/*

  * 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.

  *

  ******************************************************************************

  * TODO: 

  *	1) Man page

  *	2) Add the "cl_respawn recover" function, for combining with recovery

  *	   manager. But what's its strategy ?

  * 	   The pid will passed by environment

  *	3) Add the function for "-l" option ?

  ******************************************************************************

  *

  * File: cl_respawn.c

  * Description: 

  * 	A small respawn tool which will start a program as a child process, and

  * unless it exits with the "magic" exit code, will restart the program again 

  * if it exits(dies).  It is intended that this respawn program should be usable

  * in resource agent scripts and other places.  The respawn tool should properly

  * log all restarts, and all exits which it doesn't respawn, and run itself as a

  * client of the apphb application heartbeating program, so that it can be 

  * restarted if the program it is monitoring dies.  

  * 

  * Author: Sun Jiang Dong <sunjd@cn.ibm.com>

  * Copyright (c) 2004 International Business Machines

  */ 

 #include <lha_internal.h>

 #include <stdio.h>

 #include <unistd.h>

 #include <stdlib.h>

 #include <fcntl.h>

 #include <signal.h>

 #ifdef HAVE_GETOPT_H

 #include <getopt.h>

 #endif

 #include <stdarg.h>

 #include <errno.h>

 #include <string.h>

 #include <sys/types.h>

 #include <sys/stat.h>

 #include <sys/wait.h>

 #include <glib.h>

 #include <clplumbing/cl_log.h>

 #include <clplumbing/cl_signal.h>

 #include <clplumbing/uids.h>

 #include <clplumbing/lsb_exitcodes.h>

 #include <clplumbing/GSource.h>

 #include <clplumbing/proctrack.h>

 #include <clplumbing/Gmain_timeout.h>

 #include <clplumbing/cl_pidfile.h>

 #include <apphb.h>

 static const char * Simple_helpscreen =

 "Usage cl_respawn [<options>] <monitored_program> [<arg1>] [<arg2>] ...\n"

 "Options are as below:\n"

 "-m magic_exit_code\n"

 "	When monitored_program exit as this magic_exit_code, then cl_respawn\n"

 "	will not try to respawn it.\n"

 "-i interval\n"

 "	Set the interval(ms) of application hearbeat or plumbing its client.\n" 

 "-w warntime\n"

 "	Set the warning time (ms) of application heartbeat.\n"

 "-p pidfile\n"

 "	Set the name of a pid file to use.\n"

 "-r	Recover itself from crash. Only called by other monitor programs like"

 "	recovery manager.\n"

 "-l	List the program monitored by cl_respawn.\n"

 "	Notice: donnot support yet.\n"

 "-h	Display this simple help.\n";

 static void become_daemon(void);

 static int  run_client_as_child(char * client_argv[]);

 static gboolean plumb_client_and_emit_apphb(gpointer data);

 static gboolean cl_respawn_quit(int signo, gpointer user_data);

 static void separate_argv(int * argc_p, char *** argv_p, char *** client_argv);

 static int cmd_str_to_argv(char * cmd_str, char *** argv);

 static void free_argv(char ** argv);

 /* Functions for handling the child quit/abort event

  */

 static void monitoredProcessDied(ProcTrack* p, int status, int signo

             ,	int exitcode, int waslogged);

 static void monitoredProcessRegistered(ProcTrack* p);

 static const char * monitoredProcessName(ProcTrack* p);

 static ProcTrack_ops MonitoredProcessTrackOps = {

         monitoredProcessDied,

         monitoredProcessRegistered,

         monitoredProcessName

 };

 static const int

 	INSTANCE_NAME_LEN = 20,

 	APPHB_INTVL_DETLA = 30;    /* Avoid the incorrect warning message */ 

 static const unsigned long 

 	DEFAULT_APPHB_INTERVAL 	= 2000, /* MS */

 	DEFAULT_APPHB_WARNTIME  = 6000; /* MS */

 static int MAGIC_EXIT_CODE = 100;

 static const char * app_name = "cl_respawn";

 static gboolean	REGTO_APPHBD = FALSE;

 static char * pidfile = NULL;

 /* 

  * This pid will equal to the PID of the process who was ever the child of 

  * that dead cl_respawn.

