module: create new API with dynamic loading support

Knot.files

@@ -177,6 +177,8 @@ src/knot/conf/confio.c
 src/knot/conf/confio.h
 src/knot/conf/migration.c
 src/knot/conf/migration.h
+src/knot/conf/module.c
+src/knot/conf/module.h
 src/knot/conf/scheme.c
 src/knot/conf/scheme.h
 src/knot/conf/tools.c

src/Makefile.am

@@ -241,6 +241,8 @@ libknotd_la_SOURCES =				\
 	knot/conf/confio.h			\
 	knot/conf/migration.c			\
 	knot/conf/migration.h			\
+	knot/conf/module.h			\
+	knot/conf/module.c			\
 	knot/conf/scheme.c			\
 	knot/conf/scheme.h			\
 	knot/conf/tools.c			\
@@ -424,6 +426,10 @@ if HAVE_DAEMON
 sbin_PROGRAMS = knotc knotd keymgr
 noinst_LTLIBRARIES += libknotd.la libknotus.la
 
+knotddir = $(includedir)/knot
+knotd_HEADERS =					\
+	knot/include/module.h
+
 knotc_SOURCES =					\
 	utils/knotc/commands.c			\
 	utils/knotc/commands.h			\

src/knot/common/stats.c

@@ -79,7 +79,7 @@ static void dump_counters(FILE *fd, int level, mod_ctr_t *ctr)
 static void dump_modules(dump_ctx_t *ctx)
 {
 	int level = 0;
-	struct query_module *mod = NULL;
+	knotd_mod_t *mod = NULL;
 	WALK_LIST(mod, *ctx->query_modules) {
 		// Skip modules without statistics.
 		if (mod->stats_count == 0) {

src/knot/conf/base.c

@@ -18,6 +18,7 @@
 
 #include "knot/conf/base.h"
 #include "knot/conf/confdb.h"
+#include "knot/conf/module.h"
 #include "knot/conf/tools.h"
 #include "knot/common/log.h"
 #include "knot/nameserver/query_module.h"
@@ -232,6 +233,27 @@ int conf_new(
 	// Initialize cached values.
 	init_cache(out);
 
+	// Load module schemas.
+	if (flags & (CONF_FREQMODULES | CONF_FOPTMODULES)) {
+		ret = conf_mod_load_common(out);
+		if (ret != KNOT_EOK && (flags & CONF_FREQMODULES)) {
+			goto new_error;
+		}
+
+		for (conf_iter_t iter = conf_iter(out, C_MODULE);
+		     iter.code == KNOT_EOK; conf_iter_next(out, &iter)) {
+			conf_val_t id = conf_iter_id(out, &iter);
+			conf_val_t file = conf_id_get(out, C_MODULE, C_FILE, &id);
+			ret = conf_mod_load_extra(out, conf_str(&id), conf_str(&file), false);
+			if (ret != KNOT_EOK && (flags & CONF_FREQMODULES)) {
+				conf_iter_finish(out, &iter);
+				goto new_error;
+			}
+		}
+
+		conf_mod_load_purge(out, false);
+	}
+
 	*conf = out;
 
 	return KNOT_EOK;
@@ -297,7 +319,7 @@ int conf_clone(
 	return KNOT_EOK;
 }
 
-void conf_update(
+conf_t *conf_update(
 	conf_t *conf,
 	conf_update_flag_t flags)
 {
@@ -311,7 +333,7 @@ void conf_update(
 		}
 		if ((flags & CONF_UPD_FMODULES) && s_conf != NULL) {
 			list_dup(&conf->query_modules, &s_conf->query_modules,
-			         sizeof(struct query_module));
+			         sizeof(knotd_mod_t));
 			conf->query_plan = s_conf->query_plan;
 		}
 	}
@@ -332,9 +354,13 @@ void conf_update(
 			WALK_LIST_FREE(old_conf->query_modules);
 			old_conf->query_plan = NULL;
 		}
-
-		conf_free(old_conf);
+		if (!(flags & CONF_UPD_FNOFREE)) {
+			conf_free(old_conf);
+			old_conf = NULL;
+		}
 	}
+
+	return old_conf;
 }
 
 void conf_free(
@@ -359,7 +385,9 @@ void conf_free(
 		mm_free(conf->mm, conf->io.zones);
 	}
 
+	conf_mod_load_purge(conf, false);
 	conf_deactivate_modules(&conf->query_modules, &conf->query_plan);
+	conf_mod_unload_shared(conf);
 
 	if (!conf->is_clone) {
 		if (conf->api != NULL) {
@@ -374,126 +402,6 @@ void conf_free(
 	free(conf);
 }
 
