X-Git-Url: https://git.tokkee.org/?p=sysdb.git;a=blobdiff_plain;f=src%2Fcore%2Fplugin.c;h=f10a904169f5d3993dc89894535e6a7b4ca01513;hp=26677979b26257e4a9ef89aeed363e9d032e3418;hb=56b97a180a53aecbfe9f7162b8ece3faae973cf9;hpb=b088698015415fb88edad1db598c69511b6163d2

diff --git a/src/core/plugin.c b/src/core/plugin.c
index 2667797..f10a904 100644
--- a/src/core/plugin.c
+++ b/src/core/plugin.c
@@ -25,10 +25,14 @@
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#if HAVE_CONFIG_H
+#	include "config.h"
+#endif /* HAVE_CONFIG_H */
+
 #include "sysdb.h"
 #include "core/plugin.h"
-#include "core/error.h"
 #include "core/time.h"
+#include "utils/error.h"
 #include "utils/llist.h"
 #include "utils/strbuf.h"
 
@@ -46,31 +50,36 @@
 
 #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 *name;
+typedef struct {
+	sdb_object_t super;
+	sdb_plugin_ctx_t public;
 
-	char *description;
-	char *copyright;
-	char *license;
+	sdb_plugin_info_t info;
+	lt_dlhandle handle;
 
-	int   version;
-	int   plugin_version;
-};
-#define SDB_PLUGIN_INFO_INIT { /* 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")
+	/* The usage count differs from the object's ref count
+	 * in that it provides higher level information about how
+	 * the plugin is in use. */
+	size_t use_cnt;
+} ctx_t;
+#define CTX_INIT { SDB_OBJECT_INIT, \
+	SDB_PLUGIN_CTX_INIT, SDB_PLUGIN_INFO_INIT, NULL, 0 }
+
+#define CTX(obj) ((ctx_t *)(obj))
 
 typedef struct {
 	sdb_object_t super;
 	void *cb_callback;
 	sdb_object_t *cb_user_data;
-	sdb_plugin_ctx_t cb_ctx;
+	ctx_t *cb_ctx;
 } sdb_plugin_cb_t;
 #define SDB_PLUGIN_CB_INIT { SDB_OBJECT_INIT, \
 	/* callback = */ NULL, /* user_data = */ NULL, \
@@ -86,16 +95,22 @@ typedef struct {
 } 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))
 
 /*
  * private variables
  */
 
-static sdb_plugin_ctx_t  plugin_default_ctx = SDB_PLUGIN_CTX_INIT;
+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 pthread_key_t    plugin_ctx_key;
-static _Bool            plugin_ctx_key_initialized = 0;
+/* a list of the plugin contexts of all registered plugins */
+static sdb_llist_t      *all_plugins = NULL;
 
 static sdb_llist_t      *config_list = NULL;
 static sdb_llist_t      *init_list = NULL;
@@ -104,19 +119,34 @@ static sdb_llist_t      *cname_list = NULL;
 static sdb_llist_t      *shutdown_list = NULL;
 static sdb_llist_t      *log_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 },
+};
+
 /*
  * private helper functions
  */
 
 static void
-sdb_plugin_info_clear(sdb_plugin_info_t *info)
+plugin_info_clear(sdb_plugin_info_t *info)
 {
 	sdb_plugin_info_t empty_info = SDB_PLUGIN_INFO_INIT;
 	if (! info)
 		return;
 
-	if (info->name)
-		free(info->name);
+	if (info->plugin_name)
+		free(info->plugin_name);
+	if (info->filename)
+		free(info->filename);
+
 	if (info->description)
 		free(info->description);
 	if (info->copyright)
@@ -125,45 +155,20 @@ sdb_plugin_info_clear(sdb_plugin_info_t *info)
 		free(info->license);
 
