1 files changed, 544 insertions, 0 deletions
diff --git a/lib/ns/hooks.c b/lib/ns/hooks.c
new file mode 100644
index 0000000..1b8b8d0
--- /dev/null
+++ b/lib/ns/hooks.c
@@ -0,0 +1,544 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+/*! \file */
+
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+#if HAVE_DLFCN_H
+#include <dlfcn.h>
+#elif _WIN32
+#include <windows.h>
+#endif /* if HAVE_DLFCN_H */
+
+#include <isc/errno.h>
+#include <isc/list.h>
+#include <isc/log.h>
+#include <isc/mem.h>
+#include <isc/mutex.h>
+#include <isc/platform.h>
+#include <isc/print.h>
+#include <isc/result.h>
+#include <isc/types.h>
+#include <isc/util.h>
+
+#include <dns/view.h>
+
+#include <ns/hooks.h>
+#include <ns/log.h>
+#include <ns/query.h>
+
+#define CHECK(op)                              \
+	do {                                   \
+		result = (op);                 \
+		if (result != ISC_R_SUCCESS) { \
+			goto cleanup;          \
+		}                              \
+	} while (0)
+
+struct ns_plugin {
+	isc_mem_t *mctx;
+	void *handle;
+	void *inst;
+	char *modpath;
+	ns_plugin_check_t *check_func;
+	ns_plugin_register_t *register_func;
+	ns_plugin_destroy_t *destroy_func;
+	LINK(ns_plugin_t) link;
+};
+
+static ns_hooklist_t default_hooktable[NS_HOOKPOINTS_COUNT];
+LIBNS_EXTERNAL_DATA ns_hooktable_t *ns__hook_table = &default_hooktable;
+
+isc_result_t
+ns_plugin_expandpath(const char *src, char *dst, size_t dstsize) {
+	int result;
+
+#ifndef WIN32
+	/*
+	 * On Unix systems, differentiate between paths and filenames.
+	 */
+	if (strchr(src, '/') != NULL) {
+		/*
+		 * 'src' is an absolute or relative path.  Copy it verbatim.
+		 */
+		result = snprintf(dst, dstsize, "%s", src);
+	} else {
+		/*
+		 * 'src' is a filename.  Prepend default plugin directory path.
+		 */
+		result = snprintf(dst, dstsize, "%s/%s", NAMED_PLUGINDIR, src);
+	}
+#else  /* ifndef WIN32 */
+	/*
+	 * On Windows, always copy 'src' do 'dst'.
+	 */
+	result = snprintf(dst, dstsize, "%s", src);
+#endif /* ifndef WIN32 */
+
+	if (result < 0) {
+		return (isc_errno_toresult(errno));
+	} else if ((size_t)result >= dstsize) {
+		return (ISC_R_NOSPACE);
+	} else {
+		return (ISC_R_SUCCESS);
+	}
+}
+
+#if HAVE_DLFCN_H && HAVE_DLOPEN
+static isc_result_t
+load_symbol(void *handle, const char *modpath, const char *symbol_name,
+	    void **symbolp) {
+	void *symbol = NULL;
+
+	REQUIRE(handle != NULL);
+	REQUIRE(symbolp != NULL && *symbolp == NULL);
+
+	/*
+	 * Clear any pre-existing error conditions before running dlsym().
+	 * (In this case, we expect dlsym() to return non-NULL values
+	 * and will always return an error if it returns NULL, but
+	 * this ensures that we'll report the correct error condition
+	 * if there is one.)
