feat(libsinsp): plugin dynamic reconfiguration

userspace/libsinsp/plugin.cpp

@@ -166,8 +166,9 @@ bool sinsp_plugin::init(const std::string &config, std::string &errstr)
 	}
 
 	ss_plugin_rc rc;
+
 	std::string conf = config;
-	validate_init_config(conf);
+	validate_config(conf);
 
 	ss_plugin_init_input in = {};
 	in.owner = this;
@@ -635,7 +636,7 @@ const libsinsp::events::set<ppm_event_code>& sinsp_plugin::parse_event_codes() c
 	return m_parse_event_codes;
 }
 
-void sinsp_plugin::validate_init_config(std::string& config)
+void sinsp_plugin::validate_config(std::string& config)
 {
 	ss_plugin_schema_type schema_type;
 	std::string schema = get_init_schema(schema_type);
@@ -644,7 +645,7 @@ void sinsp_plugin::validate_init_config(std::string& config)
 		switch (schema_type)
 		{
 			case SS_PLUGIN_SCHEMA_JSON:
-				validate_init_config_json_schema(config, schema);
+				validate_config_json_schema(config, schema);
 				break;
 			default:
 				ASSERT(false);
@@ -657,7 +658,7 @@ void sinsp_plugin::validate_init_config(std::string& config)
 	}
 }
 
-void sinsp_plugin::validate_init_config_json_schema(std::string& config, std::string &schema)
+void sinsp_plugin::validate_config_json_schema(std::string& config, std::string &schema)
 {
 	Json::Value schemaJson;
 	if(!Json::Reader().parse(schema, schemaJson) || schemaJson.type() != Json::objectValue)
@@ -712,6 +713,27 @@ void sinsp_plugin::validate_init_config_json_schema(std::string& config, std::st
 	}
 }
 
+bool sinsp_plugin::set_config(const std::string& config)
+{
+	if(!m_inited)
+	{
+		throw sinsp_exception(std::string(s_not_init_err) + ": " + m_name);
+	}
+
+	std::string conf = config;
+	validate_config(conf);
+
+	ss_plugin_set_config_input input;
+	input.config = conf.c_str();
+
+	if(!m_handle->api.set_config)
+	{
+		return false;
+	}
+
+	return m_handle->api.set_config(m_state, &input) == SS_PLUGIN_SUCCESS;
+}
+
 /** Event Source CAP **/
 
 scap_source_plugin& sinsp_plugin::as_scap_source()

userspace/libsinsp/plugin.h

@@ -158,6 +158,7 @@ class sinsp_plugin
 	void destroy();
 	std::string get_last_error() const;
 	std::string get_init_schema(ss_plugin_schema_type& schema_type) const;
+	bool set_config(const std::string& config);
 
 	/** Event Sourcing **/
 	inline uint32_t id() const
@@ -263,7 +264,7 @@ class sinsp_plugin
 	std::atomic<async_event_handler_t*> m_async_evt_handler; // note: we don't have thread-safe smart pointers
 
 	/** Generic helpers **/
-	void validate_init_config(std::string& config);
+	void validate_config(std::string& config);
 	bool resolve_dylib_symbols(std::string& errstr);
 	void resolve_dylib_field_arg(Json::Value root, filtercheck_field_info& tf);
 	void resolve_dylib_compatible_sources(
@@ -274,7 +275,7 @@ class sinsp_plugin
 		uint16_t *(*get_codes)(uint32_t* numtypes,ss_plugin_t* s),
 		const std::unordered_set<std::string>& sources,
 		libsinsp::events::set<ppm_event_code>& codes);
-	void validate_init_config_json_schema(std::string& config, std::string& schema);
+	void validate_config_json_schema(std::string& config, std::string& schema);
 	static const char* get_owner_last_error(ss_plugin_owner_t* o);
 