 	*info = empty_info;
-} /* sdb_plugin_info_clear */
+} /* plugin_info_clear */
 
 static void
-sdb_plugin_ctx_destructor(void *ctx)
-{
-	if (! ctx)
-		return;
-	free(ctx);
-} /* sdb_plugin_ctx_destructor */
-
-static void
-sdb_plugin_ctx_init(void)
+ctx_key_init(void)
 {
 	if (plugin_ctx_key_initialized)
 		return;
 
-	pthread_key_create(&plugin_ctx_key, sdb_plugin_ctx_destructor);
+	pthread_key_create(&plugin_ctx_key, /* destructor */ NULL);
 	plugin_ctx_key_initialized = 1;
-} /* sdb_plugin_ctx_init */
-
-static sdb_plugin_ctx_t *
-sdb_plugin_ctx_create(void)
-{
-	sdb_plugin_ctx_t *ctx;
-
-	ctx = malloc(sizeof(*ctx));
-	if (! ctx)
-		return NULL;
-
-	*ctx = plugin_default_ctx;
-
-	if (! plugin_ctx_key_initialized)
-		sdb_plugin_ctx_init();
-	pthread_setspecific(plugin_ctx_key, ctx);
-	return ctx;
-} /* sdb_plugin_ctx_create */
+} /* ctx_key_init */
 
 static int
-sdb_plugin_cmp_next_update(const sdb_object_t *a, const sdb_object_t *b)
+plugin_cmp_next_update(const sdb_object_t *a, const sdb_object_t *b)
 {
 	const sdb_plugin_collector_cb_t *ccb1
 		= (const sdb_plugin_collector_cb_t *)a;
@@ -175,14 +180,174 @@ sdb_plugin_cmp_next_update(const sdb_object_t *a, const sdb_object_t *b)
 	return (ccb1->ccb_next_update > ccb2->ccb_next_update)
 		? 1 : (ccb1->ccb_next_update < ccb2->ccb_next_update)
 		? -1 : 0;
-} /* sdb_plugin_cmp_next_update */
+} /* plugin_cmp_next_update */
+
+static int
+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);
+
+	/* 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;
+
+	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;
+
+		while (1) {
+			sdb_plugin_cb_t *cb;
+
+			cb = SDB_PLUGIN_CB(sdb_llist_remove(list,
+						plugin_lookup_by_name, 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);
+			sdb_object_deref(SDB_OBJ(cb));
+		}
+	}
+
+	obj = sdb_llist_search_by_name(all_plugins, plugin_name);
+	/* 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 */
+} /* 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
  */
 
 static int
-sdb_plugin_cb_init(sdb_object_t *obj, va_list ap)
+ctx_init(sdb_object_t *obj, va_list __attribute__((unused)) ap)
+{
+	ctx_t *ctx = CTX(obj);
+
+	assert(ctx);
+
+	ctx->public = plugin_default_ctx;
+	ctx->info = plugin_default_info;
+	ctx->handle = NULL;
+	ctx->use_cnt = 1;
+	return 0;
+} /* ctx_init */
+
+static void
+ctx_destroy(sdb_object_t *obj)
+{
+	ctx_t *ctx = CTX(obj);
+
+	if (ctx->handle) {
+		const char *err;
+
+		sdb_log(SDB_LOG_INFO, "core: Unloading module %s",
+				ctx->info.plugin_name);
+
+		lt_dlerror();
+		lt_dlclose(ctx->handle);
+		if ((err = lt_dlerror()))
+			sdb_log(SDB_LOG_WARNING, "core: Failed to unload module %s: %s",
+					ctx->info.plugin_name, err);
+	}
+
+	plugin_info_clear(&ctx->info);
+} /* ctx_destroy */
+
+static sdb_type_t ctx_type = {
+	sizeof(ctx_t),
+
+	ctx_init,
+	ctx_destroy
+};
+
+static ctx_t *
+ctx_get(void)
+{
+	if (! plugin_ctx_key_initialized)
+		ctx_key_init();
+	return pthread_getspecific(plugin_ctx_key);
+} /* ctx_get */
+
+static ctx_t *
+ctx_set(ctx_t *new)
+{
+	ctx_t *old;
+
+	if (! plugin_ctx_key_initialized)
+		ctx_key_init();
+
+	old = pthread_getspecific(plugin_ctx_key);
+	if (old)
+		sdb_object_deref(SDB_OBJ(old));
+	if (new)
+		sdb_object_ref(SDB_OBJ(new));
+	pthread_setspecific(plugin_ctx_key, 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)
 {
 	sdb_llist_t **list = va_arg(ap, sdb_llist_t **);
 	const char   *type = va_arg(ap, const char *);
@@ -194,115 +359,104 @@ sdb_plugin_cb_init(sdb_object_t *obj, va_list ap)
 	assert(obj);
 
