This document proposes two codes. The first one is a code which can be started up as a daemon or not and write logs either in the standard output or in syslog. This daemon listen to a port (default 1091) wait for a data from a client (either the client below or from the telnet) and return a value! This is like a “skeleton” code which is a good starting point to create a specific application.
This daemon is also accompanied by its rc file which is normally located in /etc/init.d directory to do start/stop properly.
The client is not a daemon. This is a client able to communicate with the server by sending data and receives an answer. This client is in fact developed as a NAGIOS plug-in and returns 0, 1 or 2 as described in the NAGIOS plug-in guidlines.
#include <stdio.h> #include <stdlib.h> #include <string.h> /*Libraries for communications*/ #include <signal.h> #include <sys/time.h> #include <sys/select.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> /*Libraries for the daemon*/ #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <errno.h> #include <unistd.h> /*Library for syslog*/ #include <syslog.h> /*library for options*/ #include <getopt.h> volatile sig_atomic_t done; int usage(FILE *std,char *appname){ char *msg="Usage: %s [OPTION] \n\ -D run as daemon (--daemon)\n\ -s log handled by syslog (--syslog)\n\ -V version (--version)\n\ -p port (--port)\n\ -h help (--help)\n\ -v verbose (--verbose)\n"; fprintf(std,msg,appname); return; } void inthandler(int Sig){ done=1; } int CheckForData(int sockfd){ struct timeval tv; fd_set read_fd; tv.tv_sec=0; tv.tv_usec=0; FD_ZERO(&read_fd); FD_SET(sockfd, &read_fd); if(select(sockfd+1, &read_fd, NULL, NULL, &tv) == -1){ return 0; } if(FD_ISSET(sockfd,&read_fd)){ return 1; } return 0; } int main(int argc, char **argv){ /*char *appname=argv[0];*/ char *appname="congiro_server"; static int verbose_flag=0; /* Flag set by `--verbose'. */ static int syslog_flag=0; /* Flag set by --syslog */ int demonize=0; int port=1091; char data[255]={0};/*Miscellaneous use*/ FILE *f_pid; char f_pid_name[FILENAME_MAX]="/var/run/"; strcat(f_pid_name,appname); strcat(f_pid_name,".pid"); static int c; while (1) { static struct option long_options[] = { /* These options set a flag. */ {"verbose", no_argument, &verbose_flag, 1}, {"brief", no_argument, &verbose_flag, 0}, /* These options don't set a flag. * We distinguish them by their indices. */ {"help", no_argument, 0, 'h'}, {"version", no_argument, 0, 'V'}, {"daemon", no_argument, 0, 'D'}, {"syslog", no_argument, 0, 's'}, {"port", required_argument, 0, 'p'}, {0, 0, 0, 0} }; /* getopt_long stores the option index here. */ int option_index = 0; c = getopt_long(argc, argv, "hVDvsp:",long_options, &option_index); /* Detect the end of the options. */ if (c == -1) break; switch (c) { case 0: /* If this option set a flag, do nothing else now. */ if (long_options[option_index].flag != 0) break; printf("option %s", long_options[option_index].name); if (optarg) printf(" with arg %s", optarg); printf("\n"); break; case 'h': usage(stdout,appname); return EXIT_SUCCESS; break; case 'V':/*Version*/ break; case 'p':/*Port*/ port=atoi(optarg); break; case 'D': demonize=1; syslog_flag=1; break; case 'v': verbose_flag++; break; case 's': syslog_flag=1; break; default: abort(); } } /* Open any logs here */ if (syslog_flag == 1) syslog(LOG_NOTICE, " started by User %d", getuid()); else printf("%s started by User %d\n",appname,getuid()); /* verbosity?? */ if(verbose_flag){ if (syslog_flag == 1) syslog(LOG_NOTICE, " verbosity set to %i", verbose_flag); else printf("Verbosity set to %i\n",verbose_flag); } if(demonize){ /*ONLY SYSLOG EXISTS HERE*/ /* Our process ID and Session ID */ pid_t pid, sid; /* Fork off the parent process */ pid = fork(); if (pid < 0) { exit(EXIT_FAILURE); } /* If we got a good PID, then * we can exit the parent process. */ if (pid > 0) { /*Write PID in /var/run/xxx.pid*/ f_pid=fopen(f_pid_name,"w"); if(f_pid != NULL){ fprintf(f_pid,"%i\n",pid); fclose(f_pid); }else{ syslog(LOG_NOTICE, " opening %s file failed!", f_pid_name); } exit(EXIT_SUCCESS); } /* Change the file mode mask */ umask(0); /* Create a new SID for the child process */ sid = setsid(); if (sid < 0) { /* Log