-#define LOG_ARGS(mod_id, msg, ...) "module '%s%s%.*s', " msg, \
-	mod_id->name + 1, (mod_id->len > 0) ? "/" : "", (int)mod_id->len, \
-	mod_id->data
-
-void conf_activate_modules(
-	conf_t *conf,
-	const knot_dname_t *zone_name,
-	list_t *query_modules,
-	struct query_plan **query_plan)
-{
-	int ret = KNOT_EOK;
-
-	if (conf == NULL || query_modules == NULL || query_plan == NULL) {
-		ret = KNOT_EINVAL;
-		goto activate_error;
-	}
-
-	conf_val_t val;
-
-	// Get list of associated modules.
-	if (zone_name != NULL) {
-		val = conf_zone_get(conf, C_MODULE, zone_name);
-	} else {
-		val = conf_default_get(conf, C_GLOBAL_MODULE);
-	}
-
-	switch (val.code) {
-	case KNOT_EOK:
-		break;
-	case KNOT_ENOENT: // Check if a module is configured at all.
-	case KNOT_YP_EINVAL_ID:
-		return;
-	default:
-		ret = val.code;
-		goto activate_error;
-	}
-
-	// Create query plan.
-	*query_plan = query_plan_create(conf->mm);
-	if (*query_plan == NULL) {
-		ret = KNOT_ENOMEM;
-		goto activate_error;
-	}
-
-	// Initialize query modules list.
-	init_list(query_modules);
-
-	// Open the modules.
-	while (val.code == KNOT_EOK) {
-		conf_mod_id_t *mod_id = conf_mod_id(&val);
-		if (mod_id == NULL) {
-			ret = KNOT_ENOMEM;
-			goto activate_error;
-		}
-
-		// Open the module.
-		struct query_module *mod = query_module_open(conf, mod_id, *query_plan,
-		                                             zone_name, conf->mm);
-		if (mod == NULL) {
-			ret = KNOT_ENOMEM;
-			goto activate_error;
-		}
-
-		// Check the module scope.
-		if ((zone_name == NULL && (mod->scope & MOD_SCOPE_GLOBAL) == 0) ||
-		    (zone_name != NULL && (mod->scope & MOD_SCOPE_ZONE) == 0)) {
-			if (zone_name != NULL) {
-				log_zone_warning(zone_name, LOG_ARGS(mod_id, "out of scope"));
-			} else {
-				log_warning(LOG_ARGS(mod_id, "out of scope"));
-			}
-			query_module_close(mod);
-			conf_val_next(&val);
-			continue;
-		}
-
-		// Load the module.
-		ret = mod->load(mod);
-		if (ret != KNOT_EOK) {
-			if (zone_name != NULL) {
-				log_zone_error(zone_name, LOG_ARGS(mod_id, "failed to load"));
-			} else {
-				log_error(LOG_ARGS(mod_id, "failed to load"));
-			}
-			query_module_close(mod);
-			conf_val_next(&val);
-			continue;
-		}
-
-		add_tail(query_modules, &mod->node);
-
-		conf_val_next(&val);
-	}
-
-	return;
-activate_error:
-	CONF_LOG(LOG_ERR, "failed to activate modules (%s)", knot_strerror(ret));
-}
-
-void conf_deactivate_modules(
-	list_t *query_modules,
-	struct query_plan **query_plan)
-{
-	if (query_modules == NULL || query_plan == NULL) {
-		return;
-	}
-
-	// Free query plan.
-	query_plan_free(*query_plan);
-	*query_plan = NULL;
-
-	// Free query modules list.
-	struct query_module *mod = NULL, *next = NULL;
-	WALK_LIST_DELSAFE(mod, next, *query_modules) {
-		mod->unload(mod);
-		query_module_close(mod);
-	}
-	init_list(query_modules);
-}
-
 #define CONF_LOG_LINE(file, line, msg, ...) do { \
 	CONF_LOG(LOG_ERR, "%s%s%sline %zu, " msg, \
 	         (file != NULL ? "file '" : ""), (file != NULL ? file : ""), \
@@ -513,17 +421,17 @@ static void log_parser_err(
 
 static void log_call_err(
 	yp_parser_t *parser,
-	conf_check_t *args,
+	knotd_conf_check_args_t *args,
 	int ret)
 {
-	CONF_LOG_LINE(args->file_name, args->line,
+	CONF_LOG_LINE(args->extra->file_name, args->extra->line,
 	              "item '%s', value '%.*s' (%s)", args->item->name + 1,
 	              (int)parser->data_len, parser->data,
 	              args->err_str != NULL ? args->err_str : knot_strerror(ret));
 }
 
 static void log_prev_err(
-	conf_check_t *args,
+	knotd_conf_check_args_t *args,
 	int ret)
 {
 	char buff[512] = { 0 };
@@ -537,7 +445,7 @@ static void log_prev_err(
 		}
 	}
 
