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https://github.com/MariaDB/server.git
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f40a9d2ece
The problem was that IM stoped guarded instances on shutdown, but didn't wait for them to stop. The fix is to wait for guarded instances to stop before exitting from the main thread. The idea is that Instance-monitoring thread should add itself to Thread_registry so that it will be taken into account on shutdown. However, Thread_registry should not signal it on shutdown in order to not interrupt wait()/waitpid().
382 lines
10 KiB
C++
382 lines
10 KiB
C++
/* Copyright (C) 2003 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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#include "manager.h"
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#include <my_global.h>
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#include <m_string.h>
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#include <my_sys.h>
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#include <thr_alarm.h>
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#include <signal.h>
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#ifndef __WIN__
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#include <sys/wait.h>
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#endif
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#include "exit_codes.h"
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#include "guardian.h"
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#include "instance_map.h"
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#include "listener.h"
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#include "log.h"
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#include "options.h"
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#include "priv.h"
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#include "thread_registry.h"
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#include "user_map.h"
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int create_pid_file(const char *pid_file_name, int pid)
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{
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FILE *pid_file;
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if (!(pid_file= my_fopen(pid_file_name, O_WRONLY | O_CREAT | O_BINARY,
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MYF(0))))
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{
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log_error("Error: can not create pid file '%s': %s (errno: %d)",
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(const char *) pid_file_name,
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(const char *) strerror(errno),
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(int) errno);
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return 1;
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}
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if (fprintf(pid_file, "%d\n", (int) pid) <= 0)
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{
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log_error("Error: can not write to pid file '%s': %s (errno: %d)",
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(const char *) pid_file_name,
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(const char *) strerror(errno),
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(int) errno);
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return 1;
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}
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my_fclose(pid_file, MYF(0));
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return 0;
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}
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#ifndef __WIN__
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void set_signals(sigset_t *mask)
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{
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/* block signals */
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sigemptyset(mask);
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sigaddset(mask, SIGINT);
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sigaddset(mask, SIGTERM);
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sigaddset(mask, SIGPIPE);
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sigaddset(mask, SIGHUP);
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signal(SIGPIPE, SIG_IGN);
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/*
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We want this signal to be blocked in all theads but the signal
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one. It is needed for the thr_alarm subsystem to work.
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*/
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sigaddset(mask,THR_SERVER_ALARM);
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/* all new threads will inherite this signal mask */
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pthread_sigmask(SIG_BLOCK, mask, NULL);
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/*
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In our case the signal thread also implements functions of alarm thread.
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Here we init alarm thread functionality. We suppose that we won't have
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more then 10 alarms at the same time.
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*/
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init_thr_alarm(10);
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}
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#else
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bool have_signal;
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void onsignal(int signo)
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{
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have_signal= TRUE;
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}
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void set_signals(sigset_t *set)
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{
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signal(SIGINT, onsignal);
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signal(SIGTERM, onsignal);
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have_signal= FALSE;
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}
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int my_sigwait(const sigset_t *set, int *sig)
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{
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while (!have_signal)
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{
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Sleep(100);
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}
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return 0;
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}
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#endif
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void stop_all(Guardian_thread *guardian, Thread_registry *registry)
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{
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/*
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Let guardian thread know that it should break it's processing cycle,
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once it wakes up.
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*/
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guardian->request_shutdown();
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/* wake guardian */
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pthread_cond_signal(&guardian->COND_guardian);
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/* stop all threads */
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registry->deliver_shutdown();
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}
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/*
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manager - entry point to the main instance manager process: start
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listener thread, write pid file and enter into signal handling.
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See also comments in mysqlmanager.cc to picture general Instance Manager
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architecture.
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TODO: how about returning error status.
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*/
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void manager()
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{
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int err_code;
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const char *err_msg;
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bool shutdown_complete= FALSE;
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Thread_registry thread_registry;
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/*
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All objects created in the manager() function live as long as
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thread_registry lives, and thread_registry is alive until there are
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working threads.
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*/
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User_map user_map;
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Instance_map instance_map(Options::Main::default_mysqld_path,
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thread_registry);
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Guardian_thread guardian_thread(thread_registry,
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&instance_map,
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Options::Main::monitoring_interval);
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Listener_thread_args listener_args(thread_registry, user_map, instance_map);
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manager_pid= getpid();
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instance_map.guardian= &guardian_thread;
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/* Initialize instance map. */
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if (instance_map.init())
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{
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log_error("Error: can not initialize instance list: out of memory.");
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return;
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}
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/* Initialize user map and load password file. */
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if (user_map.init())
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{
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log_error("Error: can not initialize user list: out of memory.");
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return;
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}
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if ((err_code= user_map.load(Options::Main::password_file_name, &err_msg)))
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{
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if (err_code == ERR_PASSWORD_FILE_DOES_NOT_EXIST &&
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Options::Main::mysqld_safe_compatible)
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{
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/*
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The password file does not exist, but we are running in
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mysqld_safe-compatible mode. Continue, but complain in log.
