libplugin: make init return a string.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Added: libplugin: init can return a non-NULL string to disable the plugin.

plugins/autoclean.c

@@ -64,7 +64,7 @@ static struct command_result *json_autocleaninvoice(struct command *cmd,
 					   expired_by, cycle_seconds));
 }
 
-static void init(struct plugin *p,
+static const char *init(struct plugin *p,
 			const char *buf UNUSED, const jsmntok_t *config UNUSED)
 {
 	if (cycle_seconds) {
@@ -73,6 +73,8 @@ static void init(struct plugin *p,
 					  do_clean, p);
 	} else
 		plugin_log(p, LOG_DBG, "autocleaning not active");
+
+	return NULL;
 }
 
 static const struct plugin_command commands[] = { {

plugins/bcli.c

@@ -870,12 +870,14 @@ static void wait_and_check_bitcoind(struct plugin *p)
 	tal_free(cmd);
 }
 
-static void init(struct plugin *p, const char *buffer UNUSED,
+static const char *init(struct plugin *p, const char *buffer UNUSED,
 			const jsmntok_t *config UNUSED)
 {
 	wait_and_check_bitcoind(p);
 	plugin_log(p, LOG_INFORM,
 		   "bitcoin-cli initialized and connected to bitcoind.");
+
+	return NULL;
 }
 
 static const struct plugin_command commands[] = {

plugins/fetchinvoice.c

@@ -1346,12 +1346,14 @@ static const struct plugin_command commands[] = {
 	},
 };
 
-static void init(struct plugin *p, const char *buf UNUSED,
+static const char *init(struct plugin *p, const char *buf UNUSED,
 			const jsmntok_t *config UNUSED)
 {
 	rpc_scan(p, "getinfo",
 		 take(json_out_obj(NULL, NULL, NULL)),
 		 "{id:%}", JSON_SCAN(json_to_node_id, &local_id));
+
+	return NULL;
 }
 
 static const struct plugin_hook hooks[] = {

plugins/keysend.c

@@ -92,7 +92,7 @@ REGISTER_PAYMENT_MODIFIER(keysend, struct keysend_data *, keysend_init,
  * End of keysend modifier
  *****************************************************************************/
 
-static void init(struct plugin *p, const char *buf UNUSED,
+static const char *init(struct plugin *p, const char *buf UNUSED,
 			const jsmntok_t *config UNUSED)
 {
 	rpc_scan(p, "getinfo", take(json_out_obj(NULL, NULL, NULL)),
@@ -102,6 +102,8 @@ static void init(struct plugin *p, const char *buf UNUSED,
 		 take(json_out_obj(NULL, "config", "max-locktime-blocks")),
 		 "{max-locktime-blocks:%}",
 		 JSON_SCAN(json_to_number, &maxdelay_default));
+
+	return NULL;
 }
 
 struct payment_modifier *pay_mods[8] = {

plugins/libplugin.c

@@ -71,7 +71,7 @@ struct plugin {
 	struct plugin_option *opts;
 
 	/* Anything special to do at init ? */
-	void (*init)(struct plugin *p,
+	const char *(*init)(struct plugin *p,
 			    const char *buf, const jsmntok_t *);
 	/* Has the manifest been sent already ? */
 	bool manifested;
@@ -878,8 +878,12 @@ static struct command_result *handle_init(struct command *cmd,
 		tal_free(opt);
 	}
 
-	if (p->init)
+	if (p->init) {
-		p->init(p, buf, configtok);
+		const char *disable = p->init(p, buf, configtok);
+		if (disable)
+			return command_success(cmd, json_out_obj(cmd, "disable",
+								 disable));
+	}
 
 	if (with_rpc)
 		io_new_conn(p, p->rpc_conn->fd, rpc_conn_init, p);
@@ -1296,8 +1300,9 @@ static struct io_plan *stdout_conn_init(struct io_conn *conn,
 }
 
 static struct plugin *new_plugin(const tal_t *ctx,
-				 void (*init)(struct plugin *p,
+				 const char *(*init)(struct plugin *p,
-					      const char *buf, const jsmntok_t *),
+						     const char *buf,
+						     const jsmntok_t *),
 				 const enum plugin_restartability restartability,
 				 bool init_rpc,
 				 struct feature_set *features,
@@ -1365,7 +1370,7 @@ static struct plugin *new_plugin(const tal_t *ctx,
 }
 
 void plugin_main(char *argv[],
-		 void (*init)(struct plugin *p,
+		 const char *(*init)(struct plugin *p,
 				     const char *buf, const jsmntok_t *),
 		 const enum plugin_restartability restartability,
 		 bool init_rpc,

plugins/libplugin.h

@@ -277,8 +277,9 @@ char *flag_option(const char *arg, bool *i);
 
 /* The main plugin runner: append with 0 or more plugin_option(), then NULL. */
 void NORETURN LAST_ARG_NULL plugin_main(char *argv[],
-					void (*init)(struct plugin *p,
+					const char *(*init)(struct plugin *p,
-						     const char *buf, const jsmntok_t *),
+							    const char *buf,
+							    const jsmntok_t *),
 					const enum plugin_restartability restartability,
 					bool init_rpc,
 					struct feature_set *features,

plugins/offers.c

@@ -665,7 +665,7 @@ static struct command_result *json_decode(struct command *cmd,
 	return command_finished(cmd, response);
 }
 
