thermometers/thermometers.c

/*****************************************************************************
 * Copyright (C) 2014
 *   
 * Michiel Broek <mbroek at mbse dot eu>
 *
 * This file is part of the mbsePi-apps
 *
 * This 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, or (at your option) any
 * later version.
 *
 * mbsePi-apps 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 EC-65K; see the file COPYING.  If not, write to the Free
 * Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *****************************************************************************/

#include "thermometers.h"


static int		my_shutdown = FALSE;
static pid_t		pgrp, mypid;

extern int		debug;
extern sys_config	Config;
#ifdef HAVE_WIRINGPI_H
extern int		lcdHandle;
#endif

int server(void);
void help(void);
void die(int);


void help(void)
{
    fprintf(stdout, "mbsePi-apps thermometers v%s starting\n\n", VERSION);
    fprintf(stdout, "Usage: thermomeneters [-d] [-h]\n");
    fprintf(stdout, "  -d --debug              Debug and run in foreground\n");
    fprintf(stdout, "  -h --help               Display this help\n");
}


void die(int onsig)
{
    switch (onsig) {
	case SIGHUP:	syslog(LOG_NOTICE, "Got SIGHUP, shutting down");
			break;
	case SIGINT:	syslog(LOG_NOTICE, "Keyboard interrupt, shutting down");
			break;
	case SIGTERM:	syslog(LOG_NOTICE, "Got SIGTERM, shutting down");
			break;
	default:	syslog(LOG_NOTICE, "die() on signal %d", onsig);
    }

    my_shutdown = TRUE;
}


#ifdef HAVE_WIRINGPI_H
void stopLCD(void)
{
   lcdClear(lcdHandle);
   setBacklight(0);
}
#endif


int main(int argc, char *argv[])
{
    int		rc, c, i;
    pid_t	frk;
#ifdef HAVE_WIRINGPI_H
    char	buf[80];
#endif

    while (1) {
	int option_index = 0;
	static struct option long_options[] = {
	    {"debug", 0, 0, 'c'},
	    {"help", 0, 0, 'h'},
	    {0, 0, 0, 0}
	};

	c = getopt_long(argc, argv, "dh", long_options, &option_index);
	if (c == -1)
	    break;

	switch (c) {
	    case 'd':	debug = TRUE;
			break;
	    case 'h':	help();
			return 1;
	}
    }

    openlog("thermometers", LOG_PID|LOG_CONS|LOG_NOWAIT, LOG_USER);
    syslog(LOG_NOTICE, "mbsePi-apps thermometers v%s starting", VERSION);
    if (debug)
	fprintf(stdout, "mbsePi-apps thermometers v%s starting\n", VERSION);

    if (rdconfig((char *)"thermometers.conf")) {
	fprintf(stderr, "Error reading configuration\n");
	syslog(LOG_NOTICE, "halted");
	return 1;
    }

    /*
     *  Catch all the signals we can, and ignore the rest. Note that SIGKILL can't be ignored
     *  but that's live. This daemon should only be stopped by SIGTERM.
     *  Don't catch SIGCHLD.
     */
    for (i = 0; i < NSIG; i++) {
    	if ((i != SIGCHLD) && (i != SIGKILL) && (i != SIGSTOP))
	    signal(i, (void (*))die);
    }

#ifdef HAVE_WIRINGPI_H

    if (wiringPiSetup () )
	return 1;

    if ((rc = initLCD (16, 2))) {
	fprintf(stderr, "Cannot initialize LCD display, rc=%d\n", rc);
	return 1;
    }

    lcdPosition(lcdHandle, 0, 0);
    lcdPuts(lcdHandle, "Thermometers");
    lcdPosition(lcdHandle, 0, 1);
    sprintf(buf, "Version %s", VERSION);
    lcdPuts(lcdHandle, buf);
#endif

    if (debug) {
	/*
	 * For debugging run in foreground.
	 */
	rc = server();
    } else {
	/*
	 * Server initialization is complete. Now we can fork the 
	 * daemon and return to the user. We need to do a setpgrp
	 * so that the daemon will no longer be assosiated with the
	 * users control terminal. This is done before the fork, so
	 * that the child will not be a process group leader. Otherwise,
	 * if the child were to open a terminal, it would become
	 * associated with that terminal as its control terminal.
	 */
	if ((pgrp = setpgid(0, 0)) == -1) {
	    syslog(LOG_NOTICE, "setpgpid failed");
	}

	frk = fork();
	switch (frk) {
	    case -1:	
		    	syslog(LOG_NOTICE, "Daemon fork failed: %s", strerror(errno));
			syslog(LOG_NOTICE, "Finished, rc=1");
#ifdef HAVE_WIRINGPI_H
			stopLCD();
#endif
			exit(1);
	    case 0:	/*
			 * Run the daemon
			 */
			fclose(stdin);
			if (open("/dev/null", O_RDONLY) != 0) {
			    syslog(LOG_NOTICE, "Reopen of stdin to /dev/null failed");
			    _exit(2);
			}
			fclose(stdout);
			if (open("/dev/null", O_WRONLY | O_APPEND | O_CREAT,0600) != 1) {
			    syslog(LOG_NOTICE, "Reopen of stdout to /dev/null failed");
			    _exit(2);
			}
			fclose(stderr);
			if (open("/dev/null", O_WRONLY | O_APPEND | O_CREAT,0600) != 2) {
			    syslog(LOG_NOTICE, "Reopen of stderr to /dev/null failed");
			    _exit(2);
			}
			mypid = getpid();
			rc = server();
			break;
			/* Not reached */
	    default:
			/*
			 * Here we detach this process and let the child
			 * run the deamon process.
			 */
			syslog(LOG_NOTICE, "Starting daemon with pid %d", frk);
			exit(0);
	}
    }

    syslog(LOG_NOTICE, "Finished, rc=%d", rc);
    return rc;
}


int server(void)
{
    char                hostname[256], buf[1024];
    int                 temp, rc = 0, deviation;
#ifdef HAVE_WIRINGPI_H
    int			lcdupdate;
#endif
    w1_therm		*tmp1, *old1;
    char		*device, *alias, line[60], *p = NULL;
    FILE		*fp;

