plugins/check_users.c

   1 /*****************************************************************************
   2 *
   3 * Nagios check_users plugin
   4 *
   5 * License: GPL
   6 * Copyright (c) 2000-2007 Nagios Plugins Development Team
   7 *
   8 * Last Modified: $Date$
   9 *
  10 * Description:
  11 *
  12 * This file contains the check_users plugin
  13 *
  14 * This plugin checks the number of users currently logged in on the local
  15 * system and generates an error if the number exceeds the thresholds
  16 * specified.
  17 *
  18 *
  19 * This program is free software: you can redistribute it and/or modify
  20 * it under the terms of the GNU General Public License as published by
  21 * the Free Software Foundation, either version 3 of the License, or
  22 * (at your option) any later version.
  23 *
  24 * This program is distributed in the hope that it will be useful,
  25 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  26 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  27 * GNU General Public License for more details.
  28 *
  29 * You should have received a copy of the GNU General Public License
  30 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  31 *
  32 * $Id$
  33 *
  34 *****************************************************************************/
  35
  36 const char *progname = "check_users";
  37 const char *revision = "$Revision$";
  38 const char *copyright = "2000-2007";
  39 const char *email = "nagiosplug-devel@lists.sourceforge.net";
  40
  41 #include "common.h"
  42 #include "popen.h"
  43 #include "utils.h"
  44
  45 #define possibly_set(a,b) ((a) == 0 ? (b) : 0)
  46
  47 int process_arguments (int, char **);
  48 void print_help (void);
  49 void print_usage (void);
  50
  51 int wusers = -1;
  52 int cusers = -1;
  53
  54 int
  55 main (int argc, char **argv)
  56 {
  57         int users = -1;
  58         int result = STATE_UNKNOWN;
  59         char input_buffer[MAX_INPUT_BUFFER];
  60         char *perf;
  61
  62         setlocale (LC_ALL, "");
  63         bindtextdomain (PACKAGE, LOCALEDIR);
  64         textdomain (PACKAGE);
  65
  66         perf = strdup("");
  67
  68         if (process_arguments (argc, argv) == ERROR)
  69                 usage4 (_("Could not parse arguments"));
  70
  71         /* run the command */
  72         child_process = spopen (WHO_COMMAND);
  73         if (child_process == NULL) {
  74                 printf (_("Could not open pipe: %s\n"), WHO_COMMAND);
  75                 return STATE_UNKNOWN;
  76         }
  77
  78         child_stderr = fdopen (child_stderr_array[fileno (child_process)], "r");
  79         if (child_stderr == NULL)
  80                 printf (_("Could not open stderr for %s\n"), WHO_COMMAND);
  81
  82         users = 0;
  83
  84         while (fgets (input_buffer, MAX_INPUT_BUFFER - 1, child_process)) {
  85
  86                 /* increment 'users' on all lines except total user count */
  87                 if (input_buffer[0] != '#') {
  88                         users++;
  89                         continue;
  90                 }
  91
  92                 /* get total logged in users */
  93                 if (sscanf (input_buffer, _("# users=%d"), &users) == 1)
  94                         break;
  95
  96         }
  97
  98         /* check STDERR */
  99         if (fgets (input_buffer, MAX_INPUT_BUFFER - 1, child_stderr))
 100                 result = possibly_set (result, STATE_UNKNOWN);
 101         (void) fclose (child_stderr);
 102
 103         /* close the pipe */
 104         if (spclose (child_process))
 105                 result = possibly_set (result, STATE_UNKNOWN);
 106
 107         /* else check the user count against warning and critical thresholds */
 108         if (users >= cusers)
 109                 result = STATE_CRITICAL;
 110         else if (users >= wusers)
 111                 result = STATE_WARNING;
 112         else if (users >= 0)
 113                 result = STATE_OK;
 114
 115         if (result == STATE_UNKNOWN)
 116                 printf ("%s\n", _("Unable to read output"));
 117         else {
 118                 asprintf(&perf, "%s", perfdata ("users", users, "",
 119                   TRUE, wusers,
