path to avoid mixed separator styles.
  94   sys::path::native(Path);
  95
  96   // Remove redundant leading "./" pieces and consecutive separators.
  97   Path.erase(Path.begin(), sys::path::remove_leading_dotslash(
  98                                StringRef(Path.begin(), Path.size()))
  99                                .begin());
 100 }
 101
 102 FileCollector::PathCanonicalizer::PathStorage
 103 FileCollector::PathCanonicalizer::canonicalize(StringRef SrcPath) {
 104   PathStorage Paths;
 105   Paths.VirtualPath = SrcPath;
 106   makeAbsolute(Paths.VirtualPath);
 107
 108   // If a ".." component is present after a symlink component, remove_dots may
 109   // lead to the wrong real destination path. Let the source be canonicalized
 110   // like that but make sure we always use the real path for the destination.
 111   Paths.CopyFrom = Paths.VirtualPath;
 112   updateWithRealPath(Paths.CopyFrom);
 113
 114   // Canonicalize the virtual path by removing "..", "." components.
 115   sys::path::remove_dots(Paths.VirtualPath, /*remove_dot_dot=*/true);
 116
 117   return Paths;
 118 }
 119
 120 void FileCollector::addFileImpl(StringRef SrcPath) {
 121   PathCanonicalizer::PathStorage Paths = Canonicalizer.canonicalize(SrcPath);
 122
 123   SmallString<256> DstPath = StringRef(Root);
 124   sys::path::append(DstPath, sys::path::relative_path(Paths.CopyFrom));
 125
 126   // Always map a canonical src path to its real path into the YAML, by doing
 127   // this we map different virtual src paths to the same entry in the VFS
 128   // overlay, which is a way to emulate symlink inside the VFS; this is also
 129   // needed for correctness, not doing that can lead to module redefinition
 130   // errors.
 131   addFileToMapping(Paths.VirtualPath, DstPath);
 132 }
 133
 134 llvm::vfs::directory_iterator
 135 FileCollector::addDirectoryImpl(const llvm::Twine &Dir,
 136                                 IntrusiveRefCntPtr<vfs::FileSystem> FS,
 137                                 std::error_code &EC) {
 138   auto It = FS->dir_begin(Dir, EC);
 139   if (EC)
 140     return It;
 141   addFile(Dir);
 142   for (; !EC && It != llvm::vfs::directory_iterator(); It.increment(EC)) {
 143     if (It->type() == sys::fs::file_type::regular_file ||
 144         It->type() == sys::fs::file_type::directory_file ||
 145         It->type() == sys::fs::file_type::symlink_file) {
 146       addFile(It->path());
 147     }
 148   }
 149   if (EC)
 150     return It;
 151   // Return a new iterator.
 152   return FS->dir_begin(Dir, EC);
 153 }
 154
 155 /// Set the access and modification time for the given file from the given
 156 /// status object.
 157 static std::error_code
 158 copyAccessAndModificationTime(StringRef Filename,
 159                               const sys::fs::file_status &Stat) {
 160   int FD;
 161
 162   if (auto EC =
 163           sys::fs::openFileForWrite(Filename, FD, sys::fs::CD_OpenExisting))
 164     return EC;
 165
 166   if (auto EC = sys::fs::setLastAccessAndModificationTime(
 167           FD, Stat.getLastAccessedTime(), Stat.getLastModificationTime()))
 168     return EC;
 169
 170   if (auto EC = sys::Process::SafelyCloseFileDescriptor(FD))
 171     return EC;
 172
 173   return {};
 174 }
 175
 176 std::error_code FileCollector::copyFiles(bool StopOnError) {
 177   auto Err = sys::fs::create_directories(Root, /*IgnoreExisting=*/true);
 178   if (Err) {
 179     return Err;
 180   }
 181
 182   std::lock_guard<std::mutex> lock(Mutex);
 183
 184   for (auto &entry : VFSWriter.getMappings()) {
 185     // Get the status of the original file/directory.
 186     sys::fs::file_status Stat;
 187     if (std::error_code EC = sys::fs::status(entry.VPath, Stat)) {
 188       if (StopOnError)
 189         return EC;
 190       continue;
 191     }
 192
 193     // Continue if the file doesn't exist.
 194     if (Stat.type() == sys::fs::file_type::file_not_found)
 195       continue;
 196
 197     // Create directory tree.
