/* Copyright (C) 2003 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/types.h> #include <sys/stat.h> #ifndef __WIN__ #include <pwd.h> #include <grp.h> #include <sys/wait.h> #endif #include "log.h" #include "manager.h" #include "options.h" #include "priv.h" #include "user_management_commands.h" #ifdef __WIN__ #include "IMService.h" #include "WindowsService.h" #endif /* Few notes about 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 Registry. - 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); #ifndef __WIN__ static void daemonize(const char *log_file_name); static void angel(); static struct passwd *check_user(const char *user); static int set_user(const char *user, struct passwd *user_info); #endif /* main, entry point - init environment - handle options - daemonize and run angel process (if necessary) - run manager process */ int main(int argc, char *argv[]) { int return_value= 1; init_environment(argv[0]); if ((return_value= Options::load(argc, argv))) goto main_end; if (Options::User_management::cmd) { return_value= Options::User_management::cmd->execute(); goto main_end; } #ifndef __WIN__ struct passwd *user_info; if ((user_info= check_user(Options::Daemon::user))) { if (set_user(Options::Daemon::user, user_info)) { return_value= 1; goto main_end; } } if (Options::Daemon::run_as_service) { /* forks, and returns only in child */ daemonize(Options::Daemon::log_file_name); /* forks again, and returns only in child: parent becomes angel */ angel(); } (void) Manager::main(); /* ignore the return value for now */ #else if (!Options::Service::stand_alone) { if (HandleServiceOptions()) { return_value= 1; goto main_end; } } else { (void) Manager::main(); /* ignore the return value for now */ } #endif return_value= 0; main_end: Options::cleanup(); my_end(0); return return_value; } /******************* Auxilary functions implementation **********************/ #if !defined(__WIN__) && !defined(OS2) && !defined(__NETWARE__) /* Change to run as another user if started with --user */ static struct passwd *check_user(const char *user) { struct passwd *user_info; uid_t user_id= geteuid(); /* Don't bother if we aren't superuser */ if (user_id) { if (user) { /* Don't give a warning, if real user is same as given with --user */ user_info= getpwnam(user); if ((!user_info || user_id != user_info->pw_uid)) log_info("One can only use the --user switch if running as root\n"); } return NULL; } if (!user) { log_info("You are running mysqlmanager as root! This might introduce security problems. It is safer to use --user option istead.\n"); return NULL; } if (!strcmp(user, "root")) return NULL; /* Avoid problem with dynamic libraries */ if (!(user_info= getpwnam(user))) { /* Allow a numeric uid to be used */ const char *pos; for (pos= user; my_isdigit(default_charset_info, *pos); pos++) {} if (*pos) /* Not numeric id */ goto err; if (!(user_info= getpwuid(atoi(user)))) goto err; else return user_info; } else return user_info; err: log_error("Fatal error: Can't change to run as user '%s' ; Please check that the user exists!\n", user); return NULL; } static int set_user(const char *user, struct passwd *user_info) { DBUG_ASSERT(user_info); #ifdef HAVE_INITGROUPS initgroups((char*) user,user_info->pw_gid); #endif if (setgid(user_info->pw_gid) == -1) { log_error("setgid() failed"); return 1; } if (setuid(user_info->pw_uid) == -1) { log_error("setuid() failed"); return 1; } return 0; } #endif /* Init environment, common for daemon and non-daemon */ static void init_environment(char *progname) { MY_INIT(progname); log_init(); umask(0117); srand((unsigned int) time(0)); } #ifndef __WIN__ /* 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 must 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. */ setsid(); /* 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 reap_child is not called for SIGSTOP, we should be here only if the child exited normally. */ child_status= CHILD_EXIT_ANGEL; } } static 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() { /* 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; sigemptyset(&zeromask); sigemptyset(&sa_chld.sa_mask); sigemptyset(&sa_term.sa_mask); sa_chld.sa_handler= reap_child; sa_chld.sa_flags= SA_NOCLDSTOP; sa_term.sa_handler= terminate; sa_term.sa_flags= 0; /* sigaction can fail only on wrong arguments */ sigaction(SIGCHLD, &sa_chld, &sa_chld_out); sigaction(SIGTERM, &sa_term, &sa_term_out); sigaction(SIGINT, &sa_term, &sa_int_out); sigaction(SIGHUP, &sa_term, &sa_hup_out); /* 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 */ sigaction(SIGCHLD, &sa_chld_out, 0); sigaction(SIGTERM, &sa_term_out, 0); sigaction(SIGINT, &sa_int_out, 0); sigaction(SIGHUP, &sa_hup_out, 0); /* Here we return to main, and fall into manager */ break; default: // parent, success pid= getpid(); /* Get our pid. */ log_info("Angel pid file: '%s'; PID: %d.", (const char *) Options::Daemon::angel_pid_file_name, (int) pid); create_pid_file(Options::Daemon::angel_pid_file_name, pid); while (child_status == CHILD_OK && is_terminated == 0) sigsuspend(&zeromask); if (is_terminated) log_info("angel got signal %d, exiting", 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 If we return to main we will fall into the manager functionality, so let's simply exit(). */ exit(0); } } #endif