[project @ 2003-01-25 15:54:48 by wolfgang]

[ghc-hetmet.git] / ghc / rts / Signals.c

diff --git a/ghc/rts/Signals.c b/ghc/rts/Signals.c
index 8e33d9d..d337078 100644 (file)
--- a/ghc/rts/Signals.c
+++ b/ghc/rts/Signals.c
@@ -1,5 +1,5 @@
 /* -----------------------------------------------------------------------------
- * $Id: Signals.c,v 1.32 2003/01/10 22:08:20 wolfgang Exp $
+ * $Id: Signals.c,v 1.33 2003/01/25 15:54:50 wolfgang Exp $
  *
  * (c) The GHC Team, 1998-1999
  *
@@ -49,6 +49,23 @@ StgPtr *next_pending_handler = pending_handler_buf;
 
 StgInt nocldstop = 0;
 
+
+#ifdef RTS_SUPPORTS_THREADS
+pthread_t signalHandlingThread;
+#endif
+
+       // Handle all signals in the current thread.
+       // Called from Capability.c whenever the main capability is granted to a thread
+       // and in installDefaultHandlers
+void
+handleSignalsInThisThread()
+{
+#ifdef RTS_SUPPORTS_THREADS
+    signalHandlingThread = pthread_self();
+#endif
+}
+
+
 /* -----------------------------------------------------------------------------
  * Allocate/resize the table of signal handlers.
  * -------------------------------------------------------------------------- */
@@ -105,6 +122,19 @@ generic_handler(int sig)
 {
     sigset_t signals;
 
+#if defined(THREADED_RTS)
+       // Make the thread that currently holds the main capability
+       // handle the signal.
+       // This makes sure that awaitEvent() is interrupted
+       // and it (hopefully) prevents race conditions
+       // (signal handlers are not atomic with respect to other threads)
+
+    if(pthread_self() != signalHandlingThread) {
+        pthread_kill(signalHandlingThread, sig);
+        return;
+    }
+#endif
+
     /* Can't call allocate from here.  Probably can't call malloc
        either.  However, we have to schedule a new thread somehow.
 
@@ -215,6 +245,8 @@ stg_sig_install(int sig, int spi, StgStablePtr *handler, void *mask)
 
     previous_spi = handlers[sig];
 
+    action.sa_flags = 0;
+    
     switch(spi) {
     case STG_SIG_IGN:
        handlers[sig] = STG_SIG_IGN;
@@ -348,6 +380,17 @@ shutdown_handler(int sig STG_UNUSED)
        pthread_kill(startup_guy, sig);
        return;
     }
+    // ToDo: The code for the threaded RTS below does something very
+    // similar. Maybe the SMP special case is not needed
+    // -- Wolfgang Thaller
+#elif defined(THREADED_RTS)
+       // Make the thread that currently holds the main capability
+       // handle the signal.
+       // This makes sure that awaitEvent() is interrupted
+    if(pthread_self() != signalHandlingThread) {
+        pthread_kill(signalHandlingThread, sig);
+        return;
+    }
 #endif
 
     // If we're already trying to interrupt the RTS, terminate with
@@ -383,6 +426,9 @@ initDefaultHandlers()
 #ifdef SMP
     startup_guy = pthread_self();
 #endif
+#ifdef RTS_SUPPORTS_THREADS
+       handleSignalsInThisThread();
+#endif
 
     // install the SIGINT handler
     action.sa_handler = shutdown_handler;