X-Git-Url: https://git.tokkee.org/?p=sysdb.git;a=blobdiff_plain;f=src%2Fcore%2Fplugin.c;h=4de1c3a4d93f3a8f502844bc67d4fe5801889b6b;hp=929abaee8467cf4bc7f419c324cdd7c6b46a339f;hb=f05f6dfc4e48309c916c0dcb158df66c80de6c71;hpb=3970ba2a54fdf360d425452d0d29f6cd3c09915a

diff --git a/src/core/plugin.c b/src/core/plugin.c
index 929abae..4de1c3a 100644
--- a/src/core/plugin.c
+++ b/src/core/plugin.c
@@ -50,32 +50,14 @@
 
 #include <pthread.h>
 
+/* helper to access info attributes */
+#define INFO_GET(i, attr) \
+	((i)->attr ? (i)->attr : #attr" not set")
+
 /*
  * private data types
  */
 
-struct sdb_plugin_info {
-	char *plugin_name;
-	char *filename;
-
-	/* public attributes */
-	char *name;
-
-	char *description;
-	char *copyright;
-	char *license;
-
-	int   version;
-	int   plugin_version;
-};
-#define SDB_PLUGIN_INFO_INIT { \
-	/* plugin_name */ NULL, /* filename */ NULL, \
-	/* name */ NULL, /* desc */ NULL, \
-	/* copyright */ NULL, /* license */ NULL, \
-	/* version */ -1, /* plugin_version */ -1 }
-#define INFO_GET(i, attr) \
-	((i)->attr ? (i)->attr : #attr" not set")
-
 typedef struct {
 	sdb_object_t super;
 	sdb_plugin_ctx_t public;
@@ -102,6 +84,8 @@ typedef struct {
 #define SDB_PLUGIN_CB_INIT { SDB_OBJECT_INIT, \
 	/* callback = */ NULL, /* user_data = */ NULL, \
 	SDB_PLUGIN_CTX_INIT }
+#define SDB_PLUGIN_CB(obj) ((sdb_plugin_cb_t *)(obj))
+#define SDB_CONST_PLUGIN_CB(obj) ((const sdb_plugin_cb_t *)(obj))
 
 typedef struct {
 	sdb_plugin_cb_t super;
@@ -111,12 +95,17 @@ typedef struct {
 	sdb_time_t ccb_interval;
 	sdb_time_t ccb_next_update;
 } sdb_plugin_collector_cb_t;
-
-#define SDB_PLUGIN_CB(obj) ((sdb_plugin_cb_t *)(obj))
-#define SDB_CONST_PLUGIN_CB(obj) ((const sdb_plugin_cb_t *)(obj))
 #define SDB_PLUGIN_CCB(obj) ((sdb_plugin_collector_cb_t *)(obj))
 #define SDB_CONST_PLUGIN_CCB(obj) ((const sdb_plugin_collector_cb_t *)(obj))
 
+typedef struct {
+	sdb_object_t super;
+	sdb_store_writer_t impl;
+	sdb_object_t *user_data;
+	ctx_t *ctx;
+} sdb_plugin_writer_t;
+#define SDB_PLUGIN_WRITER(obj) ((sdb_plugin_writer_t *)(obj))
+
 /*
  * private variables
  */
@@ -125,7 +114,7 @@ static sdb_plugin_ctx_t  plugin_default_ctx  = SDB_PLUGIN_CTX_INIT;
 static sdb_plugin_info_t plugin_default_info = SDB_PLUGIN_INFO_INIT;
 
 static pthread_key_t     plugin_ctx_key;
-static _Bool             plugin_ctx_key_initialized = 0;
+static bool              plugin_ctx_key_initialized = 0;
 