 	/** Event parsing helpers **/

userspace/libsinsp/test/plugins.ut.cpp

@@ -673,3 +673,27 @@ TEST(sinsp_plugin, plugin_logging)
 
 	libsinsp_logger()->remove_callback_log();
 }
+
+// Scenario: we provide the plugin with a new configuration,
+// expecting it to log when it's notified.
+TEST(sinsp_plugin, plugin_set_config)
+{
+	std::string tmp;
+	sinsp i;
+	plugin_api api;
+	get_plugin_api_sample_plugin_extract(api);
+
+	api.get_name = [](){ return "plugin_name"; };
+
+	auto p = i.register_plugin(&api);
+	p->init("", tmp);
+
+	libsinsp_logger()->add_callback_log([](std::string&& str, sinsp_logger::severity sev) {
+		std::string expected = "plugin_name: new config!"; 
+		ASSERT_TRUE(std::equal(expected.rbegin(), expected.rend(), str.rbegin()));
+	});
+
+	ASSERT_TRUE(p->set_config("some config"));
+
+	libsinsp_logger()->remove_callback_log();
+}

userspace/libsinsp/test/plugins/plugin_extract.cpp

@@ -162,6 +162,14 @@ static ss_plugin_rc plugin_extract_fields(ss_plugin_t *s, const ss_plugin_event_
     return SS_PLUGIN_SUCCESS;
 }
 
+static ss_plugin_rc plugin_set_config(ss_plugin_t *s, const ss_plugin_set_config_input* i)
+{
+    plugin_state *ps = (plugin_state *) s;
+    ps->log(ps->owner, NULL, "new config!", SS_PLUGIN_LOG_SEV_INFO);
+
+    return SS_PLUGIN_SUCCESS;
+}
+
 void get_plugin_api_sample_plugin_extract(plugin_api& out)
 {
     memset(&out, 0, sizeof(plugin_api));
@@ -177,4 +185,5 @@ void get_plugin_api_sample_plugin_extract(plugin_api& out)
     out.get_extract_event_sources = plugin_get_extract_event_sources;
     out.get_extract_event_types = plugin_get_extract_event_types;
     out.extract_fields = plugin_extract_fields;
+    out.set_config = plugin_set_config;
 }

userspace/plugin/plugin_api.h

@@ -30,7 +30,7 @@ extern "C" {
 //
 // todo(jasondellaluce): when/if major changes to v4, check and solve all todos
 #define PLUGIN_API_VERSION_MAJOR 3
-#define PLUGIN_API_VERSION_MINOR 3
+#define PLUGIN_API_VERSION_MINOR 4
 #define PLUGIN_API_VERSION_PATCH 0
 
 //
@@ -371,6 +371,14 @@ typedef struct ss_plugin_event_parse_input
 	ss_plugin_table_writer_vtable_ext* table_writer_ext;
 } ss_plugin_event_parse_input;
 
+// Input passed to the plugin when setting a new configuration
+typedef struct ss_plugin_set_config_input
+{
+	//
+	// An opaque string representing the new configuration provided by the framework
+	const char* config;
+} ss_plugin_set_config_input;
+
 //
 // Function handler used by plugin for sending asynchronous events to the
 // Falcosecurity libs during a live event capture. The asynchronous events
@@ -939,6 +947,17 @@ typedef struct
 		//
 		ss_plugin_rc (*set_async_event_handler)(ss_plugin_t* s, ss_plugin_owner_t* owner, const ss_plugin_async_event_handler_t handler);
 	};
+
+	// Sets a new plugin configuration when provided by the framework.
+	// Required: no
+	// Arguments:
+	// - s: the plugin state, returned by init(). Can be NULL.
+	// - i: configuration input provided by the framework.
+	//
+	// Return value: A ss_plugin_rc with value SS_PLUGIN_SUCCESS if the config is accepted
+	// or SS_PLUGIN_FAILURE if the config is rejected.
+	// If rejected the plugin should provide context in the string returned by get_last_error().
+	ss_plugin_rc (*set_config)(ss_plugin_t* s, const ss_plugin_set_config_input* i);
 } plugin_api;
 
 #ifdef __cplusplus

userspace/plugin/plugin_loader.c

@@ -135,6 +135,7 @@ plugin_handle_t* plugin_load(const char* path, char* err)
     SYM_RESOLVE(ret, get_async_event_sources);
     SYM_RESOLVE(ret, get_async_events);
     SYM_RESOLVE(ret, set_async_event_handler);
+    SYM_RESOLVE(ret, set_config);
     return ret;
 }