plugins/check_smtp.c

   1 /******************************************************************************
   2 *
   3 * CHECK_SMTP.C
   4 *
   5 * Program: SMTP plugin for Nagios
   6 * License: GPL
   7 * Copyright (c) 1999 Ethan Galstad (nagios@nagios.org)
   8 *
   9 * $Id$
  10 *
  11 * Description:
  12 *
  13 * This plugin will attempt to open an SMTP connection with the host.
  14 * Successul connects return STATE_OK, refusals and timeouts return
  15 * STATE_CRITICAL, other errors return STATE_UNKNOWN.  Successful
  16 * connects, but incorrect reponse messages from the host result in
  17 * STATE_WARNING return values.
  18 *
  19 * License Information:
  20 *
  21 * This program is free software; you can redistribute it and/or modify
  22 * it under the terms of the GNU General Public License as published by
  23 * the Free Software Foundation; either version 2 of the License, or
  24 * (at your option) any later version.
  25 *
  26 * This program is distributed in the hope that it will be useful,
  27 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  28 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  29 * GNU General Public License for more details.
  30 *
  31 * You should have received a copy of the GNU General Public License
  32 * along with this program; if not, write to the Free Software
  33 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  34 *
  35 *****************************************************************************/
  36
  37 #include "config.h"
  38 #include "common.h"
  39 #include "netutils.h"
  40 #include "utils.h"
  41
  42 #define PROGNAME "check_smtp"
  43
  44 #define SMTP_PORT       25
  45 #define SMTP_EXPECT     "220"
  46 #define SMTP_HELO "HELO "
  47
  48 /* sendmail will syslog a "NOQUEUE" error if session does not attempt
  49  * to do something useful. This can be prevented by giving a command
  50  * even if syntax is illegal (MAIL requires a FROM:<...> argument)
  51  * You can disable sending DUMMYCMD by undefining SMTP_USE_DUMMYCMD.
  52  *
  53  * According to rfc821 you can include a null reversepath in the from command
  54  * - but a log message is generated on the smtp server.
  55  *
  56  * Use the -f option to provide a FROM address
  57  */
  58
  59 #define SMTP_DUMMYCMD  "MAIL "
  60 #define SMTP_USE_DUMMYCMD 1
  61 #define SMTP_QUIT       "QUIT\r\n"
  62
  63 int process_arguments (int, char **);
  64 int validate_arguments (void);
  65 void print_help (void);
  66 void print_usage (void);
  67
  68 int server_port = SMTP_PORT;
  69 char *server_address = NULL;
  70 char *server_expect = NULL;
  71 char *from_arg = " ";
  72 int warning_time = 0;
  73 int check_warning_time = FALSE;
  74 int critical_time = 0;
  75 int check_critical_time = FALSE;
  76 int verbose = FALSE;
  77
  78 int
  79 main (int argc, char **argv)
  80 {
  81         int sd, c;
  82         int result;
  83         char buffer[MAX_INPUT_BUFFER] = "";
  84         char *from_str = NULL;
  85         char *helocmd = NULL;
  86
  87         if (process_arguments (argc, argv) != OK)
  88                 usage ("Invalid command arguments supplied\n");
  89
  90         /* initialize the HELO command with the localhostname */
  91 #ifndef HOST_MAX_BYTES
  92 #define HOST_MAX_BYTES 255
  93 #endif
  94         helocmd = malloc (HOST_MAX_BYTES);
  95         gethostname(helocmd, HOST_MAX_BYTES);
  96         asprintf (&helocmd, "%s%s%s", SMTP_HELO, helocmd, "\r\n");
  97
  98         /* initialize the MAIL command with optional FROM command  */
  99         asprintf (&from_str, "%sFROM: %s%s", SMTP_DUMMYCMD, from_arg, "\r\n");
 100
 101         if (verbose == TRUE)
 102                 printf ("FROMCMD: %s\n", from_str);
 103
 104         /* initialize alarm signal handling */
 105         signal (SIGALRM, socket_timeout_alarm_handler);
 106
 107         /* set socket timeout */
 108         alarm (socket_timeout);
 109
 110         /* try to connect to the host at the given port number */
 111         time (&start_time);
 112         result = my_tcp_connect (server_address, server_port, &sd);
 113
 114         /* we connected, so close connection before exiting */
 115         if (result == STATE_OK) {
 116
 117                 /* watch for the SMTP connection string */
 118                 result = recv (sd, buffer, MAX_INPUT_BUFFER - 1, 0);
 119
 120                 /* strip the buffer of carriage returns */
 121                 strip (buffer);
 122
 123                 /* return a WARNING status if we couldn't read any data */
 124                 if (result == -1) {
 125                         printf ("recv() failed\n");
 126                         result = STATE_WARNING;
 127                 }
 128
 129                 else {
 130
 131                         /* make sure we find the response we are looking for */
 132                         if (!strstr (buffer, server_expect)) {
 133                                 if (server_port == SMTP_PORT)
 134                                         printf ("Invalid SMTP response received from host\n");
 135                                 else
 136                                         printf ("Invalid SMTP response received from host on port %d\n",
 137                                                                         server_port);
 138                                 result = STATE_WARNING;