 /* a list of the plugin contexts of all registered plugins */
 static sdb_llist_t      *all_plugins = NULL;
@@ -136,6 +125,22 @@ static sdb_llist_t      *collector_list = NULL;
 static sdb_llist_t      *cname_list = NULL;
 static sdb_llist_t      *shutdown_list = NULL;
 static sdb_llist_t      *log_list = NULL;
+static sdb_llist_t      *ts_fetcher_list = NULL;
+static sdb_llist_t      *writer_list = NULL;
+
+static struct {
+	const char   *type;
+	sdb_llist_t **list;
+} all_lists[] = {
+	{ "config",             &config_list },
+	{ "init",               &init_list },
+	{ "collector",          &collector_list },
+	{ "cname",              &cname_list },
+	{ "shutdown",           &shutdown_list },
+	{ "log",                &log_list },
+	{ "timeseries fetcher", &ts_fetcher_list },
+	{ "store writer",       &writer_list },
+};
 
 /*
  * private helper functions
@@ -153,8 +158,6 @@ plugin_info_clear(sdb_plugin_info_t *info)
 	if (info->filename)
 		free(info->filename);
 
-	if (info->name)
-		free(info->name);
 	if (info->description)
 		free(info->description);
 	if (info->copyright)
@@ -196,33 +199,30 @@ plugin_lookup_by_name(const sdb_object_t *obj, const void *id)
 	const sdb_plugin_cb_t *cb = SDB_CONST_PLUGIN_CB(obj);
 	const char *name = id;
 
-	assert(cb && id && cb->cb_ctx);
+	assert(cb && id);
+
+	/* when a plugin was registered from outside a plugin (e.g. the core),
+	 * we don't have a plugin context */
+	if (! cb->cb_ctx)
+		return 1;
+
 	if (!strcasecmp(cb->cb_ctx->info.plugin_name, name))
 		return 0;
 	return 1;
 } /* plugin_lookup_by_name */
 
+/* since this function is called from sdb_plugin_reconfigure_finish()
+ * when iterating through all_plugins, we may not do any additional
+ * modifications to all_plugins except for the optional removal */
 static void
 plugin_unregister_by_name(const char *plugin_name)
 {
 	sdb_object_t *obj;
 	size_t i;
 
-	struct {
-		const char  *type;
-		sdb_llist_t *list;
-	} all_lists[] = {
-		{ "config",    config_list },
-		{ "init",      init_list },
-		{ "collector", collector_list },
-		{ "cname",     cname_list },
-		{ "shutdown",  shutdown_list },
-		{ "log",       log_list },
-	};
-
 	for (i = 0; i < SDB_STATIC_ARRAY_LEN(all_lists); ++i) {
-		const char  *type = all_lists[i].type;
-		sdb_llist_t *list = all_lists[i].list;
+		const char  *type =  all_lists[i].type;
+		sdb_llist_t *list = *all_lists[i].list;
 
 		while (1) {
 			sdb_plugin_cb_t *cb;
@@ -232,6 +232,8 @@ plugin_unregister_by_name(const char *plugin_name)
 			if (! cb)
 				break;
 
+			assert(cb->cb_ctx);
+
 			sdb_log(SDB_LOG_INFO, "core: Unregistering "
 					"%s callback '%s' (module %s)", type, cb->super.name,
 					cb->cb_ctx->info.plugin_name);
@@ -240,12 +242,35 @@ plugin_unregister_by_name(const char *plugin_name)
 	}
 
 	obj = sdb_llist_search_by_name(all_plugins, plugin_name);
-	if (obj->ref_cnt <= 1)
+	/* when called from sdb_plugin_reconfigure_finish, the object has already
+	 * been removed from the list */
+	if (obj && (obj->ref_cnt <= 1)) {
 		sdb_llist_remove_by_name(all_plugins, plugin_name);
+		sdb_object_deref(obj);
+	}
 	/* else: other callbacks still reference it */
-	sdb_object_deref(obj);
 } /* plugin_unregister_by_name */
 
+static void
+plugin_unregister_all(void)
+{
+	size_t i;
+
+	for (i = 0; i < SDB_STATIC_ARRAY_LEN(all_lists); ++i) {
+		const char  *type =  all_lists[i].type;
+		sdb_llist_t *list = *all_lists[i].list;
+
+		size_t len = sdb_llist_len(list);
+
+		if (! len)
+			continue;
+
+		sdb_llist_clear(list);
+		sdb_log(SDB_LOG_INFO, "core: Unregistered %zu %s callback%s",
+				len, type, len == 1 ? "" : "s");
+	}
+} /* plugin_unregister_all */
+
 /*
  * private types
  */
@@ -292,22 +317,6 @@ static sdb_type_t ctx_type = {
 	ctx_destroy
 };
 