-	CONF_LOG_LINE(args->file_name, args->line,
+	CONF_LOG_LINE(args->extra->file_name, args->extra->line,
 	              "%s '%s' (%s)", args->item->name + 1, buff,
 	              args->err_str != NULL ? args->err_str : knot_strerror(ret));
 }
@@ -556,14 +464,17 @@ static int finalize_previous_section(
 		return KNOT_EOK;
 	}
 
-	conf_check_t args = {
+	knotd_conf_check_extra_t extra = {
 		.conf = conf,
 		.txn = txn,
+		.file_name = parser->file.name,
+		.line = parser->line_count
+	};
+	knotd_conf_check_args_t args = {
 		.item = node->item,
 		.id = node->id,
 		.id_len = node->id_len,
-		.file_name = parser->file.name,
-		.line = parser->line_count
+		.extra = &extra
 	};
 
 	int ret = conf_exec_callbacks(&args);
@@ -587,16 +498,19 @@ static int finalize_item(
 		return KNOT_EOK;
 	}
 
-	conf_check_t args = {
+	knotd_conf_check_extra_t extra = {
 		.conf = conf,
 		.txn = txn,
+		.file_name = parser->file.name,
+		.line = parser->line_count
+	};
+	knotd_conf_check_args_t args = {
 		.item = (parser->event == YP_EID) ? node->item->var.g.id : node->item,
 		.id = node->id,
 		.id_len = node->id_len,
 		.data = node->data,
 		.data_len = node->data_len,
-		.file_name = parser->file.name,
-		.line = parser->line_count
+		.extra = &extra
 	};
 
 	int ret = conf_exec_callbacks(&args);
@@ -693,6 +607,7 @@ int conf_parse(
 		ret = check_ret;
 	}
 
+	conf_mod_load_purge(conf, false);
 	yp_scheme_check_deinit(ctx);
 parse_error:
 	yp_deinit(parser);

src/knot/conf/base.h

@@ -29,6 +29,8 @@
 #include "libknot/yparser/ypscheme.h"
 #include "contrib/qp-trie/trie.h"
 #include "contrib/ucw/lists.h"
+#include "contrib/dynarray.h"
+#include "knot/include/module.h"
 
 /*! Default template identifier. */
 #define CONF_DEFAULT_ID		((uint8_t *)"\x08""default\0")
@@ -67,6 +69,19 @@ typedef struct {
 	int code;
 } conf_val_t;
 
+/*! Query module context. */
+typedef struct {
+	/*! Module interface. */
+	const knotd_mod_api_t *api;
+	/*! Shared library dlopen handler. */
+	void *lib_handle;
+	/*! Indication of a temporary module created during confio check. */
+	bool temporary;
+} module_t;
+
+dynarray_declare(mod, module_t *, DYNARRAY_VISIBILITY_PUBLIC, 16)
+dynarray_declare(old_schema, yp_item_t *, DYNARRAY_VISIBILITY_PUBLIC, 16)
+
 /*! Configuration context. */
 typedef struct {
 	/*! Cloned configuration indicator. */
@@ -112,6 +127,10 @@ typedef struct {
 		conf_val_t srv_nsid;
 	} cache;
 
+	/*! List of dynamically loaded modules. */
+	mod_dynarray_t modules;
+	/*! List of old schemas (lazy freed). */
+	old_schema_dynarray_t old_schemas;
 	/*! List of active query modules. */
 	list_t query_modules;
 	/*! Default query modules plan. */
@@ -122,10 +141,12 @@ typedef struct {
  * Configuration access flags.
  */
 typedef enum {
-	CONF_FNONE        = 0,      /*!< Empty flag. */
-	CONF_FREADONLY    = 1 << 0, /*!< Read only access. */
-	CONF_FNOCHECK     = 1 << 1, /*!< Disabled confdb check. */
-	CONF_FNOHOSTNAME  = 1 << 2, /*!< Don't set the hostname. */
+	CONF_FNONE       = 0,      /*!< Empty flag. */
+	CONF_FREADONLY   = 1 << 0, /*!< Read only access. */
+	CONF_FNOCHECK    = 1 << 1, /*!< Disabled confdb check. */
+	CONF_FNOHOSTNAME = 1 << 2, /*!< Don't set the hostname. */
+	CONF_FREQMODULES = 1 << 3, /*!< Load module schemas (must succeed). */
+	CONF_FOPTMODULES = 1 << 4, /*!< Load module schemas (may fail). */
 } conf_flag_t;
 