 139                         }
 140
 141                         else {
 142
 143                                 time (&end_time);
 144
 145                                 result = STATE_OK;
 146
 147                                 if (check_critical_time == TRUE
 148                                                 && (end_time - start_time) > critical_time) result =
 149                                                 STATE_CRITICAL;
 150                                 else if (check_warning_time == TRUE
 151                                                                  && (end_time - start_time) > warning_time) result =
 152                                                 STATE_WARNING;
 153
 154                                 if (verbose == TRUE)
 155                                         printf ("SMTP %s - %d sec. response time, %s\n",
 156                                                                         state_text (result), (int) (end_time - start_time), buffer);
 157                                 else
 158                                         printf ("SMTP %s - %d second response time\n", state_text (result),
 159                                                                         (int) (end_time - start_time));
 160                         }
 161                 }
 162
 163                 /* close the connection */
 164
 165                 /* first send the HELO command */
 166                 send(sd, helocmd, strlen(helocmd), 0);
 167
 168                 /* allow for response to helo command to reach us */
 169                 recv(sd, buffer, MAX_INPUT_BUFFER-1, 0);
 170
 171 #ifdef SMTP_USE_DUMMYCMD
 172                 send(sd, from_str, strlen(from_str), 0);
 173
 174                 /* allow for response to DUMMYCMD to reach us */
 175                 recv(sd, buffer, MAX_INPUT_BUFFER-1, 0);
 176
 177                 if (verbose == TRUE)
 178                         printf("DUMMYCMD: %s\n%s\n",from_str,buffer);
 179 #endif /* SMTP_USE_DUMMYCMD */
 180
 181                 /* tell the server we're done */
 182                 send (sd, SMTP_QUIT, strlen (SMTP_QUIT), 0);
 183
 184                 /* finally close the connection */
 185                 close (sd);
 186         }
 187
 188         /* reset the alarm */
 189         alarm (0);
 190
 191         return result;
 192 }
 193
 194
 195
 196
 197
 198
 199 /* process command-line arguments */
 200 int
 201 process_arguments (int argc, char **argv)
 202 {
 203         int c;
 204
 205 #ifdef HAVE_GETOPT_H
 206         int option_index = 0;
 207         static struct option long_options[] = {
 208                 {"hostname", required_argument, 0, 'H'},
 209                 {"expect", required_argument, 0, 'e'},
 210                 {"critical", required_argument, 0, 'c'},
 211                 {"warning", required_argument, 0, 'w'},
 212                 {"port", required_argument, 0, 'p'},
 213                 {"from", required_argument, 0, 'f'},
 214                 {"verbose", no_argument, 0, 'v'},
 215                 {"version", no_argument, 0, 'V'},
 216                 {"help", no_argument, 0, 'h'},
 217                 {0, 0, 0, 0}
 218         };
 219 #endif
 220
 221         if (argc < 2)
 222                 return ERROR;
 223
 224         for (c = 1; c < argc; c++) {
 225                 if (strcmp ("-to", argv[c]) == 0)
 226                         strcpy (argv[c], "-t");
 227                 else if (strcmp ("-wt", argv[c]) == 0)
 228                         strcpy (argv[c], "-w");
 229                 else if (strcmp ("-ct", argv[c]) == 0)
 230                         strcpy (argv[c], "-c");
 231         }
 232
 233         while (1) {
 234 #ifdef HAVE_GETOPT_H
 235                 c =
 236                         getopt_long (argc, argv, "+hVvt:p:f:e:c:w:H:", long_options,
 237                                                                          &option_index);
 238 #else
 239                 c = getopt (argc, argv, "+?hVvt:p:f:e:c:w:H:");
 240 #endif
 241                 if (c == -1 || c == EOF)
 242                         break;
 243
 244                 switch (c) {
 245                 case 'H':                                                                       /* hostname */
 246                         if (is_host (optarg)) {
 247                                 server_address = optarg;
 248                         }
 249                         else {
 250                                 usage ("Invalid host name\n");
 251                         }
 252                         break;
 253                 case 'p':                                                                       /* port */
 254                         if (is_intpos (optarg)) {
 255                                 server_port = atoi (optarg);
 256                         }
 257                         else {
 258                                 usage ("Server port must be a positive integer\n");
 259                         }
 260                         break;
 261                 case 'f':                                                                       /* from argument */
 262                         from_arg = optarg;
 263                         break;
 264                 case 'e':                                                                       /* server expect string on 220  */
