Port the Shared Mutex logic from CoreCLR PAL to work alongside the managed wait subsystem

src/coreclr/nativeaot/Runtime/FinalizerHelpers.cpp

@@ -262,3 +262,9 @@ FCIMPL0(OBJECTREF, RhpGetNextFinalizableObject)
     }
 }
 FCIMPLEND
+
+FCIMPL0(FC_BOOL_RET, RhpCurrentThreadIsFinalizerThread)
+{
+    FC_RETURN_BOOL(ThreadStore::GetCurrentThread() == g_pFinalizerThread);
+}
+FCIMPLEND

src/coreclr/nativeaot/System.Private.CoreLib/src/System.Private.CoreLib.csproj

@@ -302,15 +302,9 @@
     <Compile Include="$(CommonPath)\Interop\Unix\System.Native\Interop.Exit.cs">
       <Link>Interop\Unix\System.Native\Interop.Exit.cs</Link>
     </Compile>
-    <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.MMap.cs">
-      <Link>Interop\Unix\System.Native\Interop.MMap.cs</Link>
-    </Compile>
     <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.MProtect.cs">
       <Link>Interop\Unix\System.Native\Interop.MProtect.cs</Link>
     </Compile>
-    <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.MUnmap.cs">
-      <Link>Interop\Unix\System.Native\Interop.MUnmap.cs</Link>
-    </Compile>
   </ItemGroup>
   <ItemGroup>
     <Compile Include="$(CompilerCommonPath)\System\Collections\Generic\ArrayBuilder.cs">

src/coreclr/vm/comsynchronizable.cpp

@@ -899,3 +899,11 @@ extern "C" void QCALLTYPE ThreadNative_ResetAbort()
         pThread->UnmarkThreadForAbort(EEPolicy::TA_Safe);
     }
 }
+
+FCIMPL0(FC_BOOL_RET, ThreadNative::CurrentThreadIsFinalizerThread)
+{
+    FCALL_CONTRACT;
+
+    FC_RETURN_BOOL(IsFinalizerThread());
+}
+FCIMPLEND

src/coreclr/vm/comsynchronizable.h

@@ -42,6 +42,7 @@ class ThreadNative
     static FCDECL0(INT32,       GetOptimalMaxSpinWaitsPerSpinIteration);
     static FCDECL1(void,        Finalize, ThreadBaseObject* pThis);
     static FCDECL0(FC_BOOL_RET, CatchAtSafePoint);
+    static FCDECL0(FC_BOOL_RET, CurrentThreadIsFinalizerThread);
 };
 
 extern "C" void QCALLTYPE ThreadNative_Start(QCall::ThreadHandle thread, int threadStackSize, int priority, BOOL isThreadPool, PCWSTR pThreadName);

src/coreclr/vm/ecalllist.h

@@ -248,6 +248,7 @@ FCFuncEnd()
 FCFuncStart(gThreadFuncs)
     FCFuncElement("InternalFinalize", ThreadNative::Finalize)
     FCFuncElement("CatchAtSafePoint", ThreadNative::CatchAtSafePoint)
+    FCFuncElement("CurrentThreadIsFinalizerThread", ThreadNative::CurrentThreadIsFinalizerThread)
     FCFuncElement("get_OptimalMaxSpinWaitsPerSpinIteration", ThreadNative::GetOptimalMaxSpinWaitsPerSpinIteration)
 FCFuncEnd()
 

src/libraries/Common/src/Interop/Unix/System.Native/Interop.LowLevelCrossProcessMutex.cs

