--- Libc/Libc-583/sys/sigaction.c
+++ Libc/Libc-1669.40.2/sys/sigaction.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 1999-2017 Apple Computer, Inc. All rights reserved.
  *
  * @APPLE_LICENSE_HEADER_START@
  * 
@@ -20,44 +20,41 @@
  * 
  * @APPLE_LICENSE_HEADER_END@
  */
-/*
- * Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved
- *
- *	@(#)sigaction.c	1.0
- */
 
+#if __has_include(<CrashReporterClient.h>)
+#include <CrashReporterClient.h>
+#else
+#define CRSetCrashLogMessage(...)
+#endif
+#include <stdlib.h>
+#include <stdio.h>
 #include <unistd.h>
 #include <signal.h>
 #include <sys/signal.h>
 #include <errno.h>
 
-/*
- *	Intercept the sigaction syscall and use our signal trampoline
- *	as the signal handler instead.  The code here is derived
- *	from sigvec in sys/kern_sig.c.
- */
-extern int __sigaction (int, struct __sigaction * __restrict, struct sigaction * __restrict);
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wstrict-prototypes"
+
+extern int __platform_sigaction (int sig,
+		const struct sigaction * __restrict nsv,
+		struct sigaction * __restrict osv);
 
 int
-sigaction (int sig, const struct sigaction * __restrict nsv, struct sigaction * __restrict osv)
+sigaction (int sig, const struct sigaction * __restrict nsv,
+		struct sigaction * __restrict osv)
 {
-	extern void _sigtramp();
-	struct __sigaction sa;
-	struct __sigaction *sap;
-
-	if (sig <= 0 || sig >= NSIG || sig == SIGKILL || sig == SIGSTOP) {
-	        errno = EINVAL;
-	        return (-1);
+	int ret = __platform_sigaction(sig, nsv, osv);
+#ifdef FEATURE_SIGNAL_RESTRICTION
+	// Note: The "sig != 0" here is to force the compiler to maintain that "sig"
+	// is live, and in a register, after __sigaction so it is visible in the
+	// crashing register state.
+	if (ret == -1 && errno == ENOTSUP && sig != 0) {
+		CRSetCrashLogMessage("sigaction on fatal signals is not supported");
+		__builtin_trap();
 	}
-	sap = (struct __sigaction *)0;
-	if (nsv) {
-		sa.sa_handler = nsv->sa_handler;
-		sa.sa_tramp = _sigtramp;
-		sa.sa_mask = nsv->sa_mask;
-		sa.sa_flags = nsv->sa_flags;	
-		sap = &sa;
-	}
-	return __sigaction(sig, sap, osv);
+#endif
+	return ret;
 }
 
 // XXX
@@ -73,3 +70,4 @@
 }
 #endif
 
+#pragma clang diagnostic pop