thermometers/main.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 "../lib/mbselib.h"
#include "main.h"


#define STATUS_CONNECTING 0
#define STATUS_CONNACK_RECVD 1
#define STATUS_WAITING 2

/* Global variables for use in callbacks. */
static int		qos = 0;
static int		status = STATUS_CONNECTING;
static int		mid_sent = 0;
static int		last_mid = -1;
static int		last_mid_sent = -1;
static bool		connected = true;
static bool		disconnect_sent = false;
static bool		shutdown = false;
static pid_t		pgrp, mypid;

extern bool		debug;
extern sys_config	Config;

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);
    }

    shutdown = true;
}


void my_connect_callback(struct mosquitto *mosq, void *obj, int result)
{
    if (!result) {
	status = STATUS_CONNACK_RECVD;
    } else {
	syslog(LOG_NOTICE, "my_connect_callback: %s\n", mosquitto_connack_string(result));
    }
}


void my_disconnect_callback(struct mosquitto *mosq, void *obj, int rc)
{
    if (shutdown) {
	syslog(LOG_NOTICE, "Acknowledged DISCONNECT from %s", Config.mosq_host);
	connected = false;
    } else {
	/*
	 * The remove server was brought down. We must keep running
	 */
	syslog(LOG_NOTICE, "Received DISCONNECT from %s but we want to run", Config.mosq_host);
	/*
	 * We need a temp state
	 */
    }
}


void my_publish_callback(struct mosquitto *mosq, void *obj, int mid)
{
    last_mid_sent = mid;
}


void my_log_callback(struct mosquitto *mosq, void *obj, int level, const char *str)
{
    syslog(LOG_NOTICE, "MQTT: %s", str);
    printf("MQTT: %s\n", str);
}


int main(int argc, char *argv[])
{
    int		rc, c, i;
    pid_t	frk;

    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()) {
	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);
    }


    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");
			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                *id = NULL, *state = NULL;
    struct mosquitto    *mosq = NULL;
    char                hostname[256], buf[1024];
    int                 temp, rc, deviation, keepalive = 60;
    unsigned int        max_inflight = 20;
    char                err[1024];
    w1_therm		*tmp1, *old1;
    char		*device, *alias, line[60], *p = NULL;
    FILE		*fp;

    /*
     * Initialize mosquitto communication
     */
    mosquitto_lib_init();

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

    id = xstrcpy((char *)"thermometers/");
    id = xstrcat(id, hostname);
    if(strlen(id) > MOSQ_MQTT_ID_MAX_LENGTH) {
	/*
	 * Enforce maximum client id length of 23 characters
	 */
	id[MOSQ_MQTT_ID_MAX_LENGTH] = '\0';
    }

    mosq = mosquitto_new(id, true, NULL);
    if(!mosq) {
	switch(errno) {
	    case ENOMEM:
		syslog(LOG_NOTICE, "mosquitto_new: Out of memory");
		break;
	    case EINVAL:
		syslog(LOG_NOTICE, "mosquitto_new: Invalid id");
		break;
	}
	mosquitto_lib_cleanup();
	return 1;
    }

    if (debug) {
	mosquitto_log_callback_set(mosq, my_log_callback);
    }

    /*
     * Set our will
     */
    state = xstrcpy((char *)"clients/");
    state = xstrcat(state, hostname);
    state = xstrcat(state, (char *)"/thermometers/state");
    sprintf(buf, "0");
    if ((rc = mosquitto_will_set(mosq, state, strlen(buf), buf, qos, true))) {
        if (rc == MOSQ_ERR_INVAL) {
            syslog(LOG_NOTICE, "mosquitto_will_set: input parameters invalid");
        } else if (rc == MOSQ_ERR_NOMEM) {
            syslog(LOG_NOTICE, "mosquitto_will_set: Out of Memory");
	} else if (rc == MOSQ_ERR_PAYLOAD_SIZE) {
	    syslog(LOG_NOTICE, "mosquitto_will_set: invalid payload size");
        }
        mosquitto_lib_cleanup();
        return rc;
    }

    mosquitto_max_inflight_messages_set(mosq, max_inflight);
    mosquitto_connect_callback_set(mosq, my_connect_callback);
    mosquitto_disconnect_callback_set(mosq, my_disconnect_callback);
    mosquitto_publish_callback_set(mosq, my_publish_callback);

    if ((rc = mosquitto_connect(mosq, Config.mosq_host, Config.mosq_port, keepalive))) {
	if (rc == MOSQ_ERR_ERRNO) {
	    strerror_r(errno, err, 1024);
	    syslog(LOG_NOTICE, "mosquitto_connect: error: %s", err);
	} else {
	    syslog(LOG_NOTICE, "mosquitto_connect: unable to connect (%d)", rc);
	}
	mosquitto_lib_cleanup();
	return rc;
    }
    syslog(LOG_NOTICE, "Connected with %s:%d", Config.mosq_host, Config.mosq_port);

    /*
     * Initialise is complete, report our presence state
     */
    mosquitto_loop_start(mosq);
    sprintf(buf, "1");
    rc = mosquitto_publish(mosq, &mid_sent, state, strlen(buf), buf, qos, 1);

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

    do {
	if (status == STATUS_CONNACK_RECVD) {
	    /*
	     * 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 *)"sensor/temperature/");
		alias = xstrcat(alias, hostname);
		alias = xstrcat(alias, (char *)"/");
		alias = xstrcat(alias, tmp1->master);
		alias = xstrcat(alias, (char *)"/");
		alias = xstrcat(alias, tmp1->alias);

		/*
		 * 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.
			     */
			    deviation = (temp + tmp1->lastval) / 10;
			    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);
			    	if ((rc = mosquitto_publish(mosq, &mid_sent, alias, strlen(buf), buf, qos, 0))) {
			            if (rc == MOSQ_ERR_NO_CONN)
				    	mosquitto_reconnect(mosq);
			    	    else
				    	syslog(LOG_NOTICE, "mainloop: error %d from mosquitto_publish", rc);
			    	}
			    } else {
				if (debug)
				    syslog(LOG_NOTICE, "deviation error deviation=%d, old=%d new=%d", deviation, tmp1->lastval, temp);
			    }
			    tmp1->lastval = temp;
			}
		    } 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;
	    }
	    usleep(1000000);

	    if (shutdown) {
		/*
		 * Final publish 0 to clients/<hostname>/thermometers/state
		 */
		sprintf(buf, "0");
		mosquitto_publish(mosq, &mid_sent, state, strlen(buf), buf, qos, true);
		last_mid = mid_sent;
		status = STATUS_WAITING;
	    }
	} else if (status == STATUS_WAITING) {
	    if (debug)
	    	fprintf(stdout, (char *)"Waiting\n");
	    if (last_mid_sent == last_mid && disconnect_sent == false) {
		mosquitto_disconnect(mosq);
		disconnect_sent = true;
	    }
	    usleep(100000);
	}
	rc = MOSQ_ERR_SUCCESS;

    } while (rc == MOSQ_ERR_SUCCESS && connected);

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

    mosquitto_loop_stop(mosq, false);
    mosquitto_destroy(mosq);
    mosquitto_lib_cleanup();

    return rc;
}