Centralise stub plug/socket functions.

In the previous few commits I noticed some repeated work in the form
of pointless empty implementations of Plug's log method, plus some
existing (and some new) empty cases of Socket's endpoint_info. As a
cleanup, I'm replacing as many as I can find with uses of a central
null implementation in the stubs directory.

Author: sgtatham

errsock.c

@@ -39,16 +39,11 @@ static const char *sk_error_socket_error(Socket *s)
     return es->error;
 }
 
-static SocketEndpointInfo *sk_error_endpoint_info(Socket *s, bool peer)
-{
-    return NULL;
-}
-
 static const SocketVtable ErrorSocket_sockvt = {
     .plug = sk_error_plug,
     .close = sk_error_close,
     .socket_error = sk_error_socket_error,
-    .endpoint_info = sk_error_endpoint_info,
+    .endpoint_info = nullsock_endpoint_info,
     /* other methods are NULL */
 };
 

network.h

@@ -386,6 +386,11 @@ void nullplug_closing(Plug *plug, PlugCloseType type, const char *error_msg);
 void nullplug_receive(Plug *plug, int urgent, const char *data, size_t len);
 void nullplug_sent(Plug *plug, size_t bufsize);
 
+/*
+ * Similar no-op socket function.
+ */
+SocketEndpointInfo *nullsock_endpoint_info(Socket *s, bool peer);
+
 /* ----------------------------------------------------------------------
  * Functions defined outside the network code, which have to be
  * declared in this header file rather than the main putty.h because

proxy/sshproxy.c

@@ -123,11 +123,6 @@ static const char *sshproxy_socket_error(Socket *s)
     return sp->errmsg;
 }
 
-static SocketEndpointInfo *sshproxy_endpoint_info(Socket *s, bool peer)
-{
-    return NULL;
-}
-
 static const SocketVtable SshProxy_sock_vt = {
     .plug = sshproxy_plug,
     .close = sshproxy_close,
@@ -136,7 +131,7 @@ static const SocketVtable SshProxy_sock_vt = {
     .write_eof = sshproxy_write_eof,
     .set_frozen = sshproxy_set_frozen,
     .socket_error = sshproxy_socket_error,
-    .endpoint_info = sshproxy_endpoint_info,
+    .endpoint_info = nullsock_endpoint_info,
 };
 
 static void sshproxy_eventlog(LogPolicy *lp, const char *event)

ssh/portfwd.c

@@ -96,20 +96,6 @@ static void free_portlistener_state(struct PortListener *pl)
     sfree(pl);
 }
 
-static void pfd_log(Plug *plug, Socket *s, PlugLogType type,
-                    SockAddr *addr, int port,
-                    const char *error_msg, int error_code)
-{
-    /* we have to dump these since we have no interface to logging.c */
-}
-
-static void pfl_log(Plug *plug, Socket *s, PlugLogType type,
-                    SockAddr *addr, int port,
-                    const char *error_msg, int error_code)
-{
-    /* we have to dump these since we have no interface to logging.c */
-}
-
 static void pfd_close(struct PortForwarding *pf);
 
 static void pfd_closing(Plug *plug, PlugCloseType type, const char *error_msg)
@@ -433,7 +419,7 @@ static void pfd_sent(Plug *plug, size_t bufsize)
 }
 
 static const PlugVtable PortForwarding_plugvt = {
-    .log = pfd_log,
+    .log = nullplug_log,
     .closing = pfd_closing,
     .receive = pfd_receive,
     .sent = pfd_sent,
@@ -556,7 +542,7 @@ static int pfl_accepting(Plug *p, accept_fn_t constructor, accept_ctx_t ctx)
 }
 
 static const PlugVtable PortListener_plugvt = {
-    .log = pfl_log,
+    .log = nullplug_log,
     .closing = pfl_closing,
     .accepting = pfl_accepting,
 };

ssh/server.c

@@ -138,14 +138,6 @@ static const SeatVtable server_seat_vt = {
     .get_cursor_position = nullseat_get_cursor_position,
 };
 