@@ -0,0 +1,43 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Runtime.InteropServices;
+
+internal static partial class Interop
+{
+    internal static unsafe partial class Sys
+    {
+        [LibraryImport(Libraries.SystemNative, EntryPoint = "SystemNative_LowLevelCrossProcessMutex_Init", SetLastError = true)]
+        internal static partial int LowLevelCrossProcessMutex_Init(void* mutex);
+
+        [LibraryImport(Libraries.SystemNative, EntryPoint = "SystemNative_LowLevelCrossProcessMutex_Acquire", SetLastError = true)]
+        internal static partial int LowLevelCrossProcessMutex_Acquire(void* mutex, int timeoutMilliseconds);
+
+        [LibraryImport(Libraries.SystemNative, EntryPoint = "SystemNative_LowLevelCrossProcessMutex_Release", SetLastError = true)]
+        internal static partial int LowLevelCrossProcessMutex_Release(void* mutex);
+
+        [LibraryImport(Libraries.SystemNative, EntryPoint = "SystemNative_LowLevelCrossProcessMutex_Destroy", SetLastError = true)]
+        internal static partial int LowLevelCrossProcessMutex_Destroy(void* mutex);
+
+        [LibraryImport(Libraries.SystemNative, EntryPoint = "SystemNative_LowLevelCrossProcessMutex_Size")]
+        [SuppressGCTransition]
+        internal static partial int LowLevelCrossProcessMutex_Size();
+
+        [LibraryImport(Libraries.SystemNative, EntryPoint = "SystemNative_LowLevelCrossProcessMutex_GetOwnerProcessAndThreadId", SetLastError = true)]
+        [SuppressGCTransition]
+        internal static partial void LowLevelCrossProcessMutex_GetOwnerProcessAndThreadId(void* mutex, out uint processId, out uint threadId);
+
+        [LibraryImport(Libraries.SystemNative, EntryPoint = "SystemNative_LowLevelCrossProcessMutex_SetOwnerProcessAndThreadId", SetLastError = true)]
+        [SuppressGCTransition]
+        internal static partial void LowLevelCrossProcessMutex_SetOwnerProcessAndThreadId(void* mutex, uint processId, uint threadId);
+
+        [LibraryImport(Libraries.SystemNative, EntryPoint = "SystemNative_LowLevelCrossProcessMutex_IsAbandoned", SetLastError = true)]
+        [SuppressGCTransition]
+        [return: MarshalAs(UnmanagedType.U1)]
+        internal static partial bool LowLevelCrossProcessMutex_IsAbandoned(void* mutex);
+
+        [LibraryImport(Libraries.SystemNative, EntryPoint = "SystemNative_LowLevelCrossProcessMutex_SetAbandoned", SetLastError = true)]
+        [SuppressGCTransition]
+        internal static partial void LowLevelCrossProcessMutex_SetAbandoned(void* mutex, [MarshalAs(UnmanagedType.U1)] bool abandoned);
+    }
+}

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

@@ -35,6 +35,7 @@ public static partial class PlatformDetection
         public static bool IsNotMonoAOT => Environment.GetEnvironmentVariable("MONO_AOT_MODE") != "aot";
         public static bool IsNativeAot => IsNotMonoRuntime && !IsReflectionEmitSupported;
         public static bool IsNotNativeAot => !IsNativeAot;
+        public static bool IsCoreCLR => IsNotMonoRuntime && IsNotNativeAot;
         public static bool IsFreeBSD => RuntimeInformation.IsOSPlatform(OSPlatform.Create("FREEBSD"));
         public static bool IsNetBSD => RuntimeInformation.IsOSPlatform(OSPlatform.Create("NETBSD"));
         public static bool IsAndroid => RuntimeInformation.IsOSPlatform(OSPlatform.Create("ANDROID"));