 /*!
@@ -133,8 +154,9 @@ typedef enum {
  */
 typedef enum {
 	CONF_UPD_FNONE    = 0,      /*!< Empty flag. */
-	CONF_UPD_FMODULES = 1 << 0, /*!< Reuse previous global modules. */
-	CONF_UPD_FCONFIO  = 1 << 1, /*!< Reuse previous cofio reload context. */
+	CONF_UPD_FNOFREE  = 1 << 0, /*!< Disable auto-free of previous config. */
+	CONF_UPD_FMODULES = 1 << 1, /*!< Reuse previous global modules. */
+	CONF_UPD_FCONFIO  = 1 << 2, /*!< Reuse previous cofio reload context. */
 } conf_update_flag_t;
 
 /*!
@@ -197,8 +219,10 @@ int conf_clone(
  *
  * \param[in] conf   New configuration.
  * \param[in] flags  Update flags.
+ *
+ * \return Previous config if CONF_UPD_FNOFREE, else NULL.
  */
-void conf_update(
+conf_t *conf_update(
 	conf_t *conf,
 	conf_update_flag_t flags
 );
@@ -212,32 +236,6 @@ void conf_free(
 	conf_t *conf
 );
 
-/*!
- * Activates configured query modules for the specified zone or for all zones.
- *
- * \param[in] conf           Configuration.
- * \param[in] zone_name      Zone name, NULL for all zones.
- * \param[in] query_modules  Destination query modules list.
- * \param[in] query_plan     Destination query plan.
- */
-void conf_activate_modules(
-	conf_t *conf,
-	const knot_dname_t *zone_name,
-	list_t *query_modules,
-	struct query_plan **query_plan
-);
-
-/*!
- * Deactivates query modules list.
- *
- * \param[in] query_modules  Destination query modules list.
- * \param[in] query_plan     Destination query plan.
- */
-void conf_deactivate_modules(
-	list_t *query_modules,
-	struct query_plan **query_plan
-);
-
 /*!
  * Parses textual configuration from the string or from the file.
  *

src/knot/conf/confio.c

@@ -16,8 +16,10 @@
 
 #include <assert.h>
 
+#include "knot/common/log.h"
 #include "knot/conf/confdb.h"
 #include "knot/conf/confio.h"
+#include "knot/conf/module.h"
 #include "knot/conf/tools.h"
 
 #define FCN(io)	(io->fcn != NULL) ? io->fcn(io) : KNOT_EOK;
@@ -878,20 +880,32 @@ static int set_item(
 	}
 
 	// Postpone group callbacks to config check.
-	if (io->key0->type == YP_TGRP) {
+	if (io->key0->type == YP_TGRP && io->id_len == 0) {
 		return KNOT_EOK;
 	}
 
-	conf_check_t args = {
+	knotd_conf_check_extra_t extra = {
 		.conf = conf(),
-		.txn = conf()->io.txn,
-		.item = (io->key1 != NULL) ? io->key1 : io->key0,
+		.txn = conf()->io.txn
+	};
+	knotd_conf_check_args_t args = {
+		.item = (io->key1 != NULL) ? io->key1 :
+		         ((io->id_len == 0) ? io->key0 : io->key0->var.g.id),
+		.id = io->id,
+		.id_len = io->id_len,
 		.data = io->data.bin,
-		.data_len = io->data.bin_len
+		.data_len = io->data.bin_len,
+		.extra = &extra
 	};
 