+	 */
+	dlerror();
+	symbol = dlsym(handle, symbol_name);
+	if (symbol == NULL) {
+		const char *errmsg = dlerror();
+		if (errmsg == NULL) {
+			errmsg = "returned function pointer is NULL";
+		}
+		isc_log_write(ns_lctx, NS_LOGCATEGORY_GENERAL,
+			      NS_LOGMODULE_HOOKS, ISC_LOG_ERROR,
+			      "failed to look up symbol %s in "
+			      "plugin '%s': %s",
+			      symbol_name, modpath, errmsg);
+		return (ISC_R_FAILURE);
+	}
+
+	*symbolp = symbol;
+
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+load_plugin(isc_mem_t *mctx, const char *modpath, ns_plugin_t **pluginp) {
+	isc_result_t result;
+	void *handle = NULL;
+	ns_plugin_t *plugin = NULL;
+	ns_plugin_check_t *check_func = NULL;
+	ns_plugin_register_t *register_func = NULL;
+	ns_plugin_destroy_t *destroy_func = NULL;
+	ns_plugin_version_t *version_func = NULL;
+	int version, flags;
+
+	REQUIRE(pluginp != NULL && *pluginp == NULL);
+
+	flags = RTLD_LAZY | RTLD_LOCAL;
+#if defined(RTLD_DEEPBIND) && !__SANITIZE_ADDRESS__ && !__SANITIZE_THREAD__
+	flags |= RTLD_DEEPBIND;
+#endif /* if defined(RTLD_DEEPBIND) && !__SANITIZE_ADDRESS__ && \
+	  !__SANITIZE_THREAD__ */
+
+	handle = dlopen(modpath, flags);
+	if (handle == NULL) {
+		const char *errmsg = dlerror();
+		if (errmsg == NULL) {
+			errmsg = "unknown error";
+		}
+		isc_log_write(ns_lctx, NS_LOGCATEGORY_GENERAL,
+			      NS_LOGMODULE_HOOKS, ISC_LOG_ERROR,
+			      "failed to dlopen() plugin '%s': %s", modpath,
+			      errmsg);
+		return (ISC_R_FAILURE);
+	}
+
+	CHECK(load_symbol(handle, modpath, "plugin_version",
+			  (void **)&version_func));
+
+	version = version_func();
+	if (version < (NS_PLUGIN_VERSION - NS_PLUGIN_AGE) ||
+	    version > NS_PLUGIN_VERSION)
+	{
+		isc_log_write(ns_lctx, NS_LOGCATEGORY_GENERAL,
+			      NS_LOGMODULE_HOOKS, ISC_LOG_ERROR,
+			      "plugin API version mismatch: %d/%d", version,
+			      NS_PLUGIN_VERSION);
+		CHECK(ISC_R_FAILURE);
+	}
+
+	CHECK(load_symbol(handle, modpath, "plugin_check",
+			  (void **)&check_func));
+	CHECK(load_symbol(handle, modpath, "plugin_register",
+			  (void **)&register_func));
+	CHECK(load_symbol(handle, modpath, "plugin_destroy",
+			  (void **)&destroy_func));
+
+	plugin = isc_mem_get(mctx, sizeof(*plugin));
+	memset(plugin, 0, sizeof(*plugin));
+	isc_mem_attach(mctx, &plugin->mctx);
+	plugin->handle = handle;
+	plugin->modpath = isc_mem_strdup(plugin->mctx, modpath);
+	plugin->check_func = check_func;
+	plugin->register_func = register_func;
+	plugin->destroy_func = destroy_func;
+
+	ISC_LINK_INIT(plugin, link);
+
+	*pluginp = plugin;
+	plugin = NULL;
+
+cleanup:
+	if (result != ISC_R_SUCCESS) {
+		isc_log_write(ns_lctx, NS_LOGCATEGORY_GENERAL,
+			      NS_LOGMODULE_HOOKS, ISC_LOG_ERROR,
+			      "failed to dynamically load "
+			      "plugin '%s': %s",
