launcher: Add more error logging to launcher backends

Add error logging in three different launcher backends:
launcher-logind, launcher-weston-launch, and launcher-direct
to indicate failures for easier debug

Signed-off-by: Anurup M <anurup.m@huawei.com>

libweston/launcher-direct.c

@@ -211,8 +211,10 @@ setup_tty(struct launcher_direct *launcher, int tty)
 	loop = wl_display_get_event_loop(launcher->compositor->wl_display);
 	launcher->vt_source =
 		wl_event_loop_add_signal(loop, SIGRTMIN, vt_handler, launcher);
-	if (!launcher->vt_source)
+	if (!launcher->vt_source) {
+		weston_log("failed to add SIGRTMIN signal\n");
 		goto err_close;
+	}
 
 	return 0;
 
@@ -229,8 +231,10 @@ launcher_direct_open(struct weston_launcher *launcher_base, const char *path, in
 	int fd;
 
 	fd = open(path, flags | O_CLOEXEC);
-	if (fd == -1)
+	if (fd == -1) {
+		weston_log("couldn't open: %s! error=%s\n", path, strerror(errno));
 		return -1;
+	}
 
 	if (geteuid() != 0) {
 		weston_log("WARNING! Succeeded opening %s as non-root user."
@@ -239,6 +243,7 @@ launcher_direct_open(struct weston_launcher *launcher_base, const char *path, in
 	}
 
 	if (fstat(fd, &s) == -1) {
+		weston_log("couldn't fstat: %s! error=%s\n", path, strerror(errno));
 		close(fd);
 		return -1;
 	}
@@ -283,7 +288,8 @@ launcher_direct_restore(struct weston_launcher *launcher_base)
 
 	mode.mode = VT_AUTO;
 	if (ioctl(launcher->tty, VT_SETMODE, &mode) < 0)
-		weston_log("could not reset vt handling\n");
+		weston_log("could not reset vt handling! error=%s\n",
+			   strerror(errno));
 }
 
 static int
@@ -300,8 +306,10 @@ launcher_direct_connect(struct weston_launcher **out, struct weston_compositor *
 	struct launcher_direct *launcher;
 
 	launcher = zalloc(sizeof(*launcher));
-	if (launcher == NULL)
+	if (launcher == NULL) {
+		weston_log("failed to alloc for launcher\n");
 		return -ENOMEM;
+	}
 
 	launcher->base.iface = &launcher_direct_iface;
 	launcher->compositor = compositor;
@@ -338,13 +346,16 @@ launcher_direct_get_vt(struct weston_launcher *base)
 {
 	struct launcher_direct *launcher = wl_container_of(base, launcher, base);
 	struct stat s;
-	if (fstat(launcher->tty, &s) < 0)
+	if (fstat(launcher->tty, &s) < 0) {
+		weston_log("couldn't fstat launcher tty: %s\n", strerror(errno));
 		return -1;
+	}
 
 	return minor(s.st_rdev);
 }
 
 const struct launcher_interface launcher_direct_iface = {
+	.name = "direct",
 	.connect = launcher_direct_connect,
 	.destroy = launcher_direct_destroy,
 	.open = launcher_direct_open,

libweston/launcher-impl.h

@@ -30,6 +30,7 @@
 struct weston_launcher;
 
 struct launcher_interface {
+	char *name;
 	int (* connect) (struct weston_launcher **launcher_out, struct weston_compositor *compositor,
 			 int tty, const char *seat_id, bool sync_drm);
 	void (* destroy) (struct weston_launcher *launcher);

libweston/launcher-logind.c

@@ -97,6 +97,7 @@ launcher_logind_take_device(struct launcher_logind *wl, uint32_t major,
 	reply = dbus_connection_send_with_reply_and_block(wl->dbus, m,
 							  -1, NULL);
 	if (!reply) {
+		weston_log("logind: TakeDevice on %d:%d failed.\n", major, minor);
 		r = -ENODEV;
 		goto err_unref;
 	}
@@ -106,6 +107,7 @@ launcher_logind_take_device(struct launcher_logind *wl, uint32_t major,
 				  DBUS_TYPE_BOOLEAN, &paused,
 				  DBUS_TYPE_INVALID);
 	if (!b) {
+		weston_log("logind: error parsing reply to TakeDevice.\n");
 		r = -ENODEV;
 		goto err_reply;
 	}
@@ -173,17 +175,25 @@ launcher_logind_open(struct weston_launcher *launcher, const char *path, int fla
 	int fl, r, fd;
 
