From 1da9e52fe56f0ee34a4ee9eb0f981a87e8e1c984 Mon Sep 17 00:00:00 2001
From: Leah Neukirchen <leah@vuxu.org>
Date: Thu, 6 Jan 2022 19:36:27 +0100
Subject: revamp signal handling, use SIGCONT to wake up main thread

support reboot via command
---
 rvnit.c | 43 ++++++++++++++++++++++++++++---------------
 1 file changed, 28 insertions(+), 15 deletions(-)

diff --git a/rvnit.c b/rvnit.c
index 4c9505c..74af39b 100644
--- a/rvnit.c
+++ b/rvnit.c
@@ -50,27 +50,29 @@ pthread_t logger_thread;
 
 int selflogfd[2];
 
-sig_atomic_t got_intr;
-sig_atomic_t got_sigusr1;
+sig_atomic_t want_shutdown;
+sig_atomic_t want_rescan;
+
+int want_reboot = 0;
 
 void
 on_sigint(int sig)
 {
 	(void)sig;
-	got_intr = 1;
+	want_shutdown = 1;
 }
 
 void
-on_sigusr1(int sig)
+on_sigusr2(int sig)
 {
 	(void)sig;
-	got_sigusr1 = 1;
 }
 
 void
-on_sigusr2(int sig)
+on_sigcont(int sig)
 {
 	(void)sig;
+	/* do nothing, but interrupt the system call */
 }
 
 void
@@ -249,12 +251,14 @@ socket_loop(void* ignored)
 						printf("setting %s down\n",
 						    services[i].name);
 						services[i].state = DOWN;
-						pthread_kill(main_thread, SIGUSR1);
+						want_rescan = 1;
+						pthread_kill(main_thread, SIGCONT);
 					} else if (cmd == 'u') {
 						printf("setting %s up\n",
 						    services[i].name);
 						services[i].state = UP;
-						pthread_kill(main_thread, SIGUSR1);
+						want_rescan = 1;
+						pthread_kill(main_thread, SIGCONT);
 					} else if (charsig(cmd) && services[i].pid > 0) {
 						printf("sending signal %d to %s\n", charsig(cmd), services[i].name);
 						kill(services[i].pid, charsig(cmd));
@@ -264,7 +268,13 @@ socket_loop(void* ignored)
 		}
 
 		if (cmd == 'X') {
-			pthread_kill(main_thread, SIGPWR);
+			want_shutdown = 1;
+			pthread_kill(main_thread, SIGCONT);
+		}
+		if (cmd == 'R') {
+			want_shutdown = 1;
+			want_reboot = 1;
+			pthread_kill(main_thread, SIGCONT);
 		}
 
 		close(connfd);
@@ -574,16 +584,15 @@ main()
 	}
 
 	sigaction(SIGINT, &(struct sigaction){.sa_handler=on_sigint}, 0);
-	sigaction(SIGPWR, &(struct sigaction){.sa_handler=on_sigint}, 0);
-	sigaction(SIGUSR1, &(struct sigaction){.sa_handler=on_sigusr1}, 0);
+	sigaction(SIGCONT, &(struct sigaction){.sa_handler=on_sigcont}, 0);
 
 	LOG("system up");
 
 	while (1) {
-		if (got_intr)
+		if (want_shutdown)
 			break;
 
-		if (got_sigusr1) {
+		if (want_rescan) {
 			printf("rescanning state\n");
 			for (i = 0; i < MAX_SV; i++) {
 				if (services[i].name[2] == 'D' ||
@@ -597,7 +606,7 @@ main()
 				}
 			}
 
-			got_sigusr1 = 0;
+			want_rescan = 0;
 		}
 
 		int status = 0;
@@ -743,7 +752,11 @@ fatal:		; // arrives with level < 99
 		}
 	}
 
-	dprintf(selflogfd[1], "shutdown\n");
+	if (want_reboot)
+		dprintf(selflogfd[1], "reboot\n");
+	else
+		dprintf(selflogfd[1], "shutdown\n");
+
 	close(selflogfd[1]);
 	pthread_join(logger_thread, 0);
 }
-- 
cgit 1.4.1