commit 265aeb316bce85a9c1941fb6e51b2b7b90760255
author Friedrich, Eugen (ADITG/SW1) <efriedrich@de.adit-jv.com> Tue Apr 05 20:43:29 2016 +0000
committer Pekka Paalanen <pekka.paalanen@collabora.co.uk> Wed Apr 06 14:12:02 2016 +0300
tree f306fb50086422512dc57f11b7f5ce6c5cc50642
parent d962be149391ac2e00e1197612f2e6ec18dfa9f3

systemd: take over sockets created by systemd

Systemd provides a feature of socket-based activation, details in [1]
This commit adds an implementation to check if sockets were provided by
systemd and adds this as an additional socket to wayland display.
before adding sockets are checked for the correctness:
only AF_UNIX of type SOCK_STREAM are accepted

This is usefull for early rendering use-cases where weston and
early-rendering-application can be started parallel.

[1] https://www.freedesktop.org/software/systemd/man/systemd.socket.html

Signed-off-by: Eugen Friedrich <efriedrich@de.adit-jv.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>

src/systemd-notify.c

diff --git a/src/systemd-notify.c b/src/systemd-notify.c
index e61db0f..4407059 100644
--- a/src/systemd-notify.c
+++ b/src/systemd-notify.c
@@ -28,6 +28,7 @@
 #include <errno.h>
 #include <stdlib.h>
 #include <systemd/sd-daemon.h>
+#include <sys/socket.h>
 #include <wayland-server.h>
 #include "shared/helpers.h"
 #include "shared/zalloc.h"
@@ -40,6 +41,47 @@
 };
 
 static int
+add_systemd_sockets(struct weston_compositor *compositor)
+{
+	int fd;
+	int cnt_systemd_sockets;
+	int current_fd = 0;
+
+	cnt_systemd_sockets = sd_listen_fds(1);
+
+	if (cnt_systemd_sockets < 0) {
+		weston_log("sd_listen_fds failed with: %d\n",
+				cnt_systemd_sockets);
+		return -1;
+	}
+
+	/* socket-based activation not used, return silently */
+	if (cnt_systemd_sockets == 0)
+		return 0;
+
+	while (current_fd < cnt_systemd_sockets) {
+		fd = SD_LISTEN_FDS_START + current_fd;
+
+		if (sd_is_socket(fd, AF_UNIX, SOCK_STREAM,1) <= 0) {
+			weston_log("invalid socket provided from systemd\n");
+			return -1;
+		}
+
+		if (wl_display_add_socket_fd(compositor->wl_display, fd)) {
+			weston_log("wl_display_add_socket_fd failed"
+					"for systemd provided socket\n");
+			return -1;
+		}
+		current_fd++;
+	}
+
+	weston_log("info: add %d socket(s) provided by systemd\n",
+			current_fd);
+
+	return current_fd;
+}
+
+static int
 watchdog_handler(void *data)
 {
 	struct systemd_notifier *notifier = data;
@@ -89,6 +131,9 @@
 	wl_signal_add(&compositor->destroy_signal,
 		      &notifier->compositor_destroy_listener);
 
+	if (add_systemd_sockets(compositor) < 0)
+		return -1;
+
 	sd_notify(0, "READY=1");
 
 	/* 'WATCHDOG_USEC' is environment variable that is set