-static ctx_t *
-ctx_create(const char *name)
-{
-	ctx_t *ctx;
-
-	ctx = CTX(sdb_object_create(name, ctx_type));
-	if (! ctx)
-		return NULL;
-
-	if (! plugin_ctx_key_initialized)
-		ctx_key_init();
-	sdb_object_ref(SDB_OBJ(ctx));
-	pthread_setspecific(plugin_ctx_key, ctx);
-	return ctx;
-} /* ctx_create */
-
 static ctx_t *
 ctx_get(void)
 {
@@ -333,6 +342,21 @@ ctx_set(ctx_t *new)
 	return old;
 } /* ctx_set */
 
+static ctx_t *
+ctx_create(const char *name)
+{
+	ctx_t *ctx;
+
+	ctx = CTX(sdb_object_create(name, ctx_type));
+	if (! ctx)
+		return NULL;
+
+	if (! plugin_ctx_key_initialized)
+		ctx_key_init();
+	ctx_set(ctx);
+	return ctx;
+} /* ctx_create */
+
 static int
 plugin_cb_init(sdb_object_t *obj, va_list ap)
 {
@@ -352,6 +376,8 @@ plugin_cb_init(sdb_object_t *obj, va_list ap)
 		return -1;
 	}
 
+	/* cb_ctx may be NULL if the plugin was not registered by a plugin */
+
 	SDB_PLUGIN_CB(obj)->cb_callback = callback;
 	SDB_PLUGIN_CB(obj)->cb_ctx      = ctx_get();
 	sdb_object_ref(SDB_OBJ(SDB_PLUGIN_CB(obj)->cb_ctx));
@@ -383,6 +409,55 @@ static sdb_type_t sdb_plugin_collector_cb_type = {
 	plugin_cb_destroy
 };
 
+static int
+plugin_writer_init(sdb_object_t *obj, va_list ap)
+{
+	sdb_store_writer_t *impl = va_arg(ap, sdb_store_writer_t *);
+	sdb_object_t       *ud   = va_arg(ap, sdb_object_t *);
+
+	assert(impl);
+
+	if ((! impl->store_host) || (! impl->store_service)
+			|| (! impl->store_metric) || (! impl->store_attribute)
+			|| (! impl->store_service_attr) || (! impl->store_metric_attr)) {
+		sdb_log(SDB_LOG_ERR, "core: store writer callback '%s' "
+				"does not fully implement the writer interface.",
+				obj->name);
+		return -1;
+	}
+	if (sdb_llist_search_by_name(writer_list, obj->name)) {
+		sdb_log(SDB_LOG_WARNING, "core: store writer callback '%s' "
+				"has already been registered. Ignoring newly "
+				"registered version.", obj->name);
+		return -1;
+	}
+
+	/* ctx may be NULL if the plugin was not registered by a plugin */
+
+	SDB_PLUGIN_WRITER(obj)->impl = *impl;
+	SDB_PLUGIN_WRITER(obj)->ctx  = ctx_get();
+	sdb_object_ref(SDB_OBJ(SDB_PLUGIN_WRITER(obj)->ctx));
+
+	sdb_object_ref(ud);
+	SDB_PLUGIN_WRITER(obj)->user_data = ud;
+	return 0;
+} /* plugin_writer_init */
+
+static void
+plugin_writer_destroy(sdb_object_t *obj)
+{
+	assert(obj);
+	sdb_object_deref(SDB_PLUGIN_WRITER(obj)->user_data);
+	sdb_object_deref(SDB_OBJ(SDB_PLUGIN_WRITER(obj)->ctx));
+} /* plugin_writer_destroy */
+
+static sdb_type_t sdb_plugin_writer_type = {
+	sizeof(sdb_plugin_writer_t),
+
+	plugin_writer_init,
+	plugin_writer_destroy
+};
+
 static int
 module_init(const char *name, lt_dlhandle lh, sdb_plugin_info_t *info)
 {
@@ -407,7 +482,8 @@ module_init(const char *name, lt_dlhandle lh, sdb_plugin_info_t *info)
 } /* module_init */
 
