main.cpp

/* 
 * File:   main.cpp
 * Author: Eckl, Máté<ecklm94@gmail.com>
 *
 * Created on 2016. április 19., 12:59
 */

#include <string.h>
#include <string>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <pwd.h>
#include <signal.h>

#include "include/general_sockaddr_wp.h"
#include "include/dns_server.h"
#include "include/exceptions/db_exception.h"
#include "include/logger.h"
#include "include/IPC_US_communicator.h"
#include "include/command.h"

#define WORKING_DIR "/home/mate/Dokumentumok/Egyetem/Tárgyak/2016 tavasz/Linux programozás/HF/DNS_server"
#define COMM_SOCK_PATH "/var/run/ecklm-dns/"

logger log_on_demand;
bool verbose = false;

void kill_handler(int);
void print_help();

int main(int argc, char *argv[])
{
	int cli_option;
	bool run_as_daemon = false;
	std::vector<command> command_list;
	while((cli_option = getopt (argc, argv, "dmskvh")) != -1)
	{
		switch(cli_option)
		{
			case 'd':
				run_as_daemon = true;
				break;
			case 'm':
				command_list.push_back(MONITOR);
				break;
			case 's':
				command_list.push_back(STATISTICS);
				break;
			case 'k':
				command_list.push_back(KILL);
				break;
			case 'v':
				verbose = true;
				break;
			case 'h':
				print_help();
				exit(EXIT_SUCCESS);
			case '?':
				print_help();
				exit(EXIT_FAILURE);
				break;
			default:
				break;
		}
	}
	if(!run_as_daemon)
	{
		log_on_demand = stdlog_on_demand;
	}
	else
	{
		openlog("ecklm-dns", LOG_PID, LOG_DAEMON);
		log_on_demand = syslog_on_demand;
#ifdef DEBUG // ezt az egész mókát parancssori paraméterektől kell majd függővé tenni
		if(daemon(0,1) < 0)
#else
		if(daemon(0,0) < 0)
#endif
		{
			PERROR_ON_DEMAND("daemon");
			exit(EXIT_FAILURE);
		}
	}

	if(getuid() != 0)
	{
		log_on_demand(LOG_ERR, "You should run with root privileges!");
		exit(EXIT_FAILURE);
	}

	log_on_demand(LOG_INFO, "Server started on pid %d", getpid()); // Enélkül nem hajlandó sudo után logolni.
	struct passwd *new_uid = getpwnam("dnsuser");

	if(chroot(WORKING_DIR) < 0)
	{
		PERROR_ON_DEMAND("chroot");
		exit(EXIT_SUCCESS);
	}
	log_on_demand(LOG_INFO, "Chrooted to \"%s\"", WORKING_DIR);
	if(chdir("/") < 0)
	{
		PERROR_ON_DEMAND("chdir");
		exit(EXIT_FAILURE);
	}
	setgid(new_uid->pw_gid);
	setuid(new_uid->pw_uid);

	IPC_US_communicator comm_link(COMM_SOCK_PATH, run_as_daemon);
	if(!run_as_daemon)
	{
		if(command_list.empty())
		{
			log_on_demand(LOG_ERR, "In this mode you must specify at least one command!");
			exit(EXIT_FAILURE);
		}
		for(command c : command_list)
		{
			comm_link.send_data(get_readable_command(c));
			log_on_demand(LOG_INFO, "Answer received: %s", comm_link.recv_data().c_str());
		}
		exit(EXIT_SUCCESS);
	}

	struct sigaction killer;
	sigemptyset(&killer.sa_mask);
	killer.sa_flags = 0;
	killer.sa_handler = kill_handler;
	killer.sa_restorer = NULL;
	if(sigaction(SIGTERM, &killer, NULL) < 0)
	{
		PERROR_ON_DEMAND("sigaction");
		exit(EXIT_FAILURE);
	}

// --------------- INIT ---------------------
	dns_server server;
	try
	{
		server.connect_db("dns.db");
	}
	catch(db_exception ex)
	{
		log_on_demand(LOG_ERR, ex.what());
		exit(EXIT_FAILURE);
	}

	// Init server
	struct in6_addr in6_addr_any = IN6ADDR_ANY_INIT; //IN6ADDR_LOOPBACK_INIT;
	struct sockaddr_in6 server_address;
	memset(&server_address, 0, sizeof(server_address));
	server_address.sin6_family = AF_INET6;
	server_address.sin6_addr = in6_addr_any;
	server_address.sin6_port = htons(10053);

	server.init(general_sockaddr_wp((sockaddr *) &server_address, sizeof(server_address)));
	if(verbose)
	{
		static char addr[INET6_ADDRSTRLEN];
		inet_ntop(server_address.sin6_family, &server_address.sin6_addr, addr, INET6_ADDRSTRLEN);
		log_on_demand(LOG_DEBUG, "Server started serving on: %s",addr);
	}

// ----------------- INIT END --------------------------

// ------------------ SERVE ----------------------------
	while(true)
	{
		server.serve_one_request();
		if(comm_link.recv_data() == "kill")
		{
			comm_link.send_data("go to hell!");
			log_on_demand(LOG_DEBUG, "Raising SIGTERM");
			raise(SIGTERM);
		}
		else
			comm_link.send_data("nothing has happened");
	}
// ---------------- SERVE END -------------------------

// ------------------- SHUTDOWN -------------------------
	server.shutdown();
// ----------------- SHUTDOWN END -----------------------
	exit(EXIT_SUCCESS);
}

void print_help() {
	printf(R"(Usage: Runs in foreground mode by default.
For more info look at the man page.

Options:
	-d Run as daemon
	-m Monitor daemon
	-s Statistics from daemon
	-k Kill daemon
	-v Verbose
	-h help
)");
}

void kill_handler(int x) {
	log_on_demand(LOG_INFO, "SIGTERM received");
	exit(EXIT_SUCCESS);
}