src/libraries/System.Private.CoreLib/src/Resources/Strings.resx

@@ -4387,5 +4387,34 @@
   </data>
   <data name="PlatformNotSupported_DynamicEntrypoint" xml:space="preserve">
     <value>Dynamic entrypoint allocation is not supported in the current environment.</value>
+  </data>  <data name="Arg_InvalidOperationException_CannotReleaseUnownedMutex" xml:space="preserve">
+    <value>Cannot release a lock that is not owned by the current thread.</value>
+  </data>
+  <data name="Arg_FailedToInitializePThreadMutex" xml:space="preserve">
+    <value>Failed to initialize pthread mutex</value>
+  </data>
+  <data name="IO_SharedMemory_InvalidHeader" xml:space="preserve">
+    <value>Cross-process shared memory file '{0}' has a header that is not supported by this version of the .NET runtime.</value>
+  </data>
+  <data name="IO_SharedMemory_FileNotOwnedByUid" xml:space="preserve">
+    <value>The file '{0}' is not owned by the current user with UID {1}.</value>
+  </data>
+  <data name="IO_SharedMemory_FilePermissionsIncorrect" xml:space="preserve">
+    <value>The file '{0}' does not have the expected permissions for user scope: {1}.</value>
+  </data>
+  <data name="IO_SharedMemory_PathExistsButNotDirectory" xml:space="preserve">
+    <value>The path '{0}' exists but is not a directory.</value>
+  </data>
+  <data name="IO_SharedMemory_DirectoryPermissionsIncorrect" xml:space="preserve">
+    <value>The directory '{0}' does not have the expected owner or permissions for system scope: {1}, {2}.</value>
+  </data>
+  <data name="IO_SharedMemory_DirectoryNotOwnedByUid" xml:space="preserve">
+    <value>The directory '{0}' is not owned by the current user with UID {1}.</value>
+  </data>
+  <data name="IO_SharedMemory_DirectoryPermissionsIncorrectUserScope" xml:space="preserve">
+    <value>The directory '{0}' does not have the expected permissions for user scope: {1}.</value>
+  </data>
+  <data name="IO_SharedMemory_DirectoryOwnerPermissionsIncorrect" xml:space="preserve">
+    <value>The directory '{0}' does not have the expected owner permissions: {1}.</value>
   </data>
 </root>

