Implement SunOS FileSystemWatcher using portfs event ports

src/libraries/Common/src/Interop/SunOS/portfs/Interop.portfs.cs

@@ -0,0 +1,76 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+// This implementation uses SunOS portfs (event ports) to watch directories.
+// portfs can detect when a directory's modification time changes via port_associate,
+// but cannot tell us WHAT changed in the directory. This makes it different from
+// Linux inotify or Windows ReadDirectoryChangesW.
+//
+// The FileSystemWatcher implementation must:
+// 1. Use port_associate to watch for FILE_MODIFIED events on directories
+// 2. When an event occurs, re-read the directory contents
+// 3. Compare with cached state to determine what actually changed
+//
+
+using System;
+using System.Runtime.InteropServices;
+using Microsoft.Win32.SafeHandles;
+
+internal static partial class Interop
+{
+    internal static partial class PortFs
+    {
+        [LibraryImport(Libraries.SystemNative, EntryPoint = "SystemNative_PortCreate",
+            SetLastError = true)]
+        internal static partial SafeFileHandle PortCreate();
+
+        // pFileObj must point to pinned memory with size >= sizeof(file_obj)
+        // because the address is used as an identifier in the kernel.
+        // dirPath string is used while making the association but is
+        // never referenced again after PortAssociate returns.
+        // mtime is the directory modification time before reading the directory
+        // cookie is returned by PortGet to identify which directory changed
+        [LibraryImport(Libraries.SystemNative, EntryPoint = "SystemNative_PortAssociate",
+            SetLastError = true, StringMarshalling = StringMarshalling.Utf8)]
+        internal static unsafe partial int PortAssociate(SafeFileHandle fd, IntPtr pFileObj, string dirPath, Interop.Sys.TimeSpec* mtime, int evmask, nuint cookie);
+
+        // Returns the cookie value from PortAssociate in the cookie parameter
+        [LibraryImport(Libraries.SystemNative, EntryPoint = "SystemNative_PortGet",
+            SetLastError = true)]
+        internal static unsafe partial int PortGet(SafeFileHandle fd, int* events, nuint* cookie, Interop.Sys.TimeSpec* tmo);
+
+        [LibraryImport(Libraries.SystemNative, EntryPoint = "SystemNative_PortDissociate",
+            SetLastError = true)]
+        internal static partial int PortDissociate(SafeFileHandle fd, IntPtr pFileObj);
+
+        // Send a synthetic event to wake up a blocked PortGet call
+        // evflags can be any PortEvent value (e.g., FILE_NOFOLLOW for cancellation)
+        // cookie is returned to PortGet to identify the event
+        [LibraryImport(Libraries.SystemNative, EntryPoint = "SystemNative_PortSend",
+            SetLastError = true)]
+        internal static partial int PortSend(SafeFileHandle fd, int evflags, nuint cookie);
+
+        [Flags]
+        internal enum PortEvent
+        {
+            FILE_ACCESS      = 0x00000001,
+            FILE_MODIFIED    = 0x00000002,
+            FILE_ATTRIB      = 0x00000004,
+            FILE_TRUNC       = 0x00100000,
+            FILE_NOFOLLOW    = 0x10000000,
+            FILE_EXCEPTION   = 0x20000000,
+
+            // Exception events
+            FILE_DELETE      = 0x00000010,
+            FILE_RENAME_TO   = 0x00000020,
+            FILE_RENAME_FROM = 0x00000040,
+            // These are unused, and the duplicate value causes warnings.
+            // UNMOUNTED     = 0x20000000,
+            // MOUNTEDOVER   = 0x40000000,
+        }
+
+        // sizeof(file_obj) = 3*sizeof(timespec) + 3*sizeof(uintptr_t) + sizeof(char*)
+        // On 64-bit: 3*16 + 3*8 + 8 = 80 bytes
+        internal const int FileObjSize = 80;
+    }
+}

src/libraries/System.IO.FileSystem.Watcher/src/System.IO.FileSystem.Watcher.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>$(NetCoreAppCurrent)-windows;$(NetCoreAppCurrent)-linux;$(NetCoreAppCurrent)-osx;$(NetCoreAppCurrent)-maccatalyst;$(NetCoreAppCurrent)-freebsd;$(NetCoreAppCurrent)</TargetFrameworks>
+    <TargetFrameworks>$(NetCoreAppCurrent)-windows;$(NetCoreAppCurrent)-linux;$(NetCoreAppCurrent)-osx;$(NetCoreAppCurrent)-maccatalyst;$(NetCoreAppCurrent)-freebsd;$(NetCoreAppCurrent)-illumos;$(NetCoreAppCurrent)-solaris;$(NetCoreAppCurrent)</TargetFrameworks>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <UseCompilerGeneratedDocXmlFile>false</UseCompilerGeneratedDocXmlFile>
   </PropertyGroup>
@@ -89,6 +89,22 @@
              Link="Common\Interop\Unix\Interop.Stat.cs" />
   </ItemGroup>
 
+  <ItemGroup Condition="'$(TargetPlatformIdentifier)' == 'illumos' or '$(TargetPlatformIdentifier)' == 'solaris'">
+    <Compile Include="System\IO\FileSystemWatcher.SunOS.cs" />
+    <Compile Include="$(CommonPath)Interop\SunOS\portfs\Interop.portfs.cs"
+             Link="Common\Interop\SunOS\portfs\Interop.portfs.cs" />
+    <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.RealPath.cs"
+             Link="Common\Interop\Unix\Interop.RealPath.cs" />
+    <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.UTimensat.cs"
+             Link="Common\Interop\Unix\System.Native\Interop.UTimensat.cs" />
+    <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.Poll.cs"
+             Link="Common\Interop\Unix\Interop.Poll.cs" />
+    <Compile Include="$(CommonPath)Interop\Unix\Interop.Poll.Structs.cs"
+             Link="Common\Interop\Unix\Interop.Poll.Structs.cs" />
+    <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.Stat.cs"
+             Link="Common\Interop\Unix\Interop.Stat.cs" />
+  </ItemGroup>
+
   <ItemGroup Condition="'$(TargetPlatformIdentifier)' == 'osx' or '$(TargetPlatformIdentifier)' == 'maccatalyst'">
     <Compile Include="System\IO\FileSystemWatcher.OSX.cs" />
     <Compile Include="$(CoreLibSharedDir)System\IO\FileSystem.Exists.Unix.cs"