plugin: Basic scaffolding for the plugin subsystem

lightningd/Makefile

@@ -78,6 +78,7 @@ LIGHTNINGD_SRC :=				\
 	lightningd/peer_control.c		\
 	lightningd/peer_htlcs.c			\
 	lightningd/ping.c			\
+	lightningd/plugin.c			\
 	lightningd/subd.c			\
 	lightningd/watch.c
 

lightningd/plugin.c

@@ -0,0 +1,34 @@
+#include "lightningd/plugin.h"
+
+#include <ccan/list/list.h>
+#include <ccan/tal/str/str.h>
+
+struct plugin {
+	int stdin, stdout;
+	pid_t pid;
+	char *cmd;
+};
+
+struct plugins {
+	struct plugin *plugins;
+};
+
+struct plugins *plugins_new(const tal_t *ctx){
+	struct plugins *p;
+	p = tal(ctx, struct plugins);
+	p->plugins = tal_arr(p, struct plugin, 0);
+	return p;
+}
+
+void plugin_register(struct plugins *plugins, const char* path TAKES)
+{
+	struct plugin *p;
+	size_t n = tal_count(plugins->plugins);
+	tal_resize(&plugins->plugins, n+1);
+	p = &plugins->plugins[n];
+	p->cmd = tal_strdup(p, path);
+}
+
+void plugins_init(struct plugins *plugins)
+{
+}

lightningd/plugin.h

@@ -0,0 +1,37 @@
+#ifndef LIGHTNING_LIGHTNINGD_PLUGIN_H
+#define LIGHTNING_LIGHTNINGD_PLUGIN_H
+#include "config.h"
+#include <ccan/take/take.h>
+#include <ccan/tal/tal.h>
+
+/**
+ * A collection of plugins, and some associated information.
+ *
+ * Mainly used as root context for calls in the plugin subsystem.
+ */
+struct plugins;
+
+/**
+ * Create a new plugins context.
+ */
+struct plugins *plugins_new(const tal_t *ctx);
+
+/**
+ * Initialize the registered plugins.
+ *
+ * Initialization includes spinning up the plugins, reading their init messages,
+ * and registering the JSON-RPC passthrough and command line arguments. In order
+ * to read the init messages from the plugins we spin up our own io_loop that
+ * exits once all plugins have responded.
+ */
+void plugins_init(struct plugins *plugins);
+
+/**
+ * Register a plugin for initialization and execution.
+ *
+ * @param plugins: Plugin context
+ * @param path: The path of the executable for this plugin
+ */
+void plugin_register(struct plugins *plugins, const char* path TAKES);
+
+#endif /* LIGHTNING_LIGHTNINGD_PLUGIN_H */