[rkward-cvs] SF.net SVN: rkward: [1458] trunk/rkward/rkward/rbackend/rkpthreadsupport. cpp

[tfry at users.sourceforge.net]

Revision: 1458
          http://svn.sourceforge.net/rkward/?rev=1458&view=rev
Author:   tfry
Date:     2007-02-23 04:15:28 -0800 (Fri, 23 Feb 2007)

Log Message:
-----------
Make sure not to mix up stack top and bottom

Modified Paths:
--------------
    trunk/rkward/rkward/rbackend/rkpthreadsupport.cpp

Modified: trunk/rkward/rkward/rbackend/rkpthreadsupport.cpp
===================================================================
--- trunk/rkward/rkward/rbackend/rkpthreadsupport.cpp	2007-02-23 11:31:44 UTC (rev 1457)
+++ trunk/rkward/rkward/rbackend/rkpthreadsupport.cpp	2007-02-23 12:15:28 UTC (rev 1458)
@@ -24,9 +24,11 @@
 #	include <pthread_np.h>
 #endif
 
-/* This code is mostly borrowed from WINE (http://www.winehq.org) */
+/* Much of this code is borrowed from WINE (http://www.winehq.org) */
 
 void RKGetCurrentThreadStackLimits (size_t *size, void **base) {
+	char dummy;
+	int direction;
 #ifdef HAVE_PTHREAD_GETATTR_NP
 	pthread_attr_t attr;
 	pthread_getattr_np (pthread_self (), &attr);
@@ -39,17 +41,26 @@
 	pthread_attr_getstack (&attr, base, size);
 	pthread_attr_destroy (&attr);
 #elif defined(HAVE_PTHREAD_GET_STACKSIZE_NP) && defined(HAVE_PTHREAD_GET_STACKADDR_NP)
-	char dummy;
-	size = pthread_get_stacksize_np (pthread_self ());
-	base = pthread_get_stackaddr_np (pthread_self ());
-	/* if base is too large assume it's the top of the stack instead */
-	if ((char *) base > &dummy)
-	base = (char *) base - size;
+	*size = pthread_get_stacksize_np (pthread_self ());
+	*base = pthread_get_stackaddr_np (pthread_self ());
 #else
 #	warning Can't determine the stack limits of a pthread on this system
 #	warning R C stack checking will be disabled
-	char dummy;
 	*base = &dummy;
 	*size = (unsigned long) -1;
+	return;
 #endif
+	// in which direction does the stack grow?
+	{
+		char dummy2;
+		direction = (&dummy) > (&dummy2) ? 1 : -1;
+	}
+
+	// in which direction does the stack base lie?
+	int base_direction = (*base) > (&dummy) ? 1 : -1;
+
+	// switch base / top, if necessary
+	if (base_direction != direction) {
+		*base = ((char *) *base) + (direction * ((unsigned long) *size));
+	}
 }


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