+			      modpath, isc_result_totext(result));
+
+		if (plugin != NULL) {
+			isc_mem_putanddetach(&plugin->mctx, plugin,
+					     sizeof(*plugin));
+		}
+
+		(void)dlclose(handle);
+	}
+
+	return (result);
+}
+
+static void
+unload_plugin(ns_plugin_t **pluginp) {
+	ns_plugin_t *plugin = NULL;
+
+	REQUIRE(pluginp != NULL && *pluginp != NULL);
+
+	plugin = *pluginp;
+	*pluginp = NULL;
+
+	isc_log_write(ns_lctx, NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_HOOKS,
+		      ISC_LOG_DEBUG(1), "unloading plugin '%s'",
+		      plugin->modpath);
+
+	if (plugin->inst != NULL) {
+		plugin->destroy_func(&plugin->inst);
+	}
+	if (plugin->handle != NULL) {
+		(void)dlclose(plugin->handle);
+	}
+	if (plugin->modpath != NULL) {
+		isc_mem_free(plugin->mctx, plugin->modpath);
+	}
+
+	isc_mem_putanddetach(&plugin->mctx, plugin, sizeof(*plugin));
+}
+#elif _WIN32
+static isc_result_t
+load_symbol(HMODULE handle, const char *modpath, const char *symbol_name,
+	    void **symbolp) {
+	void *symbol = NULL;
+
+	REQUIRE(handle != NULL);
+	REQUIRE(symbolp != NULL && *symbolp == NULL);
+
+	symbol = GetProcAddress(handle, symbol_name);
+	if (symbol == NULL) {
+		int errstatus = GetLastError();
+		isc_log_write(ns_lctx, NS_LOGCATEGORY_GENERAL,
+			      NS_LOGMODULE_HOOKS, ISC_LOG_ERROR,
+			      "failed to look up symbol %s in "
+			      "plugin '%s': %d",
+			      symbol_name, modpath, errstatus);
+		return (ISC_R_FAILURE);
+	}
+
+	*symbolp = symbol;
+
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+load_plugin(isc_mem_t *mctx, const char *modpath, ns_plugin_t **pluginp) {
+	isc_result_t result;
+	HMODULE handle;
+	ns_plugin_t *plugin = NULL;
+	ns_plugin_register_t *register_func = NULL;
+	ns_plugin_destroy_t *destroy_func = NULL;
+	ns_plugin_version_t *version_func = NULL;
+	int version;
+
+	REQUIRE(pluginp != NULL && *pluginp == NULL);
+
+	handle = LoadLibraryA(modpath);
+	if (handle == NULL) {
+		CHECK(ISC_R_FAILURE);
+	}
+
+	CHECK(load_symbol(handle, modpath, "plugin_version",
+			  (void **)&version_func));
+
+	version = version_func();
+	if (version < (NS_PLUGIN_VERSION - NS_PLUGIN_AGE) ||
+	    version > NS_PLUGIN_VERSION)
+	{
+		isc_log_write(ns_lctx, NS_LOGCATEGORY_GENERAL,
+			      NS_LOGMODULE_HOOKS, ISC_LOG_ERROR,
+			      "plugin API version mismatch: %d/%d", version,
+			      NS_PLUGIN_VERSION);
+		CHECK(ISC_R_FAILURE);
+	}
+
+	CHECK(load_symbol(handle, modpath, "plugin_register",
+			  (void **)&register_func));
+	CHECK(load_symbol(handle, modpath, "plugin_destroy",
+			  (void **)&destroy_func));
+
+	plugin = isc_mem_get(mctx, sizeof(*plugin));
+	memset(plugin, 0, sizeof(*plugin));
+	isc_mem_attach(mctx, &plugin->mctx);
+	plugin->handle = handle;
+	plugin->modpath = isc_mem_strdup(plugin->mctx, modpath);
+	plugin->register_func = register_func;