 	r = stat(path, &st);
-	if (r < 0)
+	if (r < 0) {
+		weston_log("logind: cannot stat: %s! error=%s\n", path, strerror(errno));
 		return -1;
+	}
+
 	if (!S_ISCHR(st.st_mode)) {
+		weston_log("logind: %s is not a character special file!\n", path);
 		errno = ENODEV;
 		return -1;
 	}
 
 	fd = launcher_logind_take_device(wl, major(st.st_rdev),
 				       minor(st.st_rdev), NULL);
-	if (fd < 0)
+	if (fd < 0) {
-		return fd;
+		weston_log("logind: TakeDevice on %s failed, error=%s\n",
+			   path, strerror(-fd));
+		errno = -fd;
+		return -1;
+	}
 
 	/* Compared to weston_launcher_open() we cannot specify the open-mode
 	 * directly. Instead, logind passes us an fd with sane default modes.
@@ -195,6 +205,7 @@ launcher_logind_open(struct weston_launcher *launcher, const char *path, int fla
 	fl = fcntl(fd, F_GETFL);
 	if (fl < 0) {
 		r = -errno;
+		weston_log("logind: cannot get file flags: %s\n", strerror(errno));
 		goto err_close;
 	}
 
@@ -204,6 +215,7 @@ launcher_logind_open(struct weston_launcher *launcher, const char *path, int fla
 	r = fcntl(fd, F_SETFL, fl);
 	if (r < 0) {
 		r = -errno;
+		weston_log("logind: cannot set O_NONBLOCK: %s\n", strerror(errno));
 		goto err_close;
 	}
 	return fd;
@@ -816,7 +828,8 @@ err_seat:
 err_wl:
 	free(wl);
 err_out:
-	weston_log("logind: cannot setup systemd-logind helper (%d), using legacy fallback\n", r);
+	weston_log("logind: cannot setup systemd-logind helper error: (%s), using legacy fallback\n",
+		   strerror(-r));
 	errno = -r;
 	return -1;
 }
@@ -847,6 +860,7 @@ launcher_logind_get_vt(struct weston_launcher *launcher)
 }
 
 const struct launcher_interface launcher_logind_iface = {
+	.name = "logind",
 	.connect = launcher_logind_connect,
 	.destroy = launcher_logind_destroy,
 	.open = launcher_logind_open,

libweston/launcher-util.c

@@ -54,6 +54,7 @@ weston_launcher_connect(struct weston_compositor *compositor, int tty,
 		const struct launcher_interface *iface = *it;
 		struct weston_launcher *launcher;
 
+		weston_log("Trying %s launcher...\n", iface->name);
 		if (iface->connect(&launcher, compositor, tty, seat_id, sync_drm) == 0)
 			return launcher;
 	}

libweston/launcher-weston-launch.c

@@ -253,12 +253,17 @@ launcher_weston_environment_get_fd(const char *env)
 	int fd, flags;
 
 	e = getenv(env);
-	if (!e || !safe_strtoint(e, &fd))
+	if (!e || !safe_strtoint(e, &fd)) {
+		weston_log("could not get launcher fd from env\n");
 		return -1;
+	}
 
 	flags = fcntl(fd, F_GETFD);
-	if (flags == -1)
+	if (flags == -1) {
+		weston_log("could not get fd flags!, env: %s, error: %s\n",
+			   env, strerror(errno));
 		return -1;
+	}
 
 	fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
 	unsetenv(env);
@@ -297,6 +302,7 @@ launcher_weston_launch_connect(struct weston_launcher **out, struct weston_compo
 							launcher);
 		if (launcher->source == NULL) {
 			free(launcher);
+			weston_log("failed to get weston-launcher socket fd event source\n");
 			return -ENOMEM;
 		}
 
@@ -329,13 +335,16 @@ launcher_weston_launch_get_vt(struct weston_launcher *base)
 {
 	struct launcher_weston_launch *launcher = wl_container_of(base, launcher, base);
 	struct stat s;
-	if (fstat(launcher->tty, &s) < 0)
+	if (fstat(launcher->tty, &s) < 0) {
+		weston_log("could not fstat launcher tty: %s\n", strerror(errno));
 		return -1;
+	}
 
 	return minor(s.st_rdev);
 }
 
 const struct launcher_interface launcher_weston_launch_iface = {
+	.name = "weston_launch",
 	.connect = launcher_weston_launch_connect,
 	.destroy = launcher_weston_launch_destroy,
 	.open = launcher_weston_launch_open,