mirror of
https://github.com/MariaDB/server.git
synced 2025-07-30 16:24:05 +03:00
First implementation of instance-manager carcass:
logging, options, angel process. configure.in: added support for instance-manager directory BitKeeper/etc/logging_ok: Logging to logging@openlogging.org accepted
This commit is contained in:
unknown
249
server-tools/instance-manager/mysqlmanager.cc
Normal file
249
server-tools/instance-manager/mysqlmanager.cc
Normal file
@ -0,0 +1,249 @@
|
||||
/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult 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; either version 2 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, write to the Free Software
|
||||
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
|
||||
|
||||
#include <my_global.h>
|
||||
#include <my_sys.h>
|
||||
#include <string.h>
|
||||
#include <signal.h>
|
||||
#include <sys/wait.h>
|
||||
|
||||
#include "manager.h"
|
||||
#include "options.h"
|
||||
#include "log.h"
|
||||
|
||||
/*
|
||||
Few notes about the Instance Manager architecture:
|
||||
Instance Manager consisits of two processes: the angel process, and the
|
||||
instance manager process. Responsibilities of the angel process is to
|
||||
monitor the instance manager process, and restart it in case of
|
||||
failure/shutdown. The angel process is started only if startup option
|
||||
'--run-as-service' is provided.
|
||||
The Instance Manager process consists of several
|
||||
subsystems (thread sets):
|
||||
- the signal handling thread: it's responsibilities are to handle
|
||||
user signals and propogate them to the other threads. All other threads
|
||||
are accounted in the signal handler thread Thread Repository.
|
||||
- the listener: listens all sockets. There is a listening
|
||||
socket for each (mysql, http, snmp, rendezvous (?)) subsystem.
|
||||
- mysql subsystem: Instance Manager acts like an ordinary MySQL Server,
|
||||
but with very restricted command set. Each MySQL client connection is
|
||||
handled in a separate thread. All MySQL client connections threads
|
||||
constitute mysql subsystem.
|
||||
- http subsystem: it is also possible to talk with Instance Manager via
|
||||
http. One thread per http connection is used. Threads are pooled.
|
||||
- 'snmp' connections (FIXME: I know nothing about it yet)
|
||||
- rendezvous threads
|
||||
*/
|
||||
|
||||
static void init_environment(char *progname);
|
||||
static void daemonize(const char *log_file_name);
|
||||
static void angel(const Options &options);
|
||||
|
||||
|
||||
/*
|
||||
main, entry point
|
||||
- init environment
|
||||
- handle options
|
||||
- daemonize and run angel process (if necessary)
|
||||
- run manager process
|
||||
*/
|
||||
|
||||
int main(int argc, char *argv[])
|
||||
{
|
||||
init_environment(argv[0]);
|
||||
Options options;
|
||||
options.load(argc, argv);
|
||||
if (options.run_as_service)
|
||||
{
|
||||
daemonize(options.log_file_name);
|
||||
angel(options);
|
||||
}
|
||||
else
|
||||
manager(options.log_file_name);
|
||||
return 0;
|
||||
}
|
||||
|
||||
/******************* Auxilary functions implementation **********************/
|
||||
|
||||
|
||||
/*
|
||||
Init environment, common for daemon and non-daemon
|
||||
*/
|
||||
|
||||
static void init_environment(char *progname)
|
||||
{
|
||||
MY_INIT(progname);
|
||||
log_init();
|
||||
umask(0117);
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
Become a UNIX service
|
||||
SYNOPSYS
|
||||
daemonize()
|
||||
*/
|
||||
|
||||
static void daemonize(const char *log_file_name)
|
||||
{
|
||||
pid_t pid= fork();
|
||||
switch (pid) {
|
||||
case -1: // parent, fork error
|
||||
die("daemonize(): fork failed, %s", strerror(errno));
|
||||
case 0: // child, fork ok
|
||||
int fd;
|
||||
/*
|
||||
Become a session leader: setsid should succeed because child is
|
||||
guaranteed not to be a process group leader (it belongs to the
|
||||
process group of the parent.)
|
||||
The goal is not to have a controlling terminal.
|
||||
*/
|
||||
if (setsid() == -1)
|
||||
die("daemonize(): setsid() failed, %s", strerror(errno));
|
||||
/*
|
||||
As we now don't have a controlling terminal we will not receive
|
||||
tty-related signals - no need to ignore them.
|
||||
*/
|
||||
|
||||
close(STDIN_FILENO);
|
||||
|
||||
fd= open(log_file_name, O_WRONLY | O_CREAT | O_APPEND | O_NOCTTY,
|
||||
S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
|
||||
if (fd < 0)
|
||||
die("daemonize(): failed to open log file %s, %s", log_file_name,
|
||||
strerror(errno));
|
||||
dup2(fd, STDOUT_FILENO);
|
||||
dup2(fd, STDERR_FILENO);
|
||||
if (fd != STDOUT_FILENO && fd != STDERR_FILENO)
|
||||
close(fd);
|
||||
|
||||
/* TODO: chroot() and/or chdir() here */
|
||||
break;
|
||||
default:
|
||||
/* successfully exit from parent */
|
||||
exit(0);
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
enum { CHILD_OK= 0, CHILD_NEED_RESPAWN, CHILD_EXIT_ANGEL };
|
||||
|
||||
static volatile sig_atomic_t child_status= CHILD_OK;
|
||||
|
||||
/*
|
||||
Signal handler for SIGCHLD: reap child, analyze child exit status, and set
|
||||
child_status appropriately.
