/* Copyright (c) 2003-2007 MySQL AB 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA */ #include "manager.h" #include #include #include #include #include #ifndef __WIN__ #include #endif #include "exit_codes.h" #include "guardian.h" #include "instance_map.h" #include "listener.h" #include "mysql_manager_error.h" #include "mysqld_error.h" #include "log.h" #include "options.h" #include "priv.h" #include "thread_registry.h" #include "user_map.h" /********************************************************************** {{{ Platform-specific implementation. **********************************************************************/ #ifndef __WIN__ void set_signals(sigset_t *mask) { /* block signals */ sigemptyset(mask); sigaddset(mask, SIGINT); sigaddset(mask, SIGTERM); sigaddset(mask, SIGPIPE); sigaddset(mask, SIGHUP); signal(SIGPIPE, SIG_IGN); /* We want this signal to be blocked in all theads but the signal one. It is needed for the thr_alarm subsystem to work. */ sigaddset(mask,THR_SERVER_ALARM); /* all new threads will inherite this signal mask */ pthread_sigmask(SIG_BLOCK, mask, NULL); /* In our case the signal thread also implements functions of alarm thread. Here we init alarm thread functionality. We suppose that we won't have more then 10 alarms at the same time. */ init_thr_alarm(10); } #else bool have_signal; void onsignal(int signo) { have_signal= TRUE; } void set_signals(sigset_t *set) { signal(SIGINT, onsignal); signal(SIGTERM, onsignal); have_signal= FALSE; } int my_sigwait(const sigset_t *set, int *sig) { while (!have_signal) { Sleep(100); } return 0; } #endif /********************************************************************** }}} **********************************************************************/ /********************************************************************** {{{ Implementation of checking the actual thread model. ***********************************************************************/ namespace { /* no-indent */ class ThreadModelChecker: public Thread { public: ThreadModelChecker() :main_pid(getpid()) { } public: inline bool is_linux_threads() const { return linux_threads; } protected: virtual void run() { linux_threads= main_pid != getpid(); } private: pid_t main_pid; bool linux_threads; }; bool check_if_linux_threads(bool *linux_threads) { ThreadModelChecker checker; if (checker.start() || checker.join()) return TRUE; *linux_threads= checker.is_linux_threads(); return FALSE; } } /********************************************************************** }}} ***********************************************************************/ /********************************************************************** Manager implementation ***********************************************************************/ Guardian *Manager::p_guardian; Instance_map *Manager::p_instance_map; Thread_registry *Manager::p_thread_registry; User_map *Manager::p_user_map; #ifndef __WIN__ bool Manager::linux_threads; #endif // __WIN__ /** Request shutdown of guardian and threads registered in Thread_registry. SYNOPSIS stop_all_threads() */ void Manager::stop_all_threads() { /* Let Guardian thread know that it should break it's processing cycle, once it wakes up. */ p_guardian->request_shutdown(); /* Stop all threads. */ p_thread_registry->deliver_shutdown(); /* Set error status in the thread registry. */ p_thread_registry->set_error_status(); } /** Initialize user map and load password file. SYNOPSIS init_user_map() RETURN FALSE on success TRUE on failure */ bool Manager::init_user_map(User_map *user_map) { int err_code; const char *err_msg; if (user_map->init()) { log_error("Manager: can not initialize user list: out of memory."); return TRUE; } err_code= user_map->load(Options::Main::password_file_name, &err_msg); if (!err_code) return FALSE; if (err_code == ERR_PASSWORD_FILE_DOES_NOT_EXIST && Options::Main::mysqld_safe_compatible) { /* The password file does not exist, but we are running in mysqld_safe-compatible mode. Continue, but complain in log. */ log_info("Warning: password file does not exist, " "nobody will be able to connect to Instance Manager."); return FALSE; } log_error("Manager: %s.", (const char *) err_msg); return TRUE; } /** Main manager function. SYNOPSIS main() DESCRIPTION This is an entry point to the main instance manager process: start listener thread, write pid file and enter into signal handling. See also comments in mysqlmanager.cc to picture general Instance Manager architecture. RETURNS main() returns exit status (exit code). */ int Manager::main() { bool shutdown_complete= FALSE; pid_t manager_pid= getpid(); log_info("Manager: initializing..."); #ifndef __WIN__ if (check_if_linux_threads(&linux_threads)) { log_error("Manager: can not determine thread model."); return 1; } log_info("Manager: detected threads model: %s.", (const char *) (linux_threads ? "LINUX threads" : "POSIX threads")); #endif // __WIN__ /* All objects created in the Manager object live as long as thread_registry lives, and thread_registry is alive until there are working threads. There are two main purposes of the Thread Registry: 1. Interrupt blocking I/O and signal condition variables in case of shutdown; 2. Wait for detached threads before shutting down the main thread. NOTE: 1. Handling shutdown can be done in more elegant manner by introducing Event (or Condition) object with support of logical operations. 