 265                         server_expect = optarg;
 266                         break;
 267                 case 'c':                                                                       /* critical time threshold */
 268                         if (is_intnonneg (optarg)) {
 269                                 critical_time = atoi (optarg);
 270                                 check_critical_time = TRUE;
 271                         }
 272                         else {
 273                                 usage ("Critical time must be a nonnegative integer\n");
 274                         }
 275                         break;
 276                 case 'w':                                                                       /* warning time threshold */
 277                         if (is_intnonneg (optarg)) {
 278                                 warning_time = atoi (optarg);
 279                                 check_warning_time = TRUE;
 280                         }
 281                         else {
 282                                 usage ("Warning time must be a nonnegative integer\n");
 283                         }
 284                         break;
 285                 case 'v':                                                                       /* verbose */
 286                         verbose = TRUE;
 287                         break;
 288                 case 't':                                                                       /* timeout */
 289                         if (is_intnonneg (optarg)) {
 290                                 socket_timeout = atoi (optarg);
 291                         }
 292                         else {
 293                                 usage ("Time interval must be a nonnegative integer\n");
 294                         }
 295                         break;
 296                 case 'V':                                                                       /* version */
 297                         print_revision (PROGNAME, "$Revision$");
 298                         exit (STATE_OK);
 299                 case 'h':                                                                       /* help */
 300                         print_help ();
 301                         exit (STATE_OK);
 302                 case '?':                                                                       /* help */
 303                         usage ("Invalid argument\n");
 304                 }
 305         }
 306
 307         c = optind;
 308         if (server_address == NULL) {
 309                 if (argv[c]) {
 310                         if (is_host (argv[c]))
 311                                 server_address = argv[c];
 312                         else
 313                                 usage ("Invalid host name");
 314                 }
 315                 else {
 316                         asprintf (&server_address, "127.0.0.1");
 317                 }
 318         }
 319
 320         if (server_expect == NULL)
 321                 asprintf (&server_expect, SMTP_EXPECT);
 322
 323         return validate_arguments ();
 324 }
 325
 326
 327
 328
 329
 330 int
 331 validate_arguments (void)
 332 {
 333         return OK;
 334 }
 335
 336
 337
 338
 339
 340 void
 341 print_help (void)
 342 {
 343         print_revision (PROGNAME, "$Revision$");
 344         printf
 345                 ("Copyright (c) 2000 Ethan Galstad/Karl DeBisschop\n\n"
 346                  "This plugin test the SMTP service on the specified host.\n\n");
 347         print_usage ();
 348         printf
 349                 ("\nOptions:\n"
 350                  " -H, --hostname=STRING or IPADDRESS\n"
 351                  "   Check server on the indicated host\n"
 352                  " -p, --port=INTEGER\n"
 353                  "   Make connection on the indicated port (default: %d)\n"
 354                  " -e, --expect=STRING\n"
 355                  "   String to expect in first line of server response (default: %s)\n"
 356                  " -f, --from=STRING\n"
 357                  "   from address to include in MAIL command (default NULL, Exchange2000 requires one)\n"
 358                  " -w, --warning=INTEGER\n"
 359                  "   Seconds necessary to result in a warning status\n"
 360                  " -c, --critical=INTEGER\n"
 361                  "   Seconds necessary to result in a critical status\n"
 362                  " -t, --timeout=INTEGER\n"
 363                  "   Seconds before connection attempt times out (default: %d)\n"
 364                  " -v, --verbose\n"
 365                  "   Print extra information (command-line use only)\n"
 366                  " -h, --help\n"
 367                  "   Print detailed help screen\n"
 368                  " -V, --version\n"
 369                  "   Print version information\n\n",
 370                  SMTP_PORT, SMTP_EXPECT, DEFAULT_SOCKET_TIMEOUT);
 371         support ();
 372 }
 373
 374
 375
 376
 377
 378 void
 379 print_usage (void)
 380 {
 381         printf
 382                 ("Usage: %s -H host [-e expect] [-p port] [-f from addr] [-w warn] [-c crit] [-t timeout] [-v]\n"
 383                  "       %s --help\n"
 384                  "       %s --version\n", PROGNAME, PROGNAME, PROGNAME);
 385 }