/*
 * citserver's main() function lives here.
 * 
 * Copyright (c) 1987-2018 by the citadel.org team
 *
 * This program is open source software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 3.
 *
 * 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.
 */
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <grp.h>
#include <sys/file.h>
#include <libcitadel.h>

#include "citserver.h"
#include "svn_revision.h"
#include "modules_init.h"
#include "config.h"
#include "control.h"
#include "serv_extensions.h"
#include "citadel_dirs.h"
#include "user_ops.h"
#include "ecrash.h"

uid_t ctdluid = 0;
const char *CitadelServiceUDS="citadel-UDS";
const char *CitadelServiceTCP="citadel-TCP";
void go_threading(void);


/*
 * Create or remove a lock file, so we only have one Citadel Server running at a time.
 */
void ctdl_lockfile(int yo) {
	static char lockfilename[SIZ];
	static FILE *fp;

	if (yo) {
		syslog(LOG_DEBUG, "main: creating lockfile");
		snprintf(lockfilename, sizeof lockfilename, "%s/citadel.lock", ctdl_run_dir);
		fp = fopen(lockfilename, "w");
		if (!fp) {
			syslog(LOG_ERR, "%s: %m", lockfilename);
			exit(CTDLEXIT_DB);
		}
		if (flock(fileno(fp), (LOCK_EX|LOCK_NB)) != 0) {
			syslog(LOG_ERR, "main: cannot lock %s , is another citserver running?", lockfilename);
			exit(CTDLEXIT_DB);
		}
		return;
	}

	syslog(LOG_DEBUG, "main: removing lockfile");
	unlink(lockfilename);
	flock(fileno(fp), LOCK_UN);
	fclose(fp);
}


/*
 * Here's where it all begins.
 */
int main(int argc, char **argv)
{
	size_t basesize = 64;
	char facility[32];
	int a;			/* General-purpose variables */
	struct passwd pw, *pwp = NULL;
	char pwbuf[SIZ];
	int drop_root_perms = 1;
	int relh=0;
	int home=0;
	int dbg=0;
	int max_log_level = LOG_INFO;
	char relhome[PATH_MAX]="";
	char ctdldir[PATH_MAX]=CTDLDIR;
	int syslog_facility = LOG_DAEMON;
	uid_t u = 0;
	struct passwd *p = NULL;
#ifdef HAVE_RUN_DIR
	struct stat filestats;
#endif
#ifdef HAVE_BACKTRACE
	eCrashParameters params;
//	eCrashSymbolTable symbol_table;
#endif

	/* initialize the master context */
	InitializeMasterCC();
	InitializeMasterTSD();

	/* parse command-line arguments */
	while ((a=getopt(argc, argv, "l:dh:x:t:B:Dru:")) != EOF) switch(a) {

		case 'l':
			safestrncpy(facility, optarg, sizeof(facility));
			syslog_facility = SyslogFacility(facility);
			break;

		/* run in the background if -d was specified */
		case 'd':
			running_as_daemon = 1;
			break;

		case 'h':
			relh = optarg[0] != '/';
			if (!relh) {
				safestrncpy(ctdl_home_directory, optarg, sizeof ctdl_home_directory);
			}
			else {
				safestrncpy(relhome, optarg, sizeof relhome);
			}
			home=1;
			break;

		case 'x':
			max_log_level = atoi(optarg);
			break;

		case 't':	/* deprecated */
			break;
                case 'B': /* Basesize */
                        basesize = atoi(optarg);
                        break;

		case 'D':
			dbg = 1;
			break;

		/* -r tells the server not to drop root permissions.
		 * Don't use this unless you know what you're doing.
		 */
		case 'r':
			drop_root_perms = 0;
			break;

