Socket: delete unix local endpoint filename on Close

src/libraries/System.IO.Pipes/tests/NamedPipeTests/NamedPipeTest.UnixDomainSockets.cs

@@ -49,8 +49,7 @@ public async Task NamedPipeClient_Connects_With_UnixDomainSocketEndPointServer()
                 }
             }
 
-            Assert.True(File.Exists(pipeName));
-            try { File.Delete(pipeName); } catch { }
+            Assert.False(File.Exists(pipeName));
         }
     }
 }

src/libraries/System.Net.Sockets/src/System/Net/Sockets/Socket.cs

@@ -24,8 +24,11 @@ public partial class Socket : IDisposable
 
         private SafeSocketHandle _handle;
 
-        // _rightEndPoint is null if the socket has not been bound.  Otherwise, it is any EndPoint of the
-        // correct type (IPEndPoint, etc).
+        // _rightEndPoint is null if the socket has not been bound.  Otherwise, it is an EndPoint of the
+        // correct type (IPEndPoint, etc). The Bind operation sets _rightEndPoint. Other operations must only set
+        // it when the value is still null.
+        // This enables tracking the file created by UnixDomainSocketEndPoint when the Socket is bound,
+        // and to delete that file when the Socket gets disposed.
         internal EndPoint? _rightEndPoint;
         internal EndPoint? _remoteEndPoint;
 
@@ -293,7 +296,7 @@ public int Available
                 {
                     // Update the state if we've become connected after a non-blocking connect.
                     _isConnected = true;
-                    _rightEndPoint = _nonBlockingConnectRightEndPoint;
+                    _rightEndPoint ??= _nonBlockingConnectRightEndPoint;
                     UpdateLocalEndPointOnConnect();
                     _nonBlockingConnectInProgress = false;
                 }
@@ -340,7 +343,7 @@ public int Available
                     {
                         // Update the state if we've become connected after a non-blocking connect.
                         _isConnected = true;
-                        _rightEndPoint = _nonBlockingConnectRightEndPoint;
+                        _rightEndPoint ??= _nonBlockingConnectRightEndPoint;
                         UpdateLocalEndPointOnConnect();
                         _nonBlockingConnectInProgress = false;
                     }
@@ -445,7 +448,7 @@ public bool Connected
                 {
                     // Update the state if we've become connected after a non-blocking connect.
                     _isConnected = true;
-                    _rightEndPoint = _nonBlockingConnectRightEndPoint;
+                    _rightEndPoint ??= _nonBlockingConnectRightEndPoint;
                     UpdateLocalEndPointOnConnect();
                     _nonBlockingConnectInProgress = false;
                 }
@@ -805,11 +808,16 @@ private void DoBind(EndPoint endPointSnapshot, Internals.SocketAddress socketAdd
                 UpdateStatusAfterSocketErrorAndThrowException(errorCode);
             }
 
-            if (_rightEndPoint == null)
+            if (!IsWildcardEndPoint(_rightEndPoint))
             {
-                // Save a copy of the EndPoint so we can use it for Create().
-                _rightEndPoint = endPointSnapshot;
+                _localEndPoint = _rightEndPoint;
             }
+
+            // Save a copy of the EndPoint so we can use it for Create().
+            // For UnixDomainSocketEndPoint, track the file to delete on Dispose.
+            _rightEndPoint = endPointSnapshot is UnixDomainSocketEndPoint unixEndPoint ?
+                                unixEndPoint.CreateBoundEndPoint() :
+                                endPointSnapshot;
         }
 
         // Establishes a connection to a remote system.
@@ -1363,11 +1371,8 @@ public int SendTo(byte[] buffer, int offset, int size, SocketFlags socketFlags,
                 if (SocketType == SocketType.Dgram) SocketsTelemetry.Log.DatagramSent();
             }
 
-            if (_rightEndPoint == null)
-            {
-                // Save a copy of the EndPoint so we can use it for Create().
-                _rightEndPoint = remoteEP;
-            }
+            // Save a copy of the EndPoint so we can use it for Create().
+            _rightEndPoint ??= remoteEP;
 
             if (NetEventSource.Log.IsEnabled()) NetEventSource.DumpBuffer(this, buffer, offset, size);
             return bytesTransferred;
@@ -1584,11 +1589,8 @@ public int ReceiveMessageFrom(byte[] buffer, int offset, int size, ref SocketFla
                 catch
                 {
                 }
-                if (_rightEndPoint == null)
-                {
-                    // Save a copy of the EndPoint so we can use it for Create().
-                    _rightEndPoint = endPointSnapshot;
-                }
+                // Save a copy of the EndPoint so we can use it for Create().
+                _rightEndPoint ??= endPointSnapshot;
             }
 
             if (NetEventSource.Log.IsEnabled()) NetEventSource.Error(this, errorCode);
@@ -1678,11 +1680,8 @@ public int ReceiveMessageFrom(Span<byte> buffer, ref SocketFlags socketFlags, re
                 catch
                 {
                 }
-                if (_rightEndPoint == null)
-                {
-                    // Save a copy of the EndPoint so we can use it for Create().
-                    _rightEndPoint = endPointSnapshot;
-                }
+                // Save a copy of the EndPoint so we can use it for Create().
+                _rightEndPoint ??= endPointSnapshot;
             }
 
             if (NetEventSource.Log.IsEnabled()) NetEventSource.Error(this, errorCode);
@@ -1741,11 +1740,8 @@ public int ReceiveFrom(byte[] buffer, int offset, int size, SocketFlags socketFl
                 catch
                 {
                 }
-                if (_rightEndPoint == null)
-                {
-                    // Save a copy of the EndPoint so we can use it for Create().
-                    _rightEndPoint = endPointSnapshot;
-                }
+                // Save a copy of the EndPoint so we can use it for Create().
+                _rightEndPoint ??= endPointSnapshot;
             }
 
             if (socketException != null)
@@ -3128,10 +3124,7 @@ private bool SendToAsync(SocketAsyncEventArgs e, CancellationToken cancellationT
             e.StartOperationCommon(this, SocketAsyncOperation.SendTo);
 
