/* 
 * modbuslog
 *
 * Copyright (C) 2011 Jonathan McCrohan
 *
 * 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 3 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/>.
 */

// gcc modbuslog.c -o modbuslog `pkg-config --libs --cflags libmodbus libconfig`

#ifndef VERSION_STRING
#define VERSION_STRING "[undefined version]"
#endif

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <time.h>
#include <unistd.h>
#include <sys/select.h>
#include <signal.h>
#include <fcntl.h>

#include <libconfig.h>
#include <modbus.h>

#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <net/if.h>
#include <string.h>

#include <syslog.h>

// handle SIGALRM by resetting it
void minute_check(int signum) {
	alarm(60);
}

// get mac address of primary interface eth0
char *mac_address() {
	int s;
	struct ifreq ifr;

	s = socket(PF_INET, SOCK_DGRAM, 0);
	memset(&ifr, 0x00, sizeof(ifr));
	strcpy(ifr.ifr_name, "eth0");
	ioctl(s, SIOCGIFHWADDR, &ifr);
	close(s);

	static char mac_address[12];
	sprintf(mac_address, "%.2X%.2X%.2X%.2X%.2X%.2X",
			(unsigned char) ifr.ifr_hwaddr.sa_data[0],
			(unsigned char) ifr.ifr_hwaddr.sa_data[1],
			(unsigned char) ifr.ifr_hwaddr.sa_data[2],
			(unsigned char) ifr.ifr_hwaddr.sa_data[3],
			(unsigned char) ifr.ifr_hwaddr.sa_data[4],
			(unsigned char) ifr.ifr_hwaddr.sa_data[5]);

	return mac_address;
}

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

	int DEBUG = 0;
	int SYSLOG_CONSOLE_OUTPUT = 0;
	int k;

	// check the argv array for strings matching -d
	for (k = 1; k < argc; k++) {
		if (strcmp(argv[k], "-d") == 0) {
			DEBUG = 1;
			SYSLOG_CONSOLE_OUTPUT = LOG_PERROR;
		}
	}

	openlog("modbuslog", SYSLOG_CONSOLE_OUTPUT | LOG_PID | LOG_CONS, LOG_USER);

	syslog(LOG_INFO, "");
	syslog(LOG_INFO, "modbuslog [%s] starting", VERSION_STRING);
	syslog(LOG_INFO, "");

	const char *configfile = "/etc/modbuslog.cfg";
	config_t cfg;
	//config_setting_t *setting;

	const char *modbus_device_address;
	int modbus_baud_rate;
	int modbus_data_bits;
	const char *modbus_parity;
	int modbus_stop_bits;
	int modbus_retry;

	config_init(&cfg);

	// attempt to read config
	// loads entire file to memory and destroys file descriptor
	if (!config_read_file(&cfg, configfile)) {
		fprintf(stderr, "%s:%d - %s\n", config_error_file(&cfg),
				config_error_line(&cfg), config_error_text(&cfg));
		config_destroy(&cfg);
		syslog(LOG_ERR, "Unable to find configfile");
		return -1;
	} else {
		syslog(LOG_INFO, "configfile found successfu<style>pre { line-height: 125%; }
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.highlight .il { color: #0000DD; font-weight: bold } /* Literal.Number.Integer.Long */</style><div class="highlight"><pre><span></span># Digitenne (Randstad, The Netherlands)
# T freq bw fec_hi fec_lo mod transmission-mode guard-interval hierarchy
T 474000000 8MHz 1/2 NONE QAM64 8k 1/4 NONE
T 490000000 8MHz 1/2 NONE QAM64 8k 1/4 NONE
T 578000000 8MHz 1/2 NONE QAM64 8k 1/4 NONE
T 762000000 8MHz 1/2 NONE QAM64 8k 1/4 NONE
T 818000000 8MHz 1/2 NONE QAM64 8k 1/4 NONE
</pre></div>
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stervalue = ((byte[0]) << 8) + byte[1];
					break;
				}

				struct tm utc = *gmtime(&unixtime_min);
				struct tm lc = *localtime(&unixtime_min);

				int intervalid;
				char interval_filename[50];
				sprintf(interval_filename,
						"/var/modbuslog/interval/interval.txt");

				syslog(LOG_DEBUG, "opening interval file: [%s]",
						interval_filename);

				FILE *intervalfile = fopen(interval_filename, "r+");

				if (intervalfile) {
					fclose(intervalfile);
				} else {
					// file doesn't exist. create it.
					syslog(LOG_NOTICE, "interval file does not exist");
					syslog(LOG_INFO, "attempting to create file: [%s]",
							interval_filename);
					intervalfile = fopen(interval_filename, "w");
					fprintf(intervalfile, "0\n");
					fclose(intervalfile);
				}

				// file now exists, try opening again
				intervalfile = fopen(interval_filename, "r+");

				fscanf(intervalfile, "%d", &intervalid);
				//handle 32bit signed overflow
				if (intervalid == 2147483647) {
					intervalid = 0;
				} else {
					intervalid++;
				}
				rewind(intervalfile);
				fprintf(intervalfile, "%d", intervalid);
				fclose(intervalfile);

				fprintf(
						filehandle,
						"%i|%04i%02i%02i|%02i%02i%02i|%04i%02i%02i|%02i%02i%02i|%i|%i|%i\n",
						intervalid, utc.tm_year + 1900, utc.tm_mon + 1,
						utc.tm_mday, utc.tm_hour, utc.tm_min, utc.tm_sec,
						lc.tm_year + 1900, lc.tm_mon + 1, lc.tm_mday,
						lc.tm_hour, lc.tm_min, lc.tm_sec, slaveid, startaddress,
						registervalue);
				fclose(filehandle);

				syslog(
						LOG_DEBUG,
						"[%i|%04i%02i%02i|%02i%02i%02i|%04i%02i%02i|%02i%02i%02i|%i|%i|%i]\n",
						intervalid, utc.tm_year + 1900, utc.tm_mon + 1,
						utc.tm_mday, utc.tm_hour, utc.tm_min, utc.tm_sec,
						lc.tm_year + 1900, lc.tm_mon + 1, lc.tm_mday,
						lc.tm_hour, lc.tm_min, lc.tm_sec, slaveid, startaddress,
						registervalue);

				modbus_close(ctx);
				modbus_free(ctx);

				sleep(1);
				//return 0;

			}
			//printf("%d ", slaveid);
		}
		// revert to normal timing
		firstrun = 0;
		//printf("%d\n", unixtime_min);
	}
}