int main(int argc, char **argv) { char *a[2]; argv = a; a[0] = "lockfile"; a[1] = LOCK_FILE; argc = 2; if (argc != 2) { printf("Usage: %s <file>\n", argv[0]); return 1; } fildes_t fd = open_lock(argv[1], FM_READ, 1, 0); if (fd < 0) { printf("%s cannot be opened: %s\n", argv[1], sos_error_msg(fd)); return 1; } thread_block(); close(fd); return 0; }
/* * main function */ int main(int argc, char *argv[]) { int sock = -1, ret; unsigned groups; /* set option */ ret = set_options(argc, argv); if(ret < 0) close_exit(sock, 0, ret); /* open log file */ ret = open_log(log_file); if(ret < 0) close_exit(sock, 0, ret); /* open debug file */ if(log_opts & L_DEBUG) { ret = open_dbg(dbg_file); if(ret < 0) close_exit(sock, 0, ret); } /* create lock file */ ret = open_lock(); if(ret < 0) close_exit(sock, 0, ret); /* set signal handlers */ ret = set_signal_handlers(); if(ret < 0) close_exit(sock, 0, ret); /* initizlize daemon */ ret = init_daemon(); if(ret < 0) close_exit(sock, 0, ret); rec_log("info: nield %s started(PID: %ld)", VERSION, (long)getpid()); /* write pid to lock file */ ret = write_lock(); if(ret < 0) close_exit(sock, 0, ret); /* open netlink socket to create list */ groups = 0; sock = open_netlink_socket(groups, NETLINK_ROUTE); if(sock < 0) close_exit(sock, 1, ret); /* request interface list */ ret = send_request(sock, RTM_GETLINK, AF_UNSPEC); if(ret < 0) close_exit(sock, 1, ret); /* receive interface list */ ret = recv_reply(sock, RTM_GETLINK); if(ret != 0) close_exit(sock, 1, ret); /* request bridge interface list */ ret = send_request(sock, RTM_GETLINK, AF_BRIDGE); if(ret < 0) close_exit(sock, 1, ret); /* receive bridge interface list */ ret = recv_reply(sock, RTM_GETLINK); if(ret != 0) close_exit(sock, 1, ret); /* request neighbor cache list */ ret = send_request(sock, RTM_GETNEIGH, AF_UNSPEC); if(ret < 0) close_exit(sock, 1, ret); /* receive & create interface list */ ret = recv_reply(sock, RTM_GETNEIGH); if(ret != 0) close_exit(sock, 1, ret); /* close socket */ close(sock); /* set rtnetlink multicast groups */ groups = set_rtnetlink_groups(); sock = open_netlink_socket(groups, NETLINK_ROUTE); if(sock < 0) close_exit(sock, 1, ret); /* recevie events */ ret = recv_events(sock); close_exit(sock, 1, ret); return(0); }
int main(int argc, char **argv) { static VSTREAM *lock_fp; static VSTREAM *data_lock_fp; VSTRING *lock_path; VSTRING *data_lock_path; off_t inherited_limit; int debug_me = 0; int ch; int fd; int n; int test_lock = 0; VSTRING *why; WATCHDOG *watchdog; ARGV *import_env; /* * Fingerprint executables and core dumps. */ MAIL_VERSION_STAMP_ALLOCATE; /* * Initialize. */ umask(077); /* never fails! */ /* * Process environment options as early as we can. */ if (getenv(CONF_ENV_VERB)) msg_verbose = 1; if (getenv(CONF_ENV_DEBUG)) debug_me = 1; /* * Don't die when a process goes away unexpectedly. */ signal(SIGPIPE, SIG_IGN); /* * Strip and save the process name for diagnostics etc. */ var_procname = mystrdup(basename(argv[0])); /* * When running a child process, don't leak any open files that were * leaked to us by our own (privileged) parent process. Descriptors 0-2 * are taken care of after we have initialized error logging. * * Some systems such as AIX have a huge per-process open file limit. In * those cases, limit the search for potential file descriptor leaks to * just the first couple hundred. * * The Debian post-installation script passes an open file descriptor into * the master process and waits forever for someone to close it. Because * of this we have to close descriptors > 2, and pray that doing so does * not break things. */ closefrom(3); /* * Initialize logging and exit handler. */ msg_syslog_init(mail_task(var_procname), LOG_PID, LOG_FACILITY); /* * Check the Postfix library version as soon as we enable logging. */ MAIL_VERSION_CHECK; /* * The mail system must be run by the superuser so it can revoke * privileges for selected operations. That's right - it takes privileges * to toss privileges. */ if (getuid() != 0) msg_fatal("the master command is reserved for the superuser"); if (unsafe() != 0) msg_fatal("the master command must not run as a set-uid process"); /* * Process JCL. */ while ((ch = GETOPT(argc, argv, "c:Dde:tv")) > 0) { switch (ch) { case 'c': if (setenv(CONF_ENV_PATH, optarg, 1) < 0) msg_fatal("out of memory"); break; case 'd': master_detach = 0; break; case 'e': event_request_timer(master_exit_event, (char *) 0, atoi(optarg)); break; case 'D': debug_me = 1; break; case 't': test_lock = 1; break; case 'v': msg_verbose++; break; default: usage(argv[0]); /* NOTREACHED */ } } /* * This program takes no other arguments. */ if (argc > optind) usage(argv[0]); /* * If started from a terminal, get rid of any tty association. This also * means that all errors and warnings must go to the syslog daemon. */ if (master_detach) for (fd = 0; fd < 3; fd++) { (void) close(fd); if (open("/dev/null", O_RDWR, 0) != fd) msg_fatal("open /dev/null: %m"); } /* * Run in a separate