 	if (sdb_llist_search_by_name(*list, obj->name)) {
-		sdb_log(SDB_LOG_WARNING, "plugin: %s callback '%s' "
+		sdb_log(SDB_LOG_WARNING, "core: %s callback '%s' "
 				"has already been registered. Ignoring newly "
 				"registered version.", type, obj->name);
 		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      = sdb_plugin_get_ctx();
+	SDB_PLUGIN_CB(obj)->cb_ctx      = ctx_get();
+	sdb_object_ref(SDB_OBJ(SDB_PLUGIN_CB(obj)->cb_ctx));
 
 	sdb_object_ref(ud);
 	SDB_PLUGIN_CB(obj)->cb_user_data = ud;
 	return 0;
-} /* sdb_plugin_cb_init */
+} /* plugin_cb_init */
 
 static void
-sdb_plugin_cb_destroy(sdb_object_t *obj)
+plugin_cb_destroy(sdb_object_t *obj)
 {
 	assert(obj);
 	sdb_object_deref(SDB_PLUGIN_CB(obj)->cb_user_data);
-} /* sdb_plugin_cb_destroy */
+	sdb_object_deref(SDB_OBJ(SDB_PLUGIN_CB(obj)->cb_ctx));
+} /* plugin_cb_destroy */
 
 static sdb_type_t sdb_plugin_cb_type = {
 	sizeof(sdb_plugin_cb_t),
 
-	sdb_plugin_cb_init,
-	sdb_plugin_cb_destroy
+	plugin_cb_init,
+	plugin_cb_destroy
 };
 
 static sdb_type_t sdb_plugin_collector_cb_type = {
 	sizeof(sdb_plugin_collector_cb_t),
 
-	sdb_plugin_cb_init,
-	sdb_plugin_cb_destroy
+	plugin_cb_init,
+	plugin_cb_destroy
 };
 
 static int
-sdb_plugin_add_callback(sdb_llist_t **list, const char *type,
-		const char *name, void *callback, sdb_object_t *user_data)
+module_init(const char *name, lt_dlhandle lh, sdb_plugin_info_t *info)
 {
-	sdb_object_t *obj;
-
-	if ((! name) || (! callback))
-		return -1;
-
-	assert(list);
-
-	if (! *list)
-		*list = sdb_llist_create();
-	if (! *list)
-		return -1;
+	int (*mod_init)(sdb_plugin_info_t *);
+	int status;
 
-	obj = sdb_object_create(name, sdb_plugin_cb_type,
-			list, type, callback, user_data);
-	if (! obj)
+	mod_init = (int (*)(sdb_plugin_info_t *))lt_dlsym(lh, "sdb_module_init");
+	if (! mod_init) {
+		sdb_log(SDB_LOG_ERR, "core: Failed to load plugin '%s': "
+				"could not find symbol 'sdb_module_init'", name);
 		return -1;
+	}
 
