Allow HttpSys zero-byte reads #41305 (#41500)

src/Servers/HttpSys/src/RequestProcessing/RequestStream.cs

@@ -102,11 +102,11 @@ namespace Microsoft.AspNetCore.Server.HttpSys
             {
                 throw new ArgumentNullException(nameof(buffer));
             }
-            if (offset < 0 || offset > buffer.Length)
+            if ((uint)offset > (uint)buffer.Length)
             {
                 throw new ArgumentOutOfRangeException(nameof(offset), offset, string.Empty);
             }
-            if (size <= 0 || size > buffer.Length - offset)
+            if ((uint)size > (uint)(buffer.Length - offset))
             {
                 throw new ArgumentOutOfRangeException(nameof(size), size, string.Empty);
             }
@@ -163,7 +163,14 @@ namespace Microsoft.AspNetCore.Server.HttpSys
 
                     dataRead += extraDataRead;
                 }
-                if (statusCode != UnsafeNclNativeMethods.ErrorCodes.ERROR_SUCCESS && statusCode != UnsafeNclNativeMethods.ErrorCodes.ERROR_HANDLE_EOF)
+
+                // Zero-byte reads
+                if (statusCode == UnsafeNclNativeMethods.ErrorCodes.ERROR_MORE_DATA && size == 0)
+                {
+                    // extraDataRead returns 1 to let us know there's data available. Don't count it against the request body size yet.
+                    dataRead = 0;
+                }
+                else if (statusCode != UnsafeNclNativeMethods.ErrorCodes.ERROR_SUCCESS && statusCode != UnsafeNclNativeMethods.ErrorCodes.ERROR_HANDLE_EOF)
                 {
                     Exception exception = new IOException(string.Empty, new HttpSysException((int)statusCode));
                     Log.ErrorWhileRead(Logger, exception);
@@ -183,7 +190,8 @@ namespace Microsoft.AspNetCore.Server.HttpSys
 
         internal void UpdateAfterRead(uint statusCode, uint dataRead)
         {
-            if (statusCode == UnsafeNclNativeMethods.ErrorCodes.ERROR_HANDLE_EOF || dataRead == 0)
+            if (statusCode == UnsafeNclNativeMethods.ErrorCodes.ERROR_HANDLE_EOF
+                || statusCode != UnsafeNclNativeMethods.ErrorCodes.ERROR_MORE_DATA && dataRead == 0)
             {
                 Dispose();
             }
@@ -244,7 +252,7 @@ namespace Microsoft.AspNetCore.Server.HttpSys
                 cancellationRegistration = RequestContext.RegisterForCancellation(cancellationToken);
             }
 
-            asyncResult = new RequestStreamAsyncResult(this, null, null, buffer, offset, dataRead, cancellationRegistration);
+            asyncResult = new RequestStreamAsyncResult(this, null, null, buffer, offset, size, dataRead, cancellationRegistration);
             uint bytesReturned;
 
             try

src/Servers/HttpSys/src/RequestProcessing/RequestStreamAsyncResult.cs

@@ -17,38 +17,24 @@ namespace Microsoft.AspNetCore.Server.HttpSys
 
         private readonly SafeNativeOverlapped? _overlapped;
         private readonly IntPtr _pinnedBuffer;
+        private readonly int _size;
         private readonly uint _dataAlreadyRead;
         private readonly TaskCompletionSource<int> _tcs;
         private readonly RequestStream _requestStream;
         private readonly AsyncCallback? _callback;
         private readonly CancellationTokenRegistration _cancellationRegistration;
 
-        internal RequestStreamAsyncResult(RequestStream requestStream, object? userState, AsyncCallback? callback)
+        internal RequestStreamAsyncResult(RequestStream requestStream, object? userState, AsyncCallback? callback, byte[] buffer, int offset, int size, uint dataAlreadyRead, CancellationTokenRegistration cancellationRegistration)
         {
             _requestStream = requestStream;
             _tcs = new TaskCompletionSource<int>(userState);
             _callback = callback;
-        }
-
-        internal RequestStreamAsyncResult(RequestStream requestStream, object? userState, AsyncCallback? callback, uint dataAlreadyRead)
-            : this(requestStream, userState, callback)
-        {
-            _dataAlreadyRead = dataAlreadyRead;
-        }
-
-        internal RequestStreamAsyncResult(RequestStream requestStream, object? userState, AsyncCallback? callback, byte[] buffer, int offset, uint dataAlreadyRead)
-            : this(requestStream, userState, callback, buffer, offset, dataAlreadyRead, new CancellationTokenRegistration())
-        {
-        }
-
-        internal RequestStreamAsyncResult(RequestStream requestStream, object? userState, AsyncCallback? callback, byte[] buffer, int offset, uint dataAlreadyRead, CancellationTokenRegistration cancellationRegistration)
-            : this(requestStream, userState, callback)
-        {
             _dataAlreadyRead = dataAlreadyRead;
             var boundHandle = requestStream.RequestContext.Server.RequestQueue.BoundHandle;
             _overlapped = new SafeNativeOverlapped(boundHandle,
                 boundHandle.AllocateNativeOverlapped(IOCallback, this, buffer));
             _pinnedBuffer = (Marshal.UnsafeAddrOfPinnedArrayElement(buffer, offset));
+            _size = size;
             _cancellationRegistration = cancellationRegistration;
         }
 