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*/
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log_error("Warning: password file does not exist, "
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"nobody will be able to connect to Instance Manager.");
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}
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else
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{
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log_error("Error: %s.", (const char *) err_msg);
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return;
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}
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}
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/* write Instance Manager pid file */
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log_info("IM pid file: '%s'; PID: %d.",
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(const char *) Options::Main::pid_file_name,
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(int) manager_pid);
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if (create_pid_file(Options::Main::pid_file_name, manager_pid))
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return; /* necessary logging has been already done. */
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/*
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Initialize signals and alarm-infrastructure.
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NOTE: To work nicely with LinuxThreads, the signal thread is the first
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thread in the process.
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NOTE:
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After init_thr_alarm() call it's possible to call thr_alarm() (from
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different threads), that results in sending ALARM signal to the alarm
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thread (which can be the main thread). That signal can interrupt
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blocking calls.
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In other words, a blocking call can be interrupted in the main thread
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after init_thr_alarm().
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*/
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sigset_t mask;
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set_signals(&mask);
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/* create guardian thread */
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{
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pthread_t guardian_thd_id;
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pthread_attr_t guardian_thd_attr;
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int rc;
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/*
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NOTE: Guardian should be shutdown first. Only then all other threads
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need to be stopped. This should be done, as guardian is responsible
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for shutting down the instances, and this is a long operation.
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NOTE: Guardian uses thr_alarm() when detects current state of
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instances (is_running()), but it is not interfere with
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flush_instances() later in the code, because until flush_instances()
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complete in the main thread, Guardian thread is not permitted to
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process instances. And before flush_instances() there is no instances
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to proceed.
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*/
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pthread_attr_init(&guardian_thd_attr);
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pthread_attr_setdetachstate(&guardian_thd_attr, PTHREAD_CREATE_DETACHED);
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rc= set_stacksize_n_create_thread(&guardian_thd_id, &guardian_thd_attr,
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guardian, &guardian_thread);
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pthread_attr_destroy(&guardian_thd_attr);
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if (rc)
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{
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log_error("manager(): set_stacksize_n_create_thread(guardian) failed");
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goto err;
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}
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}
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/* Load instances. */
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{
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instance_map.guardian->lock();
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instance_map.lock();
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int flush_instances_status= instance_map.flush_instances();
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instance_map.unlock();
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instance_map.guardian->unlock();
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if (flush_instances_status)
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{
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log_error("Cannot init instances repository. This might be caused by "
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"the wrong config file options. For instance, missing mysqld "
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"binary. Aborting.");
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stop_all(&guardian_thread, &thread_registry);
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goto err;
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}
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}
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/* create the listener */
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{
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pthread_t listener_thd_id;
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pthread_attr_t listener_thd_attr;
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int rc;
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pthread_attr_init(&listener_thd_attr);
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pthread_attr_setdetachstate(&listener_thd_attr, PTHREAD_CREATE_DETACHED);
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rc= set_stacksize_n_create_thread(&listener_thd_id, &listener_thd_attr,
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listener, &listener_args);
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pthread_attr_destroy(&listener_thd_attr);
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if (rc)
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{
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log_error("manager(): set_stacksize_n_create_thread(listener) failed");
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stop_all(&guardian_thread, &thread_registry);
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goto err;
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}
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}
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/*
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After the list of guarded instances have been initialized,
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Guardian should start them.
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*/
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pthread_cond_signal(&guardian_thread.COND_guardian);
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log_info("Main loop: started.");
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while (!shutdown_complete)
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{
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int signo;
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int status= 0;
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if ((status= my_sigwait(&mask, &signo)) != 0)
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{
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log_error("sigwait() failed");
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stop_all(&guardian_thread, &thread_registry);
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goto err;
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}
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/*
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The general idea in this loop is the following:
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- we are waiting for SIGINT, SIGTERM -- signals that mean we should
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shutdown;
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- as shutdown signal is caught, we stop Guardian thread (by calling
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Guardian_thread::request_shutdown());
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- as Guardian_thread is stopped, it sends SIGTERM to this thread
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(by calling Thread_registry::request_shutdown()), so that the
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my_sigwait() above returns;
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- as we catch the second SIGTERM, we send signals to all threads
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registered in Thread_registry (by calling
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Thread_registry::deliver_shutdown()) and waiting for threads to stop;
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*/
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#ifndef __WIN__
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/*
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On some Darwin kernels SIGHUP is delivered along with most
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signals. This is why we skip it's processing on these
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platforms. For more details and test program see
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Bug #14164 IM tests fail on MacOS X (powermacg5)
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*/
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#ifdef IGNORE_SIGHUP_SIGQUIT
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if ( SIGHUP == signo )
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continue;
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#endif
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if (THR_SERVER_ALARM == signo)
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process_alarm(signo);
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else
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#endif
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{
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log_info("Main loop: got shutdown signal.");
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if (!guardian_thread.is_stopped())
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{
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guardian_thread.request_shutdown();
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pthread_cond_signal(&guardian_thread.COND_guardian);
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}
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else
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{
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thread_registry.deliver_shutdown();
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shutdown_complete= TRUE;
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}
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}
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}
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log_info("Main loop: finished.");
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err:
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/* delete the pid file */
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my_delete(Options::Main::pid_file_name, MYF(0));
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#ifndef __WIN__
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/* free alarm structures */
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end_thr_alarm(1);
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/* don't pthread_exit to kill all threads who did not shut down in time */
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#endif
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}
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