monitoring-plugins/plugins/check_nagios.c

/*****************************************************************************
 *
 * Monitoring check_nagios plugin
 *
 * License: GPL
 * Copyright (c) 1999-2024 Monitoring Plugins Development Team
 *
 * Description:
 *
 * This file contains the check_nagios plugin
 *
 * This plugin checks the status of the Nagios process on the local machine.
 * The plugin will check to make sure the Nagios status log is no older than
 * the number of minutes specified by the expires option.
 * It also checks the process table for a process matching the command
 * argument.
 *
 *
 * 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/>.
 *
 *
 *****************************************************************************/

const char *progname = "check_nagios";
const char *copyright = "1999-2024";
const char *email = "devel@monitoring-plugins.org";

#include "common.h"
#include "runcmd.h"
#include "utils.h"
#include "states.h"
#include "check_nagios.d/config.h"

typedef struct {
	int errorcode;
	check_nagios_config config;
} check_nagios_config_wrapper;
static check_nagios_config_wrapper process_arguments(int /*argc*/, char ** /*argv*/);
static void print_help(void);
void print_usage(void);

static int verbose = 0;

int main(int argc, char **argv) {
	setlocale(LC_ALL, "");
	bindtextdomain(PACKAGE, LOCALEDIR);
	textdomain(PACKAGE);

	/* Parse extra opts if any */
	argv = np_extra_opts(&argc, argv, progname);

	check_nagios_config_wrapper tmp_config = process_arguments(argc, argv);

	if (tmp_config.errorcode == ERROR) {
		usage_va(_("Could not parse arguments"));
	}

	const check_nagios_config config = tmp_config.config;

	/* Set signal handling and alarm timeout */
	if (signal(SIGALRM, timeout_alarm_handler) == SIG_ERR) {
		usage_va(_("Cannot catch SIGALRM"));
	}

	/* handle timeouts gracefully... */
	alarm(timeout_interval);

	/* open the status log */
	FILE *log_file = fopen(config.status_log, "r");
	if (log_file == NULL) {
		die(STATE_CRITICAL, "NAGIOS %s: %s\n", _("CRITICAL"), _("Cannot open status log for reading!"));
	}

	unsigned long latest_entry_time = 0L;
	unsigned long temp_entry_time = 0L;
	char input_buffer[MAX_INPUT_BUFFER];
	char *temp_ptr;
	/* get the date/time of the last item updated in the log */
	while (fgets(input_buffer, MAX_INPUT_BUFFER - 1, log_file)) {
		if ((temp_ptr = strstr(input_buffer, "created=")) != NULL) {
			temp_entry_time = strtoul(temp_ptr + 8, NULL, 10);
			latest_entry_time = temp_entry_time;
			break;
		}
		if ((temp_ptr = strtok(input_buffer, "]")) != NULL) {
			temp_entry_time = strtoul(temp_ptr + 1, NULL, 10);
			if (temp_entry_time > latest_entry_time) {
				latest_entry_time = temp_entry_time;
			}
		}
	}
	fclose(log_file);

	if (verbose >= 2) {
		printf("command: %s\n", PS_COMMAND);
	}

	/* run the command to check for the Nagios process.. */
	mp_state_enum result = STATE_UNKNOWN;
	output chld_out;
	output chld_err;
	if ((result = np_runcmd(PS_COMMAND, &chld_out, &chld_err, 0)) != 0) {
		result = STATE_WARNING;
	}

	int procuid = 0;
	int procpid = 0;
	int procppid = 0;
	int procvsz = 0;
	int procrss = 0;
	int proc_entries = 0;
	float procpcpu = 0;
	char procstat[8];
	char procprog[MAX_INPUT_BUFFER];
	char *procargs;
#ifdef PS_USES_PROCETIME
	char procetime[MAX_INPUT_BUFFER];
#endif /* PS_USES_PROCETIME */
	int pos;
	int expected_cols = PS_COLS - 1;
	const char *zombie = "Z";
	/* count the number of matching Nagios processes... */
	for (size_t i = 0; i < chld_out.lines; i++) {
		int cols = sscanf(chld_out.line[i], PS_FORMAT, PS_VARLIST);
		/* Zombie processes do not give a procprog command */
		if (cols == (expected_cols - 1) && strstr(procstat, zombie)) {
			cols = expected_cols;
			/* Set some value for procargs for the strip command further below
			 * Seen to be a problem on some Solaris 7 and 8 systems */
			chld_out.line[i][pos] = '\n';
			chld_out.line[i][pos + 1] = 0x0;
		}
		if (cols >= expected_cols) {
			xasprintf(&procargs, "%s", chld_out.line[i] + pos);
			strip(procargs);

			/* Some ps return full pathname for command. This removes path */
			char *temp_string = strtok((char *)procprog, "/");
			while (temp_string) {
				strcpy(procprog, temp_string);
				temp_string = strtok(NULL, "/");
			}

			/* May get empty procargs */
			if (!strstr(procargs, argv[0]) && strstr(procargs, config.process_string) && strcmp(procargs, "")) {
				proc_entries++;
				if (verbose >= 2) {
					printf(_("Found process: %s %s\n"), procprog, procargs);
				}
			}
		}
	}

	/* If we get anything on stderr, at least set warning */
	if (chld_err.buflen) {
		result = max_state(result, STATE_WARNING);
	}