2. Using Thread Registry to wait for detached threads is definitely not the best way, because when Thread Registry unregisters an thread, the thread is still alive. Accurate way to wait for threads to stop is not using detached threads and join all threads before shutdown. */ Thread_registry thread_registry; User_map user_map; Instance_map instance_map; Guardian guardian(&thread_registry, &instance_map); Listener listener(&thread_registry, &user_map); p_instance_map= &instance_map; p_guardian= &guardian; p_thread_registry= &thread_registry; p_user_map= &user_map; /* Initialize instance map. */ if (instance_map.init()) { log_error("Manager: can not initialize instance list: out of memory."); return 1; } /* Initialize user db. */ if (init_user_map(&user_map)) return 1; /* logging has been already done. */ /* Write Instance Manager pid file. */ if (create_pid_file(Options::Main::pid_file_name, manager_pid)) return 1; /* necessary logging has been already done. */ log_info("Manager: pid file (%s) created.", (const char *) Options::Main::pid_file_name); /* Initialize signals and alarm-infrastructure. NOTE: To work nicely with LinuxThreads, the signal thread is the first thread in the process. NOTE: After init_thr_alarm() call it's possible to call thr_alarm() (from different threads), that results in sending ALARM signal to the alarm thread (which can be the main thread). That signal can interrupt blocking calls. In other words, a blocking call can be interrupted in the main thread after init_thr_alarm(). */ sigset_t mask; set_signals(&mask); /* Create the guardian thread. The newly started thread will block until we actually load instances. NOTE: Guardian should be shutdown first. Only then all other threads can be stopped. This should be done in this order because the guardian is responsible for shutting down all the guarded instances, and this is a long operation. NOTE: Guardian uses thr_alarm() when detects the current state of an instance (is_running()), but this does not interfere with flush_instances() call later in the code, because until flush_instances() completes in the main thread, Guardian thread is not permitted to process instances. And before flush_instances() has completed, there are no instances to guard. */ if (guardian.start(Thread::DETACHED)) { log_error("Manager: can not start Guardian thread."); goto err; } /* Load instances. */ if (Manager::flush_instances()) { log_error("Manager: can not init instances repository."); stop_all_threads(); goto err; } /* Initialize the Listener. */ if (listener.start(Thread::DETACHED)) { log_error("Manager: can not start Listener thread."); stop_all_threads(); goto err; } /* After the list of guarded instances have been initialized, Guardian should start them. */ guardian.ping(); /* Main loop. */ log_info("Manager: started."); while (!shutdown_complete) { int signo; int status= 0; if ((status= my_sigwait(&mask, &signo)) != 0) { log_error("Manager: sigwait() failed"); stop_all_threads(); goto err; } /* The general idea in this loop is the following: - we are waiting for SIGINT, SIGTERM -- signals that mean we should shutdown; - as shutdown signal is caught, we stop Guardian thread (by calling Guardian::request_shutdown()); - as Guardian is stopped, it sends SIGTERM to this thread (by calling Thread_registry::request_shutdown()), so that the my_sigwait() above returns; - as we catch the second SIGTERM, we send signals to all threads registered in Thread_registry (by calling Thread_registry::deliver_shutdown()) and waiting for threads to stop; */ #ifndef __WIN__ /* On some Darwin kernels SIGHUP is delivered along with most signals. This is why we skip it's processing on these platforms. For more details and test program see Bug #14164 IM tests fail on MacOS X (powermacg5) */ #ifdef IGNORE_SIGHUP_SIGQUIT if (SIGHUP == signo) continue; #endif if (THR_SERVER_ALARM == signo) process_alarm(signo); else #endif { log_info("Manager: got shutdown signal."); if (!guardian.is_stopped()) { guardian.request_shutdown(); } else { thread_registry.deliver_shutdown(); shutdown_complete= TRUE; } } } log_info("Manager: finished."); err: /* delete the pid file */ my_delete(Options::Main::pid_file_name, MYF(0)); #ifndef __WIN__ /* free alarm structures */ end_thr_alarm(1); #endif return thread_registry.get_error_status() ? 1 : 0; } /** Re-read instance configuration file. SYNOPSIS flush_instances() DESCRIPTION This function will: - clear the current list of instances. This removes both running and stopped instances. - load a new instance configuration from the file. - pass on the new map to the guardian thread: it will start all instances that are marked `guarded' and not yet started. Note, as the check whether an instance is started is currently very simple (returns TRUE if there is a MySQL server running at the given port), this function has some peculiar side-effects: * if the port number of a running instance was changed, the old instance is forgotten, even if it was running. The new instance will be started at the new port. * if the configuration was changed in a way that two instances swapped their port numbers, the guardian thread will not notice that and simply report that both instances are configured successfully and running. In order to avoid such side effects one should never call FLUSH INSTANCES without prior stop of all running instances. RETURN 0 On success ER_OUT_OF_RESOURCES Not enough resources to complete the operation ER_THERE_IS_ACTIVE_INSTACE If there is an active instance */ int Manager::flush_instances() { p_instance_map->lock(); if (p_instance_map->is_there_active_instance()) { p_instance_map->unlock(); return ER_THERE_IS_ACTIVE_INSTACE; } if (p_instance_map->reset()) { p_instance_map->unlock(); return ER_OUT_OF_RESOURCES; } if (p_instance_map->load()) { p_instance_map->unlock(); /* Don't init guardian if we failed to load instances. */ return ER_OUT_OF_RESOURCES; } get_guardian()->init(); get_guardian()->ping(); p_instance_map->unlock(); return 0; }