From b5182915d75c1d4ef055d0ab040356e4836bc7ea Mon Sep 17 00:00:00 2001
From: Jeffrey Pfau <jeffrey@endrift.com>
Date: Fri, 12 Apr 2013 21:27:43 -0700
Subject: [PATCH] Command to break into attached debugger

---
 src/debugger.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/debugger.c b/src/debugger.c
index fb2501efb..47d2f4949 100644
--- a/src/debugger.c
+++ b/src/debugger.c
@@ -2,14 +2,17 @@
 
 #include "arm.h"
 
+#include <signal.h>
 #include <stdio.h>
 #include <stdarg.h>
 #include <stdlib.h>
 #include <strings.h>
+#include <unistd.h>
 #include "linenoise.h"
 
 typedef void (DebuggerComamnd)(struct ARMDebugger*);
 
+static void _breakInto(struct ARMDebugger*);
 static void _printStatus(struct ARMDebugger*);
 static void _quit(struct ARMDebugger*);
 
@@ -22,6 +25,7 @@ struct {
 	{ "q", _quit },
 	{ "quit", _quit },
 	{ "status", _printStatus },
+	{ "x", _breakInto },
 	{ 0, 0 }
 };
 
@@ -36,6 +40,18 @@ static inline void _printPSR(union PSR psr) {
 		psr.t ? 'T' : '-');
 }
 
+static void _handleDeath(int sig) {
+	(void)(sig);
+	printf("No debugger attached!\n");
+}
+
+static void _breakInto(struct ARMDebugger* debugger) {
+	(void)(debugger);
+	sig_t oldSignal = signal(SIGTRAP, _handleDeath);
+	kill(getpid(), SIGTRAP);
+	signal(SIGTRAP, oldSignal);
+}
+
 static void _printStatus(struct ARMDebugger* debugger) {
 	int r;
 	for (r = 0; r < 4; ++r) {