src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems

@@ -24,6 +24,7 @@
     <Is64Bit Condition="'$(Platform)' == 'arm64' or '$(Platform)' == 'x64' or '$(Platform)' == 's390x' or '$(Platform)' == 'loongarch64' or '$(Platform)' == 'ppc64le' or '$(Platform)' == 'riscv64'">true</Is64Bit>
     <UseMinimalGlobalizationData Condition="'$(TargetsBrowser)' == 'true' or '$(TargetsWasi)' == 'true'">true</UseMinimalGlobalizationData>
     <EnableLibraryImportGenerator>true</EnableLibraryImportGenerator>
+    <FeatureCrossProcessMutex Condition="'$(IsMobileLike)' != 'true'">true</FeatureCrossProcessMutex>
   </PropertyGroup>
   <PropertyGroup>
     <DefineConstants Condition="'$(IsBigEndian)' == 'true'">$(DefineConstants);BIGENDIAN</DefineConstants>
@@ -49,6 +50,9 @@
     <DefineConstants Condition="'$(TargetsSolaris)' == 'true'">$(DefineConstants);TARGET_SOLARIS</DefineConstants>
     <DefineConstants Condition="'$(TargetsHaiku)' == 'true'">$(DefineConstants);TARGET_HAIKU</DefineConstants>
   </PropertyGroup>
+  <PropertyGroup>
+    <DefineConstants Condition="'$(FeatureCrossProcessMutex)' == 'true'">$(DefineConstants);FEATURE_CROSS_PROCESS_MUTEX</DefineConstants>
+  </PropertyGroup>
   <ItemGroup>
     <ApiCompatSuppressionFile Include="$(MSBuildThisFileDirectory)CompatibilitySuppressions.xml" />
   </ItemGroup>
@@ -2463,6 +2467,12 @@
     <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.MksTemps.cs">
       <Link>Common\Interop\Unix\System.Native\Interop.MksTemps.cs</Link>
     </Compile>
+    <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.MMap.cs">
+      <Link>Common\Interop\Unix\System.Native\Interop.MMap.cs</Link>
+    </Compile>
+    <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.MUnmap.cs">
+      <Link>Common\Interop\Unix\System.Native\Interop.MUnmap.cs</Link>
+    </Compile>
     <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.MountPoints.cs">
       <Link>Common\Interop\Unix\System.Native\Interop.MountPoints.cs</Link>
     </Compile>
@@ -2622,6 +2632,9 @@
     <Compile Include="$(CommonPath)\Interop\Unix\System.Native\Interop.GetPid.cs">
       <Link>Common\Interop\Unix\System.Native\Interop.GetPid.cs</Link>
     </Compile>
+    <Compile Include="$(CommonPath)\Interop\Unix\System.Native\Interop.GetSid.cs">
+      <Link>Common\Interop\Unix\System.Native\Interop.GetSid.cs</Link>
+    </Compile>
     <Compile Include="$(CommonPath)Interop\FreeBSD\Interop.Process.GetProcInfo.cs" Condition="'$(TargetsFreeBSD)' == 'true'" Link="Common\Interop\FreeBSD\Interop.Process.GetProcInfo.cs" />
     <Compile Include="$(CommonPath)Interop\BSD\System.Native\Interop.Sysctl.cs" Condition="'$(TargetsFreeBSD)' == 'true'" Link="Common\Interop\BSD\System.Native\Interop.Sysctl.cs" />
     <Compile Include="$(CommonPath)Interop\Linux\procfs\Interop.ProcFsStat.TryReadStatusFile.cs" Condition="'$(TargetsLinux)' == 'true'" Link="Common\Interop\Linux\Interop.ProcFsStat.TryReadStatusFile.cs" />
@@ -2844,6 +2857,13 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\WaitSubsystem.Unix.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\WaitSubsystem.WaitableObject.Unix.cs" />
   </ItemGroup>
+  <ItemGroup Condition="'$(FeatureCoreCLR)' != 'true' and '$(TargetsUnix)' == 'true' and '$(FeatureCrossProcessMutex)' == 'true'">
+    <Compile Include="$(MSBuildThisFileDirectory)System\IO\SharedMemoryManager.Unix.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\Threading\NamedMutex.Unix.cs" />
+    <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.LowLevelCrossProcessMutex.cs">
+      <Link>Common\Interop\Unix\System.Native\Interop.LowLevelCrossProcessMutex.cs</Link>
+    </Compile>
+  </ItemGroup>
   <ItemGroup Condition="'$(FeatureCoreCLR)' != 'true' and '$(TargetsWindows)' == 'true'">
     <Compile Include="$(MSBuildThisFileDirectory)System\Threading\WaitHandle.Windows.cs" />
   </ItemGroup>

src/libraries/System.Private.CoreLib/src/System/IO/PersistedFiles.Unix.cs

@@ -56,6 +56,11 @@ private static void EnsureUserDirectories()
 
             // In initialization conditions, however, the "HOME" environment variable may
             // not yet be set. For such cases, consult with the password entry.
+            return GetHomeDirectoryFromPasswd();
+        }
+
+        internal static string GetHomeDirectoryFromPasswd()
+        {
             unsafe
             {
                 // First try with a buffer that should suffice for 99% of cases.
@@ -65,8 +70,8 @@ private static void EnsureUserDirectories()
                 // what to do.
                 const int BufLen = Interop.Sys.Passwd.InitialBufferSize;
                 byte* stackBuf = stackalloc byte[BufLen];
-                if (TryGetHomeDirectoryFromPasswd(stackBuf, BufLen, out userHomeDirectory))
-                    return userHomeDirectory;
+                if (TryGetHomeDirectoryFromPasswd(stackBuf, BufLen, out string? userHomeDirectory))
+                    return userHomeDirectory!;
 
                 // Fallback to heap allocations if necessary, growing the buffer until
                 // we succeed.  TryGetHomeDirectory will throw if there's an unexpected error.
@@ -78,7 +83,7 @@ private static void EnsureUserDirectories()
                     fixed (byte* buf = &heapBuf[0])
                     {
                         if (TryGetHomeDirectoryFromPasswd(buf, heapBuf.Length, out userHomeDirectory))
-                            return userHomeDirectory;
+                            return userHomeDirectory!;
                     }
                 }
             }