-	if (sdb_llist_append(*list, obj)) {
-		sdb_object_deref(obj);
+	status = mod_init(info);
+	if (status) {
+		sdb_log(SDB_LOG_ERR, "core: Failed to initialize "
+				"module '%s'", name);
+		plugin_unregister_by_name(name);
 		return -1;
 	}
-
-	/* pass control to the list */
-	sdb_object_deref(obj);
-
-	sdb_log(SDB_LOG_INFO, "plugin: Registered %s callback '%s'.",
-			type, name);
 	return 0;
-} /* sdb_plugin_add_callback */
+} /* module_init */
 
-/*
- * public API
- */
-
-int
-sdb_plugin_load(const char *name)
+static int
+module_load(const char *basedir, const char *name,
+		const sdb_plugin_ctx_t *plugin_ctx)
 {
-	char  real_name[strlen(name) > 0 ? strlen(name) : 1];
+	char  base_name[name ? strlen(name) + 1 : 1];
 	const char *name_ptr;
 	char *tmp;
 
 	char filename[1024];
-
 	lt_dlhandle lh;
 
-	int (*mod_init)(sdb_plugin_info_t *);
-	sdb_plugin_info_t info = SDB_PLUGIN_INFO_INIT;
+	ctx_t *ctx;
 
 	int status;
 
-	if ((! name) || (! *name))
-		return -1;
+	assert(name);
 
-	real_name[0] = '\0';
+	base_name[0] = '\0';
 	name_ptr = name;
 
 	while ((tmp = strstr(name_ptr, "::"))) {
-		strncat(real_name, name_ptr, (size_t)(tmp - name_ptr));
-		strcat(real_name, "/");
+		strncat(base_name, name_ptr, (size_t)(tmp - name_ptr));
+		strcat(base_name, "/");
 		name_ptr = tmp + strlen("::");
 	}
-	strcat(real_name, name_ptr);
+	strcat(base_name, name_ptr);
+
+	if (! basedir)
+		basedir = PKGLIBDIR;
 
-	snprintf(filename, sizeof(filename), "%s/%s.so",
-			PKGLIBDIR, real_name);
+	snprintf(filename, sizeof(filename), "%s/%s.so", basedir, base_name);
 	filename[sizeof(filename) - 1] = '\0';
 
 	if (access(filename, R_OK)) {
 		char errbuf[1024];
-		sdb_log(SDB_LOG_ERR, "plugin: Failed to load plugin '%s' (%s): %s",
+		sdb_log(SDB_LOG_ERR, "core: Failed to load plugin '%s' (%s): %s",
 				name, filename, sdb_strerror(errno, errbuf, sizeof(errbuf)));
 		return -1;
 	}
@@ -312,44 +466,151 @@ sdb_plugin_load(const char *name)
 
 	lh = lt_dlopen(filename);
 	if (! lh) {
-		sdb_log(SDB_LOG_ERR, "plugin: Failed to load plugin '%s': %s"
+		sdb_log(SDB_LOG_ERR, "core: Failed to load plugin '%s': %s"
 				"The most common cause for this problem are missing "
 				"dependencies.\n", name, lt_dlerror());
 		return -1;
 	}
 
-	mod_init = (int (*)(sdb_plugin_info_t *))lt_dlsym(lh, "sdb_module_init");
-	if (! mod_init) {
-		sdb_log(SDB_LOG_ERR, "plugin: Failed to load plugin '%s': "
-				"could not find symbol 'sdb_module_init'", name);
+	if (ctx_get())
+		sdb_log(SDB_LOG_WARNING, "core: Discarding old plugin context");
+
+	ctx = ctx_create(name);
+	if (! ctx) {
+		sdb_log(SDB_LOG_ERR, "core: Failed to initialize plugin context");
 		return -1;
 	}
 
