lightningd/plugin.c: Make builtin plugins important.

Changelog-Changed: plugin: Builtin plugins are now marked as important, and if they crash, will cause C-lightning to stop as well.

Makefile

@@ -268,6 +268,15 @@ include tools/Makefile
 include plugins/Makefile
 include tests/plugins/Makefile
 
+# Generated from PLUGINS definition in plugins/Makefile
+gen_list_of_builtin_plugins.h : plugins/Makefile Makefile
+	@echo GEN $@
+	@rm -f $@ || true
+	@echo 'static const char *list_of_builtin_plugins[] = {' >> $@
+	@echo '$(PLUGINS)' | sed 's@plugins/\([^ 	]*\)@"\1",@g'>> $@
+	@echo 'NULL' >> $@
+	@echo '};' >> $@
+
 # Git doesn't maintain timestamps, so we only regen if git says we should.
 CHANGED_FROM_GIT = [ x"`git log $@ | head -n1`" != x"`git log $< | head -n1`" -o x"`git diff $<`" != x"" ]
 

doc/lightningd-config.5

@@ -557,6 +557,8 @@ plugin stops for any reason (including via \fBlightning-plugin\fR(7) \fBstop\fR)
 C-lightning will also stop running\.
 This way, you can monitor crashes of important plugins by simply monitoring
 if C-lightning terminates\.
+Built-in plugins, which are installed with \fBlightningd\fR(8), are automatically
+considered important\.
 
 .SH BUGS
 

doc/lightningd-config.5.md

@@ -460,6 +460,8 @@ plugin stops for any reason (including via lightning-plugin(7) `stop`),
 C-lightning will also stop running.
 This way, you can monitor crashes of important plugins by simply monitoring
 if C-lightning terminates.
+Built-in plugins, which are installed with lightningd(8), are automatically
+considered important.
 
 BUGS
 ----

lightningd/Makefile

@@ -137,6 +137,9 @@ LIGHTNINGD_HEADERS = $(LIGHTNINGD_HEADERS_NOGEN) $(LIGHTNINGD_HEADERS_GEN) $(WAL
 
 $(LIGHTNINGD_OBJS): $(LIGHTNINGD_HEADERS)
 
+# Only the plugin component needs to depend on this header.
+lightningd/plugin.o : gen_list_of_builtin_plugins.h
+
 lightningd/gen_channel_state_names.h: lightningd/channel_state.h ccan/ccan/cdump/tools/cdump-enumstr
 	ccan/ccan/cdump/tools/cdump-enumstr lightningd/channel_state.h > $@
 

lightningd/plugin.c

@@ -16,6 +16,9 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
+/* Only this file can include this generated header! */
+# include <gen_list_of_builtin_plugins.h>
+
 /* How many seconds may the plugin take to reply to the `getmanifest`
  * call? This is the maximum delay to `lightningd --help` and until
  * we can start the main `io_loop` to communicate with peers. If this
@@ -1582,11 +1585,13 @@ struct log *plugin_get_log(struct plugin *plugin)
 void plugins_set_builtin_plugins_dir(struct plugins *plugins,
 				     const char *dir)
 {
-	/*~ The builtin-plugins dir does not need to exist, but
-	 * we would error those anyway for our important built-in
-	 * plugins.
-	 */
-	add_plugin_dir(plugins, dir, true);
+	/*~ Load the builtin plugins as important.  */
+	for (size_t i = 0; list_of_builtin_plugins[i]; ++i)
+		plugin_register(plugins,
+				take(path_join(NULL, dir,
+					       list_of_builtin_plugins[i])),
+				NULL,
+				/* important = */ true);
 }
 
 struct plugin_destroyed {

tests/test_misc.py

@@ -844,9 +844,9 @@ def test_listconfigs_plugins(node_factory, bitcoind, chainparams):
 
     # assert that we have pay plugin and that plugins have a name and path
     configs = l1.rpc.listconfigs()
-    assert configs['plugins']
-    assert len([p for p in configs['plugins'] if p['name'] == "pay"]) == 1
-    for p in configs['plugins']:
+    assert configs['important-plugins']
+    assert len([p for p in configs['important-plugins'] if p['name'] == "pay"]) == 1
+    for p in configs['important-plugins']:
         assert p['name'] and len(p['name']) > 0
         assert p['path'] and len(p['path']) > 0
         assert os.path.isfile(p['path']) and os.access(p['path'], os.X_OK)