-static void server_socket_log(Plug *plug, Socket *s, PlugLogType type,
-                              SockAddr *addr, int port,
-                              const char *error_msg, int error_code)
-{
-    /* server *srv = container_of(plug, server, plug); */
-    /* FIXME */
-}
-
 static void server_closing(Plug *plug, PlugCloseType type,
                            const char *error_msg)
 {
@@ -254,7 +246,7 @@ Conf *make_ssh_server_conf(void)
 void ssh_check_sendok(Ssh *ssh) {}
 
 static const PlugVtable ssh_server_plugvt = {
-    .log = server_socket_log,
+    .log = nullplug_log,
     .closing = server_closing,
     .receive = server_receive,
     .sent = server_sent,

ssh/sesschan.c

@@ -371,12 +371,6 @@ bool sesschan_run_subsystem(Channel *chan, ptrlen subsys)
     return false;
 }
 
-static void fwd_log(Plug *plug, Socket *s, PlugLogType type, SockAddr *addr,
-                    int port, const char *error_msg, int error_code)
-{ /* don't expect any weirdnesses from a listening socket */ }
-static void fwd_closing(Plug *plug, PlugCloseType type, const char *error_msg)
-{ /* not here, either */ }
-
 static int xfwd_accepting(Plug *p, accept_fn_t constructor, accept_ctx_t ctx)
 {
     sesschan *sess = container_of(p, sesschan, xfwd_plug);
@@ -400,8 +394,8 @@ static int xfwd_accepting(Plug *p, accept_fn_t constructor, accept_ctx_t ctx)
 }
 
 static const PlugVtable xfwd_plugvt = {
-    .log = fwd_log,
-    .closing = fwd_closing,
+    .log = nullplug_log,
+    .closing = nullplug_closing,
     .accepting = xfwd_accepting,
 };
 
@@ -473,8 +467,8 @@ static int agentfwd_accepting(
 }
 
 static const PlugVtable agentfwd_plugvt = {
-    .log = fwd_log,
-    .closing = fwd_closing,
+    .log = nullplug_log,
+    .closing = nullplug_closing,
     .accepting = agentfwd_accepting,
 };
 

ssh/x11fwd.c

@@ -277,12 +277,6 @@ static char *x11_verify(unsigned long peer_ip, int peer_port,
     return NULL;
 }
 
-static void x11_log(Plug *p, Socket *s, PlugLogType type, SockAddr *addr,
-                    int port, const char *error_msg, int error_code)
-{
-    /* We have no interface to the logging module here, so we drop these. */
-}
-
 static void x11_send_init_error(struct X11Connection *conn,
                                 const char *err_message);
 
@@ -336,7 +330,7 @@ static void x11_sent(Plug *plug, size_t bufsize)
 }
 
 static const PlugVtable X11Connection_plugvt = {
-    .log = x11_log,
+    .log = nullplug_log,
     .closing = x11_closing,
     .receive = x11_receive,
     .sent = x11_sent,

stubs/CMakeLists.txt

@@ -28,4 +28,5 @@ add_sources_from_current_dir(utils
   null-mac.c
   null-opener.c
   null-plug.c
-  null-seat.c)
+  null-seat.c
+  null-socket.c)

stubs/null-socket.c

@@ -0,0 +1,12 @@
+/*
+ * null-socket.c: provide a null implementation of any Socket vtable
+ * method that might otherwise need to be reimplemented in multiple
+ * places as a no-op.
+ */
+
+#include "putty.h"
+
+SocketEndpointInfo *nullsock_endpoint_info(Socket *s, bool peer)
+{
+    return NULL;
+}

unix/fd-socket.c

@@ -315,11 +315,6 @@ static void fdsocket_select_result_input_error(int fd, int event)
     }
 }
 
-static SocketEndpointInfo *fdsocket_endpoint_info(Socket *s, bool peer)
-{
-    return NULL;
-}
-
 static const SocketVtable FdSocket_sockvt = {
     .plug = fdsocket_plug,
     .close = fdsocket_close,
@@ -328,7 +323,7 @@ static const SocketVtable FdSocket_sockvt = {
     .write_eof = fdsocket_write_eof,
     .set_frozen = fdsocket_set_frozen,
     .socket_error = fdsocket_socket_error,
-    .endpoint_info = fdsocket_endpoint_info,
+    .endpoint_info = nullsock_endpoint_info,
 };
 
 static void fdsocket_connect_success_callback(void *ctx)