-	status = mod_init(&info);
-	if (status) {
-		sdb_log(SDB_LOG_ERR, "plugin: Failed to initialize "
-				"plugin '%s'", name);
-		sdb_plugin_info_clear(&info);
-		return -1;
+	ctx->info.plugin_name = strdup(name);
+	ctx->info.filename = strdup(filename);
+	ctx->handle = lh;
+
+	if (plugin_ctx)
+		ctx->public = *plugin_ctx;
+
+	if ((status = module_init(name, lh, &ctx->info))) {
+		sdb_object_deref(SDB_OBJ(ctx));
+		return status;
 	}
 
 	/* compare minor version */
-	if ((info.version < 0)
-			|| ((int)(info.version / 100) != (int)(SDB_VERSION / 100)))
-		sdb_log(SDB_LOG_WARNING, "plugin: WARNING: version of "
+	if ((ctx->info.version < 0)
+			|| ((int)(ctx->info.version / 100) != (int)(SDB_VERSION / 100)))
+		sdb_log(SDB_LOG_WARNING, "core: WARNING: version of "
 				"plugin '%s' (%i.%i.%i) does not match our version "
 				"(%i.%i.%i); this might cause problems",
-				name, SDB_VERSION_DECODE(info.version),
+				name, SDB_VERSION_DECODE(ctx->info.version),
 				SDB_VERSION_DECODE(SDB_VERSION));
 
-	sdb_log(SDB_LOG_INFO, "plugin: Successfully loaded "
-			"plugin '%s' v%i (%s)\n\t%s\n\tLicense: %s",
-			INFO_GET(&info, name), info.plugin_version,
-			INFO_GET(&info, description),
-			INFO_GET(&info, copyright),
-			INFO_GET(&info, license));
-	sdb_plugin_info_clear(&info);
+	sdb_llist_append(all_plugins, SDB_OBJ(ctx));
+
+	sdb_log(SDB_LOG_INFO, "core: Successfully loaded "
+			"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));
+
+	/* any registered callbacks took ownership of the context */
+	sdb_object_deref(SDB_OBJ(ctx));
+
+	/* reset */
+	ctx_set(NULL);
+	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)
+{
+	sdb_object_t *obj;
+
+	if ((! name) || (! callback))
+		return -1;
+
+	assert(list);
+
+	if (! *list)
+		*list = sdb_llist_create();
+	if (! *list)
+		return -1;
+
+	obj = sdb_object_create(name, sdb_plugin_cb_type,
+			list, type, callback, user_data);
+	if (! obj)
+		return -1;
+
+	if (sdb_llist_append(*list, obj)) {
+		sdb_object_deref(obj);
+		return -1;
+	}
+
+	/* pass control to the list */
+	sdb_object_deref(obj);
+
+	sdb_log(SDB_LOG_INFO, "core: Registered %s callback '%s'.",
+			type, name);
 	return 0;
+} /* plugin_add_callback */
+
+/*
+ * public API
+ */
+
+int
+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;
+
+	if (! all_plugins) {
+		if (! (all_plugins = sdb_llist_create())) {
+			sdb_log(SDB_LOG_ERR, "core: Failed to load plugin '%s': "
+					"internal error while creating linked list", name);
+			return -1;
+		}
+	}
+
+	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(basedir, name, plugin_ctx);
 } /* sdb_plugin_load */
 
 int
@@ -363,16 +624,6 @@ 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 *);
@@ -422,48 +673,64 @@ 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 sdb_plugin_add_callback(&config_list, "init", name,
-			callback, NULL);
+	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 */
 
 int
 sdb_plugin_register_init(const char *name, sdb_plugin_init_cb callback,
 		sdb_object_t *user_data)
 {
-	return sdb_plugin_add_callback(&init_list, "init", name,
-			callback, user_data);
+	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 */
 
 int
 sdb_plugin_register_shutdown(const char *name, sdb_plugin_shutdown_cb callback,
 		sdb_object_t *user_data)
 {
-	return sdb_plugin_add_callback(&shutdown_list, "shutdown", name,
-			callback, user_data);
+	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 */
 