 static int
-module_load(const char *name, const sdb_plugin_ctx_t *plugin_ctx)
+module_load(const char *basedir, const char *name,
+		const sdb_plugin_ctx_t *plugin_ctx)
 {
 	char  base_name[name ? strlen(name) + 1 : 1];
 	const char *name_ptr;
@@ -420,6 +496,8 @@ module_load(const char *name, const sdb_plugin_ctx_t *plugin_ctx)
 
 	int status;
 
+	assert(name);
+
 	base_name[0] = '\0';
 	name_ptr = name;
 
@@ -430,8 +508,10 @@ module_load(const char *name, const sdb_plugin_ctx_t *plugin_ctx)
 	}
 	strcat(base_name, name_ptr);
 
-	snprintf(filename, sizeof(filename), "%s/%s.so",
-			PKGLIBDIR, base_name);
+	if (! basedir)
+		basedir = PKGLIBDIR;
+
+	snprintf(filename, sizeof(filename), "%s/%s.so", basedir, base_name);
 	filename[sizeof(filename) - 1] = '\0';
 
 	if (access(filename, R_OK)) {
@@ -485,9 +565,11 @@ module_load(const char *name, const sdb_plugin_ctx_t *plugin_ctx)
 	sdb_llist_append(all_plugins, SDB_OBJ(ctx));
 
 	sdb_log(SDB_LOG_INFO, "core: Successfully loaded "
-			"plugin '%s' v%i (%s)\n\t%s\n\tLicense: %s",
-			INFO_GET(&ctx->info, name), ctx->info.plugin_version,
-			INFO_GET(&ctx->info, description),
+			"plugin %s v%i (%s)", ctx->info.plugin_name,
+			ctx->info.plugin_version,
+			INFO_GET(&ctx->info, description));
+	sdb_log(SDB_LOG_INFO, "core: Plugin %s: %s, License: %s",
+			ctx->info.plugin_name,
 			INFO_GET(&ctx->info, copyright),
 			INFO_GET(&ctx->info, license));
 
@@ -499,6 +581,18 @@ module_load(const char *name, const sdb_plugin_ctx_t *plugin_ctx)
 	return 0;
 } /* module_load */
 
+static char *
+plugin_get_name(const char *name, char *buf, size_t bufsize)
+{
+	ctx_t *ctx = ctx_get();
+
+	if (ctx)
+		snprintf(buf, bufsize, "%s::%s", ctx->info.plugin_name, name);
+	else
+		snprintf(buf, bufsize, "core::%s", name);
+	return buf;
+} /* plugin_get_name */
+
 static int
 plugin_add_callback(sdb_llist_t **list, const char *type,
 		const char *name, void *callback, sdb_object_t *user_data)
@@ -538,10 +632,13 @@ plugin_add_callback(sdb_llist_t **list, const char *type,
  */
 
 int
-sdb_plugin_load(const char *name, const sdb_plugin_ctx_t *plugin_ctx)
+sdb_plugin_load(const char *basedir, const char *name,
+		const sdb_plugin_ctx_t *plugin_ctx)
 {
 	ctx_t *ctx;
 
+	int status;
+
 	if ((! name) || (! *name))
 		return -1;
 
@@ -556,11 +653,24 @@ sdb_plugin_load(const char *name, const sdb_plugin_ctx_t *plugin_ctx)
 	ctx = CTX(sdb_llist_search_by_name(all_plugins, name));
 	if (ctx) {
 		/* plugin already loaded */
+		if (! ctx->use_cnt) {
+			/* reloading plugin */
+			ctx_t *old_ctx = ctx_set(ctx);
+
+			status = module_init(ctx->info.plugin_name, ctx->handle, NULL);
+			if (status)
+				return status;
+
+			sdb_log(SDB_LOG_INFO, "core: Successfully reloaded plugin "
+					"'%s' (%s)", ctx->info.plugin_name,
+					INFO_GET(&ctx->info, description));
+			ctx_set(old_ctx);
+		}
 		++ctx->use_cnt;
 		return 0;
 	}
 