process group, so that "postfix stop" can terminate * all MTA processes cleanly. Give up if we can't separate from our * parent process. We're not supposed to blow away the parent. */ if (debug_me == 0 && master_detach != 0 && setsid() == -1 && getsid(0) != getpid()) msg_fatal("unable to set session and process group ID: %m"); /* * Make some room for plumbing with file descriptors. XXX This breaks * when a service listens on many ports. In order to do this right we * must change the master-child interface so that descriptors do not need * to have fixed numbers. * * In a child we need two descriptors for the flow control pipe, one for * child->master status updates and at least one for listening. */ for (n = 0; n < 5; n++) { if (close_on_exec(dup(0), CLOSE_ON_EXEC) < 0) msg_fatal("dup(0): %m"); } /* * Final initializations. Unfortunately, we must read the global Postfix * configuration file after doing command-line processing, so that we get * consistent results when we SIGHUP the server to reload configuration * files. */ master_vars_init(); /* * In case of multi-protocol support. This needs to be done because * master does not invoke mail_params_init() (it was written before that * code existed). */ (void) inet_proto_init(VAR_INET_PROTOCOLS, var_inet_protocols); /* * Environment import filter, to enforce consistent behavior whether * Postfix is started by hand, or at system boot time. */ import_env = argv_split(var_import_environ, ", \t\r\n"); clean_env(import_env->argv); argv_free(import_env); if ((inherited_limit = get_file_limit()) < 0) set_file_limit(OFF_T_MAX); if (chdir(var_queue_dir)) msg_fatal("chdir %s: %m", var_queue_dir); /* * Lock down the master.pid file. In test mode, no file means that it * isn't locked. */ lock_path = vstring_alloc(10); data_lock_path = vstring_alloc(10); why = vstring_alloc(10); vstring_sprintf(lock_path, "%s/%s.pid", DEF_PID_DIR, var_procname); if (test_lock && access(vstring_str(lock_path), F_OK) < 0) exit(0); lock_fp = open_lock(vstring_str(lock_path), O_RDWR | O_CREAT, 0644, why); if (test_lock) exit(lock_fp ? 0 : 1); if (lock_fp == 0) msg_fatal("open lock file %s: %s", vstring_str(lock_path), vstring_str(why)); vstream_fprintf(lock_fp, "%*lu\n", (int) sizeof(unsigned long) * 4, (unsigned long) var_pid); if (vstream_fflush(lock_fp)) msg_fatal("cannot update lock file %s: %m", vstring_str(lock_path)); close_on_exec(vstream_fileno(lock_fp), CLOSE_ON_EXEC); /* * Lock down the Postfix-writable data directory. */ vstring_sprintf(data_lock_path, "%s/%s.lock", var_data_dir, var_procname); set_eugid(var_owner_uid, var_owner_gid); data_lock_fp = open_lock(vstring_str(data_lock_path), O_RDWR | O_CREAT, 0644, why); set_ugid(getuid(), getgid()); if (data_lock_fp == 0) msg_fatal("open lock file %s: %s", vstring_str(data_lock_path), vstring_str(why)); vstream_fprintf(data_lock_fp, "%*lu\n", (int) sizeof(unsigned long) * 4, (unsigned long) var_pid); if (vstream_fflush(data_lock_fp)) msg_fatal("cannot update lock file %s: %m", vstring_str(data_lock_path)); close_on_exec(vstream_fileno(data_lock_fp), CLOSE_ON_EXEC); /* * Clean up. */ vstring_free(why); vstring_free(lock_path); vstring_free(data_lock_path); /* * Optionally start the debugger on ourself. */ if (debug_me) debug_process(); /* * Finish initialization, last part. We must process configuration files * after processing command-line parameters, so that we get consistent * results when we SIGHUP the server to reload configuration files. */ master_config(); master_sigsetup(); master_flow_init(); msg_info("daemon started -- version %s, configuration %s", var_mail_version, var_config_dir); /* * Process events. The event handler will execute the read/write/timer * action routines. Whenever something has happened, see if we received * any signal in the mean time. Although the master process appears to do * multiple things at the same time, it really is all a single thread, so * that there are no concurrency conflicts within the master process. */ #define MASTER_WATCHDOG_TIME 1000 watchdog = watchdog_create(MASTER_WATCHDOG_TIME, (WATCHDOG_FN) 0, (char *) 0); for (;;) { #ifdef HAS_VOLATILE_LOCKS if (myflock(vstream_fileno(lock_fp), INTERNAL_LOCK, MYFLOCK_OP_EXCLUSIVE) < 0) msg_fatal("refresh exclusive lock: %m"); if (myflock(vstream_fileno(data_lock_fp), INTERNAL_LOCK, MYFLOCK_OP_EXCLUSIVE) < 0) msg_fatal("refresh exclusive lock: %m"); #endif watchdog_start(watchdog); /* same as trigger servers */ event_loop(MASTER_WATCHDOG_TIME / 2); if (master_gotsighup) { msg_info("reload -- version %s, configuration %s", var_mail_version, var_config_dir); master_gotsighup = 0; /* this first */ master_vars_init(); /* then this */ master_refresh(); /* then this */ } if (master_gotsigchld) { if (msg_verbose) msg_info("got sigchld"); master_gotsigchld = 0; /* this first */ master_reap_child(); /* then this */ } } }
fildes_t open(const char *path, fmode_t mode) { return open_lock(path, mode, FM_UNLIMITED_RW, FM_UNLIMITED_RW); }