src/tincd.c

   1 /*
   2     tincd.c -- the main file for tincd
   3     Copyright (C) 1998-2005 Ivo Timmermans
   4                   2000-2017 Guus Sliepen <guus@tinc-vpn.org>
   5                   2008      Max Rijevski <maksuf@gmail.com>
   6                   2009      Michael Tokarev <mjt@tls.msk.ru>
   7                   2010      Julien Muchembled <jm@jmuchemb.eu>
   8                   2010      Timothy Redaelli <timothy@redaelli.eu>
   9
  10     This program is free software; you can redistribute it and/or modify
  11     it under the terms of the GNU General Public License as published by
  12     the Free Software Foundation; either version 2 of the License, or
  13     (at your option) any later version.
  14
  15     This program is distributed in the hope that it will be useful,
  16     but WITHOUT ANY WARRANTY; without even the implied warranty of
  17     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18     GNU General Public License for more details.
  19
  20     You should have received a copy of the GNU General Public License along
  21     with this program; if not, write to the Free Software Foundation, Inc.,
  22     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  23 */
  24
  25 #include "system.h"
  26
  27 /* Darwin (MacOS/X) needs the following definition... */
  28 #ifndef _P1003_1B_VISIBLE
  29 #define _P1003_1B_VISIBLE
  30 #endif
  31
  32 #ifdef HAVE_SYS_MMAN_H
  33 #include <sys/mman.h>
  34 #endif
  35
  36 #include <openssl/rand.h>
  37 #include <openssl/rsa.h>
  38 #include <openssl/pem.h>
  39 #include <openssl/evp.h>
  40 #include <openssl/engine.h>
  41
  42 #ifdef HAVE_LZO
  43 #include LZO1X_H
  44 #endif
  45
  46 #ifndef HAVE_MINGW
  47 #include <pwd.h>
  48 #include <grp.h>
  49 #include <time.h>
  50 #endif
  51
  52 #ifdef HAVE_GETOPT_LONG
  53 #include <getopt.h>
  54 #else
  55 #include "getopt.h"
  56 #endif
  57
  58 #include "pidfile.h"
  59
  60 #include "conf.h"
  61 #include "device.h"
  62 #include "logger.h"
  63 #include "net.h"
  64 #include "netutl.h"
  65 #include "process.h"
  66 #include "protocol.h"
  67 #include "utils.h"
  68 #include "xalloc.h"
  69
  70 /* The name this program was run with. */
  71 char *program_name = NULL;
  72
  73 /* If nonzero, display usage information and exit. */
  74 bool show_help = false;
  75
  76 /* If nonzero, print the version on standard output and exit.  */
  77 bool show_version = false;
  78
  79 /* If nonzero, it will attempt to kill a running tincd and exit. */
  80 int kill_tincd = 0;
  81
  82 /* If nonzero, generate public/private keypair for this host/net. */
  83 int generate_keys = 0;
  84
  85 /* If nonzero, use null ciphers and skip all key exchanges. */
  86 bool bypass_security = false;
  87
  88 /* If nonzero, disable swapping for this process. */
  89 bool do_mlock = false;
  90
  91 /* If nonzero, chroot to netdir after startup. */
  92 static bool do_chroot = false;
  93
  94 /* If !NULL, do setuid to given user after startup */
  95 static const char *switchuser = NULL;
  96
  97 /* If nonzero, write log entries to a separate file. */
  98 bool use_logfile = false;
  99
 100 char *identname = NULL;                         /* program name for syslog */
 101 char *pidfilename = NULL;                       /* pid file location */
 102 char *logfilename = NULL;                       /* log file location */
 103 char **g_argv;                                  /* a copy of the cmdline arguments */
 104
 105 static int status = 1;
 106
 107 static struct option const long_options[] = {
 108         {"config", required_argument, NULL, 'c'},
 109         {"kill", optional_argument, NULL, 'k'},
 110         {"net", required_argument, NULL, 'n'},
 111         {"help", no_argument, NULL, 1},
 112         {"version", no_argument, NULL, 2},
 113         {"no-detach", no_argument, NULL, 'D'},
 114         {"generate-keys", optional_argument, NULL, 'K'},
 115         {"debug", optional_argument, NULL, 'd'},
 116         {"bypass-security", no_argument, NULL, 3},
 117         {"mlock", no_argument, NULL, 'L'},
 118         {"chroot", no_argument, NULL, 'R'},
 119         {"user", required_argument, NULL, 'U'},
 120         {"logfile", optional_argument, NULL, 4},
 121         {"pidfile", required_argument, NULL, 5},
 122         {"option", required_argument, NULL, 'o'},
 123         {NULL, 0, NULL, 0}
 124 };
 125
 126 #ifdef HAVE_MINGW
 127 static struct WSAData wsa_state;
 128 CRITICAL_SECTION mutex;
 129 int main2(int argc, char **argv);
 130 #endif
 131
 132 static void usage(bool status) {
 133         if(status)
 134                 fprintf(stderr, "Try `%s --help\' for more information.\n",
 135                         program_name);
 136         else {
 137                 printf("Usage: %s [option]...\n\n", program_name);
 138                 printf("  -c, --config=DIR               Read configuration options from DIR.\n"