+	plugin->destroy_func = destroy_func;
+
+	ISC_LINK_INIT(plugin, link);
+
+	*pluginp = plugin;
+	plugin = NULL;
+
+cleanup:
+	if (result != ISC_R_SUCCESS) {
+		isc_log_write(ns_lctx, NS_LOGCATEGORY_GENERAL,
+			      NS_LOGMODULE_HOOKS, ISC_LOG_ERROR,
+			      "failed to dynamically load "
+			      "plugin '%s': %d (%s)",
+			      modpath, GetLastError(),
+			      isc_result_totext(result));
+
+		if (plugin != NULL) {
+			isc_mem_putanddetach(&plugin->mctx, plugin,
+					     sizeof(*plugin));
+		}
+
+		if (handle != NULL) {
+			FreeLibrary(handle);
+		}
+	}
+
+	return (result);
+}
+
+static void
+unload_plugin(ns_plugin_t **pluginp) {
+	ns_plugin_t *plugin = NULL;
+
+	REQUIRE(pluginp != NULL && *pluginp != NULL);
+
+	plugin = *pluginp;
+	*pluginp = NULL;
+
+	isc_log_write(ns_lctx, NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_HOOKS,
+		      ISC_LOG_DEBUG(1), "unloading plugin '%s'",
+		      plugin->modpath);
+
+	if (plugin->inst != NULL) {
+		plugin->destroy_func(&plugin->inst);
+	}
+	if (plugin->handle != NULL) {
+		FreeLibrary(plugin->handle);
+	}
+
+	if (plugin->modpath != NULL) {
+		isc_mem_free(plugin->mctx, plugin->modpath);
+	}
+
+	isc_mem_putanddetach(&plugin->mctx, plugin, sizeof(*plugin));
+}
+#else  /* HAVE_DLFCN_H || _WIN32 */
+static isc_result_t
+load_plugin(isc_mem_t *mctx, const char *modpath, ns_plugin_t **pluginp) {
+	UNUSED(mctx);
+	UNUSED(modpath);
+	UNUSED(pluginp);
+
+	isc_log_write(ns_lctx, NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_HOOKS,
+		      ISC_LOG_ERROR, "plugin support is not implemented");
+
+	return (ISC_R_NOTIMPLEMENTED);
+}
+
+static void
+unload_plugin(ns_plugin_t **pluginp) {
+	UNUSED(pluginp);
+}
+#endif /* HAVE_DLFCN_H */
+
+isc_result_t
+ns_plugin_register(const char *modpath, const char *parameters, const void *cfg,
+		   const char *cfg_file, unsigned long cfg_line,
+		   isc_mem_t *mctx, isc_log_t *lctx, void *actx,
+		   dns_view_t *view) {
+	isc_result_t result;
+	ns_plugin_t *plugin = NULL;
+
+	REQUIRE(mctx != NULL);
+	REQUIRE(lctx != NULL);
+	REQUIRE(view != NULL);
+
+	isc_log_write(ns_lctx, NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_HOOKS,
+		      ISC_LOG_INFO, "loading plugin '%s'", modpath);
+
+	CHECK(load_plugin(mctx, modpath, &plugin));
+
+	isc_log_write(ns_lctx, NS_LOGCATEGORY_GENERAL, NS_LOGMODULE_HOOKS,
+		      ISC_LOG_INFO, "registering plugin '%s'", modpath);
+
+	CHECK(plugin->register_func(parameters, cfg, cfg_file, cfg_line, mctx,
+				    lctx, actx, view->hooktable,
+				    &plugin->inst));
+
+	ISC_LIST_APPEND(*(ns_plugins_t *)view->plugins, plugin, link);
+
+cleanup:
+	if (result != ISC_R_SUCCESS && plugin != NULL) {
+		unload_plugin(&plugin);
+	}
+
+	return (result);
+}
+
+isc_result_t