the failure */ exit(EXIT_FAILURE); } /* Change the current working directory */ if ((chdir("/")) < 0) { /* Log the failure */ exit(EXIT_FAILURE); } /* Close out the standard file descriptors */ close(STDIN_FILENO); close(STDOUT_FILENO); close(STDERR_FILENO); } /* Daemon-specific initialization goes here */ int sockfd=0; int new_fd=0; struct sockaddr_in my_addr; struct sockaddr_in their_addr; socklen_t sin_size=0; if(signal(SIGINT,SIG_IGN) != SIG_IGN){ signal(SIGINT,inthandler); } if(signal(SIGTERM,SIG_IGN) != SIG_IGN){ signal(SIGTERM,inthandler); } my_addr.sin_family=AF_INET; my_addr.sin_addr.s_addr=INADDR_ANY; my_addr.sin_port=htons(port); memset(my_addr.sin_zero,0,sizeof my_addr.sin_zero); if((sockfd=socket(AF_INET,SOCK_STREAM,0)) == -1){ if (syslog_flag == 1) syslog(LOG_NOTICE, " Unexpected error on socket()"); else printf("Unexpected error on socket()\n"); return EXIT_FAILURE; } if(bind(sockfd,(struct sockaddr *)&my_addr,sizeof(struct sockaddr)) == -1){ if (syslog_flag == 1) syslog(LOG_NOTICE, " Unexpected error on bind()"); else printf("Unexpected error on bind()\n"); return EXIT_FAILURE; } if(listen(sockfd,4)==-1){ if (syslog_flag == 1) syslog(LOG_NOTICE, " Unexpected error on listen()"); else printf("Unexpected error on listen()\n"); shutdown(sockfd,2); return EXIT_FAILURE; } /* The Big Loop */ while(!done){ /* Do some task here ... */ /*ICI*/ if(0!=CheckForData(sockfd)){ sin_size=sizeof(struct sockaddr_in); if((new_fd=accept(sockfd,(struct sockaddr *)&their_addr,&sin_size)) == -1){ if (syslog_flag == 1) syslog(LOG_NOTICE, " Unexpected error on accept()"); else printf("Unexpected error on accept()\n"); continue; } memset(data,0,sizeof data); if(recv(new_fd,data,sizeof data,0) == -1){ if (syslog_flag == 1) syslog(LOG_NOTICE, " Unexpected error on recv()"); else printf("Unexpected error on recv()\n"); }else{ if(syslog_flag == 1) syslog(LOG_NOTICE, " Received: %s", data); else printf("Received: %s\n",data); } memset(data,0,sizeof data); sprintf(data,"00"); if(send(new_fd,data,sizeof data, 0) == -1){ if (syslog_flag == 1) syslog(LOG_NOTICE, " Unexpected error on send()"); else printf("Unexpected error on send()\n"); } shutdown(new_fd,2); } sleep(5); /*wait 5 seconds*/ } shutdown(sockfd,2); remove(f_pid_name); if (syslog_flag == 1) syslog(LOG_NOTICE, " User requested program to halt."); else printf("User requested program to halt.\n"); exit(EXIT_SUCCESS); }
# Makefile for main atas # Sylvain Bolay # # History: # 09/03/04 -- created # # Please read the file README.makefile that came # with your distribution for an overview # on using this Makefile ###################################################### ################## Miscellaneous ##################### ###################################################### # The following variables apply to compilation # Destination bin directory for executables. Note: this # directory *must* exist, or compilation will fail during # linkage. BINDIR = ./ ###################################################### ############### Sequential Code Variables ############ ###################################################### # Edit the following when compiling. # C compiler for sequential code LCC = gcc WCC = i586-mingw32msvc-gcc CFLAGS= -O3 ############################################################ #/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\# ############################################################ # # # You shouldn't need to change anything beyond this point. # # # ############################################################ #/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\# ############################################################ ###################################################### ################# common object files ################ ###################################################### linux_obj = \ linux_main.o win32_obj = \ win32_main.o ###################################################### #################### targets ######################### ###################################################### ################## sequential targets ############### linux : $(linux_obj) $(LCC) -lm -o congiro_server $(linux_obj) win32 : $(win32_obj) $(WCC) -lm -o congiro_server.exe $(win32_obj) ###################################################### ############## implicit rules for object files ####### ###################################################### ############## main rules linux_main.o : main.c $(LCC) -c $(CFLAGS) main.c -o linux_main.o win32_main.o : main.c $(WCC) -c $(CFLAGS) main.c -o win32_main.o ###################################################### ############# cleanup rules ########################## ###################################################### clean: -$(RM) *.o ###################################################### ############## dependencies ########################## ###################################################### linux_main.o : main.c win32_main.o : main.c
#! /bin/sh ### BEGIN INIT INFO # Provides: congiro # Required-Start: $remote_fs # Required-Stop: $remote_fs # Default-Start: 2 3 4 5 # Default-Stop: 0 1 6 # Short-Description: Init script for the congiro_server daemon # Description: This file should be used to start stop the congiro_server and be # placed in /etc/init.d. # This is based on the /etc/init.d/skeleton file provided by Debian ### END INIT INFO # Author: Sylvain Bolay <sylvain.bolay@irovision.ch> # Do NOT "set -e" # PATH should only include /usr/* if it runs after the mountnfs.sh script PATH=/sbin:/usr/sbin:/bin:/usr/bin DESC="Daemon which checks RS485 clients and report status in case of failure!" NAME=congiro_server DAEMON=/usr/sbin/$NAME DAEMON_ARGS="--daemon --port 9001" PIDFILE=/var/run/$NAME.pid SCRIPTNAME=/etc/init.d/$NAME # Exit if the package is not installed [ -x "$DAEMON" ] || exit 0 # Read configuration variable file if it is present [ -r /etc/default/$NAME ] && . /etc/default/$NAME # Load the VERBOSE setting and other rcS variables . /lib/init/vars.sh # Define LSB log_* functions. # Depend on lsb-base (>= 3.0-6) to ensure that this file is present. . /lib/lsb/init-functions # # Function that starts the daemon/service # do_start() { # Return # 0 if daemon has been started # 1 if daemon was already running # 2 if daemon could not be started start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $DAEMON --test > /dev/null \ || return 1 start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $DAEMON -- \ $DAEMON_ARGS \ || return 2 # Add code here, if necessary, that waits for the process to be ready # to handle requests from services started subsequently which depend # on this one. As a last resort, sleep for some time. } # # Function that stops the daemon/service # do_stop() { # Return # 0 if daemon has been stopped # 1 if daemon was already stopped # 2 if daemon could not be stopped # other if a failure occurred start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 --pidfile $PIDFILE --name $NAME RETVAL="$?" [ "$RETVAL" = 2 ] && return 2 # Wait for children to finish too if this is a daemon that forks # and if the daemon is only ever run from this initscript. # If the above conditions are not satisfied then add some other code # that waits for the process to drop all resources that could be # needed by services started subsequently. A last resort is to # sleep for some time. start-stop-daemon --stop --quiet --oknodo --retry=0/30/KILL/5 --exec $DAEMON [ "$?" = 2 ] && return 2 # Many daemons don't delete their pidfiles when they exit. rm -f $PIDFILE return "$RETVAL" } # # Function that sends a SIGHUP to the daemon/service # do_reload() { # # If the daemon can reload its configuration without # restarting (for example, when it is sent a SIGHUP), # then implement that here. # start-stop-daemon --stop --signal 1 --quiet --pidfile $PIDFILE --name $NAME return 0 } case "$1" in start) [ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC" "$NAME" do_start case "$?" in 0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;; 2) [ "$VERBOSE" != no ] && log_end_msg 1 ;; esac ;; stop) [ "$VERBOSE" != no ] && log_daemon_msg "Stopping $DESC" "$NAME" do_stop case "$?" in 0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;; 2) [ "$VERBOSE" != no ] && log_end_msg 1 ;; esac ;; #reload|force-reload) # # If do_reload() is not implemented then leave this commented out # and leave 'force-reload' as an alias for 'restart'. # #log_daemon_msg "Reloading $DESC" "$NAME" #do_reload #log_end_msg $? #;; restart|force-reload) # # If the "reload" option is implemented then remove the # 'force-reload' alias # log_daemon_msg "Restarting $DESC" "$NAME" do_stop case "$?" in 0|1) do_start case "$?" in 0) log_end_msg 0 ;; 1) log_end_msg 1 ;; # Old process is still running *) log_end_msg 1 ;; # Failed to start esac ;; *) # Failed to stop log_end_msg 1 ;; esac ;; *) #echo "Usage: $SCRIPTNAME {start|stop|restart|reload|force-reload}" >&2 echo "Usage: $SCRIPTNAME {start|stop|restart|force-reload}" >&2 exit 3 ;; esac :