		/* -u tells the server what uid to run under... */
		case 'u':
			u = atoi(optarg);
			if (u > 0) {
				ctdluid = u;
			}
			else {
				p = getpwnam(optarg);
				if (p) {
					u = p->pw_uid;
				}
			}
			if (u > 0) {
				ctdluid = u;
			}
			break;

		default:
		/* any other parameter makes it crash and burn */
			fprintf(stderr,	"citserver: usage: "
					"citserver "
					"[-l LogFacility] "
					"[-x MaxLogLevel] "
					"[-d] [-D] [-r] "
					"[-u user] "
					"[-h HomeDir]\n"
			);
			exit(1);
	}

	/* Last ditch effort to determine the user name ... if there's a user called "citadel" then use that */
	if (ctdluid == 0) {
		p = getpwnam("citadel");
		if (!p) {
			p = getpwnam("bbs");
		}
		if (!p) {
			p = getpwnam("guest");
		}
		if (p) {
			u = p->pw_uid;
		}
		if (u > 0) {
			ctdluid = u;
		}
	}

	if ((ctdluid == 0) && (drop_root_perms == 0)) {
		fprintf(stderr, "citserver: cannot determine user to run as; please specify -r or -u options\n");
		exit(CTDLEXIT_UNUSER);
	}

	StartLibCitadel(basesize);
	setlogmask(LOG_UPTO(max_log_level));
	openlog("citserver",
		( running_as_daemon ? (LOG_PID) : (LOG_PID | LOG_PERROR) ),
		syslog_facility
	);

	calc_dirs_n_files(relh, home, relhome, ctdldir, dbg);
	/* daemonize, if we were asked to */
	if (running_as_daemon) {
		start_daemon(0);
		drop_root_perms = 1;
	}

	/* Tell 'em who's in da house */
	syslog(LOG_INFO, " ");
	syslog(LOG_INFO, " ");
	syslog(LOG_INFO, "*** Citadel server engine ***\n");
 	syslog(LOG_INFO, "Version %d (build %s) ***", REV_LEVEL, svn_revision());
	syslog(LOG_INFO, "Copyright (C) 1987-2018 by the Citadel development team.");
	syslog(LOG_INFO, " ");
	syslog(LOG_INFO, "This program is open source software: you can redistribute it and/or");
	syslog(LOG_INFO, "modify it under the terms of the GNU General Public License, version 3.");
	syslog(LOG_INFO, " ");
	syslog(LOG_INFO, "This program is distributed in the hope that it will be useful,");
	syslog(LOG_INFO, "but WITHOUT ANY WARRANTY; without even the implied warranty of");
	syslog(LOG_INFO, "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the");
	syslog(LOG_INFO, "GNU General Public License for more details.");
	syslog(LOG_INFO, " ");
	syslog(LOG_INFO, "%s", libcitadel_version_string());

#ifdef HAVE_RUN_DIR
	/* on some dists rundir gets purged on startup. so we need to recreate it. */

	if (stat(ctdl_run_dir, &filestats) == -1) {
#ifdef HAVE_GETPWUID_R
#ifdef SOLARIS_GETPWUID
		pwp = getpwuid_r(ctdluid, &pw, pwbuf, sizeof(pwbuf));
#else // SOLARIS_GETPWUID
		getpwuid_r(ctdluid, &pw, pwbuf, sizeof(pwbuf), &pwp);
#endif // SOLARIS_GETPWUID
#else // HAVE_GETPWUID_R
		pwp = NULL;
#endif // HAVE_GETPWUID_R

		if ((mkdir(ctdl_run_dir, 0755) != 0) && (errno != EEXIST)) {
			syslog(LOG_ERR, "main: unable to create run directory [%s]: %m", ctdl_run_dir);
		}

		if (chown(ctdl_run_dir, ctdluid, (pwp==NULL)?-1:pw.pw_gid) != 0) {
			syslog(LOG_ERR, "main: unable to set the access rights for [%s]: %m", ctdl_run_dir);
		}
	}
#endif

	ctdl_lockfile(1);

	/* Initialize... */
	init_sysdep();

	/*
	 * Do non system dependent startup functions.
	 */
	master_startup();