+ns_plugin_check(const char *modpath, const char *parameters, const void *cfg,
+		const char *cfg_file, unsigned long cfg_line, isc_mem_t *mctx,
+		isc_log_t *lctx, void *actx) {
+	isc_result_t result;
+	ns_plugin_t *plugin = NULL;
+
+	CHECK(load_plugin(mctx, modpath, &plugin));
+
+	result = plugin->check_func(parameters, cfg, cfg_file, cfg_line, mctx,
+				    lctx, actx);
+
+cleanup:
+	if (plugin != NULL) {
+		unload_plugin(&plugin);
+	}
+
+	return (result);
+}
+
+void
+ns_hooktable_init(ns_hooktable_t *hooktable) {
+	int i;
+
+	for (i = 0; i < NS_HOOKPOINTS_COUNT; i++) {
+		ISC_LIST_INIT((*hooktable)[i]);
+	}
+}
+
+isc_result_t
+ns_hooktable_create(isc_mem_t *mctx, ns_hooktable_t **tablep) {
+	ns_hooktable_t *hooktable = NULL;
+
+	REQUIRE(tablep != NULL && *tablep == NULL);
+
+	hooktable = isc_mem_get(mctx, sizeof(*hooktable));
+
+	ns_hooktable_init(hooktable);
+
+	*tablep = hooktable;
+
+	return (ISC_R_SUCCESS);
+}
+
+void
+ns_hooktable_free(isc_mem_t *mctx, void **tablep) {
+	ns_hooktable_t *table = NULL;
+	ns_hook_t *hook = NULL, *next = NULL;
+	int i = 0;
+
+	REQUIRE(tablep != NULL && *tablep != NULL);
+
+	table = *tablep;
+	*tablep = NULL;
+
+	for (i = 0; i < NS_HOOKPOINTS_COUNT; i++) {
+		for (hook = ISC_LIST_HEAD((*table)[i]); hook != NULL;
+		     hook = next)
+		{
+			next = ISC_LIST_NEXT(hook, link);
+			ISC_LIST_UNLINK((*table)[i], hook, link);
+			if (hook->mctx != NULL) {
+				isc_mem_putanddetach(&hook->mctx, hook,
+						     sizeof(*hook));
+			}
+		}
+	}
+
+	isc_mem_put(mctx, table, sizeof(*table));
+}
+
+void
+ns_hook_add(ns_hooktable_t *hooktable, isc_mem_t *mctx,
+	    ns_hookpoint_t hookpoint, const ns_hook_t *hook) {
+	ns_hook_t *copy = NULL;
+
+	REQUIRE(hooktable != NULL);
+	REQUIRE(mctx != NULL);
+	REQUIRE(hookpoint < NS_HOOKPOINTS_COUNT);
+	REQUIRE(hook != NULL);
+
+	copy = isc_mem_get(mctx, sizeof(*copy));
+	memset(copy, 0, sizeof(*copy));
+
+	copy->action = hook->action;
+	copy->action_data = hook->action_data;
+	isc_mem_attach(mctx, &copy->mctx);
+
+	ISC_LINK_INIT(copy, link);
+	ISC_LIST_APPEND((*hooktable)[hookpoint], copy, link);
+}
+
+void
+ns_plugins_create(isc_mem_t *mctx, ns_plugins_t **listp) {
+	ns_plugins_t *plugins = NULL;
+
+	REQUIRE(listp != NULL && *listp == NULL);
+
+	plugins = isc_mem_get(mctx, sizeof(*plugins));
+	memset(plugins, 0, sizeof(*plugins));
+	ISC_LIST_INIT(*plugins);
+
+	*listp = plugins;
+}
+
+void
+ns_plugins_free(isc_mem_t *mctx, void **listp) {
+	ns_plugins_t *list = NULL;
+	ns_plugin_t *plugin = NULL, *next = NULL;
+
+	REQUIRE(listp != NULL && *listp != NULL);
+
+	list = *listp;
+	*listp = NULL;
+
+	for (plugin = ISC_LIST_HEAD(*list); plugin != NULL; plugin = next) {
+		next = ISC_LIST_NEXT(plugin, link);
+		ISC_LIST_UNLINK(*list, plugin, link);
+		unload_plugin(&plugin);
+	}
+
+	isc_mem_put(mctx, list, sizeof(*list));
+}