watchfrr: print specific error for removed options

... and document them in the man page.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>

doc/watchfrr.8.in

@@ -127,6 +127,20 @@ Display the version information and exit.
 .TP
 .BR \-h ", " \-\-help
 Display the usage information and exit.
+.SH PREVIOUS OPTIONS
+Prior versions of \fBwatchfrr\fR supported some additional options that no
+longer exist:
+.IP
+.BR \-a ,\  \-A ,\  \-e ,\  \-R ,\  \-z
+.PP
+The \fB-a\fR, \fB-A\fR and \fB-R\fR options were used to select alternate
+monitoring modes that offered different patterns of restarting daemons.  The
+"correct" mode (phased restart) is now the default. The \fB-e\fR and \fB-z\fR
+options used to disable some monitoring aspects, watchfrr now always has all
+monitoring features enabled.
+.PP
+Removing these options should result in correct operation, if it does not
+please file a bug report.
 .SH SEE ALSO
 .BR zebra (8),
 .BR bgpd (8),

watchfrr/watchfrr.c

@@ -964,6 +964,8 @@ FRR_DAEMON_INFO(watchfrr, WATCHFRR,
 
 		.privs = &watchfrr_privs, )
 
+#define DEPRECATED_OPTIONS "aAezR:"
+
 int main(int argc, char **argv)
 {
 	int opt;
@@ -977,10 +979,18 @@ int main(int argc, char **argv)
 	frr_preinit(&watchfrr_di, argc, argv);
 	progname = watchfrr_di.progname;
 
-	frr_opt_add("b:dk:l:i:p:r:S:s:t:T:", longopts, "");
+	frr_opt_add("b:dk:l:i:p:r:S:s:t:T:" DEPRECATED_OPTIONS, longopts, "");
 
 	gs.restart.name = "all";
 	while ((opt = frr_getopt(argc, argv, NULL)) != EOF) {
+		if (opt && opt < 128 && strchr(DEPRECATED_OPTIONS, opt)) {
+			fprintf(stderr,
+				"The -%c option no longer exists.\n"
+				"Please refer to the watchfrr(8) man page.\n",
+				opt);
+			exit(1);
+		}
+
 		switch (opt) {
 		case 0:
 			break;