From b0fb676d39b3be6e231b86edf348d47888bb26f7 Mon Sep 17 00:00:00 2001
From: Thomas Osterried <ax25@x-berg.in-berlin.de>
Date: Mon, 4 Jul 2016 14:16:15 +0200
Subject: beacon with new option -H: -> beacon intervals relative to the hour.
 Idea by Folkert van Heusden <mail@vanheusden.com>.

Signed-off-by: Thomas Osterried <ax25@x-berg.in-berlin.de>
---
 ax25/beacon.8 |  5 ++++-
 ax25/beacon.c | 36 +++++++++++++++++++++++++++++-------
 2 files changed, 33 insertions(+), 8 deletions(-)

(limited to 'ax25')

diff --git a/ax25/beacon.8 b/ax25/beacon.8
index b4ca83c..62be7d3 100644
--- a/ax25/beacon.8
+++ b/ax25/beacon.8
@@ -2,7 +2,7 @@
 .SH NAME
 beacon \- transmit periodic messages on an AX.25 port.
 .SH SYNOPSIS
-.B beacon [-c <src_call>] [-d <dest_call>[digi ..]] [-f] [-l] [-m] [-s] [-t interval] [-v] port \(lqmessage\(rq
+.B beacon [-c <src_call>] [-d <dest_call>[digi ..]] [-f] [-H] [-l] [-m] [-s] [-t interval] [-v] port \(lqmessage\(rq
 .SH DESCRIPTION
 .LP
 .B Beacon
@@ -29,6 +29,9 @@ Do not fork into the background.
 .BI \-l
 Enables the logging of errors to the system log, the default is off.
 .TP 16
+.BI \-H
+Start interval relative to the hour.
+.TP 16
 .BI \-m
 Changes the destination address to \(lqMAIL\(rq and sends the message text
 once only. This option overrides any destination callsign given with the \-d option.
diff --git a/ax25/beacon.c b/ax25/beacon.c
index e4e4749..18ccc93 100644
--- a/ax25/beacon.c
+++ b/ax25/beacon.c
@@ -5,6 +5,7 @@
 #include <syslog.h>
 #include <signal.h>
 #include <string.h>
+#include <time.h>
 
 #include <sys/types.h>
 #include <sys/socket.h>
@@ -20,7 +21,7 @@ static int logging = FALSE;
 static int mail = FALSE;
 static int single = FALSE;
 
-#define STR_USAGE "usage: beacon [-c <src_call>] [-d <dest_call>] [-f] [-l] [-m] [-s] [-t interval] [-v] <port> <message>\n"
+#define STR_USAGE "usage: beacon [-c <src_call>] [-d <dest_call>] [-f] [-H] [-l] [-m] [-s] [-t interval] [-v] <port> <message>\n"
 
 static void terminate(int sig)
 {
@@ -36,12 +37,14 @@ int main(int argc, char *argv[])
 {
 	struct full_sockaddr_ax25 dest;
 	struct full_sockaddr_ax25 src;
-	int s, n, dlen, len, interval = 30;
+	int s, n, dlen, len;
 	char *addr, *port, *message, *portcall;
 	char *srccall = NULL, *destcall = NULL;
 	int dofork = 1;
+	time_t interval = 30;
+	int interval_relative = 0;
 
-	while ((n = getopt(argc, argv, "c:d:flmst:v")) != -1) {
+	while ((n = getopt(argc, argv, "c:d:fHlmst:v")) != -1) {
 		switch (n) {
 		case 'c':
 			srccall = optarg;
@@ -52,6 +55,9 @@ int main(int argc, char *argv[])
 		case 'f':
 			dofork = 0;
 			break;
+		case 'H':
+			interval_relative = 1;
+			break;
 		case 'l':
 			logging = TRUE;
 			break;
@@ -62,7 +68,7 @@ int main(int argc, char *argv[])
 			single = TRUE;
 			break;
 		case 't':
-			interval = atoi(optarg);
+			interval = (time_t ) atoi(optarg);
 			if (interval < 1) {
 				fprintf(stderr, "beacon: interval must be greater than on minute\n");
 				return 1;
@@ -78,6 +84,11 @@ int main(int argc, char *argv[])
 		}
 	}
 
+	if (interval_relative && interval > 60L) {
+		fprintf(stderr, "beacon: can't align interval > 60min to an hour\n");
+		return 1;
+	}
+
 	signal(SIGTERM, terminate);
 
 	if (optind == argc || optind == argc - 1) {
@@ -141,7 +152,17 @@ int main(int argc, char *argv[])
 		syslog(LOG_INFO, "starting");
 	}
 
+	/* interval has a one minute resolution */
+	interval *= 60L;
+
 	for (;;) {
+
+		if (interval_relative) {
+			time_t t_sleep = interval - (time(NULL) % interval);
+			if (t_sleep > 0)
+				sleep(t_sleep);
+		}
+
 		if ((s = socket(AF_AX25, SOCK_DGRAM, 0)) == -1) {
 			if (logging) {
 				syslog(LOG_ERR, "socket: %m");
@@ -168,10 +189,11 @@ int main(int argc, char *argv[])
 
 		close(s);
 
-		if (!single)
-			sleep(interval * 60);
-		else
+		if (single)
 			break;
+
+		if (!interval_relative)
+			sleep(interval);
 	}
 
 	return 0;
-- 
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