	/*
	 * Check that the control record is correct and place sensible values if it isn't
	 */
	check_control();
	
	/*
	 * Run any upgrade entry points
	 */
	syslog(LOG_INFO, "main: upgrading modules");
	upgrade_modules();
	
/*
 * Load the user for the masterCC or create them if they don't exist
 */
	if (CtdlGetUser(&masterCC.user, "SYS_Citadel"))
	{
		/* User doesn't exist. We can't use create user here as the user number needs to be 0 */
		strcpy (masterCC.user.fullname, "SYS_Citadel") ;
		CtdlPutUser(&masterCC.user);
		CtdlGetUser(&masterCC.user, "SYS_Citadel"); /* Just to be safe */
	}
	
	/*
	 * Bind the server to a Unix-domain socket (user client access)
	 */
	CtdlRegisterServiceHook(0,
				file_citadel_socket,
				citproto_begin_session,
				do_command_loop,
				do_async_loop,
				CitadelServiceUDS);

	/*
	 * Bind the server to a Unix-domain socket (admin client access)
	 */
	CtdlRegisterServiceHook(0,
				file_citadel_admin_socket,
				citproto_begin_admin_session,
				do_command_loop,
				do_async_loop,
				CitadelServiceUDS);
	chmod(file_citadel_admin_socket, S_IRWXU);	/* for your eyes only */

	/*
	 * Bind the server to our favorite TCP port (usually 504).
	 */
	CtdlRegisterServiceHook(CtdlGetConfigInt("c_port_number"),
				NULL,
				citproto_begin_session,
				do_command_loop,
				do_async_loop,
				CitadelServiceTCP);

				
	
	
	/*
	 * Load any server-side extensions available here.
	 */
	syslog(LOG_INFO, "main: initializing server extensions");
	
	initialise_modules(0);

	/*
	 * If we need host auth, start our chkpwd daemon.
	 */
	if (CtdlGetConfigInt("c_auth_mode") == AUTHMODE_HOST) {
		start_chkpwd_daemon();
	}

	/*
	 * check, whether we're fired up another time after a crash.
	 * if, post an aide message, so the admin has a chance to react.
	 */
	checkcrash();

	/*
	 * Now that we've bound the sockets, change to the Citadel user id and its
	 * corresponding group ids
	 */
	if (drop_root_perms) {
		cdb_chmod_data();	/* make sure we own our data files */

#ifdef HAVE_GETPWUID_R
#ifdef SOLARIS_GETPWUID
		pwp = getpwuid_r(ctdluid, &pw, pwbuf, sizeof(pwbuf));
#else // SOLARIS_GETPWUID
		getpwuid_r(ctdluid, &pw, pwbuf, sizeof(pwbuf), &pwp);
#endif // SOLARIS_GETPWUID
#else // HAVE_GETPWUID_R
		pwp = NULL;
#endif // HAVE_GETPWUID_R

		if (pwp == NULL)
			syslog(LOG_ERR, "main: WARNING, getpwuid(%ld): %m Group IDs will be incorrect.", (long)CTDLUID);
		else {
			initgroups(pw.pw_name, pw.pw_gid);
			if (setgid(pw.pw_gid))
				syslog(LOG_ERR, "main: setgid(%ld): %m", (long)pw.pw_gid);
		}
		syslog(LOG_INFO, "main: changing uid to %ld", (long)CTDLUID);
		if (setuid(CTDLUID) != 0) {
			syslog(LOG_ERR, "main: setuid() failed: %m");
		}
#if defined (HAVE_SYS_PRCTL_H) && defined (PR_SET_DUMPABLE)
		prctl(PR_SET_DUMPABLE, 1);
#endif
	}

	/* We want to check for idle sessions once per minute */
	CtdlRegisterSessionHook(terminate_idle_sessions, EVT_TIMER, PRIO_CLEANUP + 1);

	go_threading();
	
	int exit_code = master_cleanup(exit_signal);
	ctdl_lockfile(0);
	return(exit_code);
}