commit 3b3867f76d97f19db41389505954f29400488c4f
Author: Dave Cottlehuber <dch@skunkwerks.at>
Date:   Thu Sep 22 11:00:45 2016 +0200

    add optional flag -H to propagate SIGHUP to child process

diff --git a/daemon.c b/daemon.c
index 23051fd..2d8bec7 100644
--- a/daemon.c
+++ b/daemon.c
@@ -55,14 +55,14 @@ main(int argc, char *argv[])
 {
 	struct pidfh  *ppfh, *pfh;
 	sigset_t mask, oldmask;
-	int ch, nochdir, noclose, restart, serrno;
+	int ch, nochdir, noclose, nohup, restart, serrno;
 	const char *pidfile, *ppidfile, *title, *user;
 	pid_t otherpid, pid;
 
 	nochdir = noclose = 1;
-	restart = 0;
+	restart = nohup = 0 ;
 	ppidfile = pidfile = title = user = NULL;
-	while ((ch = getopt(argc, argv, "cfp:P:rt:u:")) != -1) {
+	while ((ch = getopt(argc, argv, "cfp:P:rt:u:H")) != -1) {
 		switch (ch) {
 		case 'c':
 			nochdir = 0;
@@ -85,6 +85,9 @@ main(int argc, char *argv[])
 		case 'u':
 			user = optarg;
 			break;
+		case 'H':
+			nohup = 1;
+			break;
 		default:
 			usage();
 		}
@@ -165,6 +168,9 @@ main(int argc, char *argv[])
 		sigemptyset(&mask);
 		sigaddset(&mask, SIGTERM);
 		sigaddset(&mask, SIGCHLD);
+		if (nohup) {
+			sigaddset(&mask, SIGHUP);
+		}
 		if (sigprocmask(SIG_SETMASK, &mask, &oldmask) == -1) {
 			warn("sigprocmask");
 			goto exit;
@@ -265,7 +271,13 @@ wait_child(pid_t pid, sigset_t *mask)
 				return (-1);
 			}
 			continue;
-		default:
+		case SIGHUP:
+			if (nohup) {}
+			if (kill(pid, signo) == -1) {
+				warn("hup");
+				return (-1);
+			}
+			continue;		default:
 			warnx("sigwaitinfo: invalid signal: %d", signo);
 			return (-1);
 		}
@@ -276,7 +288,7 @@ static void
 usage(void)
 {
 	(void)fprintf(stderr, "%s\n\t%s\n",
-	    "usage: daemon [-cfr] [-p child_pidfile] [-P supervisor_pidfile]",
+	    "usage: daemon [-cfrH] [-p child_pidfile] [-P supervisor_pidfile]",
 	    "[-t title] [-u user] command arguments ...");
 	exit(1);
 }