 120                   TRUE, cusers,
 121                   TRUE, 0,
 122                   FALSE, 0));
 123                 printf (_("USERS %s - %d users currently logged in |%s\n"), state_text (result),
 124                   users, perf);
 125         }
 126
 127         return result;
 128 }
 129
 130
 131
 132 /* process command-line arguments */
 133 int
 134 process_arguments (int argc, char **argv)
 135 {
 136         int c;
 137
 138         int option = 0;
 139         static struct option longopts[] = {
 140                 {"critical", required_argument, 0, 'c'},
 141                 {"warning", required_argument, 0, 'w'},
 142                 {"version", no_argument, 0, 'V'},
 143                 {"help", no_argument, 0, 'h'},
 144                 {0, 0, 0, 0}
 145         };
 146
 147         if (argc < 2)
 148                 usage ("\n");
 149
 150         while (1) {
 151                 c = getopt_long (argc, argv, "+hVvc:w:", longopts, &option);
 152
 153                 if (c == -1 || c == EOF || c == 1)
 154                         break;
 155
 156                 switch (c) {
 157                 case '?':                                                                       /* print short usage statement if args not parsable */
 158                         usage5 ();
 159                 case 'h':                                                                       /* help */
 160                         print_help ();
 161                         exit (STATE_OK);
 162                 case 'V':                                                                       /* version */
 163                         print_revision (progname, revision);
 164                         exit (STATE_OK);
 165                 case 'c':                                                                       /* critical */
 166                         if (!is_intnonneg (optarg))
 167                                 usage4 (_("Critical threshold must be a positive integer"));
 168                         else
 169                                 cusers = atoi (optarg);
 170                         break;
 171                 case 'w':                                                                       /* warning */
 172                         if (!is_intnonneg (optarg))
 173                                 usage4 (_("Warning threshold must be a positive integer"));
 174                         else
 175                                 wusers = atoi (optarg);
 176                         break;
 177                 }
 178         }
 179
 180         c = optind;
 181         if (wusers == -1 && argc > c) {
 182                 if (is_intnonneg (argv[c]) == FALSE)
 183                         usage4 (_("Warning threshold must be a positive integer"));
 184                 else
 185                         wusers = atoi (argv[c++]);
 186         }
 187
 188         if (cusers == -1 && argc > c) {
 189                 if (is_intnonneg (argv[c]) == FALSE)
 190                         usage4 (_("Warning threshold must be a positive integer"));
 191                 else
 192                         cusers = atoi (argv[c]);
 193         }
 194
 195         return OK;
 196 }
 197
 198
 199
 200 void
 201 print_help (void)
 202 {
 203         print_revision (progname, revision);
 204
 205         printf ("Copyright (c) 1999 Ethan Galstad\n");
 206         printf (COPYRIGHT, copyright, email);
 207
 208         printf ("%s\n", _("This plugin checks the number of users currently logged in on the local"));
 209   printf ("%s\n", _("system and generates an error if the number exceeds the thresholds specified."));
 210
 211   printf ("\n\n");
 212
 213         print_usage ();
 214
 215         printf (_(UT_HELP_VRSN));
 216
 217         printf (" %s\n", "-w, --warning=INTEGER");
 218   printf ("    %s\n", _("Set WARNING status if more than INTEGER users are logged in"));
 219   printf (" %s\n", "-c, --critical=INTEGER");
 220   printf ("    %s\n", _("Set CRITICAL status if more than INTEGER users are logged in"));
 221
 222         printf (_(UT_SUPPORT));
 223 }
 224
 225
 226 void
 227 print_usage (void)
 228 {
 229   printf (_("Usage:"));
 230         printf ("%s -w <users> -c <users>\n", progname);
 231 }