Remove some GCHandles from SendHeaders()

src/Servers/HttpSys/src/Helpers.cs

@@ -8,8 +8,8 @@ namespace Microsoft.AspNetCore.Server.HttpSys;
 
 internal static class Helpers
 {
-    internal static readonly byte[] ChunkTerminator = new byte[] { (byte)'0', (byte)'\r', (byte)'\n', (byte)'\r', (byte)'\n' };
-    internal static readonly byte[] CRLF = new byte[] { (byte)'\r', (byte)'\n' };
+    public static ReadOnlySpan<byte> ChunkTerminator => "0\r\n\r\n"u8;
+    public static ReadOnlySpan<byte> CRLF => "\r\n"u8;
 
     internal static ArraySegment<byte> GetChunkHeader(long size)
     {

src/Servers/HttpSys/src/HttpSysListener.cs

@@ -3,7 +3,6 @@
 
 using System.Buffers;
 using System.Diagnostics;
-using System.Runtime.InteropServices;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.HttpSys.Internal;
 using Microsoft.Extensions.Logging;
@@ -310,103 +309,79 @@ internal unsafe void SendError(ulong requestId, int httpStatusCode, IList<string
         httpResponse.Response_V1.Version.MajorVersion = (ushort)1;
         httpResponse.Response_V1.Version.MinorVersion = (ushort)1;
 
-        List<GCHandle>? pinnedHeaders = null;
-        GCHandle gcHandle;
-        try
-        {
-            // Copied from the multi-value headers section of SerializeHeaders
-            if (authChallenges != null && authChallenges.Count > 0)
-            {
-                pinnedHeaders = new List<GCHandle>(authChallenges.Count + 3);
+        using UnmanagedBufferAllocator allocator = new();
 
-                HttpApiTypes.HTTP_RESPONSE_INFO[] knownHeaderInfo = new HttpApiTypes.HTTP_RESPONSE_INFO[1];
-                gcHandle = GCHandle.Alloc(knownHeaderInfo, GCHandleType.Pinned);
-                pinnedHeaders.Add(gcHandle);
-                httpResponse.pResponseInfo = (HttpApiTypes.HTTP_RESPONSE_INFO*)gcHandle.AddrOfPinnedObject();
+        byte* bytes;
+        int bytesLength;
 
-                knownHeaderInfo[httpResponse.ResponseInfoCount].Type = HttpApiTypes.HTTP_RESPONSE_INFO_TYPE.HttpResponseInfoTypeMultipleKnownHeaders;
-                knownHeaderInfo[httpResponse.ResponseInfoCount].Length =
-                    (uint)Marshal.SizeOf<HttpApiTypes.HTTP_MULTIPLE_KNOWN_HEADERS>();
+        // Copied from the multi-value headers section of SerializeHeaders
+        if (authChallenges != null && authChallenges.Count > 0)
+        {
+            HttpApiTypes.HTTP_RESPONSE_INFO* knownHeaderInfo = allocator.AllocAsPointer<HttpApiTypes.HTTP_RESPONSE_INFO>(1);
+            httpResponse.pResponseInfo = knownHeaderInfo;
 
-                HttpApiTypes.HTTP_MULTIPLE_KNOWN_HEADERS header = new HttpApiTypes.HTTP_MULTIPLE_KNOWN_HEADERS();
+            knownHeaderInfo[httpResponse.ResponseInfoCount].Type = HttpApiTypes.HTTP_RESPONSE_INFO_TYPE.HttpResponseInfoTypeMultipleKnownHeaders;
+            knownHeaderInfo[httpResponse.ResponseInfoCount].Length =
+                (uint)sizeof(HttpApiTypes.HTTP_MULTIPLE_KNOWN_HEADERS);
 
-                header.HeaderId = HttpApiTypes.HTTP_RESPONSE_HEADER_ID.Enum.HttpHeaderWwwAuthenticate;
-                header.Flags = HttpApiTypes.HTTP_RESPONSE_INFO_FLAGS.PreserveOrder; // The docs say this is for www-auth only.
+            HttpApiTypes.HTTP_MULTIPLE_KNOWN_HEADERS* header = allocator.AllocAsPointer<HttpApiTypes.HTTP_MULTIPLE_KNOWN_HEADERS>(1);
 
-                HttpApiTypes.HTTP_KNOWN_HEADER[] nativeHeaderValues = new HttpApiTypes.HTTP_KNOWN_HEADER[authChallenges.Count];
-                gcHandle = GCHandle.Alloc(nativeHeaderValues, GCHandleType.Pinned);
-                pinnedHeaders.Add(gcHandle);
-                header.KnownHeaders = (HttpApiTypes.HTTP_KNOWN_HEADER*)gcHandle.AddrOfPinnedObject();
+            header->HeaderId = HttpApiTypes.HTTP_RESPONSE_HEADER_ID.Enum.HttpHeaderWwwAuthenticate;
+            header->Flags = HttpApiTypes.HTTP_RESPONSE_INFO_FLAGS.PreserveOrder; // The docs say this is for www-auth only.
+            header->KnownHeaderCount = 0;
 
