[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 => IsQemu();
+        public static bool IsNotQemuLinux => !IsQemuLinux;
 
         // OSX family
         public static bool IsApplePlatform => IsOSX || IsiOS || IstvOS || IsMacCatalyst;
@@ -301,6 +304,15 @@ private static bool IsDistroAndVersionOrHigher(Predicate<string> distroPredicate
             return false;
         }
 
+        private static bool IsQemu()
+        {
+            if (IsLinux)
+            {
+                return Environment.GetEnvironmentVariable("DOTNET_RUNNING_UNDER_QEMU") != null;
+            }
+            return false;
+        }
+
         private static bool VersionEquivalentTo(int major, int minor, int build, int revision, Version actualVersionId)
         {
             return (major == -1 || major == actualVersionId.Major)

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

@@ -800,6 +800,11 @@ public void Connect_ConnectTwice_NotSupported(int invalidatingAction)
         {
             using (Socket client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
             {
+                // Skip on Qemu due to [ActiveIssue(https://github.com/dotnet/runtime/issues/104542)]
+                if (PlatformDetection.IsQemuLinux && invalidatingAction == 1)
+                {
+                    return;
+                }
                 switch (invalidatingAction)
                 {
                     case 0:
@@ -833,6 +838,11 @@ public void ConnectAsync_ConnectTwice_NotSupported(int invalidatingAction)
 
             using (Socket client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
             {
+                // Skip on Qemu due to [ActiveIssue(https://github.com/dotnet/runtime/issues/104542)]
+                if (PlatformDetection.IsQemuLinux && invalidatingAction == 1)
+                {
+                    return;
+                }
                 switch (invalidatingAction)
                 {
                     case 0:

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

@@ -122,6 +122,7 @@ 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))
@@ -144,6 +145,11 @@ public void Socket_Get_KeepAlive_Time_AsByteArray_OptionLengthZero_Failure()
         [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))
+            {
+                // Skip on Qemu due to [ActiveIssue(https://github.com/dotnet/runtime/issues/104545)]
+                return;
+            }
             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"