1 files changed, 257 insertions, 0 deletions

diff --git a/plugins/check_users.c b/plugins/check_users.c
new file mode 100644
index 0000000..2b8fa15
--- /dev/null
+++ b/plugins/check_users.c
@@ -0,0 +1,257 @@
+/******************************************************************************
+ *
+ * CHECK_USERS.C
+ *
+ * Program: Current users plugin for Nagios
+ * License: GPL
+ * Copyright (c) 1999 Ethan Galstad (nagios@nagios.org)
+ *
+ * Last Modified: $Date$
+ * Modifications: 
+ *
+ * 1999-11-17 Karl DeBisschop
+ *  - check stderr and status from spoen/spclose
+ *  - reformat commenst to fit 80-cahr screen
+ *  - set default result to STATE_UNKNOWN
+ *  - initialize users at -1, eliminate 'found' variable
+ *
+ * Command line: CHECK_USERS <wusers> <cusers>
+ *
+ * Description:
+ *
+ * This plugin will use the /usr/bin/who command to check the number
+ * of users currently logged into the system.  If number of logged in
+ * user exceeds the number specified by the <cusers> option, a
+ * STATE_CRITICAL is return.  It it exceeds <wusers>, a STATE_WARNING
+ * is returned.  Errors reading the output from the who command result
+ * in a STATE_UNKNOWN error.
+ *
+ * License Information:
+ *
+ * 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 2 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, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ *****************************************************************************/
+
+#include "common.h"
+#include "popen.h"
+#include "utils.h"
+
+#define PROGNAME "check_users"
+
+#define possibly_set(a,b) ((a) == 0 ? (b) : 0)
+
+int process_arguments (int, char **);
+int call_getopt (int, char **);
+void print_usage (void);
+void print_help (void);
+
+int wusers = -1;
+int cusers = -1;
+
+int
+main (int argc, char **argv)
+{
+        int users = -1;
+        int result = STATE_OK;
+        char input_buffer[MAX_INPUT_BUFFER];
+
+        if (process_arguments (argc, argv) == ERROR)
+                usage ("Could not parse arguments\n");
+
+        /* run the command */
+        child_process = spopen (WHO_COMMAND);
+        if (child_process == NULL) {
+                printf ("Could not open pipe: %s\n", WHO_COMMAND);
+                return STATE_UNKNOWN;
+        }
+
+        child_stderr = fdopen (child_stderr_array[fileno (child_process)], "r");
+        if (child_stderr == NULL)
+                printf ("Could not open stderr for %s\n", WHO_COMMAND);
+
+        users = 0;
+
+        while (fgets (input_buffer, MAX_INPUT_BUFFER - 1, child_process)) {
+
+                /* increment 'users' on all lines except total user count */
+                if (input_buffer[0] != '#') {
+                        users++;
+                        continue;
+                }
+
+                /* get total logged in users */
+                if (sscanf (input_buffer, "# users=%d", &users) == 1)
+                        break;
+
+        }
+
+        /* check STDERR */
+        if (fgets (input_buffer, MAX_INPUT_BUFFER - 1, child_stderr))
+                result = possibly_set (result, STATE_UNKNOWN);
+        (void) fclose (child_stderr);
+
+        /* close the pipe */
+        if (spclose (child_process))
+                result = possibly_set (result, STATE_UNKNOWN);
+
+        /* else check the user count against warning and critical thresholds */
+        if (users >= cusers)
+                result = STATE_CRITICAL;
+        else if (users >= wusers)
+                result = STATE_WARNING;
+        else if (users >= 0)
+                result = STATE_OK;
+
+        if (result == STATE_UNKNOWN)
+                printf ("Unable to read output\n");
+        else
+                printf ("USERS %s - %d users currently logged in\n", state_text (result),
+                                                users);
+
+        return result;
+}
+
+
+
+
+
+/* process command-line arguments */
+int
+process_arguments (int argc, char **argv)
+{
+        int c;
+
+        if (argc < 2)
+                usage ("\n");
+
+        c = 0;
+        while ((c += call_getopt (argc - c, &argv[c])) < argc) {
+
+                if (is_option (argv[c]))
+                        continue;
+
+                if (wusers == -1 && argc > c) {
+                        if (is_intnonneg (argv[c]) == FALSE)
+                                usage ("Warning threshold must be a nonnegative integer\n");
+                        wusers = atoi (argv[c]);
+
+                }
+                else if (cusers == -1 && argc > c) {
+                        if (is_intnonneg (argv[c]) == FALSE)
+                                usage ("Warning threshold must be a nonnegative integer\n");
+                        cusers = atoi (argv[c]);
+                }
+        }
+
+        return OK;
+}
+
+
+
+
+
+int
+call_getopt (int argc, char **argv)
+{
+        int c, i = 0;
+
+#ifdef HAVE_GETOPT_H
+        int option_index = 0;
+        static struct option long_options[] = {
+                {"critical", required_argument, 0, 'c'},
+                {"warning", required_argument, 0, 'w'},
+                {"version", no_argument, 0, 'V'},
+                {"help", no_argument, 0, 'h'},
+                {0, 0, 0, 0}
+        };
+#endif
+
+        while (1) {
+#ifdef HAVE_GETOPT_H
+                c = getopt_long (argc, argv, "+hVvc:w:", long_options, &option_index);
+#else
+                c = getopt (argc, argv, "+hVvc:w:");
+#endif
+
+                i++;
+
+                if (c == -1 || c == EOF || c == 1)
+                        break;
+
+                switch (c) {
+                case 'c':
+                case 'w':
+                        i++;
+                }
+
+                switch (c) {
+                case '?':                                                                       /* print short usage statement if args not parsable */
+                        printf ("%s: Unknown argument: %s\n\n", my_basename (argv[0]), optarg);
+                        print_usage ();
+                        exit (STATE_UNKNOWN);
+                case 'h':                                                                       /* help */
+                        print_help ();
+                        exit (STATE_OK);
+                case 'V':                                                                       /* version */
+                        print_revision (my_basename (argv[0]), "$Revision$");
+                        exit (STATE_OK);
+                case 'c':                                                                       /* critical */
+                        if (!is_intnonneg (optarg))
+                                usage ("Critical threshold must be a nonnegative integer\n");
+                        cusers = atoi (optarg);
+                        break;
+                case 'w':                                                                       /* warning */
+                        if (!is_intnonneg (optarg))
+                                usage ("Warning threshold must be a nonnegative integer\n");
+                        wusers = atoi (optarg);
+                        break;
+                }
+        }
+        return i;
+}
+
+
+
+
+
+void
+print_usage (void)
+{
+        printf ("Usage: %s -w <users> -c <users>\n", PROGNAME);
+}
+
+
+
+
+
+void
+print_help (void)
+{
+        print_revision (PROGNAME, "$Revision$");
+        printf
+                ("Copyright (c) 1999 Ethan Galstad (nagios@nagios.org)\n\n"
+                 "This plugin checks the number of users currently logged in on the local\n"
+                 "system and generates an error if the number exceeds the thresholds specified.\n");
+        print_usage ();
+        printf
+                ("Options:\n"
+                 " -w, --warning=INTEGER\n"
+                 "    Set WARNING status if more than INTEGER users are logged in\n"
+                 " -c, --critical=INTEGER\n"
+                 "    Set CRITICAL status if more than INTEGER users are logged in\n"
+                 " -h, --help\n"
+                 "    Print detailed help screen\n"
+                 " -V, --version\n" "    Print version information\n");
+}