-	// Call the item callbacks (include).
-	return conf_exec_callbacks(&args);
+	// Call the item callbacks (include, item check, mod-id check).
+	ret = conf_exec_callbacks(&args);
+	if (ret != KNOT_EOK) {
+		CONF_LOG(LOG_DEBUG, "item '%s' (%s)", args.item->name + 1,
+		         args.err_str != NULL ? args.err_str : knot_strerror(ret));
+	}
+
+	return ret;
 }
 
 int conf_io_set(
@@ -1276,11 +1290,15 @@ static int check_section(
 	size_t id_len,
 	conf_io_t *io)
 {
-	conf_check_t args = {
+	knotd_conf_check_extra_t extra = {
 		.conf = conf(),
 		.txn = conf()->io.txn,
+		.check = true
+	};
+	knotd_conf_check_args_t args = {
 		.id = id,
-		.id_len = id_len
+		.id_len = id_len,
+		.extra = &extra
 	};
 
 	bool non_empty = false;
@@ -1482,6 +1500,7 @@ int conf_io_check(
 
 	ret = KNOT_EOK;
 check_error:
+	conf_mod_load_purge(conf(), true);
 
 	return ret;
 }

src/knot/conf/module.c

+/*  Copyright (C) 2017 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <dlfcn.h>
+#include <glob.h>
+#include <sys/stat.h>
+#include <urcu.h>
+
+#include "knot/conf/conf.h"
+#include "knot/conf/confio.h"
+#include "knot/conf/module.h"
+#include "knot/common/log.h"
+#include "knot/modules/static_modules.h"
+#include "knot/nameserver/query_module.h"
+#include "contrib/openbsd/strlcat.h"
+#include "contrib/string.h"
+
+#define LIB_EXTENSION ".so"
+
+dynarray_define(mod, module_t *, DYNARRAY_VISIBILITY_PUBLIC, 16)
+dynarray_define(old_schema, yp_item_t *, DYNARRAY_VISIBILITY_PUBLIC, 16)
+
+static module_t STATIC_MODULES[] = {
+	STATIC_MODULES_INIT
+	{ NULL }
+};
+
+module_t *conf_mod_find(
+	conf_t *conf,
+	const char *name,
+	size_t len,
+	bool temporary)
+{
+	if (conf == NULL || name == NULL) {
+		return NULL;
+	}
+
+	// First, search in static modules.
+	for (module_t *mod = STATIC_MODULES; mod->api != NULL; mod++) {
+		if (strncmp(name, mod->api->name, len) == 0) {
+			return mod;
+		}
+	}
+
+	// Second, search in dynamic modules.
+	dynarray_foreach(mod, module_t *, module, conf->modules) {
+		if ((*module) != NULL && (*module)->temporary == temporary &&
+		    strncmp(name, (*module)->api->name, len) == 0) {
+			return (*module);
+		}
+	}
+
+	return NULL;
+}
+
+static int mod_load(
+	conf_t *conf,
+	module_t *mod)
+{
+	static const yp_item_t module_common[] = {
+		{ C_ID,      YP_TSTR,  YP_VNONE, CONF_IO_FREF },
+		{ C_COMMENT, YP_TSTR,  YP_VNONE },
+		{ NULL }
+	};
+
+	yp_item_t *sub_items = NULL;
+
+	int ret;
+	if (mod->api->config != NULL) {
+		ret = yp_scheme_merge(&sub_items, module_common, mod->api->config);
+	} else {
+		ret = yp_scheme_copy(&sub_items, module_common);
+	}
+	if (ret != KNOT_EOK) {
+		return ret;
+	}
+
+	/* Synthesise module config section name. */
+	const size_t name_len = strlen(mod->api->name);
+	if (name_len > YP_MAX_ITEM_NAME_LEN) {
+		return KNOT_YP_EINVAL_ITEM;
+	}
+	char name[1 + YP_MAX_ITEM_NAME_LEN + 1];
+	name[0] = name_len;
+	memcpy(name + 1, mod->api->name, name_len + 1);
+
+	const yp_item_t scheme[] = {
+		{ name, YP_TGRP, YP_VGRP = { sub_items },
+		        YP_FALLOC | YP_FMULTI | CONF_IO_FRLD_MOD | CONF_IO_FRLD_ZONES },
+		{ NULL }
+	};
+
+	yp_item_t *merged = NULL;
+	ret = yp_scheme_merge(&merged, conf->scheme, scheme);
+	yp_scheme_free(sub_items);
+	if (ret != KNOT_EOK) {
+		return ret;
+	}
+
+	// Update configuration schema (with lazy free).
+	yp_item_t **current_schema = &conf->scheme;
+	yp_item_t *old_schema = rcu_xchg_pointer(current_schema, merged);
+	synchronize_rcu();
+	old_schema_dynarray_add(&conf->old_schemas, &old_schema);
+
+	return KNOT_EOK;
+}
+
+int conf_mod_load_common(
+	conf_t *conf)
+{
+	if (conf == NULL) {
+		return KNOT_EINVAL;
+	}
+
+	int ret = KNOT_EOK;
+