systemd: try harder to bind to notify socket

Without the socket open we are going to crash and burn. If for
whatever reason we fail during deserialization we will fail when
trying to open the socket. In this case it is better to unlink the old
socket and maybe lose some messages, than to continue without the
notification socket.

Of course this situation should not happen, but we should handle
it as gracefully as possible anyway.

https://bugzilla.redhat.com/show_bug.cgi?id=1099299

diff --git a/src/core/manager.c b/src/core/manager.c
index 1bf75e20b0217d5d66f35223a492419dbe696bec..726977fcfc34ad54ffb2404445a831c43daddf10 100644 (file)
--- a/src/core/manager.c
+++ b/src/core/manager.c
@@ -565,7 +565,21 @@ static int manager_setup_notify(Manager *m) {
                 r = bind(fd, &sa.sa, offsetof(struct sockaddr_un, sun_path) + strlen(sa.un.sun_path));
                 if (r < 0) {
                         log_error("bind(%s) failed: %m", sa.un.sun_path);
-                        return -errno;
+                        if (errno == EADDRINUSE) {
+                                log_notice("Removing %s socket and trying again.", m->notify_socket);
+                                r = unlink(m->notify_socket);
+                                if (r < 0) {
+                                        log_error("Failed to remove %s: %m", m->notify_socket);
+                                        return -EADDRINUSE;
+                                }
+
+                                r = bind(fd, &sa.sa, offsetof(struct sockaddr_un, sun_path) + strlen(sa.un.sun_path));
+                                if (r < 0) {
+                                        log_error("bind(%s) failed: %m", sa.un.sun_path);
+                                        return -errno;
+                                }
+                        } else
+                                return -errno;
                 }
 
                 r = setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one));