	/* reset the alarm handler */
	alarm(0);

	if (proc_entries == 0) {
		die(STATE_CRITICAL, "NAGIOS %s: %s\n", _("CRITICAL"), _("Could not locate a running Nagios process!"));
	}

	if (latest_entry_time == 0L) {
		die(STATE_CRITICAL, "NAGIOS %s: %s\n", _("CRITICAL"), _("Cannot parse Nagios log file for valid time"));
	}

	time_t current_time;
	time(&current_time);
	if ((int)(current_time - latest_entry_time) > (config.expire_minutes * 60)) {
		result = STATE_WARNING;
	} else {
		result = STATE_OK;
	}

	printf("NAGIOS %s: ", (result == STATE_OK) ? _("OK") : _("WARNING"));
	printf(ngettext("%d process", "%d processes", proc_entries), proc_entries);
	printf(", ");
	printf(ngettext("status log updated %d second ago", "status log updated %d seconds ago", (int)(current_time - latest_entry_time)),
		   (int)(current_time - latest_entry_time));
	printf("\n");

	exit(result);
}

/* process command-line arguments */
check_nagios_config_wrapper process_arguments(int argc, char **argv) {
	static struct option longopts[] = {{"filename", required_argument, 0, 'F'}, {"expires", required_argument, 0, 'e'},
									   {"command", required_argument, 0, 'C'},  {"timeout", optional_argument, 0, 't'},
									   {"version", no_argument, 0, 'V'},        {"help", no_argument, 0, 'h'},
									   {"verbose", no_argument, 0, 'v'},        {0, 0, 0, 0}};

	check_nagios_config_wrapper result = {
		.errorcode = OK,
		.config = check_nagios_config_init(),
	};
	if (argc < 2) {
		result.errorcode = ERROR;
		return result;
	}

	if (!is_option(argv[1])) {
		result.config.status_log = argv[1];
		if (is_intnonneg(argv[2])) {
			result.config.expire_minutes = atoi(argv[2]);
		} else {
			die(STATE_UNKNOWN, _("Expiration time must be an integer (seconds)\n"));
		}
		result.config.process_string = argv[3];
		return result;
	}

	int option = 0;
	while (true) {
		int option_index = getopt_long(argc, argv, "+hVvF:C:e:t:", longopts, &option);

		if (option_index == -1 || option_index == EOF || option_index == 1) {
			break;
		}

		switch (option_index) {
		case 'h': /* help */
			print_help();
			exit(STATE_UNKNOWN);
		case 'V': /* version */
			print_revision(progname, NP_VERSION);
			exit(STATE_UNKNOWN);
		case 'F': /* status log */
			result.config.status_log = optarg;
			break;
		case 'C': /* command */
			result.config.process_string = optarg;
			break;
		case 'e': /* expiry time */
			if (is_intnonneg(optarg)) {
				result.config.expire_minutes = atoi(optarg);
			} else {
				die(STATE_UNKNOWN, _("Expiration time must be an integer (seconds)\n"));
			}
			break;
		case 't': /* timeout */
			if (is_intnonneg(optarg)) {
				timeout_interval = atoi(optarg);
			} else {
				die(STATE_UNKNOWN, _("Timeout must be an integer (seconds)\n"));
			}
			break;
		case 'v':
			verbose++;
			break;
		default: /* print short usage_va statement if args not parsable */
			usage5();
		}
	}

	if (result.config.status_log == NULL) {
		die(STATE_UNKNOWN, _("You must provide the status_log\n"));
	}

	if (result.config.process_string == NULL) {
		die(STATE_UNKNOWN, _("You must provide a process string\n"));
	}

	return result;
}

void print_help(void) {
	print_revision(progname, NP_VERSION);

	printf(_(COPYRIGHT), copyright, email);

	printf("%s\n", _("This plugin checks the status of the Nagios process on the local machine"));
	printf("%s\n", _("The plugin will check to make sure the Nagios status log is no older than"));
	printf("%s\n", _("the number of minutes specified by the expires option."));
	printf("%s\n", _("It also checks the process table for a process matching the command argument."));

	printf("\n\n");

	print_usage();

	printf(UT_HELP_VRSN);
	printf(UT_EXTRA_OPTS);

	printf(" %s\n", "-F, --filename=FILE");
	printf("    %s\n", _("Name of the log file to check"));
	printf(" %s\n", "-e, --expires=INTEGER");
	printf("    %s\n", _("Minutes aging after which logfile is considered stale"));
	printf(" %s\n", "-C, --command=STRING");
	printf("    %s\n", _("Substring to search for in process arguments"));
	printf(" %s\n", "-t, --timeout=INTEGER");
	printf("    %s\n", _("Timeout for the plugin in seconds"));
	printf(UT_VERBOSE);

	printf("\n");
	printf("%s\n", _("Examples:"));
	printf(" %s\n", "check_nagios -t 20 -e 5 -F /usr/local/nagios/var/status.log -C /usr/local/nagios/bin/nagios");

	printf(UT_SUPPORT);
}

void print_usage(void) {
	printf("%s\n", _("Usage:"));
	printf("%s -F <status log file> -t <timeout_seconds> -e <expire_minutes> -C <process_string>\n", progname);
}