QueryDirectoryFile requires 64 bit alignment to work on ARM32. (dotne…

…t/corefx#33713) * QueryDirectoryFile requires 64 bit alignment to work on ARM32. Using Marshal.AllocHGlobal instead of byte[] will do that (and avoid the need to pin). * Address feedback. Commit migrated from dotnet/corefx@a75f96a
hgdiaz · Nov 29, 2018 · 07cbca2 · 07cbca2
1 parent ad66b62
commit 07cbca2
Show file tree

Hide file tree

Showing 5 changed files with 18 additions and 17 deletions.
diff --git a/src/libraries/Common/src/Interop/Windows/NtDll/Interop.NtQueryDirectoryFile.cs b/src/libraries/Common/src/Interop/Windows/NtDll/Interop.NtQueryDirectoryFile.cs
@@ -18,7 +18,7 @@ public unsafe static extern int NtQueryDirectoryFile(
             IntPtr ApcRoutine,
             IntPtr ApcContext,
             out IO_STATUS_BLOCK IoStatusBlock,
-            byte[] FileInformation,
+            IntPtr FileInformation,
             uint Length,
             FILE_INFORMATION_CLASS FileInformationClass,
             BOOLEAN ReturnSingleEntry,

diff --git a/src/libraries/Common/src/Interop/Windows/kernel32/Interop.GetFileInformationByHandleEx.cs b/src/libraries/Common/src/Interop/Windows/kernel32/Interop.GetFileInformationByHandleEx.cs
@@ -11,10 +11,10 @@ internal partial class Kernel32
     {
         // https://msdn.microsoft.com/en-us/library/windows/desktop/aa364953.aspx
         [DllImport(Libraries.Kernel32, SetLastError = true, CharSet = CharSet.Unicode, ExactSpelling = true)]
-        public unsafe static extern bool GetFileInformationByHandleEx(
+        public static extern bool GetFileInformationByHandleEx(
             IntPtr hFile,
             FILE_INFO_BY_HANDLE_CLASS FileInformationClass,
-            byte[] lpFileInformation,
+            IntPtr lpFileInformation,
             uint dwBufferSize);
     }
 }
diff --git a/src/libraries/System.IO.FileSystem/src/System/IO/Enumeration/FileSystemEnumerator.Win32.cs b/src/libraries/System.IO.FileSystem/src/System/IO/Enumeration/FileSystemEnumerator.Win32.cs
@@ -28,7 +28,7 @@ private unsafe bool GetData()
                 ApcContext: IntPtr.Zero,
                 IoStatusBlock: out Interop.NtDll.IO_STATUS_BLOCK statusBlock,
                 FileInformation: _buffer,
-                Length: (uint)_buffer.Length,
+                Length: (uint)_bufferLength,
                 FileInformationClass: Interop.NtDll.FILE_INFORMATION_CLASS.FileFullDirectoryInformation,
                 ReturnSingleEntry: Interop.BOOLEAN.FALSE,
                 FileName: null,

diff --git a/src/libraries/System.IO.FileSystem/src/System/IO/Enumeration/FileSystemEnumerator.WinRT.cs b/src/libraries/System.IO.FileSystem/src/System/IO/Enumeration/FileSystemEnumerator.WinRT.cs
@@ -16,7 +16,7 @@ private unsafe bool GetData()
                 _directoryHandle,
                 Interop.Kernel32.FILE_INFO_BY_HANDLE_CLASS.FileFullDirectoryInfo,
                 _buffer,
-                (uint)_buffer.Length))
+                (uint)_bufferLength))
             {
                 int error = Marshal.GetLastWin32Error();
                 switch (error)

diff --git a/src/libraries/System.IO.FileSystem/src/System/IO/Enumeration/FileSystemEnumerator.Windows.cs b/src/libraries/System.IO.FileSystem/src/System/IO/Enumeration/FileSystemEnumerator.Windows.cs
@@ -34,12 +34,12 @@ public unsafe abstract partial class FileSystemEnumerator<TResult> : CriticalFin
         private Interop.NtDll.FILE_FULL_DIR_INFORMATION* _entry;
         private TResult _current;
 
-        private byte[] _buffer;
+        private IntPtr _buffer;
+        private int _bufferLength;
         private IntPtr _directoryHandle;
         private string _currentPath;
         private bool _lastEntryFound;
         private Queue<(IntPtr Handle, string Path)> _pending;
-        private GCHandle _pinnedBuffer;
 
         /// <summary>
         /// Encapsulates a find operation.
@@ -67,13 +67,15 @@ public FileSystemEnumerator(string directory, EnumerationOptions options = null)
             _currentPath = _rootDirectory;
 
             int requestedBufferSize = _options.BufferSize;
-            int bufferSize = requestedBufferSize <= 0 ? StandardBufferSize
+            _bufferLength = requestedBufferSize <= 0 ? StandardBufferSize
                 : Math.Max(MinimumBufferSize, requestedBufferSize);
 
             try
             {
-                _buffer = ArrayPool<byte>.Shared.Rent(bufferSize);
-                _pinnedBuffer = GCHandle.Alloc(_buffer, GCHandleType.Pinned);
+                // NtQueryDirectoryFile needs its buffer to be 64bit aligned to work
+                // successfully with FileFullDirectoryInformation on ARM32. AllocHGlobal
+                // will return pointers aligned as such, new byte[] does not.
+                _buffer = Marshal.AllocHGlobal(_bufferLength);
             }
             catch
             {
@@ -209,7 +211,7 @@ private unsafe void FindNextEntry()
 
             // We need more data
             if (GetData())
-                _entry = (Interop.NtDll.FILE_FULL_DIR_INFORMATION*)_pinnedBuffer.AddrOfPinnedObject();
+                _entry = (Interop.NtDll.FILE_FULL_DIR_INFORMATION*)_buffer;
         }
 
         private bool DequeueNextDirectory()
@@ -239,13 +241,12 @@ private void InternalDispose(bool disposing)
                         _pending = null;
                     }
 
-                    if (_pinnedBuffer.IsAllocated)
-                        _pinnedBuffer.Free();
-
-                    if (_buffer != null)
-                        ArrayPool<byte>.Shared.Return(_buffer);
+                    if (_buffer != default)
+                    {
+                        Marshal.FreeHGlobal(_buffer);
+                    }
 
-                    _buffer = null;
+                    _buffer = default;
                 }
             }