diff --git a/common/readline.c b/common/readline.c
index a2c690185..58652429e 100644
--- a/common/readline.c
+++ b/common/readline.c
@@ -70,28 +70,3 @@ char *peek_line(FILE *file, int line_offset, long *position) {
 	fseek(file, pos, SEEK_SET);
 	return line;
 }
-
-char *read_line_buffer(FILE *file, char *string, size_t string_len) {
-	size_t length = 0;
-	if (!string) {
-		return NULL;
-	}
-	while (1) {
-		int c = getc(file);
-		if (c == EOF || c == '\n' || c == '\0') {
-			break;
-		}
-		if (c == '\r') {
-			continue;
-		}
-		string[length++] = c;
-		if (string_len <= length) {
-			return NULL;
-		}
-	}
-	if (length + 1 == string_len) {
-		return NULL;
-	}
-	string[length] = '\0';
-	return string;
-}
diff --git a/swaybar/status_line.c b/swaybar/status_line.c
index 54a68b401..fcc0cb935 100644
--- a/swaybar/status_line.c
+++ b/swaybar/status_line.c
@@ -31,7 +31,6 @@ void status_error(struct status_line *status, const char *text) {
 
 bool status_handle_readable(struct status_line *status) {
 	ssize_t read_bytes = 1;
-	char *line;
 	switch (status->protocol) {
 	case PROTOCOL_I3BAR:
 		if (i3bar_handle_readable(status) > 0) {
@@ -39,36 +38,37 @@ bool status_handle_readable(struct status_line *status) {
 		}
 		break;
 	case PROTOCOL_UNDEF:
-		line = read_line_buffer(status->read,
-				status->buffer, status->buffer_size);
-		if (!line) {
+		errno = 0;
+		read_bytes = getline(&status->buffer,
+				&status->buffer_size, status->read);
+		if (errno == EAGAIN) {
+			clearerr(status->read);
+		} else if (errno) {
 			status_error(status, "[error reading from status command]");
-			return false;
+			return true;
 		}
-		if (line[0] == '{') {
-			json_object *proto = json_tokener_parse(line);
-			if (proto) {
-				json_object *version;
-				if (json_object_object_get_ex(proto, "version", &version)
-							&& json_object_get_int(version) == 1) {
-					wlr_log(WLR_DEBUG, "Switched to i3bar protocol.");
-					status->protocol = PROTOCOL_I3BAR;
+
+		// the header must be sent completely the first time round
+		json_object *header, *version;
+		if (status->buffer[read_bytes - 1] == '\n'
+				&& (header = json_tokener_parse(status->buffer))
+				&& json_object_object_get_ex(header, "version", &version)
+				&& json_object_get_int(version) == 1) {
+			wlr_log(WLR_DEBUG, "Using i3bar protocol.");
+			status->protocol = PROTOCOL_I3BAR;
+
+			json_object *click_events;
+			if (json_object_object_get_ex(header, "click_events", &click_events)
+					&& json_object_get_boolean(click_events)) {
+				wlr_log(WLR_DEBUG, "Enabling click events.");
+				status->i3bar_state.click_events = true;
+				if (write(status->write_fd, "[\n", 2) != 2) {
+					status_error(status, "[failed to write to status command]");
+					json_object_put(header);
+					return true;
 				}
-				json_object *click_events;
-				if (json_object_object_get_ex(
-							proto, "click_events", &click_events)
-						&& json_object_get_boolean(click_events)) {
-					wlr_log(WLR_DEBUG, "Enabled click events.");
-					status->i3bar_state.click_events = true;
-					const char *events_array = "[\n";
-					ssize_t len = strlen(events_array);
-					if (write(status->write_fd, events_array, len) != len) {
-						status_error(status,
-								"[failed to write to status command]");
-					}
-				}
-				json_object_put(proto);
 			}
+			json_object_put(header);
 
 			status->protocol = PROTOCOL_I3BAR;
 			free(status->buffer);
@@ -76,11 +76,13 @@ bool status_handle_readable(struct status_line *status) {
 			status->i3bar_state.buffer_size = 4096;
 			status->i3bar_state.buffer =
 				malloc(status->i3bar_state.buffer_size);
-		} else {
-			status->protocol = PROTOCOL_TEXT;
-			status->text = line;
+			return false;
 		}
-		return true;
+
+		wlr_log(WLR_DEBUG, "Using text protocol.");
+		status->protocol = PROTOCOL_TEXT;
+		status->text = status->buffer;
+		// intentional fall-through
 	case PROTOCOL_TEXT:
 		errno = 0;
 		while (true) {