PERFORCE change 122167 for review

[Peter Wemm]

http://perforce.freebsd.org/chv.cgi?CH=122167

Change 122167 by peter at peter_daintree on 2007/06/22 21:38:41

	Add kern.do_sigsys to control whether an enosys() also causes SIGSYS.  This would
	have been very useful to probe for presence of syscalls.  Avoids the need to install
	a sigsys handler.   If only this was present for the last 10 years....

Affected files ...

.. //depot/projects/hammer/sys/kern/kern_sig.c#80 edit

Differences ...

==== //depot/projects/hammer/sys/kern/kern_sig.c#80 (text+ko) ====

@@ -111,6 +111,10 @@
 SYSCTL_INT(_kern, OID_AUTO, forcesigexit, CTLFLAG_RW,
     &kern_forcesigexit, 0, "Force trap signal to be handled");
 
+static int	kern_do_sigsys = 1;
+SYSCTL_INT(_kern, OID_AUTO, do_sigsys, CTLFLAG_RW,
+    &kern_do_sigsys, 0, "Have the kernel send SIGSYS on a bad syscall");
+
 SYSCTL_NODE(_kern, OID_AUTO, sigqueue, CTLFLAG_RW, 0, "POSIX real time signal");
 
 static int	max_pending_per_proc = 128;
@@ -3168,9 +3172,11 @@
 {
 	struct proc *p = td->td_proc;
 
-	PROC_LOCK(p);
-	psignal(p, SIGSYS);
-	PROC_UNLOCK(p);
+	if (kern_do_sigsys) {
+		PROC_LOCK(p);
+		psignal(p, SIGSYS);
+		PROC_UNLOCK(p);
+	}
 	return (ENOSYS);
 }