-	return module_load(name, plugin_ctx);
+	return module_load(basedir, name, plugin_ctx);
 } /* sdb_plugin_load */
 
 int
@@ -574,16 +684,6 @@ sdb_plugin_set_info(sdb_plugin_info_t *info, int type, ...)
 	va_start(ap, type);
 
 	switch (type) {
-		case SDB_PLUGIN_INFO_NAME:
-			{
-				char *name = va_arg(ap, char *);
-				if (name) {
-					if (info->name)
-						free(info->name);
-					info->name = strdup(name);
-				}
-			}
-			break;
 		case SDB_PLUGIN_INFO_DESC:
 			{
 				char *desc = va_arg(ap, char *);
@@ -633,9 +733,16 @@ sdb_plugin_set_info(sdb_plugin_info_t *info, int type, ...)
 } /* sdb_plugin_set_info */
 
 int
-sdb_plugin_register_config(const char *name, sdb_plugin_config_cb callback)
+sdb_plugin_register_config(sdb_plugin_config_cb callback)
 {
-	return plugin_add_callback(&config_list, "init", name,
+	ctx_t *ctx = ctx_get();
+
+	if (! ctx) {
+		sdb_log(SDB_LOG_ERR, "core: Invalid attempt to register a "
+				"config callback from outside a plugin");
+		return -1;
+	}
+	return plugin_add_callback(&config_list, "init", ctx->info.plugin_name,
 			(void *)callback, NULL);
 } /* sdb_plugin_register_config */
 
@@ -643,7 +750,9 @@ int
 sdb_plugin_register_init(const char *name, sdb_plugin_init_cb callback,
 		sdb_object_t *user_data)
 {
-	return plugin_add_callback(&init_list, "init", name,
+	char cb_name[1024];
+	return plugin_add_callback(&init_list, "init",
+			plugin_get_name(name, cb_name, sizeof(cb_name)),
 			(void *)callback, user_data);
 } /* sdb_plugin_register_init */
 
@@ -651,7 +760,9 @@ int
 sdb_plugin_register_shutdown(const char *name, sdb_plugin_shutdown_cb callback,
 		sdb_object_t *user_data)
 {
-	return plugin_add_callback(&shutdown_list, "shutdown", name,
+	char cb_name[1024];
+	return plugin_add_callback(&shutdown_list, "shutdown",
+			plugin_get_name(name, cb_name, sizeof(cb_name)),
 			(void *)callback, user_data);
 } /* sdb_plugin_register_shutdown */
 
@@ -659,22 +770,27 @@ int
 sdb_plugin_register_log(const char *name, sdb_plugin_log_cb callback,
 		sdb_object_t *user_data)
 {
-	return plugin_add_callback(&log_list, "log", name, (void *)callback,
-			user_data);
+	char cb_name[1024];
+	return plugin_add_callback(&log_list, "log",
+			plugin_get_name(name, cb_name, sizeof(cb_name)),
+			callback, user_data);
 } /* sdb_plugin_register_log */
 
 int
 sdb_plugin_register_cname(const char *name, sdb_plugin_cname_cb callback,
 		sdb_object_t *user_data)
 {
-	return plugin_add_callback(&cname_list, "cname", name, (void *)callback,
-			user_data);
+	char cb_name[1024];
+	return plugin_add_callback(&cname_list, "cname",
+			plugin_get_name(name, cb_name, sizeof(cb_name)),
+			callback, user_data);
 } /* sdb_plugin_register_cname */
 
 int
 sdb_plugin_register_collector(const char *name, sdb_plugin_collector_cb callback,
 		const sdb_time_t *interval, sdb_object_t *user_data)
 {
+	char cb_name[1024];
 	sdb_object_t *obj;
 
 	if ((! name) || (! callback))
@@ -685,7 +801,9 @@ sdb_plugin_register_collector(const char *name, sdb_plugin_collector_cb callback
 	if (! collector_list)
 		return -1;
 