 198     if (std::error_code EC =
 199             sys::fs::create_directories(sys::path::parent_path(entry.RPath),
 200                                         /*IgnoreExisting=*/true)) {
 201       if (StopOnError)
 202         return EC;
 203     }
 204
 205     if (Stat.type() == sys::fs::file_type::directory_file) {
 206       // Construct a directory when it's just a directory entry.
 207       if (std::error_code EC =
 208               sys::fs::create_directories(entry.RPath,
 209                                           /*IgnoreExisting=*/true)) {
 210         if (StopOnError)
 211           return EC;
 212       }
 213       continue;
 214     }
 215
 216     // Copy file over.
 217     if (std::error_code EC = sys::fs::copy_file(entry.VPath, entry.RPath)) {
 218       if (StopOnError)
 219         return EC;
 220     }
 221
 222     // Copy over permissions.
 223     if (auto perms = sys::fs::getPermissions(entry.VPath)) {
 224       if (std::error_code EC = sys::fs::setPermissions(entry.RPath, *perms)) {
 225         if (StopOnError)
 226           return EC;
 227       }
 228     }
 229
 230     // Copy over modification time.
 231     copyAccessAndModificationTime(entry.RPath, Stat);
 232   }
 233   return {};
 234 }
 235
 236 std::error_code FileCollector::writeMapping(StringRef MappingFile) {
 237   std::lock_guard<std::mutex> lock(Mutex);
 238
 239   VFSWriter.setOverlayDir(OverlayRoot);
 240   VFSWriter.setCaseSensitivity(isCaseSensitivePath(OverlayRoot));
 241   VFSWriter.setUseExternalNames(false);
 242
 243   std::error_code EC;
 244   raw_fd_ostream os(MappingFile, EC, sys::fs::OF_TextWithCRLF);
 245   if (EC)
 246     return EC;
 247
 248   VFSWriter.write(os);
 249
 250   return {};
 251 }
 252
 253 namespace llvm {
 254
 255 class FileCollectorFileSystem : public vfs::FileSystem {
 256 public:
 257   explicit FileCollectorFileSystem(IntrusiveRefCntPtr<vfs::FileSystem> FS,
 258                                    std::shared_ptr<FileCollector> Collector)
 259       : FS(std::move(FS)), Collector(std::move(Collector)) {}
 260
 261   llvm::ErrorOr<llvm::vfs::Status> status(const Twine &Path) override {
 262     auto Result = FS->status(Path);
 263     if (Result && Result->exists())
 264       Collector->addFile(Path);
 265     return Result;
 266   }
 267
 268   llvm::ErrorOr<std::unique_ptr<llvm::vfs::File>>
 269   openFileForRead(const Twine &Path) override {
 270     auto Result = FS->openFileForRead(Path);
 271     if (Result && *Result)
 272       Collector->addFile(Path);
 273     return Result;
 274   }
 275
 276   llvm::vfs::directory_iterator dir_begin(const llvm::Twine &Dir,
 277                                           std::error_code &EC) override {
 278     return Collector->addDirectoryImpl(Dir, FS, EC);
 279   }
 280
 281   std::error_code getRealPath(const Twine &Path,
 282                               SmallVectorImpl<char> &Output) const override {
 283     auto EC = FS->getRealPath(Path, Output);
 284     if (!EC) {
 285       Collector->addFile(Path);
 286       if (Output.size() > 0)
 287         Collector->addFile(Output);
 288     }
 289     return EC;
 290   }
 291
 292   std::error_code isLocal(const Twine &Path, bool &Result) override {
 293     return FS->isLocal(Path, Result);
 294   }
 295
 296   llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override {
 297     return FS->getCurrentWorkingDirectory();
 298   }
 299
 300   std::error_code setCurrentWorkingDirectory(const llvm::Twine &Path) override {
 301     return FS->setCurrentWorkingDirectory(Path);
 302   }
 303
 304 private:
 305   IntrusiveRefCntPtr<vfs::FileSystem> FS;
 306   std::shared_ptr<FileCollector> Collector;
 307 };
 308
 309 } // namespace llvm
 310
 311 IntrusiveRefCntPtr<vfs::FileSystem>
 312 FileCollector::createCollectorVFS(IntrusiveRefCntPtr<vfs::FileSystem> BaseFS,
 313                                   std::shared_ptr<FileCollector> Collector) {
 314   return new FileCollectorFileSystem(std::move(BaseFS), std::move(Collector));
 315 }