 139                        "  -D, --no-detach                Don't fork and detach.\n"
 140                        "  -d, --debug[=LEVEL]            Increase debug level or set it to LEVEL.\n"
 141                        "  -k, --kill[=SIGNAL]            Attempt to kill a running tincd and exit.\n"
 142                        "  -n, --net=NETNAME              Connect to net NETNAME.\n"
 143                        "  -K, --generate-keys[=BITS]     Generate public/private RSA keypair.\n"
 144                        "  -L, --mlock                    Lock tinc into main memory.\n"
 145                        "      --logfile[=FILENAME]       Write log entries to a logfile.\n"
 146                        "      --pidfile=FILENAME         Write PID to FILENAME.\n"
 147                        "  -o, --option=[HOST.]KEY=VALUE  Set global/host configuration value.\n"
 148                        "  -R, --chroot                   chroot to NET dir at startup.\n"
 149                        "  -U, --user=USER                setuid to given USER at startup.\n"
 150                        "      --help                     Display this help and exit.\n"
 151                        "      --version                  Output version information and exit.\n\n");
 152                 printf("Report bugs to tinc@tinc-vpn.org.\n");
 153         }
 154 }
 155
 156 static bool parse_options(int argc, char **argv) {
 157         config_t *cfg;
 158         int r;
 159         int option_index = 0;
 160         int lineno = 0;
 161
 162         cmdline_conf = list_alloc((list_action_t)free_config);
 163
 164         while((r = getopt_long(argc, argv, "c:DLd::k::n:o:K::RU:", long_options, &option_index)) != EOF) {
 165                 switch(r) {
 166                 case 0:                         /* long option */
 167                         break;
 168
 169                 case 'c':                               /* config file */
 170                         if(confbase) {
 171                                 fprintf(stderr, "Only one configuration directory can be given.\n");
 172                                 usage(true);
 173                                 return false;
 174                         }
 175
 176                         confbase = xstrdup(optarg);
 177                         break;
 178
 179                 case 'D':                               /* no detach */
 180                         do_detach = false;
 181                         break;
 182
 183                 case 'L':                               /* no detach */
 184 #ifndef HAVE_MLOCKALL
 185                         logger(LOG_ERR, "%s not supported on this platform", "mlockall()");
 186                         return false;
 187 #else
 188                         do_mlock = true;
 189                         break;
 190 #endif
 191
 192                 case 'd':                               /* increase debug level */
 193                         if(!optarg && optind < argc && *argv[optind] != '-') {
 194                                 optarg = argv[optind++];
 195                         }
 196
 197                         if(optarg) {
 198                                 debug_level = atoi(optarg);
 199                         } else {
 200                                 debug_level++;
 201                         }
 202
 203                         break;
 204
 205                 case 'k':                               /* kill old tincds */
 206 #ifndef HAVE_MINGW
 207                         if(!optarg && optind < argc && *argv[optind] != '-') {
 208                                 optarg = argv[optind++];
 209                         }
 210
 211                         if(optarg) {
 212                                 if(!strcasecmp(optarg, "HUP")) {
 213                                         kill_tincd = SIGHUP;
 214                                 } else if(!strcasecmp(optarg, "TERM")) {
 215                                         kill_tincd = SIGTERM;
 216                                 } else if(!strcasecmp(optarg, "KILL")) {
 217                                         kill_tincd = SIGKILL;
 218                                 } else if(!strcasecmp(optarg, "USR1")) {
 219                                         kill_tincd = SIGUSR1;
 220                                 } else if(!strcasecmp(optarg, "USR2")) {
 221                                         kill_tincd = SIGUSR2;
 222                                 } else if(!strcasecmp(optarg, "WINCH")) {
 223                                         kill_tincd = SIGWINCH;
 224                                 } else if(!strcasecmp(optarg, "INT")) {
 225                                         kill_tincd = SIGINT;
 226                                 } else if(!strcasecmp(optarg, "ALRM")) {
 227                                         kill_tincd = SIGALRM;
 228                                 } else if(!strcasecmp(optarg, "ABRT")) {