 int
 sdb_plugin_register_log(const char *name, sdb_plugin_log_cb callback,
 		sdb_object_t *user_data)
 {
-	return sdb_plugin_add_callback(&log_list, "log", name, 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 sdb_plugin_add_callback(&cname_list, "cname", name, 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))
@@ -474,7 +741,9 @@ 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;
@@ -492,14 +761,14 @@ sdb_plugin_register_collector(const char *name, sdb_plugin_collector_cb callback
 
 	if (! (SDB_PLUGIN_CCB(obj)->ccb_next_update = sdb_gettime())) {
 		char errbuf[1024];
-		sdb_log(SDB_LOG_ERR, "plugin: Failed to determine current "
+		sdb_log(SDB_LOG_ERR, "core: Failed to determine current "
 				"time: %s", sdb_strerror(errno, errbuf, sizeof(errbuf)));
 		sdb_object_deref(obj);
 		return -1;
 	}
 
 	if (sdb_llist_insert_sorted(collector_list, obj,
-				sdb_plugin_cmp_next_update)) {
+				plugin_cmp_next_update)) {
 		sdb_object_deref(obj);
 		return -1;
 	}
@@ -507,8 +776,8 @@ sdb_plugin_register_collector(const char *name, sdb_plugin_collector_cb callback
 	/* pass control to the list */
 	sdb_object_deref(obj);
 
-	sdb_log(SDB_LOG_INFO, "plugin: Registered collector callback '%s' "
-			"(interval = %.3fs).", name,
+	sdb_log(SDB_LOG_INFO, "core: Registered collector callback '%s' "
+			"(interval = %.3fs).", cb_name,
 			SDB_TIME_TO_DOUBLE(SDB_PLUGIN_CCB(obj)->ccb_interval));
 	return 0;
 } /* sdb_plugin_register_collector */
@@ -516,37 +785,33 @@ sdb_plugin_register_collector(const char *name, sdb_plugin_collector_cb callback
 sdb_plugin_ctx_t
 sdb_plugin_get_ctx(void)
 {
-	sdb_plugin_ctx_t *ctx;
+	ctx_t *c;
 
-	if (! plugin_ctx_key_initialized)
-		sdb_plugin_ctx_init();
-	ctx = pthread_getspecific(plugin_ctx_key);
-
-	if (! ctx)
-		ctx = sdb_plugin_ctx_create();
-	if (! ctx)
+	c = ctx_get();
+	if (! c) {
+		sdb_plugin_log(SDB_LOG_ERR, "core: Invalid read access to plugin "
+				"context outside a plugin");
 		return plugin_default_ctx;
-	return *ctx;
+	}
+	return c->public;
 } /* sdb_plugin_get_ctx */
 
-sdb_plugin_ctx_t
-sdb_plugin_set_ctx(sdb_plugin_ctx_t ctx)
+int
+sdb_plugin_set_ctx(sdb_plugin_ctx_t ctx, sdb_plugin_ctx_t *old)
 {
-	sdb_plugin_ctx_t *tmp;
-	sdb_plugin_ctx_t old;
-
-	if (! plugin_ctx_key_initialized)
-		sdb_plugin_ctx_init();
-	tmp = pthread_getspecific(plugin_ctx_key);
+	ctx_t *c;
 
-	if (! tmp)
-		tmp = sdb_plugin_ctx_create();
-	if (! tmp)
-		return plugin_default_ctx;
+	c = ctx_get();
+	if (! c) {
+		sdb_plugin_log(SDB_LOG_ERR, "core: Invalid write access to plugin "
+				"context outside a plugin");
+		return -1;
+	}
 
-	old = *tmp;
-	*tmp = ctx;
-	return old;
+	if (old)
+		*old = c->public;
+	c->public = ctx;
+	return 0;
 } /* sdb_plugin_set_ctx */
 
 int
@@ -555,7 +820,7 @@ sdb_plugin_configure(const char *name, oconfig_item_t *ci)
 	sdb_plugin_cb_t *plugin;
 	sdb_plugin_config_cb callback;
 