-	obj = sdb_object_create(name, sdb_plugin_collector_cb_type,
+	plugin_get_name(name, cb_name, sizeof(cb_name));
+
+	obj = sdb_object_create(cb_name, sdb_plugin_collector_cb_type,
 			&collector_list, "collector", callback, user_data);
 	if (! obj)
 		return -1;
@@ -693,12 +811,16 @@ sdb_plugin_register_collector(const char *name, sdb_plugin_collector_cb callback
 	if (interval)
 		SDB_PLUGIN_CCB(obj)->ccb_interval = *interval;
 	else {
-		sdb_time_t tmp = sdb_plugin_get_ctx().interval;
+		ctx_t *ctx = ctx_get();
 
-		if (tmp > 0)
-			SDB_PLUGIN_CCB(obj)->ccb_interval = tmp;
-		else
-			SDB_PLUGIN_CCB(obj)->ccb_interval = 0;
+		if (! ctx) {
+			sdb_log(SDB_LOG_ERR, "core: Cannot determine interval "
+					"for collector %s; none specified and no plugin "
+					"context found", cb_name);
+			return -1;
+		}
+
+		SDB_PLUGIN_CCB(obj)->ccb_interval = ctx->public.interval;
 	}
 
 	if (! (SDB_PLUGIN_CCB(obj)->ccb_next_update = sdb_gettime())) {
@@ -719,11 +841,54 @@ sdb_plugin_register_collector(const char *name, sdb_plugin_collector_cb callback
 	sdb_object_deref(obj);
 
 	sdb_log(SDB_LOG_INFO, "core: Registered collector callback '%s' "
-			"(interval = %.3fs).", name,
+			"(interval = %.3fs).", cb_name,
 			SDB_TIME_TO_DOUBLE(SDB_PLUGIN_CCB(obj)->ccb_interval));
 	return 0;
 } /* sdb_plugin_register_collector */
 
+int
+sdb_plugin_register_ts_fetcher(const char *name,
+		sdb_plugin_fetch_ts_cb callback, sdb_object_t *user_data)
+{
+	return plugin_add_callback(&ts_fetcher_list, "time-series fetcher",
+			name, callback, user_data);
+} /* sdb_plugin_register_ts_fetcher */
+
+int
+sdb_plugin_register_writer(const char *name,
+		sdb_store_writer_t *writer, sdb_object_t *user_data)
+{
+	char cb_name[1024];
+	sdb_object_t *obj;
+
+	if ((! name) || (! writer))
+		return -1;
+
+	if (! writer_list)
+		writer_list = sdb_llist_create();
+	if (! writer_list)
+		return -1;
+
+	plugin_get_name(name, cb_name, sizeof(cb_name));
+
+	obj = sdb_object_create(cb_name, sdb_plugin_writer_type,
+			writer, user_data);
+	if (! obj)
+		return -1;
+
+	if (sdb_llist_append(writer_list, obj)) {
+		sdb_object_deref(obj);
+		return -1;
+	}
+
+	/* pass control to the list */
+	sdb_object_deref(obj);
+
+	sdb_log(SDB_LOG_INFO, "core: Registered store writer callback '%s'.",
+			cb_name);
+	return 0;
+} /* sdb_store_register_writer */
+
 sdb_plugin_ctx_t
 sdb_plugin_get_ctx(void)
 {
@@ -756,6 +921,16 @@ sdb_plugin_set_ctx(sdb_plugin_ctx_t ctx, sdb_plugin_ctx_t *old)
 	return 0;
 } /* sdb_plugin_set_ctx */
 
