/* 
 * ccm.c: Consensus Cluster Service Program 
 *
 * Copyright (c) International Business Machines  Corp., 2002
 * Author: Ram Pai (linuxram@us.ibm.com)
 * 
 * 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, see <http://www.gnu.org/licenses/>
 *
 */
#include <lha_internal.h>
#include "ccm.h"
#include "ccmmisc.h"
#include <clplumbing/cl_signal.h>

#define SECOND   1000
#define OPTARGS  "dv"

GMainLoop*	mainloop = NULL;

/*
 * hearbeat event source.
 *   
 */
static gboolean hb_input_dispatch(IPC_Channel *, gpointer);
static void hb_input_destroy(gpointer);
static gboolean hb_timeout_dispatch(gpointer);
static gboolean
hb_input_dispatch(IPC_Channel * channel, gpointer user_data)
{
	if (channel && (channel->ch_status == IPC_DISCONNECT)) {
		ccm_log(LOG_ERR, "Lost connection to heartbeat service. Need to bail out.");
		return FALSE;
	}
	
	return ccm_take_control(user_data);
}

static void
hb_input_destroy(gpointer user_data)
{
	/* close connections to all the clients */
	client_delete_all();
	g_main_quit(mainloop);
	return;
}

static gboolean
hb_timeout_dispatch(gpointer user_data)
{	
	if(debug_level > 0) {
		ccm_check_memoryleak();
	}
	return hb_input_dispatch(0, user_data);
}


/*
 * client messaging  events sources...
 *   
 */
static gboolean clntCh_input_dispatch(IPC_Channel *
		,       gpointer);
static void clntCh_input_destroy(gpointer );

static gboolean
clntCh_input_dispatch(IPC_Channel *client, 
	      gpointer        user_data)
{
	if(client->ch_status == IPC_DISCONNECT){
		ccm_log(LOG_INFO, "client (pid=%d) removed from ccm", 
		       client->farside_pid);
		
		client_delete(client);
		return FALSE;
	}
	return TRUE; /* TOBEDONE */
}


static void
clntCh_input_destroy(gpointer user_data)
{
	return;
}



/*
 * client connection events source..
 *   
 */
static gboolean waitCh_input_dispatch(IPC_Channel *, gpointer);
static void waitCh_input_destroy(gpointer);

static gboolean
waitCh_input_dispatch(IPC_Channel *newclient, gpointer user_data)
{
	client_add(newclient);

	/* Some ccm clients may not consume our messages fast enough,
	 * but will have serious trouble if we kick them out for that reason.
	 * Worse, still, if send_message() "live locks" on one client, we won't
	 * be able to drain requests from other clients, possibly causing them
	 * to close their connection to us, or even causing the heartbeat MCP
	 * to kick _us_ out. Kick out the ccm! We really want to avoid that.
	 * Chose a "generous" queue length.
	 * And consider kicking out clients that still manage to have their
	 * queue fill up. (TOBEDONE)
	 */
	newclient->ops->set_send_qlen(newclient, 1024);

	G_main_add_IPC_Channel(G_PRIORITY_LOW, newclient, FALSE, 
				clntCh_input_dispatch, newclient, 
				clntCh_input_destroy);
	return TRUE;
}

static void
waitCh_input_destroy(gpointer user_data)
{
	IPC_WaitConnection *wait_ch = 
			(IPC_WaitConnection *)user_data;

	wait_ch->ops->destroy(wait_ch);
	return;
}

static IPC_WaitConnection *
wait_channel_init(void)
{
	IPC_WaitConnection *wait_ch;
	mode_t mask;
	char path[] = IPC_PATH_ATTR;
	char ccmfifo[] = CCMFIFO;
	char domainsocket[] = IPC_DOMAIN_SOCKET;

	GHashTable * attrs = g_hash_table_new(g_str_hash,g_str_equal);
	g_hash_table_insert(attrs, path, ccmfifo);

	mask = umask(0);
	wait_ch = ipc_wait_conn_constructor(domainsocket, attrs);
	if (wait_ch == NULL){
		cl_perror("Can't create wait channel");
		exit(1);
	}
	mask = umask(mask);

	g_hash_table_destroy(attrs);

	return wait_ch;
}

static void
usage(const char *cmd)
{
	fprintf(stderr, "\nUsage: %s [-v]\n", cmd);
}