-	sdb_plugin_ctx_t old_ctx;
+	ctx_t *old_ctx;
 
 	int status;
 
@@ -564,50 +829,153 @@ sdb_plugin_configure(const char *name, oconfig_item_t *ci)
 
 	plugin = SDB_PLUGIN_CB(sdb_llist_search_by_name(config_list, name));
 	if (! plugin) {
-		/* XXX: check if any such plugin has been loaded */
-		sdb_log(SDB_LOG_ERR, "plugin: Plugin '%s' did not register "
-				"a config callback.", name);
+		ctx_t *ctx = CTX(sdb_llist_search_by_name(all_plugins, name));
+		if (! ctx)
+			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);
 		errno = ENOENT;
 		return -1;
 	}
 
-	old_ctx = sdb_plugin_set_ctx(plugin->cb_ctx);
-	callback = plugin->cb_callback;
+	old_ctx = ctx_set(plugin->cb_ctx);
+	callback = (sdb_plugin_config_cb)plugin->cb_callback;
 	status = callback(ci);
-	sdb_plugin_set_ctx(old_ctx);
+	ctx_set(old_ctx);
 	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)
 {
 	sdb_llist_iter_t *iter;
+	int ret = 0;
 
 	iter = sdb_llist_get_iter(init_list);
 	while (sdb_llist_iter_has_next(iter)) {
+		sdb_plugin_cb_t *cb;
 		sdb_plugin_init_cb callback;
-		sdb_plugin_ctx_t old_ctx;
+		ctx_t *old_ctx;
 
 		sdb_object_t *obj = sdb_llist_iter_get_next(iter);
 		assert(obj);
+		cb = SDB_PLUGIN_CB(obj);
 
-		callback = SDB_PLUGIN_CB(obj)->cb_callback;
+		callback = (sdb_plugin_init_cb)cb->cb_callback;
 
-		old_ctx = sdb_plugin_set_ctx(SDB_PLUGIN_CB(obj)->cb_ctx);
-		if (callback(SDB_PLUGIN_CB(obj)->cb_user_data)) {
-			/* XXX: unload plugin */
+		old_ctx = ctx_set(cb->cb_ctx);
+		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;
 		}
-		sdb_plugin_set_ctx(old_ctx);
+		else
+			ctx_set(old_ctx);
 	}
 	sdb_llist_iter_destroy(iter);
-	return 0;
+	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)
 {
 	if (! collector_list) {
-		sdb_log(SDB_LOG_WARNING, "plugin: No collectors registered. "
+		sdb_log(SDB_LOG_WARNING, "core: No collectors registered. "
 				"Quiting main loop.");
 		return -1;
 	}
@@ -617,7 +985,7 @@ sdb_plugin_collector_loop(sdb_plugin_loop_t *loop)
 
 	while (loop->do_loop) {
 		sdb_plugin_collector_cb callback;
-		sdb_plugin_ctx_t old_ctx;
+		ctx_t *old_ctx;
 
 		sdb_time_t interval, now;
 
@@ -625,12 +993,13 @@ sdb_plugin_collector_loop(sdb_plugin_loop_t *loop)
 		if (! obj)
 			return -1;
 
-		callback = SDB_PLUGIN_CCB(obj)->ccb_callback;
+		callback = (sdb_plugin_collector_cb)SDB_PLUGIN_CCB(obj)->ccb_callback;
 
 		if (! (now = sdb_gettime())) {
 			char errbuf[1024];
-			sdb_log(SDB_LOG_ERR, "plugin: Failed to determine current "
-					"time: %s", sdb_strerror(errno, errbuf, sizeof(errbuf)));
+			sdb_log(SDB_LOG_ERR, "core: Failed to determine current "
+					"time in collector main loop: %s",
+					sdb_strerror(errno, errbuf, sizeof(errbuf)));
 			now = SDB_PLUGIN_CCB(obj)->ccb_next_update;
 		}
 