+const sdb_plugin_info_t *
+sdb_plugin_current(void)
+{
+	ctx_t *ctx = ctx_get();
+
+	if (! ctx)
+		return NULL;
+	return &ctx->info;
+} /* sdb_plugin_current */
+
 int
 sdb_plugin_configure(const char *name, oconfig_item_t *ci)
 {
@@ -773,7 +948,9 @@ sdb_plugin_configure(const char *name, oconfig_item_t *ci)
 	if (! plugin) {
 		ctx_t *ctx = CTX(sdb_llist_search_by_name(all_plugins, name));
 		if (! ctx)
-			sdb_log(SDB_LOG_ERR, "core: Plugin '%s' not loaded.", name);
+			sdb_log(SDB_LOG_ERR, "core: Cannot configure unknown "
+					"plugin '%s'. Missing 'LoadPlugin \"%s\"'?",
+					name, name);
 		else
 			sdb_log(SDB_LOG_ERR, "core: Plugin '%s' did not register "
 					"a config callback.", name);
@@ -788,6 +965,66 @@ sdb_plugin_configure(const char *name, oconfig_item_t *ci)
 	return status;
 } /* sdb_plugin_configure */
 
+int
+sdb_plugin_reconfigure_init(void)
+{
+	sdb_llist_iter_t *iter;
+
+	iter = sdb_llist_get_iter(config_list);
+	if (config_list && (! iter))
+		return -1;
+
+	/* deconfigure all plugins */
+	while (sdb_llist_iter_has_next(iter)) {
+		sdb_plugin_cb_t *plugin;
+		sdb_plugin_config_cb callback;
+		ctx_t *old_ctx;
+
+		plugin = SDB_PLUGIN_CB(sdb_llist_iter_get_next(iter));
+		old_ctx = ctx_set(plugin->cb_ctx);
+		callback = (sdb_plugin_config_cb)plugin->cb_callback;
+		callback(NULL);
+		ctx_set(old_ctx);
+	}
+	sdb_llist_iter_destroy(iter);
+
+	iter = sdb_llist_get_iter(all_plugins);
+	if (all_plugins && (! iter))
+		return -1;
+
+	/* record all plugins as being unused */
+	while (sdb_llist_iter_has_next(iter))
+		CTX(sdb_llist_iter_get_next(iter))->use_cnt = 0;
+	sdb_llist_iter_destroy(iter);
+
+	plugin_unregister_all();
+	return 0;
+} /* sdb_plugin_reconfigure_init */
+
+int
+sdb_plugin_reconfigure_finish(void)
+{
+	sdb_llist_iter_t *iter;
+
+	iter = sdb_llist_get_iter(all_plugins);
+	if (all_plugins && (! iter))
+		return -1;
+
+	while (sdb_llist_iter_has_next(iter)) {
+		ctx_t *ctx = CTX(sdb_llist_iter_get_next(iter));
+		if (ctx->use_cnt)
+			continue;
+
+		sdb_log(SDB_LOG_INFO, "core: Module %s no longer in use",
+				ctx->info.plugin_name);
+		sdb_llist_iter_remove_current(iter);
+		plugin_unregister_by_name(ctx->info.plugin_name);
+		sdb_object_deref(SDB_OBJ(ctx));
+	}
+	sdb_llist_iter_destroy(iter);
+	return 0;
+} /* sdb_plugin_reconfigure_finish */
+
 int
 sdb_plugin_init_all(void)
 {
@@ -810,15 +1047,47 @@ sdb_plugin_init_all(void)
 		if (callback(cb->cb_user_data)) {
 			sdb_log(SDB_LOG_ERR, "core: Failed to initialize plugin "
 					"'%s'. Unregistering all callbacks.", obj->name);
+			ctx_set(old_ctx);
 			plugin_unregister_by_name(cb->cb_ctx->info.plugin_name);
 			++ret;
 		}
-		ctx_set(old_ctx);
+		else
+			ctx_set(old_ctx);
 	}
 	sdb_llist_iter_destroy(iter);
 	return ret;
 } /* sdb_plugin_init_all */
 
