From f48558d2b57d051f48cd6511e2f32098caffa91b Mon Sep 17 00:00:00 2001
From: Con Kolivas <kernel@kolivas.org>
Date: Fri, 23 May 2014 10:05:22 +1000
Subject: [PATCH] Detach child processes from the tty leaving only the main
 process to talk to it and exit all processes in a consistent way with more
 information on termination

---
 configure.ac     |  2 +-
 src/ckpool.c     | 21 +++++++++++++++++++++
 src/ckpool.h     |  2 ++
 src/connector.c  |  7 +------
 src/generator.c  |  7 +------
 src/stratifier.c |  8 +-------
 6 files changed, 27 insertions(+), 20 deletions(-)

diff --git a/configure.ac b/configure.ac
index 042c953f..3af808b4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -39,7 +39,7 @@ AC_CHECK_HEADERS(ctype.h errno.h byteswap.h string.h time.h)
 AC_CHECK_HEADERS(endian.h sys/endian.h arpa/inet.h sys/poll.h syslog.h)
 AC_CHECK_HEADERS(alloca.h pthread.h stdio.h math.h signal.h sys/prctl.h)
 AC_CHECK_HEADERS(sys/types.h sys/socket.h sys/stat.h linux/un.h netdb.h)
-AC_CHECK_HEADERS(stdint.h netinet/in.h netinet/tcp.h)
+AC_CHECK_HEADERS(stdint.h netinet/in.h netinet/tcp.h sys/ioctl.h)
 AC_CHECK_HEADERS(jansson.h)
 
 PTHREAD_LIBS="-lpthread"
diff --git a/src/ckpool.c b/src/ckpool.c
index bfdd20be..01a9639e 100644
--- a/src/ckpool.c
+++ b/src/ckpool.c
@@ -7,6 +7,7 @@
  * any later version.  See COPYING for more details.
  */
 
+#include <sys/ioctl.h>
 #include <sys/prctl.h>
 #include <sys/socket.h>
 #include <sys/stat.h>
@@ -147,6 +148,8 @@ static void childsighandler(int sig)
 {
 	pid_t ppid = getppid();
 
+	LOGWARNING("Child process received signal %d, forwarding signal to %s main process",
+		   sig, global_ckp->name);
 	kill(ppid, sig);
 }
 
@@ -167,6 +170,9 @@ static void launch_process(proc_instance_t *pi)
 		sigaction(SIGTERM, &handler, NULL);
 		sigaction(SIGINT, &handler, NULL);
 
+		/* Detach child processes leaving main only to communicate with
+		 * the terminal. */
+		ioctl(0, TIOCNOTTY, NULL);
 		rename_proc(pi->processname);
 		write_namepid(pi);
 		ret = pi->process(pi);
@@ -185,6 +191,21 @@ static void launch_processes(ckpool_t *ckp)
 		launch_process(ckp->children[i]);
 }
 
+int process_exit(ckpool_t *ckp, proc_instance_t *pi, int ret)
+{
+	if (ret) {
+		/* Abnormal termination, kill entire process */
+		LOGWARNING("%s %s exiting with return code %d, shutting down!",
+			   ckp->name, pi->processname, ret);
+		send_proc(&ckp->main, "shutdown");
+		sleep(1);
+		ret = 1;
+	} else /* Should be part of a normal shutdown */
+		LOGNOTICE("%s %s exited normally", ckp->name, pi->processname);
+
+	return ret;
+}
+
 static void clean_up(ckpool_t *ckp)
 {
 	int i, children = ckp->proc_instances;
diff --git a/src/ckpool.h b/src/ckpool.h
index 1482ba60..f59004dd 100644
--- a/src/ckpool.h
+++ b/src/ckpool.h
@@ -103,6 +103,8 @@ struct ckpool_instance {
 
 ckpool_t *global_ckp;
 
+int process_exit(ckpool_t *ckp, proc_instance_t *pi, int ret);
+
 /* Placeholders for when we have more comprehensive logging facilities */
 
 #define LOGMSG(_loglevel, fmt, ...) do { \
diff --git a/src/connector.c b/src/connector.c
index 6ed11b33..0ef18cdf 100644
--- a/src/connector.c
+++ b/src/connector.c
@@ -593,10 +593,5 @@ int connector(proc_instance_t *pi)
 
 	//join_pthread(pth_acceptor);
 out:
-	LOGINFO("%s connector exiting with return code %d", ckp->name, ret);
-	if (ret) {
-		send_proc(&ckp->main, "shutdown");
-		sleep(1);
-	}
-	exit(ret? 1: 0);
+	return process_exit(ckp, pi, ret);
 }
diff --git a/src/generator.c b/src/generator.c
index 4af6da6c..63775138 100644
--- a/src/generator.c
+++ b/src/generator.c
@@ -1244,10 +1244,5 @@ int generator(proc_instance_t *pi)
 	else
 		ret = server_mode(ckp, pi);
 
-	LOGINFO("%s generator exiting with return code %d", ckp->name, ret);
-	if (ret) {
-		send_proc(&ckp->main, "shutdown");
-		sleep(1);
-	}
-	exit(ret? 1: 0);
+	return process_exit(ckp, pi, ret);
 }
diff --git a/src/stratifier.c b/src/stratifier.c
index 1a803d04..d3b479ad 100644
--- a/src/stratifier.c
+++ b/src/stratifier.c
@@ -2037,11 +2037,5 @@ int stratifier(proc_instance_t *pi)
 	cklock_init(&share_lock);
 
 	ret = stratum_loop(ckp, pi);
-	LOGINFO("%s stratifier exiting with return code %d", ckp->name, ret);
-	if (ret) {
-		send_proc(&ckp->main, "shutdown");
-		sleep(1);
-	}
-
-	exit(ret? 1: 0);
+	return process_exit(ckp, pi, ret);
 }