[RISC-V] Fix System.Net.Sockets.Tests on Qemu

src/libraries/Common/tests/TestUtilities/System/PlatformDetection.Unix.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System;
 using System.IO;
 using System.Runtime.InteropServices;
 
@@ -30,6 +31,8 @@ public static partial class PlatformDetection
 
         public static bool IsMonoLinuxArm64 => IsMonoRuntime && IsLinux && IsArm64Process;
         public static bool IsNotMonoLinuxArm64 => !IsMonoLinuxArm64;
+        public static bool IsQemuLinux => IsLinux && Environment.GetEnvironmentVariable("DOTNET_RUNNING_UNDER_QEMU") != null;
+        public static bool IsNotQemuLinux => !IsQemuLinux;
 
         // OSX family
         public static bool IsApplePlatform => IsOSX || IsiOS || IstvOS || IsMacCatalyst;

src/libraries/System.Net.Sockets/tests/FunctionalTests/ArgumentValidationTests.cs

@@ -6,7 +6,7 @@
 using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
-
+using Microsoft.DotNet.XUnitExtensions;
 using Xunit;
 
 namespace System.Net.Sockets.Tests
@@ -792,14 +792,19 @@ await Task.WhenAll(
             }
         }
 
-        [Theory]
+        [ConditionalTheory]
         [PlatformSpecific(TestPlatforms.AnyUnix)]  // API throws PNSE on Unix
         [InlineData(0)]
         [InlineData(1)]
         public void Connect_ConnectTwice_NotSupported(int invalidatingAction)
         {
             using (Socket client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
             {
+                if (PlatformDetection.IsQemuLinux && invalidatingAction == 1)
+                {
+                    throw new SkipTestException("Skip on Qemu due to [ActiveIssue(https://github.com/dotnet/runtime/issues/104542)]");
+                }
+
                 switch (invalidatingAction)
                 {
                     case 0:
@@ -823,7 +828,7 @@ public void Connect_ConnectTwice_NotSupported(int invalidatingAction)
             }
         }
 
-        [Theory]
+        [ConditionalTheory]
         [PlatformSpecific(TestPlatforms.AnyUnix)]  // API throws PNSE on Unix
         [InlineData(0)]
         [InlineData(1)]
@@ -833,6 +838,11 @@ public void ConnectAsync_ConnectTwice_NotSupported(int invalidatingAction)
 
             using (Socket client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
             {
+                if (PlatformDetection.IsQemuLinux && invalidatingAction == 1)
+                {
+                    throw new SkipTestException("Skip on Qemu due to [ActiveIssue(https://github.com/dotnet/runtime/issues/104542)]");
+                }
+
                 switch (invalidatingAction)
                 {
                     case 0:

src/libraries/System.Net.Sockets/tests/FunctionalTests/KeepAliveTest.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Runtime.InteropServices;
+using Microsoft.DotNet.XUnitExtensions;
 using Xunit;
 
 namespace System.Net.Sockets.Tests
@@ -122,6 +123,7 @@ public void Socket_KeepAlive_Interval_And_Time()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/104545", typeof(PlatformDetection), nameof(PlatformDetection.IsQemuLinux))]
         public void Socket_Get_KeepAlive_Time_AsByteArray_OptionLengthZero_Failure()
         {
             using (Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
@@ -138,12 +140,17 @@ public void Socket_Get_KeepAlive_Time_AsByteArray_OptionLengthZero_Failure()
             }
         }
 
-        [Theory]
+        [ConditionalTheory]
         [InlineData(null)]
         [InlineData(new byte[0])]
         [InlineData(new byte[3] { 0, 0, 0 })]
         public void Socket_Get_KeepAlive_Time_AsByteArray_BufferNullOrTooSmall_Failure(byte[] buffer)
         {
+            if (PlatformDetection.IsQemuLinux && (buffer == null || buffer.Length == 0))
+            {
+                throw new SkipTestException("Skip on Qemu due to [ActiveIssue(https://github.com/dotnet/runtime/issues/104545)]");
+            }
+
             using (Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
             {
                 if (PlatformDetection.IsWindows)

src/libraries/System.Net.Sockets/tests/FunctionalTests/SocketOptionNameTest.cs

@@ -51,6 +51,7 @@ public void ReuseUnicastPort_CreateSocketSetOption()
         }
 
         [Fact]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/104547", typeof(PlatformDetection), nameof(PlatformDetection.IsQemuLinux))]
         public void MulticastOption_CreateSocketSetGetOption_GroupAndInterfaceIndex_SetSucceeds_GetThrows()
         {
             int interfaceIndex = 0;
@@ -65,6 +66,7 @@ public void MulticastOption_CreateSocketSetGetOption_GroupAndInterfaceIndex_SetS
         }
 
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsNotWindowsNanoNorServerCore))] // Skip on Nano: https://github.com/dotnet/runtime/issues/26286
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/104547", typeof(PlatformDetection), nameof(PlatformDetection.IsQemuLinux))]
         public async Task MulticastInterface_Set_AnyInterface_Succeeds()
         {
             // On all platforms, index 0 means "any interface"
@@ -123,6 +125,7 @@ public void MulticastInterface_Set_InvalidIndex_Throws()
         [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsNotWindowsNanoNorServerCore))] // Skip on Nano: https://github.com/dotnet/runtime/issues/26286
         [SkipOnPlatform(TestPlatforms.OSX | TestPlatforms.FreeBSD, "Expected behavior is different on OSX or FreeBSD")]
         [ActiveIssue("https://github.com/dotnet/runtime/issues/52124", TestPlatforms.iOS | TestPlatforms.tvOS | TestPlatforms.MacCatalyst)]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/104547", typeof(PlatformDetection), nameof(PlatformDetection.IsQemuLinux))]
         public async Task MulticastInterface_Set_IPv6_AnyInterface_Succeeds()
         {
             // On all platforms, index 0 means "any interface"