+int
+sdb_plugin_shutdown_all(void)
+{
+	sdb_llist_iter_t *iter;
+	int ret = 0;
+
+	iter = sdb_llist_get_iter(shutdown_list);
+	while (sdb_llist_iter_has_next(iter)) {
+		sdb_plugin_cb_t *cb;
+		sdb_plugin_shutdown_cb callback;
+		ctx_t *old_ctx;
+
+		sdb_object_t *obj = sdb_llist_iter_get_next(iter);
+		assert(obj);
+		cb = SDB_PLUGIN_CB(obj);
+
+		callback = (sdb_plugin_shutdown_cb)cb->cb_callback;
+
+		old_ctx = ctx_set(cb->cb_ctx);
+		if (callback(cb->cb_user_data)) {
+			sdb_log(SDB_LOG_ERR, "core: Failed to shutdown plugin '%s'.",
+					obj->name);
+			++ret;
+		}
+		ctx_set(old_ctx);
+	}
+	sdb_llist_iter_destroy(iter);
+	return ret;
+} /* sdb_plugin_shutdown_all */
+
 int
 sdb_plugin_collector_loop(sdb_plugin_loop_t *loop)
 {
@@ -861,13 +1130,21 @@ sdb_plugin_collector_loop(sdb_plugin_loop_t *loop)
 					sdb_log(SDB_LOG_ERR, "core: Failed to sleep "
 							"in collector main loop: %s",
 							sdb_strerror(errno, errbuf, sizeof(errbuf)));
+					sdb_llist_insert_sorted(collector_list, obj,
+							plugin_cmp_next_update);
+					sdb_object_deref(obj);
 					return -1;
 				}
 				errno = 0;
 			}
 
-			if (! loop->do_loop)
+			if (! loop->do_loop) {
+				/* put back; don't worry about errors */
+				sdb_llist_insert_sorted(collector_list, obj,
+						plugin_cmp_next_update);
+				sdb_object_deref(obj);
 				return 0;
+			}
 		}
 
 		old_ctx = ctx_set(SDB_PLUGIN_CCB(obj)->ccb_ctx);
@@ -957,12 +1234,11 @@ sdb_plugin_log(int prio, const char *msg)
 	sdb_llist_iter_t *iter;
 	int ret = -1;
 
+	bool logged = 0;
+
 	if (! msg)
 		return 0;
 
-	if (! log_list)
-		return fprintf(stderr, "[%s] %s\n", SDB_LOG_PRIO_TO_STRING(prio), msg);
-
 	iter = sdb_llist_get_iter(log_list);
 	while (sdb_llist_iter_has_next(iter)) {
 		sdb_plugin_log_cb callback;
@@ -975,8 +1251,15 @@ sdb_plugin_log(int prio, const char *msg)
 		tmp = callback(prio, msg, SDB_PLUGIN_CB(obj)->cb_user_data);
 		if (tmp > ret)
 			ret = tmp;
+
+		if (SDB_PLUGIN_CB(obj)->cb_ctx)
+			logged = 1;
+		/* else: this is an internally registered callback */
 	}
 	sdb_llist_iter_destroy(iter);
+
+	if (! logged)
+		return fprintf(stderr, "[%s] %s\n", SDB_LOG_PRIO_TO_STRING(prio), msg);
 	return ret;
 } /* sdb_plugin_log */
 
@@ -1021,5 +1304,33 @@ sdb_plugin_logf(int prio, const char *fmt, ...)
 	return ret;
 } /* sdb_plugin_logf */
 
+sdb_timeseries_t *
+sdb_plugin_fetch_timeseries(const char *type, const char *id,
+		sdb_timeseries_opts_t *opts)
+{
+	sdb_plugin_cb_t *plugin;
+	sdb_plugin_fetch_ts_cb callback;
+	sdb_timeseries_t *ts;
+
+	ctx_t *old_ctx;
+
+	if ((! type) || (! id) || (! opts))
+		return NULL;
+
+	plugin = SDB_PLUGIN_CB(sdb_llist_search_by_name(ts_fetcher_list, type));
+	if (! plugin) {
+		sdb_log(SDB_LOG_ERR, "core: Cannot fetch time-series of type %s: "
+				"no such plugin loaded", type);
+		errno = ENOENT;
+		return NULL;
+	}
+
+	old_ctx = ctx_set(plugin->cb_ctx);
+	callback = (sdb_plugin_fetch_ts_cb)plugin->cb_callback;
+	ts = callback(id, opts, plugin->cb_user_data);
+	ctx_set(old_ctx);
+	return ts;
+} /* sdb_plugin_fetch_timeseries */
+
 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */