Add support for getting file system permissions and implement sys::fs::permissions to set them.

Patch by James Henderson.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297617 91177308-0d34-0410-b5e6-96231b3b80d8

Author: AaronBallman

include/llvm/Support/FileSystem.h

@@ -178,23 +178,23 @@ class file_status
         Perms(Perms) {}
   #elif defined(LLVM_ON_WIN32)
   file_status() = default;
-
-  file_status(file_type Type) : Type(Type) {}
-
-  file_status(file_type Type, uint32_t LastAccessTimeHigh,
-              uint32_t LastAccessTimeLow, uint32_t LastWriteTimeHigh,
-              uint32_t LastWriteTimeLow, uint32_t VolumeSerialNumber,
-              uint32_t FileSizeHigh, uint32_t FileSizeLow,
+
+  file_status(file_type Type) : Type(Type) {}
+
+  file_status(file_type Type, perms Perms, uint32_t LastAccessTimeHigh,
+              uint32_t LastAccessTimeLow, uint32_t LastWriteTimeHigh,
+              uint32_t LastWriteTimeLow, uint32_t VolumeSerialNumber,
+              uint32_t FileSizeHigh, uint32_t FileSizeLow,
               uint32_t FileIndexHigh, uint32_t FileIndexLow)
       : LastAccessedTimeHigh(LastAccessTimeHigh), LastAccessedTimeLow(LastAccessTimeLow),
         LastWriteTimeHigh(LastWriteTimeHigh),
-        LastWriteTimeLow(LastWriteTimeLow),
-        VolumeSerialNumber(VolumeSerialNumber), FileSizeHigh(FileSizeHigh),
-        FileSizeLow(FileSizeLow), FileIndexHigh(FileIndexHigh),
-        FileIndexLow(FileIndexLow), Type(Type) {}
-  #endif
-
-  // getters
+        LastWriteTimeLow(LastWriteTimeLow),
+        VolumeSerialNumber(VolumeSerialNumber), FileSizeHigh(FileSizeHigh),
+        FileSizeLow(FileSizeLow), FileIndexHigh(FileIndexHigh),
+        FileIndexLow(FileIndexLow), Type(Type), Perms(Perms) {}
+  #endif
+
+  // getters
   file_type type() const { return Type; }
   perms permissions() const { return Perms; }
   TimePoint<> getLastAccessedTime() const;
@@ -602,12 +602,33 @@ std::error_code is_other(const Twine &path, bool &result);
 std::error_code status(const Twine &path, file_status &result,
                        bool follow = true);
 
-/// @brief A version for when a file descriptor is already available.
-std::error_code status(int FD, file_status &Result);
-
-/// @brief Get file size.
-///
-/// @param Path Input path.
+/// @brief A version for when a file descriptor is already available.
+std::error_code status(int FD, file_status &Result);
+
+/// @brief Set file permissions.
+///
+/// @param Path File to set permissions on.
+/// @param Permissions New file permissions.
+/// @returns errc::success if the permissions were successfully set, otherwise
+///          a platform-specific error_code.
+/// @note On Windows, all permissions except *_write are ignored. Using any of
+///       owner_write, group_write, or all_write will make the file writable.
+///       Otherwise, the file will be marked as read-only.
+std::error_code setPermissions(const Twine &Path, perms Permissions);
+
+/// @brief Get file permissions.
+///
+/// @param Path File to get permissions from.
+/// @returns the permissions if they were successfully retrieved, otherwise a
+///          platform-specific error_code.
+/// @note On Windows, if the file does not have the FILE_ATTRIBUTE_READONLY
+///       attribute, all_all will be returned. Otherwise, all_read | all_exe
+///       will be returned.
+ErrorOr<perms> getPermissions(const Twine &Path);
+
+/// @brief Get file size.
+///
+/// @param Path Input path.
 /// @param Result Set to the size of the file in \a Path.
 /// @returns errc::success if result has been successfully set, otherwise a
 ///          platform-specific error_code.

lib/Support/Path.cpp

@@ -1189,12 +1189,20 @@ std::error_code identify_magic(const Twine &Path, file_magic &Result) {
 }
 
 std::error_code directory_entry::status(file_status &result) const {
-  return fs::status(Path, result, FollowSymlinks);
-}
-
-} // end namespace fs
-} // end namespace sys
-} // end namespace llvm
+  return fs::status(Path, result, FollowSymlinks);
+}
+
+ErrorOr<perms> getPermissions(const Twine &Path) {
+  file_status Status;
+  if (std::error_code EC = status(Path, Status))
+    return EC;
+
+  return Status.permissions();
+}
+
+} // end namespace fs
+} // end namespace sys
+} // end namespace llvm
 