-                for (int headerValueIndex = 0; headerValueIndex < authChallenges.Count; headerValueIndex++)
-                {
-                    // Add Value
-                    string headerValue = authChallenges[headerValueIndex];
-                    byte[] bytes = HeaderEncoding.GetBytes(headerValue);
-                    nativeHeaderValues[header.KnownHeaderCount].RawValueLength = (ushort)bytes.Length;
-                    gcHandle = GCHandle.Alloc(bytes, GCHandleType.Pinned);
-                    pinnedHeaders.Add(gcHandle);
-                    nativeHeaderValues[header.KnownHeaderCount].pRawValue = (byte*)gcHandle.AddrOfPinnedObject();
-                    header.KnownHeaderCount++;
-                }
+            HttpApiTypes.HTTP_KNOWN_HEADER* nativeHeaderValues = allocator.AllocAsPointer<HttpApiTypes.HTTP_KNOWN_HEADER>(authChallenges.Count);
+            header->KnownHeaders = nativeHeaderValues;
 
-                // This type is a struct, not an object, so pinning it causes a boxed copy to be created. We can't do that until after all the fields are set.
-                gcHandle = GCHandle.Alloc(header, GCHandleType.Pinned);
-                pinnedHeaders.Add(gcHandle);
-                knownHeaderInfo[0].pInfo = (HttpApiTypes.HTTP_MULTIPLE_KNOWN_HEADERS*)gcHandle.AddrOfPinnedObject();
-
-                httpResponse.ResponseInfoCount = 1;
+            for (int headerValueIndex = 0; headerValueIndex < authChallenges.Count; headerValueIndex++)
+            {
+                // Add Value
+                string headerValue = authChallenges[headerValueIndex];
+                bytes = allocator.GetHeaderEncodedBytes(headerValue, out bytesLength);
+                nativeHeaderValues[header->KnownHeaderCount].RawValueLength = checked((ushort)bytesLength);
+                nativeHeaderValues[header->KnownHeaderCount].pRawValue = bytes;
+                header->KnownHeaderCount++;
             }
 
-            httpResponse.Response_V1.StatusCode = (ushort)httpStatusCode;
-            string? statusDescription = HttpReasonPhrase.Get(httpStatusCode);
-            uint dataWritten = 0;
-            uint statusCode;
-            byte[] byteReason = statusDescription != null ? HeaderEncoding.GetBytes(statusDescription) : Array.Empty<byte>();
-            fixed (byte* pReason = byteReason)
-            {
-                httpResponse.Response_V1.pReason = (byte*)pReason;
-                httpResponse.Response_V1.ReasonLength = (ushort)byteReason.Length;
+            knownHeaderInfo[0].pInfo = header;
 
-                byte[] byteContentLength = new byte[] { (byte)'0' };
-                fixed (byte* pContentLength = byteContentLength)
-                {
-                    (&httpResponse.Response_V1.Headers.KnownHeaders)[(int)HttpSysResponseHeader.ContentLength].pRawValue = (byte*)pContentLength;
-                    (&httpResponse.Response_V1.Headers.KnownHeaders)[(int)HttpSysResponseHeader.ContentLength].RawValueLength = (ushort)byteContentLength.Length;
-                    httpResponse.Response_V1.Headers.UnknownHeaderCount = 0;
-
-                    statusCode =
-                        HttpApi.HttpSendHttpResponse(
-                            _requestQueue.Handle,
-                            requestId,
-                            0,
-                            &httpResponse,
-                            null,
-                            &dataWritten,
-                            IntPtr.Zero,
-                            0,
-                            SafeNativeOverlapped.Zero,
-                            IntPtr.Zero);
-                }
-            }
-            if (statusCode != UnsafeNclNativeMethods.ErrorCodes.ERROR_SUCCESS)
-            {
-                // if we fail to send a 401 something's seriously wrong, abort the request
-                HttpApi.HttpCancelHttpRequest(_requestQueue.Handle, requestId, IntPtr.Zero);
-            }
+            httpResponse.ResponseInfoCount = 1;
         }
-        finally
+
+        httpResponse.Response_V1.StatusCode = checked((ushort)httpStatusCode);
+        string statusDescription = HttpReasonPhrase.Get(httpStatusCode) ?? string.Empty;
+        uint dataWritten = 0;
+        uint statusCode;
+
+        bytes = allocator.GetHeaderEncodedBytes(statusDescription, out bytesLength);
+        httpResponse.Response_V1.pReason = bytes;
+        httpResponse.Response_V1.ReasonLength = checked((ushort)bytesLength);
+
+        const int contentLengthLength = 1;
+        byte* pContentLength = allocator.AllocAsPointer<byte>(contentLengthLength + 1);
+        pContentLength[0] = (byte)'0';
+        pContentLength[1] = 0; // null terminator
+
+        (&httpResponse.Response_V1.Headers.KnownHeaders)[(int)HttpSysResponseHeader.ContentLength].pRawValue = pContentLength;
+        (&httpResponse.Response_V1.Headers.KnownHeaders)[(int)HttpSysResponseHeader.ContentLength].RawValueLength = contentLengthLength;
+        httpResponse.Response_V1.Headers.UnknownHeaderCount = 0;
+
+        statusCode =
+            HttpApi.HttpSendHttpResponse(
+                _requestQueue.Handle,
+                requestId,
+                0,
+                &httpResponse,
+                null,
+                &dataWritten,
+                IntPtr.Zero,
+                0,
+                SafeNativeOverlapped.Zero,
+                IntPtr.Zero);
+        if (statusCode != UnsafeNclNativeMethods.ErrorCodes.ERROR_SUCCESS)
         {
-            if (pinnedHeaders != null)
-            {
-                foreach (GCHandle handle in pinnedHeaders)
-                {
-                    if (handle.IsAllocated)
-                    {
-                        handle.Free();
-                    }
-                }
-            }
+            // if we fail to send a 401 something's seriously wrong, abort the request
+            HttpApi.HttpCancelHttpRequest(_requestQueue.Handle, requestId, IntPtr.Zero);
         }
     }