  */

 static pid_t monitored_PID = 0;

 static const char * optstr = "rm:i:w:p:lh";

 static GMainLoop * mainloop = NULL;

 static gboolean IS_RECOVERY = FALSE;

 static gboolean shutting_down = FALSE;

 int main(int argc, char * argv[])

 {

 	char app_instance[INSTANCE_NAME_LEN];

 	int option_char;

 	int interval = DEFAULT_APPHB_INTERVAL;

 	int apphb_warntime = DEFAULT_APPHB_WARNTIME;

 	char ** client_argv = NULL;

 	pid_t child_tmp = 0;

 	cl_log_set_entity(app_name);

 	cl_log_enable_stderr(TRUE);

 	cl_log_set_facility(HA_LOG_FACILITY);

 	if (argc == 1) { /* no arguments */

 		printf("%s\n", Simple_helpscreen);

 		exit(LSB_EXIT_EINVAL);

 	}

 	/* 

 	 * Try to separate the option parameter between myself and the client.

 	 * Maybe rewrite the argc and argv. 

 	 */

 	separate_argv(&argc, &argv, &client_argv);

 	/* code for debug */

 #if 0

 	{

 		int j;

 		cl_log(LOG_INFO, "client_argv: 0x%08lx", (unsigned long) client_argv);

 		cl_log(LOG_INFO, "Called arg");

 		for (j=0; argv[j] != NULL; ++j) {

 			cl_log(LOG_INFO, "argv[%d]: %s", j, argv[j]);

 		}

 		for (j=0; client_argv && client_argv[j] != NULL; ++j) {

 			if (ANYDEBUG) {

 				cl_log(LOG_INFO, "client_argv[%d]: %s", j, client_argv[j]);

 			}

 		}

 	}

 #endif

 	do {

 		option_char = getopt(argc, argv, optstr);

 		if (option_char == -1) {

 			break;

 		}

 		switch (option_char) {

 			case 'r':

 				IS_RECOVERY = TRUE;

 				break;

 			case 'm':

 				if (optarg) {

 					MAGIC_EXIT_CODE = atoi(optarg); 

 				}

 				break;

 			case 'i':

 				if (optarg) {

 					interval = atoi(optarg);

 				} else {

 					printf("error.\n");

 				}

 				break;

 			case 'p':

 				if (optarg) {

 					pidfile = optarg;

 				}

 				break;

 			case 'w':

 				if (optarg) {

 					apphb_warntime = atoi(optarg);

 				}

 				break;

 			case 'l':

 				break;

 				/* information */

 				return LSB_EXIT_OK;

 			case 'h':

 				printf("%s\n",Simple_helpscreen);

 				return LSB_EXIT_OK;

 			default:

 				cl_log(LOG_ERR, "getopt returned" 

 					"character code %c.", option_char);

 				printf("%s\n",Simple_helpscreen);

 				return LSB_EXIT_EINVAL;

 		}

 	} while (1);

 	/* 

 	 * Now I suppose recovery program only pass the client name via 

 	 * environment variables.

 	 */

 	if ( (IS_RECOVERY == FALSE) && (client_argv == NULL) ) {

 		cl_log(LOG_ERR, "Please give the program name which will be " 

 			"run as a child process of cl_respawn.");

 		printf("%s\n", Simple_helpscreen);

 		exit(LSB_EXIT_EINVAL);

 	}

 	if ((IS_RECOVERY == TRUE ) && ( client_argv == NULL)) {

 		/*

 		 * Here the client_argv must be NULL. At least now just 

 		 * suppose so.

 		 */

 		/* 

 		 * From the environment variables to acquire the necessary

 		 * information set by other daemons like recovery manager.

 		 * RSP_PID:  the PID of the process which need to be monitored.

 		 * RSP_CMD:  the command line to restart the program, which is

 		 * the same as the input in command line as above. 

 		 */

 		if ( getenv("RSP_PID") == NULL ) {

 			cl_log(LOG_ERR, "cannot get monitored PID from the "

 				"environment variable which should be set by "

 				"the recovery program.");

 			exit(LSB_EXIT_EINVAL);

 		} else {

 			monitored_PID = atoi(getenv("RSP_PID"));

 		}

 		/* 

 		 * client_argv == NULL" indicates no client program passed as 

 		 * a parameter by others such as a recovery manager, so expect 

 		 * it will be passed by environment variable RSP_CMD, see as 

 		 * below. If cannot get it, quit.

