mka2.c

/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 4; tab-width: 4 -*-  */
/*
 * main.c
 * Copyright (C) 2014 Vassiliy K <hedgeven@linux.com>
 *
 *
 */

#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <sys/stat.h>
#include <sysexits.h>
#include <time.h>
#include <utime.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <syslog.h>
#include <ctype.h>

#define BUFFSIZE 4096
#define EXPIRE_TIME 8          // Timeout to update the cache file
#define SOCK_TIMEOUT 3         // Timeout to blocking socket operations
#define CTRL_TIMEOUT 3         // Timeout to wait for data from the controller
#define DEFAULT_PORT 1000
#define GET_PORT "get_port\r\n"
#define GET_T "get_t\r\n"
#define CACHEDIR "/var/cache/zabbix/mka2/"

static char *args;
static char msg[200];

int main(int argc, char **argv)
{
    int             port = DEFAULT_PORT;
    int             uptate_status;
    int             i;
    int             argl = 0;
    char            *cache_dir = CACHEDIR;
    char            *host;
    char            cache_file[100];
    char            pattern[20];
    char            result[10];

    struct stat     dst, fst;
    struct utimbuf  t;
    FILE            *fp;

    setlogmask (LOG_UPTO (LOG_NOTICE));
    openlog ("mka2", LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1);

    for (i = 0; i<argc; i++) 
        argl+=((int)(strlen(argv[i])) + 1);
    args = (char *) malloc(argl);
    for (i = 0; i<argc; i++) {
        strcat(args, argv[i]);
        if (argc != i+1) strcat(args, " ");
    }

    // Analysis of parameters
    if (argc > 1) {
        /* Parse first parameter as search pattern.
         * ^[0-2].$ - Port #.{1,2}
         * ^T.$ - T_sensor #.
         */
        char num[3];
        if (isdigit(argv[1][0])) {
            strcpy(pattern, "Port # ");
            sscanf(argv[1], "%2s", num);
        } else if (argv[1][0] == 'T' && isdigit(argv[1][1])) {
            strcpy(pattern, "T_sensor #");
            sscanf(argv[1], "T%1s", num);
        } else {
            sprintf (msg, "%s: Invalid search pattern %s\n", args, argv[1]);
            printf ("%s", msg);
            syslog (LOG_ERR, "%s: %s", args, msg);
            return (EX_USAGE);
        }
        strcat(pattern, num);
        strcat(pattern, " = ");

        // Parse second parameter as ip address.
        if (argc > 2)
            host = argv[2];
        else {
            sprintf (msg, "Host is not specified\n");
            printf ("%s", msg);
            syslog (LOG_ERR, "%s: %s", args, msg);
            return (EX_USAGE);
        }

        // Parse third parameter as port.
        if (argc > 3)
            port = atoi(argv[3]);

    } else {
        printf("Usage: mta2 pattern host [port]\n");
        return (EX_USAGE);
    }

    // Create cache directory
    if (stat(cache_dir, &dst) == -1)
        if (mkdir(cache_dir, 0755)) {
            sprintf (msg, "No access to the %s\n", cache_dir);
            printf ("%s", msg);
            syslog (LOG_ERR, "%s: %s", args, msg);
            return (EX_NOPERM);
        }

    // Create cache file if not exists and get data
    strcpy(cache_file, cache_dir);
    strcat(cache_file, host);
    if ((stat(cache_file, &fst) == -1)) {
        if ((fp = fopen(cache_file, "a")) == NULL) {
            sprintf (msg, "No access to the %s\n", cache_file);
            return (EX_NOPERM);
        } else {
            fclose(fp);
            if (uptate_status = cache_update(host, port, cache_file))
                return (uptate_status);
        }
    }