/* */
/* debug facilitator. */
/* */
static void
usr_signal_handler(int signum) 
{
	switch(signum) {
	case SIGUSR1:
		debug_level++;
		break;

	case SIGUSR2:
		debug_level--;
		if (debug_level < 0) {
			debug_level = 0;
		}
		break;
	}
	
	if(debug_level > 0){
		cl_log_enable_stderr(TRUE);
	} else {
		cl_log_enable_stderr(FALSE);
	}
	ccm_log(LOG_INFO, "set debug_level to %d", debug_level);

}

static gboolean
ccm_shutdone(int sig, gpointer userdata)
{	
	ccm_t*		ccm = (ccm_t*)userdata;
	ccm_info_t *	info = (ccm_info_t*)ccm->info;

	ccm_log(LOG_INFO, "received SIGTERM, going to shut down");
	if (info == NULL){
		ccm_log(LOG_ERR, "ccm_shutdone: invalid arguments");
		return FALSE;
	}
	
	ccm_reset(info);
	g_main_quit(mainloop);
	
	return TRUE;
}

/* */
/* The main function! */
/* */
int
main(int argc, char **argv)
{
	IPC_WaitConnection *wait_ch;
	
	char *cmdname;
	char *tmp_cmdname;
	int  flag;
	ccm_t*	ccm;
	
	tmp_cmdname = g_strdup(argv[0]);
	if ((cmdname = strrchr(tmp_cmdname, '/')) != NULL) {
		++cmdname;
	} else {
		cmdname = tmp_cmdname;
	}
	cl_log_set_entity(cmdname);
	cl_log_set_facility(HA_LOG_FACILITY);
	while ((flag = getopt(argc, argv, OPTARGS)) != EOF) {
		switch(flag) {
		case 'v':		/* Debug mode, more logs*/
				++debug_level;
				break;
		default:
				usage(cmdname);
				return 1;
		}
	}
	if(debug_level > 0)
		cl_log_enable_stderr(TRUE);


	CL_SIGNAL(SIGUSR1, usr_signal_handler);
	CL_SIGNAL(SIGUSR2, usr_signal_handler);
	CL_IGNORE_SIG(SIGPIPE);
	
	cl_inherit_logging_environment(0);

	/* initialize the client tracking system */
	client_init();

	/* 
	 * heartbeat is the main source of events. 
	 * This source must be listened 
	 * at high priority 
	 */
	ccm = ccm_initialize();
	if(ccm == NULL){
		ccm_log(LOG_ERR, "Initialization failed. Exit");
		exit(1);
	}
	
	G_main_add_SignalHandler(G_PRIORITY_HIGH, SIGTERM, 
				 ccm_shutdone, ccm, NULL);
	/* we want hb_input_dispatch to be called when some input is
	 * pending on the heartbeat fd, and every 1 second 
	 */
	G_main_add_IPC_Channel(G_PRIORITY_HIGH, ccm_get_ipcchan(ccm), 
			FALSE, hb_input_dispatch, ccm, hb_input_destroy);
	Gmain_timeout_add_full(G_PRIORITY_HIGH, SECOND, hb_timeout_dispatch,
				ccm, hb_input_destroy);

	/* the clients wait channel is the other source of events.
	 * This source delivers the clients connection events.
	 * listen to this source at a relatively lower priority.
	 */
	wait_ch = wait_channel_init();
	G_main_add_IPC_WaitConnection(G_PRIORITY_LOW, wait_ch, NULL,
		FALSE, waitCh_input_dispatch, wait_ch,
		waitCh_input_destroy);

	mainloop = g_main_loop_new(NULL, FALSE);
	g_main_run(mainloop);
	g_main_destroy(mainloop);
	
	g_free(tmp_cmdname);
	/*this program should never terminate,unless killed*/
	return(1);
}
