Fix a crash when running as systemd service

- Fix a NULL dereference if a signal is raised in the constructor of the
class InspIRCd
- Resolve the parent's process exit code being SIGTERM=15 and typically not
EXIT_SUCCESS thus

A combination of the two caused crashes when running as systemd unit.

1 files changed, 13 insertions, 6 deletions

diff --git a/src/inspircd.cpp b/src/inspircd.cpp
index 9516449a0..9d92888a3 100644
--- a/src/inspircd.cpp
+++ b/src/inspircd.cpp
@@ -63,7 +63,6 @@
 #include "testsuite.h"
 
 InspIRCd* ServerInstance = NULL;
-int* mysig = NULL;
 
 /** Seperate from the other casemap tables so that code *can* still exclusively rely on RFC casemapping
  * if it must.
@@ -244,13 +243,20 @@ void InspIRCd::QuickExit(int status)
 	exit(status);
 }
 
+// Required for returning the proper value of EXIT_SUCCESS for the parent process
+static void VoidSignalHandler(int signalreceived)
+{
+	exit(0);
+}
+
 bool InspIRCd::DaemonSeed()
 {
 #ifdef _WIN32
 	std::cout << "InspIRCd Process ID: " << con_green << GetCurrentProcessId() << con_reset << std::endl;
 	return true;
 #else
-	signal(SIGTERM, InspIRCd::QuickExit);
+	// Do not use QuickExit here: It will exit with status SIGTERM which would break e.g. daemon scripts
+	signal(SIGTERM, VoidSignalHandler);
 
 	int childpid;
 	if ((childpid = fork ()) < 0)
@@ -847,10 +853,10 @@ int InspIRCd::Run()
 		GlobalCulls.Apply();
 		AtomicActions.Run();
 
-		if (this->s_signal)
+		if (s_signal)
 		{
 			this->SignalHandler(s_signal);
-			this->s_signal = 0;
+			s_signal = 0;
 		}
 	}
 
@@ -874,9 +880,11 @@ bool InspIRCd::AllModulesReportReady(LocalUser* user)
 	return (res == MOD_RES_PASSTHRU);
 }
 
+sig_atomic_t InspIRCd::s_signal = 0;
+
 void InspIRCd::SetSignal(int signal)
 {
-	*mysig = signal;
+	s_signal = signal;
 }
 
 /* On posix systems, the flow of the program starts right here, with
@@ -888,7 +896,6 @@ void InspIRCd::SetSignal(int signal)
 ENTRYPOINT
 {
 	new InspIRCd(argc, argv);
-	mysig = &ServerInstance->s_signal;
 	ServerInstance->Run();
 	delete ServerInstance;
 	return 0;