From 0dd7cc2d659af5c723bdd27507f4be917377e2f8 Mon Sep 17 00:00:00 2001
From: hyung-hwan <hyunghwan.chung@gmail.com>
Date: Tue, 11 Sep 2018 15:11:48 +0000
Subject: [PATCH] enhanded guardProcess() with setpgid() and kill()

---
 qse/include/qse/si/App.hpp  | 22 +---------------------
 qse/lib/si/App.cpp          | 29 +++++++++++++++++++++--------
 qse/samples/si/tcpsvr01.cpp |  4 ++--
 3 files changed, 24 insertions(+), 31 deletions(-)

diff --git a/qse/include/qse/si/App.hpp b/qse/include/qse/si/App.hpp
index 46c083c9..915757c3 100644
--- a/qse/include/qse/si/App.hpp
+++ b/qse/include/qse/si/App.hpp
@@ -88,7 +88,7 @@ public:
 	static int setSignalHandler (int sig, SignalHandler sighr);
 	static int unsetSignalHandler (int sig, bool ignore = false);
 
-	int guardProcess (const qse_mchar_t* proc_name, const SignalSet& signals);
+	int guardProcess (const SignalSet& signals, const qse_mchar_t* proc_name = QSE_NULL);
 
 private:
 	App* _prev_app;
@@ -116,26 +116,6 @@ protected:
 
 };
 
-// functor as a template parameter
-template <typename F>
-class QSE_EXPORT AppF: public App
-{
-public:
-	AppF (Mmgr* mmgr = QSE_NULL) QSE_CPP_NOEXCEPT: App(mmgr) {}
-	AppF (const F& f, Mmgr* mmgr = QSE_NULL) QSE_CPP_NOEXCEPT: App(mmgr), __lfunc(f) {}
-#if defined(QSE_CPP_ENABLE_CPP11_MOVE)
-	AppF (F&& f, Mmgr* mmgr = QSE_NULL) QSE_CPP_NOEXCEPT: App(mmgr), __lfunc(QSE_CPP_RVREF(f)) {}
-#endif
-
-protected:
-	F __lfunc;
-
-	void on_signal (int sig)
-	{
-		this->__lfunc(this, sig);
-	}
-};
-
 /////////////////////////////////
 QSE_END_NAMESPACE(QSE)
 /////////////////////////////////
diff --git a/qse/lib/si/App.cpp b/qse/lib/si/App.cpp
index 58328378..5c122256 100644
--- a/qse/lib/si/App.cpp
+++ b/qse/lib/si/App.cpp
@@ -30,7 +30,6 @@
 #include "../cmn/syscall.h"
 #include <qse/cmn/mbwc.h>
 
-extern "C" { int printf (const char* fmt, ...); }
 /////////////////////////////////
 QSE_BEGIN_NAMESPACE(QSE)
 /////////////////////////////////
@@ -43,7 +42,6 @@ static struct
 	sigset_t sa_mask;
 	int      sa_flags;
 } g_app_oldsi[QSE_NSIGS] = { { 0, 0 }, };
-static bool g_app_sigign_on_exit = false;
 
 class SigScopedMutexLocker
 {
@@ -334,7 +332,6 @@ int App::unset_signal_handler_no_mutex(int sig, int ignore)
 
 void App::on_guard_signal (int sig)
 {
-printf ("relaying %d to %d\n", sig, (int)this->_guarded_child_pid);
 	::kill (this->_guarded_child_pid, sig);
 }
 
@@ -422,7 +419,7 @@ int App::set_signal_subscription_no_mutex (int sig, SignalState reqstate)
 	return reqstate;
 }
 
-int App::guardProcess (const qse_mchar_t* proc_name, const SignalSet& signals)
+int App::guardProcess (const SignalSet& signals, const qse_mchar_t* proc_name)
 {
 	SignalState old_ss[QSE_NSIGS];
 
@@ -430,7 +427,11 @@ int App::guardProcess (const qse_mchar_t* proc_name, const SignalSet& signals)
 	{
 		pid_t pid = ::fork();
 		if (pid == -1) return -1;
-		if (pid == 0) break; // child
+		if (pid == 0) 
+		{
+			::setpgid (0, 0); // change the process group id. 
+			break; // child
+		}
 
 		for (int i = 0; i < QSE_NSIGS; i++)
 		{
@@ -460,10 +461,22 @@ int App::guardProcess (const qse_mchar_t* proc_name, const SignalSet& signals)
 			if (signals.isSet(i)) this->setSignalSubscription (i, old_ss[i]);
 		}
 
-printf ("child exited - exited %d exit status %d\n", WIFEXITED(status), WEXITSTATUS(status));
-		if (WIFEXITED(status) && WEXITSTATUS(status) == 0) 
+		if (WIFEXITED(status))
 		{
-			return 0; 
+			if (WEXITSTATUS(status) == 0) 
+			{
+				// the child has terminated normally and successfully.
+				return 0; 
+			}
+		}
+		else
+		{
+			// the child process aborted or crashed.
+			// let's kill all other processes in the same process group as the child
+			// but is it safe to do this after waitpid() has been called on 'pid'?
+			// it should be mostly safe because most OSes doesn't reuse the same pid
+			// within a very short time.
+			::kill (-pid, SIGKILL); 
 		}
 	}
 
diff --git a/qse/samples/si/tcpsvr01.cpp b/qse/samples/si/tcpsvr01.cpp
index e23b6479..44b5e751 100644
--- a/qse/samples/si/tcpsvr01.cpp
+++ b/qse/samples/si/tcpsvr01.cpp
@@ -81,9 +81,9 @@ public:
 		signals.set (SIGTERM);
 		signals.set (SIGUSR1);
 		signals.set (SIGUSR2);
-		if (this->guardProcess("myapp", signals) > 0)
+		if (this->guardProcess(signals) > 0)
 		{
-qse_printf (QSE_T("Stareting workd\n"));
+			qse_printf (QSE_T("Stareting server\n"));
 			this->server.setThreadStackSize (256000);
 			return this->server.start (QSE_T("[::]:9998,0.0.0.0:9998"));
 		}