diff options
Diffstat (limited to 'sql-common/client_plugin.c')
| -rw-r--r-- | sql-common/client_plugin.c | 471 |
1 files changed, 471 insertions, 0 deletions
diff --git a/sql-common/client_plugin.c b/sql-common/client_plugin.c new file mode 100644 index 00000000000..6b4cca8aeea --- /dev/null +++ b/sql-common/client_plugin.c @@ -0,0 +1,471 @@ +/* Copyright (C) 2010 Sun Microsystems, Inc. + + 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; version 2 of the License. + + 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, write to the Free Software + Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ + +/** + @file + + Support code for the client side (libmysql) plugins + + Client plugins are somewhat different from server plugins, they are simpler. + + They do not need to be installed or in any way explicitly loaded on the + client, they are loaded automatically on demand. + One client plugin per shared object, soname *must* match the plugin name. + + There is no reference counting and no unloading either. +*/ + +#include <my_global.h> +#include "mysql.h" +#include <my_sys.h> +#include <m_string.h> +#include <my_pthread.h> + +#include <sql_common.h> +#include "errmsg.h" +#include <mysql/client_plugin.h> + +struct st_client_plugin_int { + struct st_client_plugin_int *next; + void *dlhandle; + struct st_mysql_client_plugin *plugin; +}; + +static my_bool initialized= 0; +static MEM_ROOT mem_root; + +static const char *plugin_declarations_sym= "_mysql_client_plugin_declaration_"; +static uint plugin_version[MYSQL_CLIENT_MAX_PLUGINS]= +{ + 0, /* these two are taken by Connector/C */ + 0, /* these two are taken by Connector/C */ + MYSQL_CLIENT_AUTHENTICATION_PLUGIN_INTERFACE_VERSION +}; + +/* + Loaded plugins are stored in a linked list. + The list is append-only, the elements are added to the head (like in a stack). + The elements are added under a mutex, but the list can be read and traversed + without any mutex because once an element is added to the list, it stays + there. The main purpose of a mutex is to prevent two threads from + loading the same plugin twice in parallel. +*/ +struct st_client_plugin_int *plugin_list[MYSQL_CLIENT_MAX_PLUGINS]; +static pthread_mutex_t LOCK_load_client_plugin; + +static int is_not_initialized(MYSQL *mysql, const char *name) +{ + if (initialized) + return 0; + + set_mysql_extended_error(mysql, CR_AUTH_PLUGIN_CANNOT_LOAD, + unknown_sqlstate, ER(CR_AUTH_PLUGIN_CANNOT_LOAD), + name, "not initialized"); + return 1; +} + +/** + finds a plugin in the list + + @param name plugin name to search for + @param type plugin type + + @note this does NOT necessarily need a mutex, take care! + + @retval a pointer to a found plugin or 0 +*/ +static struct st_mysql_client_plugin * +find_plugin(const char *name, int type) +{ + struct st_client_plugin_int *p; + + DBUG_ASSERT(initialized); + DBUG_ASSERT(type >= 0 && type < MYSQL_CLIENT_MAX_PLUGINS); + if (type < 0 || type >= MYSQL_CLIENT_MAX_PLUGINS) + return 0; + + for (p= plugin_list[type]; p; p= p->next) + { + if (strcmp(p->plugin->name, name) == 0) + return p->plugin; + } + return NULL; +} + +/** + verifies the plugin and adds it to the list + + @param mysql MYSQL structure (for error reporting) + @param plugin plugin to install + @param dlhandle a handle to the shared object (returned by dlopen) + or 0 if the plugin was not dynamically loaded + @param argc number of arguments in the 'va_list args' + @param args arguments passed to the plugin initialization function + + @retval a pointer to an installed plugin or 0 +*/ +static struct st_mysql_client_plugin * +add_plugin(MYSQL *mysql, struct st_mysql_client_plugin *plugin, void *dlhandle, + int argc, va_list args) +{ + const char *errmsg; + struct st_client_plugin_int plugin_int, *p; + char errbuf[1024]; + + DBUG_ASSERT(initialized); + + plugin_int.plugin= plugin; + plugin_int.dlhandle= dlhandle; + + if (plugin->type >= MYSQL_CLIENT_MAX_PLUGINS) + { + errmsg= "Unknown client plugin type"; + goto err1; + } + + if (plugin->interface_version < plugin_version[plugin->type] || + (plugin->interface_version >> 8) > + (plugin_version[plugin->type] >> 8)) + { + errmsg= "Incompatible client plugin interface"; + goto err1; + } + + /* Call the plugin initialization function, if any */ + if (plugin->init && plugin->init(errbuf, sizeof(errbuf), argc, args)) + { + errmsg= errbuf; + goto err1; + } + + p= (struct st_client_plugin_int *) + memdup_root(&mem_root, &plugin_int, sizeof(plugin_int)); + + if (!p) + { + errmsg= "Out of memory"; + goto err2; + } + + safe_mutex_assert_owner(&LOCK_load_client_plugin); + + p->next= plugin_list[plugin->type]; + plugin_list[plugin->type]= p; + + return plugin; + +err2: + if (plugin->deinit) + plugin->deinit(); +err1: + set_mysql_extended_error(mysql, CR_AUTH_PLUGIN_CANNOT_LOAD, unknown_sqlstate, + ER(CR_AUTH_PLUGIN_CANNOT_LOAD), plugin->name, + errmsg); + if (dlhandle) + dlclose(dlhandle); + return NULL; +} + +/** + Loads plugins which are specified in the environment variable + LIBMYSQL_PLUGINS. + + Multiple plugins must be separated by semicolon. This function doesn't + return or log an error. + + The function is be called by mysql_client_plugin_init + + @todo + Support extended syntax, passing parameters to plugins, for example + LIBMYSQL_PLUGINS="plugin1(param1,param2);plugin2;..." + or + LIBMYSQL_PLUGINS="plugin1=int:param1,str:param2;plugin2;..." +*/ +static void load_env_plugins(MYSQL *mysql) +{ + char *plugs, *free_env, *s= getenv("LIBMYSQL_PLUGINS"); + + /* no plugins to load */ + if(!s) + return; + + free_env= plugs= my_strdup(s, MYF(MY_WME)); + + do { + if ((s= strchr(plugs, ';'))) + *s= '\0'; + mysql_load_plugin(mysql, plugs, -1, 0); + plugs= s + 1; + } while (s); + + my_free(free_env); +} + +/********** extern functions to be used by libmysql *********************/ + +/** + Initializes the client plugin layer. + + This function must be called before any other client plugin function. + + @retval 0 successful + @retval != 0 error occured +*/ +int mysql_client_plugin_init() +{ + MYSQL mysql; + struct st_mysql_client_plugin **builtin; + + if (initialized) + return 0; + + bzero(&mysql, sizeof(mysql)); /* dummy mysql for set_mysql_extended_error */ + + pthread_mutex_init(&LOCK_load_client_plugin, MY_MUTEX_INIT_SLOW); + init_alloc_root(&mem_root, 128, 128); + + bzero(&plugin_list, sizeof(plugin_list)); + + initialized= 1; + + pthread_mutex_lock(&LOCK_load_client_plugin); + + for (builtin= mysql_client_builtins; *builtin; builtin++) + add_plugin(&mysql, *builtin, 0, 0, 0); + + pthread_mutex_unlock(&LOCK_load_client_plugin); + + load_env_plugins(&mysql); + + return 0; +} + +/** + Deinitializes the client plugin layer. + + Unloades all client plugins and frees any associated resources. +*/ +void mysql_client_plugin_deinit() +{ + int i; + struct st_client_plugin_int *p; + + if (!initialized) + return; + + for (i=0; i < MYSQL_CLIENT_MAX_PLUGINS; i++) + for (p= plugin_list[i]; p; p= p->next) + { + if (p->plugin->deinit) + p->plugin->deinit(); + if (p->dlhandle) + dlclose(p->dlhandle); + } + + bzero(&plugin_list, sizeof(plugin_list)); + initialized= 0; + free_root(&mem_root, MYF(0)); + pthread_mutex_destroy(&LOCK_load_client_plugin); +} + +/************* public facing functions, for client consumption *********/ + +/* see <mysql/client_plugin.h> for a full description */ +struct st_mysql_client_plugin * +mysql_client_register_plugin(MYSQL *mysql, + struct st_mysql_client_plugin *plugin) +{ + if (is_not_initialized(mysql, plugin->name)) + return NULL; + + pthread_mutex_lock(&LOCK_load_client_plugin); + + /* make sure the plugin wasn't loaded meanwhile */ + if (find_plugin(plugin->name, plugin->type)) + { + set_mysql_extended_error(mysql, CR_AUTH_PLUGIN_CANNOT_LOAD, + unknown_sqlstate, ER(CR_AUTH_PLUGIN_CANNOT_LOAD), + plugin->name, "it is already loaded"); + plugin= NULL; + } + else + plugin= add_plugin(mysql, plugin, 0, 0, 0); + + pthread_mutex_unlock(&LOCK_load_client_plugin); + return plugin; +} + +/* see <mysql/client_plugin.h> for a full description */ +struct st_mysql_client_plugin * +mysql_load_plugin_v(MYSQL *mysql, const char *name, int