Implement PosixSignal API

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

@@ -0,0 +1,27 @@
+// 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 partial class Sys
+    {
+        [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_SetPosixSignalHandler")]
+        [SuppressGCTransition]
+        internal static extern unsafe void SetPosixSignalHandler(delegate* unmanaged<int, PosixSignal, int> handler);
+
+        [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_EnablePosixSignalHandling", SetLastError = true)]
+        internal static extern bool EnablePosixSignalHandling(int signal);
+
+        [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_DisablePosixSignalHandling")]
+        internal static extern void DisablePosixSignalHandling(int signal);
+
+        [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_HandleNonCanceledPosixSignal")]
+        internal static extern bool HandleNonCanceledPosixSignal(int signal, int handlersDisposed);
+
+        [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_GetPlatformSignalNumber")]
+        [SuppressGCTransition]
+        internal static extern int GetPlatformSignalNumber(PosixSignal signal);
+    }
+}

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

@@ -8,6 +8,6 @@ internal static partial class Interop
     internal static partial class Sys
     {
         [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_RegisterForSigChld")]
-        internal static extern unsafe void RegisterForSigChld(delegate* unmanaged<int, void> handler);
+        internal static extern unsafe void RegisterForSigChld(delegate* unmanaged<int, int, int> handler);
     }
 }

src/libraries/Common/src/Interop/Unix/System.Native/Interop.RestoreAndHandleCtrl.cs → src/libraries/Common/src/Interop/Unix/System.Native/Interop.SetDelayedSigChildConsoleConfigurationHandler.cs

@@ -7,7 +7,8 @@ internal static partial class Interop
 {
     internal static partial class Sys
     {
-        [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_RestoreAndHandleCtrl")]
-        internal static extern void RestoreAndHandleCtrl(CtrlCode ctrlCode);
+        [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_SetDelayedSigChildConsoleConfigurationHandler")]
+        [SuppressGCTransition]
+        internal static extern unsafe void SetDelayedSigChildConsoleConfigurationHandler(delegate* unmanaged<void> callback);
     }
 }

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

@@ -8,7 +8,6 @@ internal static partial class Interop
     internal static partial class Sys
     {
         [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_SetTerminalInvalidationHandler")]
-        [SuppressGCTransition]
         internal static extern unsafe void SetTerminalInvalidationHandler(delegate* unmanaged<void> handler);
     }
 }

src/libraries/Native/Unix/System.Native/entrypoints.c

@@ -216,10 +216,8 @@ static const Entry s_sysNative[] =
     DllImportEntry(SystemNative_GetOSArchitecture)
     DllImportEntry(SystemNative_GetProcessArchitecture)
     DllImportEntry(SystemNative_SearchPath)
-    DllImportEntry(SystemNative_RegisterForCtrl)
-    DllImportEntry(SystemNative_UnregisterForCtrl)
     DllImportEntry(SystemNative_RegisterForSigChld)
-    DllImportEntry(SystemNative_RestoreAndHandleCtrl)
+    DllImportEntry(SystemNative_SetDelayedSigChildConsoleConfigurationHandler)
     DllImportEntry(SystemNative_SetTerminalInvalidationHandler)
     DllImportEntry(SystemNative_InitializeTerminalAndSignalHandling)
     DllImportEntry(SystemNative_SNPrintF)
@@ -251,6 +249,11 @@ static const Entry s_sysNative[] =
     DllImportEntry(SystemNative_PWrite)
     DllImportEntry(SystemNative_PReadV)
     DllImportEntry(SystemNative_PWriteV)
+    DllImportEntry(SystemNative_EnablePosixSignalHandling)
+    DllImportEntry(SystemNative_DisablePosixSignalHandling)
+    DllImportEntry(SystemNative_HandleNonCanceledPosixSignal)
+    DllImportEntry(SystemNative_SetPosixSignalHandler)
+    DllImportEntry(SystemNative_GetPlatformSignalNumber)
 };
 
 EXTERN_C const void* SystemResolveDllImport(const char* name);

src/libraries/Native/Unix/System.Native/pal_console.c

@@ -97,23 +97,11 @@ static bool g_hasTty = false;                  // cache we are not a tty
 
 static volatile bool g_receivedSigTtou = false;
 
-static void ttou_handler(int signo)
+static void ttou_handler()
 {
-    (void)signo;
     g_receivedSigTtou = true;
 }
 
-static void InstallTTOUHandler(void (*handler)(int), int flags)
-{
-    struct sigaction action;
-    memset(&action, 0, sizeof(action));
-    action.sa_handler = handler;
-    action.sa_flags = flags;
-    int rvSigaction = sigaction(SIGTTOU, &action, NULL);
-    assert(rvSigaction == 0);
-    (void)rvSigaction;
-}
-
 static bool TcSetAttr(struct termios* termios, bool blockIfBackground)
 {
     if (g_terminalUninitialized)
@@ -131,7 +119,7 @@ static bool TcSetAttr(struct termios* termios, bool blockIfBackground)
         // stdout. We set SA_RESETHAND to avoid that handler's write loops infinitly
         // on EINTR when the process is running in background and the terminal
         // configured with TOSTOP.
-        InstallTTOUHandler(ttou_handler, (int)SA_RESETHAND);
+        InstallTTOUHandlerForConsole(ttou_handler);
 
         g_receivedSigTtou = false;
     }
@@ -147,8 +135,7 @@ static bool TcSetAttr(struct termios* termios, bool blockIfBackground)
             rv = true;
         }
 
-        // Restore default SIGTTOU handler.
-        InstallTTOUHandler(SIG_DFL, 0);
+        UninstallTTOUHandlerForConsole();
     }
 
     // On success, update the cached value.
@@ -205,8 +192,6 @@ static bool ConfigureTerminal(bool signalForBreak, bool forChild, uint8_t minCha
 
 void UninitializeTerminal()
 {
-    assert(g_hasTty);
-
     // This method is called on SIGQUIT/SIGINT from the signal dispatching thread
     // and on atexit.
 
@@ -473,7 +458,7 @@ int32_t SystemNative_InitializeTerminalAndSignalHandling()
 {
     static int32_t initialized = 0;
 
-    // Both the Process and Console class call this method for initialization.
+    // The Process, Console and PosixSignalRegistration classes call this method for initialization.
     if (pthread_mutex_lock(&g_lock) == 0)
     {
         if (initialized == 0)