@@ -641,28 +1010,37 @@ sdb_plugin_collector_loop(sdb_plugin_loop_t *loop)
 			while (loop->do_loop && sdb_sleep(interval, &interval)) {
 				if (errno != EINTR) {
 					char errbuf[1024];
-					sdb_log(SDB_LOG_ERR, "plugin: Failed to sleep: %s",
+					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 = sdb_plugin_set_ctx(SDB_PLUGIN_CCB(obj)->ccb_ctx);
+		old_ctx = ctx_set(SDB_PLUGIN_CCB(obj)->ccb_ctx);
 		if (callback(SDB_PLUGIN_CCB(obj)->ccb_user_data)) {
 			/* XXX */
 		}
-		sdb_plugin_set_ctx(old_ctx);
+		ctx_set(old_ctx);
 
 		interval = SDB_PLUGIN_CCB(obj)->ccb_interval;
 		if (! interval)
 			interval = loop->default_interval;
 		if (! interval) {
-			sdb_log(SDB_LOG_WARNING, "plugin: No interval configured "
+			sdb_log(SDB_LOG_WARNING, "core: No interval configured "
 					"for plugin '%s'; skipping any further "
 					"iterations.", obj->name);
 			sdb_object_deref(obj);
@@ -673,21 +1051,22 @@ sdb_plugin_collector_loop(sdb_plugin_loop_t *loop)
 
 		if (! (now = sdb_gettime())) {
 			char errbuf[1024];
-			sdb_log(SDB_LOG_ERR, "plugin: Failed to determine current "
-					"time: %s", sdb_strerror(errno, errbuf, sizeof(errbuf)));
+			sdb_log(SDB_LOG_ERR, "core: Failed to determine current "
+					"time in collector main loop: %s",
+					sdb_strerror(errno, errbuf, sizeof(errbuf)));
 			now = SDB_PLUGIN_CCB(obj)->ccb_next_update;
 		}
 
 		if (now > SDB_PLUGIN_CCB(obj)->ccb_next_update) {
-			sdb_log(SDB_LOG_WARNING, "plugin: Plugin '%s' took too "
+			sdb_log(SDB_LOG_WARNING, "core: Plugin '%s' took too "
 					"long; skipping iterations to keep up.",
 					obj->name);
 			SDB_PLUGIN_CCB(obj)->ccb_next_update = now;
 		}
 
 		if (sdb_llist_insert_sorted(collector_list, obj,
-					sdb_plugin_cmp_next_update)) {
-			sdb_log(SDB_LOG_ERR, "plugin: Failed to re-insert "
+					plugin_cmp_next_update)) {
+			sdb_log(SDB_LOG_ERR, "core: Failed to re-insert "
 					"plugin '%s' into collector list. Unable to further "
 					"use the plugin.",
 					obj->name);
@@ -720,7 +1099,7 @@ sdb_plugin_cname(char *hostname)
 		sdb_object_t *obj = sdb_llist_iter_get_next(iter);
 		assert(obj);
 
-		callback = SDB_PLUGIN_CB(obj)->cb_callback;
+		callback = (sdb_plugin_cname_cb)SDB_PLUGIN_CB(obj)->cb_callback;
 		cname = callback(hostname, SDB_PLUGIN_CB(obj)->cb_user_data);
 		if (cname) {
 			free(hostname);
@@ -738,12 +1117,11 @@ 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;
@@ -752,12 +1130,19 @@ sdb_plugin_log(int prio, const char *msg)
 		sdb_object_t *obj = sdb_llist_iter_get_next(iter);
 		assert(obj);
 
-		callback = SDB_PLUGIN_CB(obj)->cb_callback;
+		callback = (sdb_plugin_log_cb)SDB_PLUGIN_CB(obj)->cb_callback;
 		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 */