/* Sylvain Bolay (sylvain.bolay@irovision.ch) * Jan 14, 2009 * Plugin for Nagios 2 witch is used to query the congIRO server daemon * Follows this guidline: http://nagiosplug.sourceforge.net/developer-guidelines.html */ #include <stdio.h> #include <stdlib.h> #include <errno.h> #include <string.h> #include <netdb.h> #include <netinet/in.h> #include <sys/socket.h> #include <getopt.h> #define NAGIOS_OK 0 #define NAGIOS_WARNING 1 #define NAGIOS_CRITICAL 2 #define NAGIOS_UNKNOWN 3 #define NAGIOS_OTHERS 4 /*This is for garbage errors, and is not from the nagios documentation*/ int Random(int n){ return (int)(n * (rand() / (1.0 + (double)RAND_MAX))); } int usage(FILE *std,char *appname){ char *msg="Usage: %s [OPTION]... -H hostname \n\ -D detector [0..32] (--detector)\n\ -V version (--version)\n\ -h help (--help)\n\ -t timeout (--timeout)\n\ -w warning threshold (--warning)\n\ -c critical threshold (--critical)\n\ -p port (--port)\n\ -H hostname (--hostname)\n\ -v verbose (--verbose)\n"; fprintf(std,msg,appname); return; } int main(int argc, char *argv[]){ int sockfd=0; char data[255]={0}; struct hostent *he; struct sockaddr_in their_addr; char *hostname=NULL; char *appname=argv[0]; int port=1091; int detector=0; int verbose=0; /* Flag set by `--verbose'. */ static int verbose_flag; static int c; int status=0; int alarmFound=0; srand(time(NULL)); if(argc < 2){ usage(stderr,appname); return NAGIOS_UNKNOWN;/*UNKNOWN*/ } while (1) { static struct option long_options[] = { /* These options set a flag. */ {"verbose", no_argument, &verbose_flag, 1}, {"brief", no_argument, &verbose_flag, 0}, /* These options don't set a flag. * We distinguish them by their indices. */ {"help", no_argument, 0, 'h'}, {"version", no_argument, 0, 'V'}, {"timeout", required_argument, 0, 't'}, {"warning", required_argument, 0, 'w'}, {"critical", required_argument, 0, 'c'}, {"hostname", required_argument, 0, 'H'}, {"detector", required_argument, 0, 'D'}, {"port", required_argument, 0, 'p'}, {0, 0, 0, 0} }; /* getopt_long stores the option index here. */ int option_index = 0; c = getopt_long(argc, argv, "hVt:w:c:H:D:p:v",long_options, &option_index); /* Detect the end of the options. */ if (c == -1) break; switch (c) { case 0: /* If this option set a flag, do nothing else now. */ if (long_options[option_index].flag != 0) break; printf ("option %s", long_options[option_index].name); if (optarg) printf (" with arg %s", optarg); printf ("\n"); break; case 'h': usage(stdout,appname); return NAGIOS_OTHERS;/*OTHERS*/ break; case 'V': break; case 't': break; case 'w': break; case 'c': break; case 'p': port=atoi(optarg); break; case 'H': hostname=optarg; if(verbose) printf("hostname: %s\n",hostname); break; case 'D': detector=atoi(optarg); if(verbose) printf("Detector: %i\n",detector); break; case 'v': verbose++; break; default: abort(); } } if(detector<0 || detector>=33){ printf("Detector number out of range!\n"); return NAGIOS_UNKNOWN;/*UNKNOWN*/ } if(hostname==NULL){ usage(stderr,appname); return NAGIOS_OTHERS;/*OTHERS*/ } if((he= gethostbyname(hostname)) == NULL){ printf("Error with gethostbyname()\n"); return NAGIOS_OTHERS;/*OTHERS*/ } if((sockfd = socket(AF_INET,SOCK_STREAM, 0)) == -1){ printf("Error with socket()\n"); return NAGIOS_UNKNOWN;/*UNKNOWN*/ } their_addr.sin_family = AF_INET; their_addr.sin_port = htons(port); their_addr.sin_addr = *((struct in_addr *)he->h_addr); memset(their_addr.sin_zero,0,sizeof their_addr.sin_zero); if(connect(sockfd,(struct sockaddr *)&their_addr, sizeof(struct sockaddr)) == -1){ /*printf("Error with connect()\n");*/ printf("Not able to establish a communication with the server!