|
||||
*/
|
||||
|
||||
void reap_child(int __attribute__((unused)) signo)
|
||||
{
|
||||
int child_exit_status;
|
||||
/* As we have only one child, no need to cycle waitpid */
|
||||
if (waitpid(0, &child_exit_status, WNOHANG) > 0)
|
||||
{
|
||||
if (WIFSIGNALED(child_exit_status))
|
||||
child_status= CHILD_NEED_RESPAWN;
|
||||
else
|
||||
/*
|
||||
As we reap_child is not called for SIGSTOP, we should be here only
|
||||
if the child exited normally.
|
||||
*/
|
||||
child_status= CHILD_EXIT_ANGEL;
|
||||
}
|
||||
}
|
||||
|
||||
/* Not static to reuse it in childs */
|
||||
|
||||
volatile sig_atomic_t is_terminated= 0;
|
||||
|
||||
/*
|
||||
Signal handler for terminate signals - SIGTERM, SIGHUP, SIGINT.
|
||||
Set termination status and return.
|
||||
(q) do we need to handle SIGQUIT?
|
||||
*/
|
||||
|
||||
void terminate(int signo)
|
||||
{
|
||||
is_terminated= signo;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
Fork a child and monitor it.
|
||||
User can explicitly kill the angel process with SIGTERM/SIGHUP/SIGINT.
|
||||
Angel process will exit silently if mysqlmanager exits normally.
|
||||
*/
|
||||
|
||||
static void angel(const Options &options)
|
||||
{
|
||||
/* install signal handlers */
|
||||
sigset_t zeromask; // to sigsuspend in parent
|
||||
struct sigaction sa_chld, sa_term;
|
||||
struct sigaction sa_chld_out, sa_term_out, sa_int_out, sa_hup_out;
|
||||
if (sigemptyset(&zeromask) ||
|
||||
sigemptyset(&sa_chld.sa_mask) ||
|
||||
sigemptyset(&sa_term.sa_mask)) // how can it fail?
|
||||
die("angel(): sigemptyset() failed, %s", strerror(errno));
|
||||
sa_chld.sa_handler= reap_child;
|
||||
sa_chld.sa_flags= SA_NOCLDSTOP;
|
||||
sa_term.sa_handler= terminate;
|
||||
sa_term.sa_flags= 0;
|
||||
if (sigaction(SIGCHLD, &sa_chld, &sa_chld_out) == -1 ||
|
||||
sigaction(SIGTERM, &sa_term, &sa_term_out) == -1 ||
|
||||
sigaction(SIGINT, &sa_term, &sa_int_out) == -1 ||
|
||||
sigaction(SIGHUP, &sa_term, &sa_hup_out) == -1)
|
||||
die("angel(): sigaction() failed, %s", strerror(errno));
|
||||
|
||||
/* spawn a child */
|
||||
spawn:
|
||||
pid_t pid= fork();
|
||||
switch (pid) {
|
||||
case -1:
|
||||
die("angel(): fork failed, %s", strerror(errno));
|
||||
case 0: // child, success
|
||||
/*
|
||||
restore default actions for signals to let the manager work with
|
||||
signals as he wishes
|
||||
*/
|
||||
if (sigaction(SIGCHLD, &sa_chld_out, 0) == -1 ||
|
||||
sigaction(SIGTERM, &sa_term_out, 0) == -1 ||
|
||||
sigaction(SIGINT, &sa_int_out, 0) == -1 ||
|
||||
sigaction(SIGHUP, &sa_hup_out, 0) == -1)
|
||||
die("angel(): child failed to restore old signal actions, %s",
|
||||
strerror(errno));
|
||||
|
||||
manager(options.socket_file_name);
|
||||
default: // parent, success
|
||||
while (child_status == CHILD_OK && is_terminated == 0)
|
||||
{
|
||||
errno= 0;
|
||||
sigsuspend(&zeromask);
|
||||
if (errno != EINTR)
|
||||
die("angel(): sigsuspend failed, %s", strerror(errno));
|
||||
}
|
||||
if (is_terminated)
|
||||
log_info("angel got signal %d (%s), exiting",
|
||||
is_terminated, sys_siglist[is_terminated]);
|
||||
else if (child_status == CHILD_NEED_RESPAWN)
|
||||
{
|
||||
child_status= CHILD_OK;
|
||||
log_error("angel(): mysqlmanager exited abnormally: respawning...");
|
||||
sleep(1); /* don't respawn too fast */
|
||||
goto spawn;
|
||||
}
|
||||
/* mysqlmanager successfully exited, let's silently evaporate */
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user