    /*
     * Build MQTT id
     */
    hostname[0] = '\0';
    gethostname(hostname, 256);
    hostname[255] = '\0';

    /*
     * Initialise is complete, report our presence state
     */
#ifdef HAVE_WIRINGPI_H
//    setBacklight(0);
#endif

    if (debug)
	fprintf(stdout, (char *)"Enter loop\n");

    do {
#ifdef HAVE_WIRINGPI_H
	    lcdupdate = FALSE;
#endif

	    /*
	     * Here send our 1-wire sensors values
	     */
	    for (tmp1 = Config.w1therms; tmp1; tmp1 = old1) {
		old1 = tmp1->next;

		/*
		 * Build path and alias topic
		 */
		device = xstrcpy((char *)"/sys/bus/w1/devices/");
		device = xstrcat(device, tmp1->master);
		device = xstrcat(device, (char *)"/");
		device = xstrcat(device, tmp1->name);
		device = xstrcat(device, (char *)"/w1_slave");
		alias = xstrcpy((char *)"/raw/");
		alias = xstrcat(alias, hostname);
		alias = xstrcat(alias, (char *)"/thermometers/w1/");
		alias = xstrcat(alias, tmp1->master);
		alias = xstrcat(alias, (char *)"/");
		alias = xstrcat(alias, tmp1->name);
		alias = xstrcat(alias, (char *)"/temperature");

		/*
		 * Read sensor data
		 */
		if ((fp = fopen(device, "r"))) {
		    /*
		     * The output looks like:
		     * 72 01 4b 46 7f ff 0e 10 57 : crc=57 YES
		     * 72 01 4b 46 7f ff 0e 10 57 t=23125
		     */
		    fgets(line, 50, fp);
		    line[strlen(line)-1] = '\0';
		    if ((line[36] == 'Y') && (line[37] == 'E')) {
			/*
			 * CRC is Ok, continue
			 */
		    	fgets(line, 50, fp);
			line[strlen(line)-1] = '\0';
			strtok(line, (char *)"=");
			p = strtok(NULL, (char *)"=");
			rc = sscanf(p, "%d", &temp);
			if ((rc == 1) && (tmp1->lastval != temp)) {
			    /*
			     * It is possible to have read errors or extreme values.
			     * This can happen with bad connections so we compare the
			     * value with the previous one. If the difference is too
			     * much, we don't send that value. That also means that if
			     * the next value is ok again, it will be marked invalid too.
			     * Maximum error is 20 degrees for now.
			     */
			    deviation = 20000;
			    if ((tmp1->lastval == 0) ||
				(tmp1->lastval && (temp > (tmp1->lastval - deviation)) && (temp < (tmp1->lastval + deviation)))) {
			    	/*
			    	 * Temperature is changed and valid, update and publish this.
			    	 */
			    	sprintf(buf, "%.1f", temp / 1000.0);
			    } else {
				syslog(LOG_NOTICE, "deviation error deviation=%d, old=%d new=%d", deviation, tmp1->lastval, temp);
				if (debug) {
				    fprintf(stdout, "deviation error deviation=%d, old=%d new=%d\n", deviation, tmp1->lastval, temp);
				}
			    }
			    tmp1->lastval = temp;
#ifdef HAVE_WIRINGPI_H
			    lcdupdate = TRUE;
#endif
			}
		    } else {
			syslog(LOG_NOTICE, "sensor %s/%s CRC error", tmp1->master, tmp1->name);
		    }
		    fclose(fp);
		    tmp1->present = 1;
		} else {
		    tmp1->present = 0;
		    if (debug)
		    	printf("sensor %s is missing\n", tmp1->name);
		}

		free(device);
		device = NULL;
		free(alias);
		alias = NULL;
	    }

#ifdef HAVE_WIRINGPI_H
	    if (lcdupdate) {
		lcdPosition(lcdHandle, 0, 0);
		tmp1 = Config.w1therms;
		snprintf(buf, 16, "%5.1f %cC %s            ", tmp1->lastval / 1000.0, 0xdf, tmp1->alias);
		lcdPuts(lcdHandle, buf);
		old1 = tmp1->next;
		tmp1 = old1;
		lcdPosition(lcdHandle, 0, 1);
		snprintf(buf, 16, "%5.1f %cC %s            ", tmp1->lastval / 1000.0, 0xdf, tmp1->alias);
		lcdPuts(lcdHandle, buf);
	    }
#endif

	    if (my_shutdown) {
#ifdef HAVE_WIRINGPI_H
		lcdClear(lcdHandle);
		lcdPosition(lcdHandle, 0, 0);
		lcdPuts(lcdHandle, "Shuting down ...");
#endif
	    }

	    usleep(100000);

    } while (! my_shutdown);

    if (debug)
	fprintf(stdout, (char *)"Out of loop\n");

#ifdef HAVE_WIRINGPI_H
    stopLCD();
#endif

    return rc;
}