-static void init(struct plugin *p,
+static const char *init(struct plugin *p,
 			const char *buf UNUSED,
 			const jsmntok_t *config UNUSED)
 {
@@ -681,6 +681,8 @@ static void init(struct plugin *p,
 	rpc_scan(p, "listconfigs",
 		 take(json_out_obj(NULL, "config", "cltv-final")),
 		 "{cltv-final:%}", JSON_SCAN(json_to_number, &cltv_final));
+
+	return NULL;
 }
 
 static const struct plugin_command commands[] = {

plugins/pay.c

@@ -1902,7 +1902,7 @@ static struct command_result *json_listpays(struct command *cmd,
 	return send_outreq(cmd->plugin, req);
 }
 
-static void init(struct plugin *p,
+static const char *init(struct plugin *p,
 			const char *buf UNUSED, const jsmntok_t *config UNUSED)
 {
 	rpc_scan(p, "getinfo", take(json_out_obj(NULL, NULL, NULL)),
@@ -1912,6 +1912,8 @@ static void init(struct plugin *p,
 		 take(json_out_obj(NULL, "config", "max-locktime-blocks")),
 		 "{max-locktime-blocks:%}",
 		 JSON_SCAN(json_to_number, &maxdelay_default));
+
+	return NULL;
 }
 
 struct payment_modifier *paymod_mods[] = {

plugins/spender/main.c

@@ -9,10 +9,11 @@
  * spending from the onchain wallet.  */
 
 static
-void spender_init(struct plugin *p, const char *b, const jsmntok_t *t)
+const char *spender_init(struct plugin *p, const char *b, const jsmntok_t *t)
 {
 	openchannel_init(p, b, t);
 	/* whatever_init(p, b, t); */
+	return NULL;
 }
 
 int main(int argc, char **argv)

tests/plugins/test_libplugin.c

@@ -5,7 +5,7 @@
 
 
 const char *name_option;
-
+static bool self_disable = false;
 
 static struct command_result *json_helloworld(struct command *cmd,
 					      const char *buf,
@@ -86,10 +86,15 @@ static struct command_result *json_testrpc(struct command *cmd,
 	return send_outreq(cmd->plugin, req);
 }
 
-static void init(struct plugin *p,
+static const char *init(struct plugin *p,
-		  const char *buf UNUSED, const jsmntok_t *config UNUSED)
+			const char *buf UNUSED,
+			const jsmntok_t *config UNUSED)
 {
 	plugin_log(p, LOG_DBG, "test_libplugin initialised!");
+
+	if (self_disable)
+		return "Disabled via selfdisable option";
+	return NULL;
 }
 
 static const struct plugin_command commands[] = { {
@@ -149,5 +154,9 @@ int main(int argc, char *argv[])
 					     "string",
 					     "Who to say hello to.",
 					     charp_option, &name_option),
+		    plugin_option("selfdisable",
+				  "flag",
+				  "Whether to disable.",
+				  flag_option, &self_disable),
 		    NULL);
 }

tests/test_plugin.py

@@ -2326,19 +2326,26 @@ def test_pyln_request_notify(node_factory):
 def test_self_disable(node_factory):
     """Test that plugin can disable itself without penalty.
     """
-    plugin_path = os.path.join(
+    # This disables in response to getmanifest.
-        os.path.dirname(__file__), 'plugins/test_selfdisable'
+    p1 = os.path.join(
+        os.path.dirname(__file__), 'plugins/test_selfdisable_after_getmanifest'
     )
-    l1 = node_factory.get_node(options={'important-plugin': plugin_path})
+    # This disables in response to init.
+    p2 = os.path.join(os.getcwd(), "tests/plugins/test_libplugin")
+    l1 = node_factory.get_node(options={'important-plugin': [p1, p2], 'selfdisable': None})
 
     # Could happen before it gets set up.
     l1.daemon.logsearch_start = 0
-    l1.daemon.wait_for_log('test_selfdisable: disabled itself: "Self-disable test after getmanifest"')
+    l1.daemon.wait_for_logs(['test_selfdisable_after_getmanifest: disabled itself: "Self-disable test after getmanifest"',
+                             'test_libplugin: disabled itself at init: Disabled via selfdisable option'])
 
-    assert plugin_path not in [p['name'] for p in l1.rpc.plugin_list()['plugins']]
+    assert p1 not in [p['name'] for p in l1.rpc.plugin_list()['plugins']]
+    assert p2 not in [p['name'] for p in l1.rpc.plugin_list()['plugins']]
 
     # Also works with dynamic load attempts
     with pytest.raises(RpcError, match="Self-disable test after getmanifest"):
-        l1.rpc.plugin_start(plugin_path)
+        l1.rpc.plugin_start(p1)
 
-    # Now test the disable-in-init-response.
+    # Also works with dynamic load attempts
+    with pytest.raises(RpcError, match="Disabled via selfdisable option"):
+        l1.rpc.plugin_start(p2, selfdisable=True)