             EndPoint? oldEndPoint = _rightEndPoint;
-            if (_rightEndPoint == null)
-            {
-                _rightEndPoint = endPointSnapshot;
-            }
+            _rightEndPoint ??= endPointSnapshot;
 
             SocketError socketError;
             try
@@ -3140,7 +3133,7 @@ private bool SendToAsync(SocketAsyncEventArgs e, CancellationToken cancellationT
             }
             catch
             {
-                _rightEndPoint = null;
+                _rightEndPoint = oldEndPoint;
                 _localEndPoint = null;
                 // Clear in-use flag on event args object.
                 e.Complete();
@@ -3248,11 +3241,8 @@ private void DoConnect(EndPoint endPointSnapshot, Internals.SocketAddress socket
 
             if (SocketsTelemetry.Log.IsEnabled()) SocketsTelemetry.Log.AfterConnect(SocketError.Success);
 
-            if (_rightEndPoint == null)
-            {
-                // Save a copy of the EndPoint so we can use it for Create().
-                _rightEndPoint = endPointSnapshot;
-            }
+            // Save a copy of the EndPoint so we can use it for Create().
+            _rightEndPoint ??= endPointSnapshot;
 
             if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(this, $"connection to:{endPointSnapshot}");
 
@@ -3380,6 +3370,18 @@ protected virtual void Dispose(bool disposing)
                     {
                     }
                 }
+
+                // Delete file of bound UnixDomainSocketEndPoint.
+                if (_rightEndPoint is UnixDomainSocketEndPoint unixEndPoint &&
+                    unixEndPoint.BoundFileName is not null)
+                {
+                    try
+                    {
+                        File.Delete(unixEndPoint.BoundFileName);
+                    }
+                    catch
+                    { }
+                }
             }
 
             // Clean up any cached data
@@ -3634,9 +3636,24 @@ internal Socket UpdateAcceptSocket(Socket socket, EndPoint remoteEP)
             socket._addressFamily = _addressFamily;
             socket._socketType = _socketType;
             socket._protocolType = _protocolType;
-            socket._rightEndPoint = _rightEndPoint;
             socket._remoteEndPoint = remoteEP;
 
+            // If the _rightEndpoint tracks a UnixDomainSocketEndPoint to delete,
+            // create a new EndPoint.
+            if (_localEndPoint != null)
+            {
+                socket._rightEndPoint = _localEndPoint;
+            }
+            else if (_rightEndPoint is UnixDomainSocketEndPoint unixEndPoint &&
+                     unixEndPoint.BoundFileName is not null)
+            {
+                socket._rightEndPoint = unixEndPoint.CreateUnboundEndPoint();
+            }
+            else
+            {
+                socket._rightEndPoint = _rightEndPoint;
+            }
+
             // If the listener socket was bound to a wildcard address, then the `accept` system call
             // will assign a specific address to the accept socket's local endpoint instead of a
             // wildcard address. In that case we should not copy listener's wildcard local endpoint.

src/libraries/System.Net.Sockets/src/System/Net/Sockets/UnixDomainSocketEndPoint.cs

@@ -3,6 +3,7 @@
 
 using System.Diagnostics;
 using System.Text;
+using System.IO;
 
 namespace System.Net.Sockets
 {
@@ -14,13 +15,22 @@ public sealed partial class UnixDomainSocketEndPoint : EndPoint
         private readonly string _path;
         private readonly byte[] _encodedPath;
 
+        // Tracks the file Socket should delete on Dispose.
+        internal string? BoundFileName { get; }
+
         public UnixDomainSocketEndPoint(string path)
+            : this(path, null)
+        { }
+
+        private UnixDomainSocketEndPoint(string path, string? boundFileName)
         {
             if (path == null)
             {
                 throw new ArgumentNullException(nameof(path));
             }
 
+            BoundFileName = boundFileName;
+
             // Pathname socket addresses should be null-terminated.
             // Linux abstract socket addresses start with a zero byte, they must not be null-terminated.
             bool isAbstract = IsAbstract(path);
@@ -120,6 +130,24 @@ public override string ToString()
             }
         }
 
+        internal UnixDomainSocketEndPoint CreateBoundEndPoint()
+        {
+            if (IsAbstract(_path))
+            {
+                return this;
+            }
+            return new UnixDomainSocketEndPoint(_path, Path.GetFullPath(_path));
+        }
+
+        internal UnixDomainSocketEndPoint CreateUnboundEndPoint()
+        {
+            if (IsAbstract(_path) || BoundFileName is null)
+            {
+                return this;
+            }
+            return new UnixDomainSocketEndPoint(_path, null);
+        }
+
         private static bool IsAbstract(string path) => path.Length > 0 && path[0] == '\0';
 
         private static bool IsAbstract(byte[] encodedPath) => encodedPath.Length > 0 && encodedPath[0] == 0;