add option to start swayidle in locked state

main.c

@@ -68,6 +68,8 @@ static const char *verbosity_colors[] = {
 	[LOG_DEBUG ] = "\x1B[1;30m",
 };
 
+static bool lock_on_start = false;
+
 static enum log_importance log_importance = LOG_INFO;
 
 void swayidle_log_init(enum log_importance verbosity) {
@@ -827,7 +829,7 @@ static int parse_idlehint(int argc, char **argv) {
 
 static int parse_args(int argc, char *argv[], char **config_path) {
 	int c;
-	while ((c = getopt(argc, argv, "C:hdwS:")) != -1) {
+	while ((c = getopt(argc, argv, "C:hdwlS:")) != -1) {
 		switch (c) {
 		case 'C':
 			free(*config_path);
@@ -842,6 +844,9 @@ static int parse_args(int argc, char *argv[], char **config_path) {
 		case 'S':
 			state.seat_name = strdup(optarg);
 			break;
+		case 'l':
+			lock_on_start = true;
+			break;
 		case 'h':
 		case '?':
 			printf("Usage: %s [OPTIONS]\n", argv[0]);
@@ -1118,6 +1123,11 @@ int main(int argc, char *argv[]) {
 		display_event, NULL);
 	wl_event_source_check(source);
 
+
+	if (lock_on_start) {
+		kill(getpid(), SIGUSR1);
+	}
+
 	while (wl_event_loop_dispatch(state.event_loop, -1) != 1) {
 		// This space intentionally left blank
 	}

swayidle.1.scd

@@ -30,6 +30,10 @@ swayidle - Idle manager for Wayland
 *-S* <seat-name>
 	Specify which seat to use. By default, if no name is specified, an arbitrary seat will be picked instead.
 
+*-l*
+	Lock the screen when swayidle starts. Useful in case of auto-login, when we want the wayland session
+	automatically started, but locked.
+
 # DESCRIPTION
 
 swayidle listens for idle activity on your Wayland compositor and executes tasks