 		 */

 		if (client_argv == NULL) {

 			if (getenv("RSP_CMD") == NULL) {

 				cl_log(LOG_ERR, "cannot get the argument of the "

 					"monitored program from the environment "

 					"variable, which should be set by the "

 					"recovery program.");

 			}

 			if (0!=cmd_str_to_argv(getenv("RSP_CMD"), &client_argv)) {

 				cl_log(LOG_ERR, "Failed to transfer the CLI "

 					"string to the argv[] style.");

 				exit(LSB_EXIT_EINVAL);

 			}	

 		}

 	}

 	/* Not use the API 'daemon' since it's not a POSIX's */

 	become_daemon();

 	/* Code for debug

 	int k = 0;

 	do {

 		cl_log(LOG_INFO,"%s", execv_argv[k]);

 	} while (execv_argv[++k] != NULL); 

 	*/

 	set_sigchld_proctrack(G_PRIORITY_HIGH,DEFAULT_MAXDISPATCHTIME);

 	if (( IS_RECOVERY == FALSE )) {

 		child_tmp = run_client_as_child(client_argv);

 		if (child_tmp > 0 ) {

 			cl_log(LOG_NOTICE, "started the monitored program %s, "

 			   "whose PID is %d", client_argv[0], child_tmp); 

 		} else {

 			exit(LSB_EXIT_GENERIC);

 		}

 	}

 	snprintf(app_instance, INSTANCE_NAME_LEN, "%s_%ldd"

 		, app_name, (long)getpid());

 	if (apphb_register(app_name, app_instance) != 0) {

 		cl_log(LOG_WARNING, "Failed to register with apphbd.");

 		cl_log(LOG_WARNING, "Maybe apphd isn't running.");

 		REGTO_APPHBD = FALSE;

 	} else {

 		REGTO_APPHBD = TRUE;

 		cl_log(LOG_INFO, "Registered with apphbd.");

 		apphb_setinterval(interval);

 		apphb_setwarn(apphb_warntime);

 		/* To avoid the warning when app_interval is very small. */

 		apphb_hb();

 	}

 	Gmain_timeout_add(interval - APPHB_INTVL_DETLA

 		, 	  plumb_client_and_emit_apphb, client_argv);

 	mainloop = g_main_new(FALSE);

 	g_main_run(mainloop);

 	if ( REGTO_APPHBD == TRUE ) {

 		apphb_hb();

 		apphb_unregister();

 	}

 	return LSB_EXIT_OK;

 }

 static int

 run_client_as_child(char * execv_argv[])

 {

 	long	pid;

 	int	i;

 	if (execv_argv[0] == NULL) {

 		cl_log(LOG_ERR, "Null pointer to program name which need to" 

 			"be executed.");

 		return LSB_EXIT_EINVAL;

 	}

 	pid = fork();

 	if (pid < 0) {

 		cl_log(LOG_ERR, "cannot start monitor program %s.", 

 			execv_argv[0]);

 		return -1;

 	} else if (pid > 0) { /* in the parent process */

 		NewTrackedProc( pid, 1, PT_LOGVERBOSE

 			, execv_argv, &MonitoredProcessTrackOps);

 		monitored_PID = pid;

 		return pid;

 	}

  	/* Now in child process */

 	execvp(execv_argv[0], execv_argv);

 	/* if go here, there must be something wrong */

 	cl_log(LOG_ERR, "%s",strerror(errno));

 	cl_log(LOG_ERR, "execving monitored program %s failed.", execv_argv[0]);

 	i = 0;

 	do {

 		free(execv_argv[i]);

 	} while (execv_argv[++i] != NULL); 

 	/* Since parameter error, donnot need to be respawned */

 	exit(MAGIC_EXIT_CODE);

 }

 /* 

  * Notes: Since the work dir is changed to "/", the client name should include

  * pathname or it's located in the system PATH

 */

 static void

 become_daemon(void)

 {

 	int j;

 	if (pidfile) {

 		int	runningpid;

 		if ((runningpid=cl_read_pidfile(pidfile)) > 0) {

 			cl_log(LOG_WARNING, "pidfile [%s] says we're already running as pid [%d]"

 			,	pidfile, runningpid);

 			exit(LSB_EXIT_OK);