\n"); return NAGIOS_UNKNOWN;/*UNKNOWN*/ } sprintf(data,"%i",detector); if(send(sockfd, data, sizeof data, 0) == -1){ printf("Error with send()\n"); return NAGIOS_UNKNOWN;/*UNKNOWN*/ } /*data initialisation*/ memset(data,0,sizeof data); if(recv(sockfd,data,sizeof data, 0) == -1){ printf("Error with recv()\n"); return NAGIOS_UNKNOWN;/*UNKNOWN*/ } if(verbose) printf("Received: %s\n",data); /*Test for alarm status */ status=0; switch(data[0]){ case '0': /*OK*/ printf("Detector %i OK\n",detector); return NAGIOS_OK; break; case '1': /*Warning*/ status=NAGIOS_WARNING; printf("WARNING: "); break; case '2': /*Alarme*/ status=NAGIOS_CRITICAL; printf("ALARME: "); break; default: printf("Undefined status (%c)!",data[0]); return NAGIOS_WARNING;/*WARNING*/ } /* Test for temperature * XXX1 */ switch (data[1]){ case '1':/*ONLY*/ case '3': case '5': case '7': case '9': case 'B': case 'D': case 'F': /*Alerte temperature*/ alarmFound=1; printf(" -- Temperature threshold reached"); break; } /* Test for contact1 * XX1X */ switch (data[1]){ case '2':/*ONLY*/ case '3': case '6': case '7': case 'A': case 'B': case 'E': case 'F': /*Alerte contact 1*/ alarmFound=1; printf(" -- Contact 1 is open!"); break; } /* Test for contact2 * X1XX */ switch (data[1]){ case '4':/*ONLY*/ case '5': case '6': case '7': case 'C': case 'D': case 'E': case 'F': /*Alerte contact 2*/ alarmFound=1; printf(" -- Contact 2 is open!"); break; } /* Test for not responding * 1XXX */ switch (data[1]){ case '8':/*ONLY*/ case '9': case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': /*Alerte detector not responding*/ alarmFound=1; printf(" -- Detector not responding!"); break; } if(!alarmFound) printf(" -- Unknown reason!"); printf("\n"); shutdown(sockfd,2); return status; }
# Makefile for main atas # Sylvain Bolay # # History: # 09/03/04 -- created # # Please read the file README.makefile that came # with your distribution for an overview # on using this Makefile ###################################################### ################## Miscellaneous ##################### ###################################################### # The following variables apply to compilation # Destination bin directory for executables. Note: this # directory *must* exist, or compilation will fail during # linkage. BINDIR = ./ ###################################################### ############### Sequential Code Variables ############ ###################################################### # Edit the following when compiling. # C compiler for sequential code LCC = gcc WCC = i586-mingw32msvc-gcc CFLAGS= -O3 ############################################################ #/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\# ############################################################ # # # You shouldn't need to change anything beyond this point. # # # ############################################################ #/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\# ############################################################ ###################################################### ################# common object files ################ ###################################################### linux_obj = \ linux_main.o win32_obj = \ win32_main.o ###################################################### #################### targets ######################### ###################################################### ################## sequential targets ############### linux : $(linux_obj) $(LCC) -lm -o congiro_client $(linux_obj) win32 : $(win32_obj) $(WCC) -lm -o congiro_client.exe $(win32_obj) ###################################################### ############## implicit rules for object files ####### ###################################################### ############## main rules linux_main.o : main.c $(LCC) -c $(CFLAGS) main.c -o linux_main.o win32_main.o : main.c $(WCC) -c $(CFLAGS) main.c -o win32_main.o ###################################################### ############# cleanup rules ########################## ###################################################### clean: -$(RM) *.o ###################################################### ############## dependencies ########################## ###################################################### linux_main.o : main.c win32_main.o : main.c