xwayland: add pid support

include/wlr/xwayland.h

@@ -45,6 +45,7 @@ struct wlr_xwayland_surface {
 	char *instance;
 	struct wlr_xwayland_surface *parent;
 	list_t *state; // list of xcb_atom_t
+	pid_t pid;
 
 	struct {
 		struct wl_signal destroy;

xwayland/xwm.c

@@ -15,6 +15,7 @@ const char *atom_map[ATOM_LAST] = {
 	"WM_S0",
 	"_NET_SUPPORTED",
 	"_NET_WM_S0",
+	"_NET_WM_PID",
 	"_NET_WM_NAME",
 	"_NET_WM_STATE",
 	"WM_TAKE_FOCUS",
@@ -199,13 +200,22 @@ static void handle_surface_state(struct wlr_xwm *xwm,
 
 static void read_surface_state(struct wlr_xwm *xwm,
 		struct wlr_xwayland_surface *surface, xcb_get_property_reply_t *reply) {
-	if (reply->type != XCB_ATOM_ATOM) { // TODO: check that
-		return;
-	}
+	// reply->type == XCB_ATOM_ANY
 	handle_surface_state(xwm, surface, xcb_get_property_value(reply),
 		reply->value_len, NET_WM_STATE_ADD);
 }
 
+static void read_surface_pid(struct wlr_xwm *xwm,
+		struct wlr_xwayland_surface *surface, xcb_get_property_reply_t *reply) {
+	if (reply->type != XCB_ATOM_CARDINAL) {
+		return;
+	}
+
+	pid_t *pid = (pid_t *)xcb_get_property_value(reply);
+	surface->pid = *pid;
+	wlr_log(L_DEBUG, "NET_WM_PID %d", surface->pid);
+}
+
 static void read_surface_property(struct wlr_xwm *xwm,
 		struct wlr_xwayland_surface *surface, xcb_atom_t property) {
 	xcb_get_property_cookie_t cookie = xcb_get_property(xwm->xcb_conn, 0,
@@ -223,6 +233,8 @@ static void read_surface_property(struct wlr_xwm *xwm,
 		read_surface_title(xwm, surface, reply);
 	} else if (property == XCB_ATOM_WM_TRANSIENT_FOR) {
 		read_surface_parent(xwm, surface, reply);
+	} else if (property == xwm->atoms[NET_WM_PID]) {
+		read_surface_pid(xwm, surface, reply);
 	} else if (property == xwm->atoms[NET_WM_STATE]) {
 		read_surface_state(xwm, surface, reply);
 	} else {
@@ -248,7 +260,7 @@ static void map_shell_surface(struct wlr_xwm *xwm,
 		xwm->atoms[NET_WM_STATE],
 		//xwm->atoms[NET_WM_WINDOW_TYPE],
 		xwm->atoms[NET_WM_NAME],
-		//xwm->atoms[NET_WM_PID],
+		xwm->atoms[NET_WM_PID],
 		//xwm->atoms[MOTIF_WM_HINTS],
 	};
 	for (size_t i = 0; i < sizeof(props)/sizeof(xcb_atom_t); i++) {

xwayland/xwm.h

@@ -52,6 +52,7 @@ enum atom_name {
 	WM_S0,
 	NET_SUPPORTED,
 	NET_WM_S0,
+	NET_WM_PID,
 	NET_WM_NAME,
 	NET_WM_STATE,
 	WM_TAKE_FOCUS,