 		}

 		if (cl_lock_pidfile(pidfile) != 0) {

 			cl_log(LOG_ERR, "Cannot create pidfile [%s]"

 			,	pidfile);

 			exit(LSB_EXIT_GENERIC);

 		}

 	}

 #if 0

 	pid_t pid;

 	pid = fork();

 	if (pid < 0) {

 		cl_log(LOG_ERR, "cannot start daemon.");

 		exit(LSB_EXIT_GENERIC);

 	} else if (pid > 0) {

 		exit(LSB_EXIT_OK);

 	}

 #endif

 	if (chdir("/") < 0) {

 		cl_log(LOG_ERR, "cannot chroot to /.");

 		exit(LSB_EXIT_GENERIC);

 	}

 	umask(022);

 	setsid();

 	for (j=0; j < 3; ++j) {

 		close(j);

 		(void)open("/dev/null", j == 0 ? O_RDONLY : O_RDWR);

 	}

 	CL_IGNORE_SIG(SIGINT);

 	CL_IGNORE_SIG(SIGHUP);

 	G_main_add_SignalHandler(G_PRIORITY_DEFAULT, SIGTERM, cl_respawn_quit, NULL, NULL);

 }

 static gboolean

 plumb_client_and_emit_apphb(gpointer data)

 {

 	pid_t new_pid;

 	char ** client_argv = (char **) data;

 	if ( REGTO_APPHBD == TRUE ) {

 		apphb_hb();

 	}

 	if (shutting_down) {

 		return TRUE;

 	}

 	/* cl_log(LOG_NOTICE,"donnot emit hb for test."); */

 	if ( IS_RECOVERY == TRUE  && !(CL_PID_EXISTS(monitored_PID)) ) {

 		cl_log(LOG_INFO, "process %d exited.", monitored_PID);

 		new_pid = run_client_as_child(client_argv);

 		if (new_pid > 0 ) {

 			cl_log(LOG_NOTICE, "restart the monitored program %s,"

 				" whose PID is %d", client_argv[0], new_pid); 

 		} else { 

 			/* 

 			 * donnot let recovery manager restart me again, avoid

 			 * infinite loop 

 			*/

 			cl_log(LOG_ERR, "Failed to restart the monitored "

 				"program %s, will exit.", client_argv[0]);

 			cl_respawn_quit(SIGTERM, NULL);

 		}

 	}

 	return TRUE;

 }

 static gboolean

 cl_respawn_quit(int signo, gpointer user_data)

 {

 	shutting_down = TRUE;

 	if (monitored_PID != 0) {

 		cl_log(LOG_INFO, "Killing pid [%d] with SIGTERM"

 		,	monitored_PID);

 		/* DisableProcLogging(); */

 		if (kill(monitored_PID, SIGTERM) < 0) {

 			monitored_PID=0;

 		}else{

 			return TRUE;

 		}

 	}

 	if (mainloop != NULL && g_main_is_running(mainloop)) {

 		DisableProcLogging();

 		g_main_quit(mainloop);

 	} else {

 		apphb_unregister();

 		DisableProcLogging();

 		exit(LSB_EXIT_OK);

 	}

 	return TRUE;

 }

 static void 

 separate_argv(int * argc_p, char *** argv_p, char *** client_argv_p)

 {

 	/* Search the first no-option parameter */

 	int i,j;

 	struct stat buf;

 	*client_argv_p = NULL;

 	for (i=1; i < *argc_p; i++) {

 		if (    ((*argv_p)[i][0] != '-') 

 		     && (0 == stat((*argv_p)[i], &buf)) ) {

 			if (   S_ISREG(buf.st_mode)

 			    && ((S_IXUSR| S_IXGRP | S_IXOTH) & buf.st_mode) ) {

 				break;

 			}

 		}

 	}

 	/* 

 	 * Cannot find a valid program name which will be run as a child

 	 * process of cl_respawn, may be a recovery.

