journald-socket: close previous socket when ForwardToSocket= is changed on reload

src/journal/journald-config.c

@@ -9,6 +9,7 @@
 #include "journald-config.h"
 #include "journald-kmsg.h"
 #include "journald-manager.h"
+#include "journald-socket.h"
 #include "log.h"
 #include "parse-util.h"
 #include "proc-cmdline.h"
@@ -366,6 +367,7 @@ int manager_dispatch_reload_signal(sd_event_source *s, const struct signalfd_sig
 
         (void) manager_reopen_dev_kmsg(m, old.read_kmsg);
         manager_reset_kernel_audit(m, old.set_audit);
+        manager_reload_forward_socket(m, &old.forward_to_socket);
 
         r = manager_reload_journals(m);
         if (r < 0)

src/journal/journald-socket.c

@@ -163,3 +163,20 @@ int manager_forward_socket(
 
         return 0;
 }
+
+void manager_reload_forward_socket(Manager *m, const SocketAddress *old) {
+        assert(m);
+        assert(old);
+
+        /* The socket is not opened yet or already closed. There is nothing we need to do now. The socket
+         * will be opened when necessary. */
+        if (m->forward_socket_fd < 0)
+                return;
+
+        if (socket_address_equal(&m->config.forward_to_socket, old))
+                return;
+
+        /* A different socket address is specified. Let's close the old socket. New socket will be opened
+         * when necessary. */
+        m->forward_socket_fd = safe_close(m->forward_socket_fd);
+}

src/journal/journald-socket.h

@@ -4,3 +4,4 @@
 #include "journald-forward.h"
 
 int manager_forward_socket(Manager *m, const struct iovec *iovec, size_t n, const dual_timestamp *ts, int priority);
+void manager_reload_forward_socket(Manager *m, const SocketAddress *old);