Description: Write pidfile in parent
 systemd expects the PID file to be written by the parent process, not the
 child.  Fixing this eliminates an error message:
     Can't open PID file /run/ntpd.pid (yet?) after start:
     Operation not permitted
Forwarded: https://gitlab.com/NTPsec/ntpsec/-/merge_requests/1301
Origin: vendor
Bug-Debian: https://bugs.debian.org/1023023
Author: Richard Laager <rlaager@wiktel.com>
Last-Update: 2023-01-16

From ee708e2c542370fe51ff61d21d90b8ba514f9a98 Mon Sep 17 00:00:00 2001
From: Richard Laager <rlaager@wiktel.com>
Date: Mon, 16 Jan 2023 21:26:18 -0600
Subject: [PATCH] Write pidfile in parent

systemd expects the PID file to be written by the parent process, not the
child.  Fixing this eliminates an error message:
    Can't open PID file /run/ntpd.pid (yet?) after start:
    Operation not permitted
---
 include/ntpd.h  |  1 +
 ntpd/ntp_util.c | 27 +++++++++++++++++++--------
 ntpd/ntpd.c     | 10 +++++-----
 3 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/include/ntpd.h b/include/ntpd.h
index d0460f1af..edc82ec52 100644
--- a/include/ntpd.h
+++ b/include/ntpd.h
@@ -219,6 +219,7 @@ extern	uptime_t	orphwait;		/* orphan wait time */
 
 /* ntp_util.c */
 extern	void	init_util	(void);
+extern	void 	write_pidfile	(const char *, int);
 extern	void	write_stats	(void);
 extern	void	stats_config	(int, const char *);
 extern	void	record_peer_stats (struct peer *, int);
diff --git a/ntpd/ntp_util.c b/ntpd/ntp_util.c
index 94a9350a8..a91d17e77 100644
--- a/ntpd/ntp_util.c
+++ b/ntpd/ntp_util.c
@@ -142,6 +142,24 @@ init_util(void)
 #endif /* DEBUG */
 }
 
+/*
+ * write_pidfile - write the PID file
+ */
+void
+write_pidfile(
+	const char *pidfile,
+	pid_t pid)
+{
+	FILE	*fp;
+
+	if ((fp = fopen(pidfile, "w")) == NULL) {
+		msyslog(LOG_ERR, "LOG: pid file %s: %s",
+		    pidfile, strerror(errno));
+		return;
+	}
+	fprintf(fp, "%ld", (long)pid);
+	fclose(fp);
+}
 
 /*
  * drift_write - write drift to file, speeds up restart
@@ -231,7 +249,6 @@ stats_config(
 	const char *invalue	/* only one type so far */
 	)
 {
-	FILE	*fp;
 	const char *value;
 	size_t	len;
 	double	new_drift = 0;
@@ -298,13 +315,7 @@ stats_config(
 	 * Open pid file.
 	 */
 	case STATS_PID_FILE:
-		if ((fp = fopen(value, "w")) == NULL) {
-			msyslog(LOG_ERR, "LOG: pid file %s: %s",
-			    value, strerror(errno));
-			break;
-		}
-		fprintf(fp, "%d", (int)getpid());
-		fclose(fp);
+		write_pidfile(value, getpid());
 		break;
 
 	/*
diff --git a/ntpd/ntpd.c b/ntpd/ntpd.c
index 3503eaedd..da3638936 100644
--- a/ntpd/ntpd.c
+++ b/ntpd/ntpd.c
@@ -563,6 +563,8 @@ main(
 		}
 		if (rc > 0) {
 			/* parent */
+			if (pidfile)
+				write_pidfile(pidfile, rc);
 			exit_code = wait_child_sync_if(pipe_fds[0],
 						       wait_sync);
 			exit(exit_code);
@@ -588,6 +590,8 @@ main(
 		sa.sa_flags = SA_RESTART;
 		sigaction(SIGDANGER, &sa, NULL);
 #endif	/* SIGDANGER */
+	} else if (pidfile) {
+		write_pidfile(pidfile, getpid());
 	}
 
 	/*
@@ -686,11 +690,7 @@ main(
             case 'm':
             case 'n':
             case 'N':
-                /* handled elsewhere */
-                break;
-	    case 'p':
-		stats_config(STATS_PID_FILE, pidfile);
-		break;
+            case 'p':
             case 'P':
             case 'q':
                 /* handled elsewhere */
-- 
2.39.0