 	 */

 	if (*argc_p == i) {

 		return;

 	}

 	*client_argv_p = calloc(*argc_p - i + 1, sizeof(char*));

 	if (*client_argv_p == NULL) {

 		cl_perror("separate_argv:calloc: ");

 		exit(1);

 	}

 	for (j=i; j < *argc_p; j++) {

 		(*client_argv_p)[j-i] = (*argv_p)[j];	

 	}

 	(*argv_p)[i] = NULL;

 	*argc_p = i;

 	return;

 }

 static int 

 cmd_str_to_argv(char * cmd_str, char *** client_argv_p)

 {

 	const int MAX_NUM_OF_PARAMETER = 80;

 	char *pre, *next;

 	int index = 0;

 	int i, len_tmp;

 	if (cmd_str == NULL) {

 		return LSB_EXIT_EINVAL;

 	}

 	*client_argv_p = calloc(MAX_NUM_OF_PARAMETER, sizeof(char *));

 	if (*client_argv_p == NULL) {

 		cl_perror("cmd_str_to_argv:calloc: ");

 		return LSB_EXIT_GENERIC;

 	}

 	pre = cmd_str;

 	do {

 		next = strchr(pre,' ');

 		if (next == NULL) {

 			len_tmp = strnlen(pre, 80);	

 			(*client_argv_p)[index] = calloc(len_tmp+1, sizeof(char));

 			if (((*client_argv_p)[index]) == NULL ) {

 				cl_perror("cmd_str_to_argv:calloc: ");

 				return LSB_EXIT_GENERIC;

 			}

 			strncpy((*client_argv_p)[index], pre, len_tmp);

 			break;

 		}

 		(*client_argv_p)[index] = calloc(next-pre+1, sizeof(char));

 		if (((*client_argv_p)[index]) == NULL ) {

 			cl_perror("cmd_str_to_argv:calloc: ");

 			return LSB_EXIT_GENERIC;

 		}

 		strncpy((*client_argv_p)[index], pre, next-pre);

 		/* remove redundant spaces between parametes */

 		while ((char)(*next)==' ') {

 			next++;

 		}

 		pre = next;

 		if (++index >= MAX_NUM_OF_PARAMETER - 1) {

 			break; 

 		}

 	} while (1==1);

 	if (index >= MAX_NUM_OF_PARAMETER - 1) {

 		for (i = 0; i < MAX_NUM_OF_PARAMETER; i++) {

 			free((*client_argv_p)[i]);

 		} 

 		free(*client_argv_p);

 		return LSB_EXIT_EINVAL; 

 	}

 	(*client_argv_p)[index+1] = NULL;

 	return 0;

 }

 static void

 monitoredProcessDied(ProcTrack* p, int status, int signo

 			, int exitcode, int waslogged)

 {

 	pid_t new_pid;

 	char ** client_argv = (char **) p->privatedata;

 	const char * pname = p->ops->proctype(p);

 	if (shutting_down) {

 		cl_respawn_quit(SIGTERM, NULL);

 		p->privatedata = NULL;

 		return;

 	}

 	if ( exitcode == MAGIC_EXIT_CODE) {

 		cl_log(LOG_INFO, "Don't restart the monitored program"

 			" %s [%d], since we got the magic exit code."

 			, pname, p->pid);

 		free_argv(client_argv);

 		cl_respawn_quit(SIGTERM, NULL);	/* Does NOT always exit */

 		return;

 	}

 	cl_log(LOG_INFO, "process %s[%d] exited, and its exit code is %d"

 		, pname, p->pid, exitcode);

 	if ( 0 < (new_pid = run_client_as_child(client_argv)) ) {

 		cl_log(LOG_NOTICE, "restarted the monitored program, whose PID "

 			" is %d", new_pid); 

 	} else {

 		cl_log(LOG_ERR, "Failed to restart the monitored program %s ,"

 			"will exit.", pname );

 		free_argv(client_argv);

 		cl_respawn_quit(SIGTERM, NULL);	/* Does NOT always exit */

 		return;

 	}

 	p->privatedata = NULL;

 }

 static void

 monitoredProcessRegistered(ProcTrack* p)

 {

 	cl_log(LOG_INFO, "Child process [%s] started [ pid: %d ]."

 			, p->ops->proctype(p), p->pid);

 }

 static const char *

 monitoredProcessName(ProcTrack* p)

 {

 	char ** argv = p->privatedata;

 	return  argv[0];

 }

 static void

 free_argv(char ** argv)

 {

 	int i = 0;

 	if ( argv == NULL ) {

 		return;

 	}

 	do {

 		if (argv[i] != NULL) {

 			free(argv[i++]);

 		} else {

 			free(argv);

 			return;

 		}

 	} while (1==1);

 }