    // If the cache is out of date, then update it
    if (difftime(time(NULL), fst.st_mtime) > EXPIRE_TIME) {
        t.modtime = time(NULL);
        utime(cache_file, &t);
        if (uptate_status = cache_update(host, port, cache_file))
            return (uptate_status);
    }

    if ((fp = fopen(cache_file, "r")) == NULL) {
        sprintf (msg, "No access to the %s\n", cache_file);
        printf ("%s", msg);
        syslog (LOG_ERR, "%s: %s", args, msg);
        return (EX_NOPERM);
    } else {
        char l[BUFFSIZE];
        while(fgets(l, BUFFSIZE, fp))
            if (strstr(l, pattern) != NULL)
                sscanf(l, strcat(pattern, "%s"), result);
        fclose(fp);
    }

    if (isdigit(result[0]))
        printf ("%s\n", result);
    else
        printf ("%s\n", "No data");

    closelog ();
    
    return (EX_OK);
}

int cache_update(char *host, int port, char *file)
{
    int                 sockfd;
    char                buffer[BUFFSIZE];
    char                result[BUFFSIZE*2];
    FILE                *fp;
    struct sockaddr_in  serv_addr;
    struct hostent      *server;
    struct timeval      timeout;

    timeout.tv_sec = SOCK_TIMEOUT;
    timeout.tv_usec = 0;

    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        sprintf (msg, "Error opening socket\n");
        printf ("%s", msg);
        syslog (LOG_ERR, "%s: %s", args, msg);
        return (EX_PROTOCOL);
    }

    if ((server = gethostbyname(host)) == NULL) {
        sprintf (msg, "No such host %s\n", host);
        printf ("%s", msg);
        syslog (LOG_ERR, "%s: %s", args, msg);
        return (EX_NOHOST);
    }

    bzero((char *) &serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    bcopy((char *)server->h_addr,
          (char *)&serv_addr.sin_addr.s_addr,server->h_length);
    serv_addr.sin_port = htons(port);
    if (connect(sockfd,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0) {
        sprintf (msg, "Error connecting to %s:%d\n", host, port);
        printf ("%s", msg);
        syslog (LOG_ERR, "%s: %s", args, msg);
        return (EX_PROTOCOL);
    }

    if (setsockopt (sockfd, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout,
                sizeof(timeout)) < 0)
        syslog (LOG_ERR, "%s: setsockopt failed\n", args);

    if (setsockopt (sockfd, SOL_SOCKET, SO_SNDTIMEO, (char *)&timeout,
                sizeof(timeout)) < 0)
        syslog (LOG_ERR, "%s: setsockopt failed\n", args);

    if ((read(sockfd,buffer,BUFFSIZE-1)) < 0) {
        sprintf (msg, "Error reading from socket\n");
        printf ("%s", msg);
        syslog (LOG_ERR, "%s: %s", args, msg);
        return (EX_PROTOCOL);
    }
    bzero(buffer,BUFFSIZE);

    if ((write(sockfd,GET_PORT,strlen(GET_PORT))) < 0) {
        sprintf (msg, "Error writing to socket\n");
        printf ("%s", msg);
        syslog (LOG_ERR, "%s: %s", args, msg);
        return (EX_PROTOCOL);
    }
    sleep (CTRL_TIMEOUT);
    if ((read(sockfd,buffer,BUFFSIZE-1)) < 0) {
        sprintf (msg, "Error Reading from socket\n");
        printf ("%s", msg);
        syslog (LOG_ERR, "%s: %s", args, msg);
        return (EX_PROTOCOL);
    }

    strcat(result, buffer);
    bzero(buffer,BUFFSIZE);
    if ((write(sockfd,GET_T,strlen(GET_T))) < 0) {
        sprintf (msg, "Error writing to socket\n");
        printf ("%s", msg);
        syslog (LOG_ERR, "%s: %s", args, msg);
        return (EX_PROTOCOL);
    }
    sleep (CTRL_TIMEOUT);
    if ((read(sockfd,buffer,BUFFSIZE-1)) < 0) {
        sprintf (msg, "Error Reading from socket\n");
        printf ("%s", msg);
        syslog (LOG_ERR, "%s: %s", args, msg);
        return (EX_PROTOCOL);
    }

    strcat(result, buffer);

    if ((fp = fopen(file, "w")) != NULL) {
        fputs(result, fp);
        fclose(fp);
    } else
        return (EX_NOPERM);

    close(sockfd);
    return (EX_OK);
}