type, + int argc, va_list args) +{ + const char *errmsg; + char dlpath[FN_REFLEN+1]; + void *sym, *dlhandle; + struct st_mysql_client_plugin *plugin; +#ifdef _WIN32 + char win_errormsg[2048]; +#endif + + DBUG_ENTER ("mysql_load_plugin_v"); + DBUG_PRINT ("entry", ("name=%s type=%d int argc=%d", name, type, argc)); + if (is_not_initialized(mysql, name)) + { + DBUG_PRINT ("leave", ("mysql not initialized")); + DBUG_RETURN (NULL); + } + + pthread_mutex_lock(&LOCK_load_client_plugin); + + /* make sure the plugin wasn't loaded meanwhile */ + if (type >= 0 && find_plugin(name, type)) + { + errmsg= "it is already loaded"; + goto err; + } + + /* Compile dll path */ + strxnmov(dlpath, sizeof(dlpath) - 1, + mysql->options.extension && mysql->options.extension->plugin_dir ? + mysql->options.extension->plugin_dir : PLUGINDIR, "/", + name, SO_EXT, NullS); + + DBUG_PRINT ("info", ("dlopeninig %s", dlpath)); + /* Open new dll handle */ + if (!(dlhandle= dlopen(dlpath, RTLD_NOW))) + { +#if defined(__APPLE__) + /* Apple supports plugins with .so also, so try this as well */ + strxnmov(dlpath, sizeof(dlpath) - 1, + mysql->options.extension && mysql->options.extension->plugin_dir ? + mysql->options.extension->plugin_dir : PLUGINDIR, "/", + name, ".so", NullS); + if ((dlhandle= dlopen(dlpath, RTLD_NOW))) + goto have_plugin; +#endif + + DBUG_PRINT ("info", ("failed to dlopen")); +#ifdef _WIN32 + if(FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, + 0, GetLastError(), 0, win_errormsg, 2048, NULL)) + errmsg= win_errormsg; + else + errmsg= ""; +#else + errmsg= dlerror(); +#endif + goto err; + } + +#if defined(__APPLE__) +have_plugin: +#endif + if (!(sym= dlsym(dlhandle, plugin_declarations_sym))) + { + errmsg= "not a plugin"; + dlclose(dlhandle); + goto err; + } + + plugin= (struct st_mysql_client_plugin*)sym; + + if (type >=0 && type != plugin->type) + { + errmsg= "type mismatch"; + goto err; + } + + if (strcmp(name, plugin->name)) + { + errmsg= "name mismatch"; + goto err; + } + + if (type < 0 && find_plugin(name, plugin->type)) + { + errmsg= "it is already loaded"; + goto err; + } + + plugin= add_plugin(mysql, plugin, dlhandle, argc, args); + + pthread_mutex_unlock(&LOCK_load_client_plugin); + + DBUG_PRINT ("leave", ("plugin loaded ok")); + DBUG_RETURN (plugin); + +err: + pthread_mutex_unlock(&LOCK_load_client_plugin); + DBUG_PRINT ("leave", ("plugin load error : %s", errmsg)); + set_mysql_extended_error(mysql, CR_AUTH_PLUGIN_CANNOT_LOAD, unknown_sqlstate, + ER(CR_AUTH_PLUGIN_CANNOT_LOAD), name, errmsg); + DBUG_RETURN (NULL); +} + +/* see <mysql/client_plugin.h> for a full description */ +struct st_mysql_client_plugin * +mysql_load_plugin(MYSQL *mysql, const char *name, int type, int argc, ...) +{ + struct st_mysql_client_plugin *p; + va_list args; + va_start(args, argc); + p= mysql_load_plugin_v(mysql, name, type, argc, args); + va_end(args); + return p; +} + +/* see <mysql/client_plugin.h> for a full description */ +struct st_mysql_client_plugin * +mysql_client_find_plugin(MYSQL *mysql, const char *name, int type) +{ + struct st_mysql_client_plugin *p; + + DBUG_ENTER ("mysql_client_find_plugin"); + DBUG_PRINT ("entry", ("name=%s, type=%d", name, type)); + if (is_not_initialized(mysql, name)) + DBUG_RETURN (NULL); + + if (type < 0 || type >= MYSQL_CLIENT_MAX_PLUGINS) + { + set_mysql_extended_error(mysql, CR_AUTH_PLUGIN_CANNOT_LOAD, unknown_sqlstate, + ER(CR_AUTH_PLUGIN_CANNOT_LOAD), name, + "invalid type"); + } + + if ((p= find_plugin(name, type))) + { + DBUG_PRINT ("leave", ("found %p", p)); + DBUG_RETURN (p); + } + + /* not found, load it */ + p= mysql_load_plugin(mysql, name, type, 0); + DBUG_PRINT ("leave", ("loaded %p", p)); + DBUG_RETURN (p); +} + + +/* see <mysql/client_plugin.h> for a full description */ +int STDCALL mysql_plugin_options(struct st_mysql_client_plugin *plugin, + const char *option, + const void *value) +{ + DBUG_ENTER("mysql_plugin_options"); + /* does the plugin support options call? */ + if (!plugin || !plugin->options) + DBUG_RETURN(1); + DBUG_RETURN(plugin->options(option, value)); +} |