 // Include the truly platform-specific parts.
 #if defined(LLVM_ON_UNIX)

lib/Support/Unix/Path.inc

@@ -568,12 +568,21 @@ std::error_code status(const Twine &Path, file_status &Result, bool Follow) {
 std::error_code status(int FD, file_status &Result) {
   struct stat Status;
   int StatRet = ::fstat(FD, &Status);
-  return fillStatus(StatRet, Status, Result);
-}
-
-std::error_code setLastModificationAndAccessTime(int FD, TimePoint<> Time) {
-#if defined(HAVE_FUTIMENS)
-  timespec Times[2];
+  return fillStatus(StatRet, Status, Result);
+}
+
+std::error_code setPermissions(const Twine &Path, perms Permissions) {
+  SmallString<128> PathStorage;
+  StringRef P = Path.toNullTerminatedStringRef(PathStorage);
+
+  if (::chmod(P.begin(), Permissions))
+    return std::error_code(errno, std::generic_category());
+  return std::error_code();
+}
+
+std::error_code setLastModificationAndAccessTime(int FD, TimePoint<> Time) {
+#if defined(HAVE_FUTIMENS)
+  timespec Times[2];
   Times[0] = Times[1] = sys::toTimeSpec(Time);
   if (::futimens(FD, Times))
     return std::error_code(errno, std::generic_category());

lib/Support/Windows/Path.inc

@@ -527,19 +527,21 @@ static std::error_code getStatus(HANDLE FileHandle, file_status &Result) {
     goto handle_status_error;
 
   {
-    file_type Type = (Info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
-                         ? file_type::directory_file
-                         : file_type::regular_file;
-    Result =
-        file_status(Type, Info.ftLastAccessTime.dwHighDateTime,
-                    Info.ftLastAccessTime.dwLowDateTime,
-                    Info.ftLastWriteTime.dwHighDateTime,
-                    Info.ftLastWriteTime.dwLowDateTime,
-                    Info.dwVolumeSerialNumber, Info.nFileSizeHigh,
-                    Info.nFileSizeLow, Info.nFileIndexHigh, Info.nFileIndexLow);
-    return std::error_code();
-  }
-
+    file_type Type = (Info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
+                         ? file_type::directory_file
+                         : file_type::regular_file;
+    perms Permissions = (Info.dwFileAttributes & FILE_ATTRIBUTE_READONLY)
+                            ? (all_read | all_exe)
+                            : all_all;
+    Result = file_status(
+        Type, Permissions, Info.ftLastAccessTime.dwHighDateTime,
+        Info.ftLastAccessTime.dwLowDateTime,
+        Info.ftLastWriteTime.dwHighDateTime, Info.ftLastWriteTime.dwLowDateTime,
+        Info.dwVolumeSerialNumber, Info.nFileSizeHigh, Info.nFileSizeLow,
+        Info.nFileIndexHigh, Info.nFileIndexLow);
+    return std::error_code();
+  }
+
 handle_status_error:
   DWORD LastError = ::GetLastError();
   if (LastError == ERROR_FILE_NOT_FOUND ||
@@ -586,12 +588,43 @@ std::error_code status(const Twine &path, file_status &result, bool Follow) {
 
 std::error_code status(int FD, file_status &Result) {
   HANDLE FileHandle = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
-  return getStatus(FileHandle, Result);
-}
-
-std::error_code setLastModificationAndAccessTime(int FD, TimePoint<> Time) {
-  FILETIME FT = toFILETIME(Time);
-  HANDLE FileHandle = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
+  return getStatus(FileHandle, Result);
+}
+
+std::error_code setPermissions(const Twine &Path, perms Permissions) {
+  SmallVector<wchar_t, 128> PathUTF16;
+  if (std::error_code EC = widenPath(Path, PathUTF16))
+    return EC;
+
+  DWORD Attributes = ::GetFileAttributesW(PathUTF16.begin());
+  if (Attributes == INVALID_FILE_ATTRIBUTES)
+    return mapWindowsError(GetLastError());
+
+  // There are many Windows file attributes that are not to do with the file
+  // permissions (e.g. FILE_ATTRIBUTE_HIDDEN). We need to be careful to preserve
+  // them.
+  if (Permissions & all_write) {
+    Attributes &= ~FILE_ATTRIBUTE_READONLY;
+    if (Attributes == 0)
+      // FILE_ATTRIBUTE_NORMAL indicates no other attributes are set.
+      Attributes |= FILE_ATTRIBUTE_NORMAL;
+  }
+  else {
+    Attributes |= FILE_ATTRIBUTE_READONLY;
+    // FILE_ATTRIBUTE_NORMAL is not compatible with any other attributes, so
+    // remove it, if it is present.
+    Attributes &= ~FILE_ATTRIBUTE_NORMAL;
+  }
+
+  if (!::SetFileAttributesW(PathUTF16.begin(), Attributes))
+    return mapWindowsError(GetLastError());
+
+  return std::error_code();
+}
+
+std::error_code setLastModificationAndAccessTime(int FD, TimePoint<> Time) {
+  FILETIME FT = toFILETIME(Time);
+  HANDLE FileHandle = reinterpret_cast<HANDLE>(_get_osfhandle(FD));
   if (!SetFileTime(FileHandle, NULL, &FT, &FT))
     return mapWindowsError(::GetLastError());
   return std::error_code();