From 9344851b057b3f6cbff69b88e86ac2b9d6086838 Mon Sep 17 00:00:00 2001
From: Ibrahn Sahir <ibrahn.sahir@gmail.com>
Date: Mon, 24 Sep 2018 22:21:05 +0100
Subject: [PATCH] Fixed hang when segfaulting after OS object destroyed (OSX
 and X11)

The two POSIX style crash handlers (OSX and X11) now remove their signal
handlers when they are destroyed.
Additonally if they are called while no OS singleton is set, they will
simply abort(). This should not happen now that they remove themselves,
but if a future change seperates OS object and crash handler lifetimes,
this may be easier to report/debug than hanging on SIGSEGV.
---
 platform/osx/crash_handler_osx.mm  | 9 ++++++---
 platform/x11/crash_handler_x11.cpp | 8 ++++++--
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/platform/osx/crash_handler_osx.mm b/platform/osx/crash_handler_osx.mm
index 10be3ba0798..e7fad69d148 100644
--- a/platform/osx/crash_handler_osx.mm
+++ b/platform/osx/crash_handler_osx.mm
@@ -27,13 +27,13 @@
 /* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
+
 #include "main/main.h"
 #include "os_osx.h"
 
 #include <string.h>
 #include <unistd.h>
 
-// Note: Dump backtrace in 32bit mode is getting a bus error on the fgets by the ->execute, so enable only on 64bit
 #if defined(DEBUG_ENABLED) && defined(__x86_64__)
 #define CRASH_HANDLER_ENABLED 1
 #endif
@@ -72,8 +72,9 @@ static uint32_t load_address() {
 }
 
 static void handle_crash(int sig) {
-	if (OS::get_singleton() == NULL || Globals::get_singleton() == NULL)
-		return;
+	if (OS::get_singleton() == NULL) {
+		abort();
+	}
 
 	void *bt_buffer[256];
 	size_t size = backtrace(bt_buffer, 256);
@@ -82,6 +83,7 @@ static void handle_crash(int sig) {
 
 	// Dump the backtrace to stderr with a message to the user
 	fprintf(stderr, "%s: Program crashed with signal %d\n", __FUNCTION__, sig);
+
 	fprintf(stderr, "Dumping the backtrace. %ls\n", msg.c_str());
 	char **strings = backtrace_symbols(bt_buffer, size);
 	if (strings) {
@@ -155,6 +157,7 @@ CrashHandler::CrashHandler() {
 }
 
 CrashHandler::~CrashHandler() {
+	disable();
 }
 
 void CrashHandler::disable() {
diff --git a/platform/x11/crash_handler_x11.cpp b/platform/x11/crash_handler_x11.cpp
index fd8b300ec4d..e973c57ddfa 100644
--- a/platform/x11/crash_handler_x11.cpp
+++ b/platform/x11/crash_handler_x11.cpp
@@ -27,6 +27,7 @@
 /* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
+
 #ifdef DEBUG_ENABLED
 #define CRASH_HANDLER_ENABLED 1
 #endif
@@ -42,8 +43,9 @@
 #include <stdlib.h>
 
 static void handle_crash(int sig) {
-	if (OS::get_singleton() == NULL || Globals::get_singleton() == NULL)
-		return;
+	if (OS::get_singleton() == NULL) {
+		abort();
+	}
 
 	void *bt_buffer[256];
 	size_t size = backtrace(bt_buffer, 256);
@@ -52,6 +54,7 @@ static void handle_crash(int sig) {
 
 	// Dump the backtrace to stderr with a message to the user
 	fprintf(stderr, "%s: Program crashed with signal %d\n", __FUNCTION__, sig);
+
 	fprintf(stderr, "Dumping the backtrace. %ls\n", msg.c_str());
 	char **strings = backtrace_symbols(bt_buffer, size);
 	if (strings) {
@@ -112,6 +115,7 @@ CrashHandler::CrashHandler() {
 }
 
 CrashHandler::~CrashHandler() {
+	disable();
 }
 
 void CrashHandler::disable() {