@@ -87,7 +73,13 @@ namespace Microsoft.AspNetCore.Server.HttpSys
         {
             try
             {
-                if (errorCode != UnsafeNclNativeMethods.ErrorCodes.ERROR_SUCCESS && errorCode != UnsafeNclNativeMethods.ErrorCodes.ERROR_HANDLE_EOF)
+                // Zero-byte reads
+                if (errorCode == UnsafeNclNativeMethods.ErrorCodes.ERROR_MORE_DATA && asyncResult._size == 0)
+                {
+                    // numBytes returns 1 to let us know there's data available. Don't count it against the request body size yet.
+                    asyncResult.Complete(0, errorCode);
+                }
+                else if (errorCode != UnsafeNclNativeMethods.ErrorCodes.ERROR_SUCCESS && errorCode != UnsafeNclNativeMethods.ErrorCodes.ERROR_HANDLE_EOF)
                 {
                     asyncResult.Fail(new IOException(string.Empty, new HttpSysException((int)errorCode)));
                 }

src/Servers/HttpSys/test/FunctionalTests/RequestBodyTests.cs

@@ -39,6 +39,28 @@ namespace Microsoft.AspNetCore.Server.HttpSys
             }
         }
 
+        [ConditionalFact]
+        public async Task RequestBody_Read0ByteSync_Success()
+        {
+            string address;
+            using (Utilities.CreateHttpServer(out address, httpContext =>
+            {
+                Assert.True(httpContext.Request.CanHaveBody());
+                byte[] input = new byte[100];
+                httpContext.Features.Get<IHttpBodyControlFeature>().AllowSynchronousIO = true;
+                int read = httpContext.Request.Body.Read(input, 0, 0);
+                Assert.Equal(0, read);
+                read = httpContext.Request.Body.Read(input, 0, input.Length);
+                httpContext.Response.ContentLength = read;
+                httpContext.Response.Body.Write(input, 0, read);
+                return Task.FromResult(0);
+            }))
+            {
+                string response = await SendRequestAsync(address, "Hello World");
+                Assert.Equal("Hello World", response);
+            }
+        }
+
         [ConditionalFact]
         public async Task RequestBody_ReadAsync_Success()
         {
@@ -57,6 +79,29 @@ namespace Microsoft.AspNetCore.Server.HttpSys
             }
         }
 
+        [ConditionalFact]
+        public async Task RequestBody_Read0ByteAsync_Success()
+        {
+            string address;
+            using (Utilities.CreateHttpServer(out address, async httpContext =>
+            {
+                Assert.True(httpContext.Request.CanHaveBody());
+                byte[] input = new byte[100];
+                await Task.Delay(1000);
+                int read = await httpContext.Request.Body.ReadAsync(input, 0, 1);
+                Assert.Equal(1, read);
+                read = await httpContext.Request.Body.ReadAsync(input, 0, 0);
+                Assert.Equal(0, read);
+                read = await httpContext.Request.Body.ReadAsync(input, 1, input.Length - 1);
+                httpContext.Response.ContentLength = read + 1;
+                await httpContext.Response.Body.WriteAsync(input, 0, read + 1);
+            }))
+            {
+                string response = await SendRequestAsync(address, "Hello World");
+                Assert.Equal("Hello World", response);
+            }
+        }
+
         [ConditionalFact]
         public async Task RequestBody_ReadBeginEnd_Success()
         {
@@ -87,7 +132,6 @@ namespace Microsoft.AspNetCore.Server.HttpSys
                 Assert.Throws<ArgumentOutOfRangeException>("offset", () => httpContext.Request.Body.Read(input, -1, 1));
                 Assert.Throws<ArgumentOutOfRangeException>("offset", () => httpContext.Request.Body.Read(input, input.Length + 1, 1));
                 Assert.Throws<ArgumentOutOfRangeException>("size", () => httpContext.Request.Body.Read(input, 10, -1));
-                Assert.Throws<ArgumentOutOfRangeException>("size", () => httpContext.Request.Body.Read(input, 0, 0));
                 Assert.Throws<ArgumentOutOfRangeException>("size", () => httpContext.Request.Body.Read(input, 1, input.Length));
                 Assert.Throws<ArgumentOutOfRangeException>("size", () => httpContext.Request.Body.Read(input, 0, input.Length + 1));
                 return Task.FromResult(0);