 229                                         kill_tincd = SIGABRT;
 230                                 } else {
 231                                         kill_tincd = atoi(optarg);
 232
 233                                         if(!kill_tincd) {
 234                                                 fprintf(stderr, "Invalid argument `%s'; SIGNAL must be a number or one of HUP, TERM, KILL, USR1, USR2, WINCH, INT or ALRM.\n",
 235                                                         optarg);
 236                                                 usage(true);
 237                                                 return false;
 238                                         }
 239                                 }
 240                         } else {
 241                                 kill_tincd = SIGTERM;
 242                         }
 243
 244 #else
 245                         kill_tincd = 1;
 246 #endif
 247                         break;
 248
 249                 case 'n':                               /* net name given */
 250
 251                         /* netname "." is special: a "top-level name" */
 252                         if(netname) {
 253                                 fprintf(stderr, "Only one netname can be given.\n");
 254                                 usage(true);
 255                                 return false;
 256                         }
 257
 258                         if(optarg && strcmp(optarg, ".")) {
 259                                 netname = xstrdup(optarg);
 260                         }
 261
 262                         break;
 263
 264                 case 'o':                               /* option */
 265                         cfg = parse_config_line(optarg, NULL, ++lineno);
 266
 267                         if(!cfg) {
 268                                 return false;
 269                         }
 270
 271                         list_insert_tail(cmdline_conf, cfg);
 272                         break;
 273
 274                 case 'K':                               /* generate public/private keypair */
 275                         if(!optarg && optind < argc && *argv[optind] != '-') {
 276                                 optarg = argv[optind++];
 277                         }
 278
 279                         if(optarg) {
 280                                 generate_keys = atoi(optarg);
 281
 282                                 if(generate_keys < 512) {
 283                                         fprintf(stderr, "Invalid argument `%s'; BITS must be a number equal to or greater than 512.\n",
 284                                                 optarg);
 285                                         usage(true);
 286                                         return false;
 287                                 }
 288
 289                                 generate_keys &= ~7;    /* Round it to bytes */
 290                         } else {
 291                                 generate_keys = 2048;
 292                         }
 293
 294                         break;
 295
 296                 case 'R':                               /* chroot to NETNAME dir */
 297                         do_chroot = true;
 298                         break;
 299
 300                 case 'U':                               /* setuid to USER */
 301                         switchuser = optarg;
 302                         break;
 303
 304                 case 1:                                 /* show help */
 305                         show_help = true;
 306                         break;
 307
 308                 case 2:                                 /* show version */
 309                         show_version = true;
 310                         break;
 311
 312                 case 3:                                 /* bypass security */
 313                         bypass_security = true;
 314                         break;
 315
 316                 case 4:                                 /* write log entries to a file */
 317                         use_logfile = true;
 318
 319                         if(!optarg && optind < argc && *argv[optind] != '-') {
 320                                 optarg = argv[optind++];
 321                         }
 322
 323                         if(optarg) {
 324                                 if(logfilename) {
 325                                         fprintf(stderr, "Only one logfile can be given.\n");
 326                                         usage(true);
 327                                         return false;
 328                                 }
 329
 330                                 logfilename = xstrdup(optarg);
 331                         }
 332
 333                         break;
 334
 335                 case 5:                                 /* write PID to a file */
 336                         if(pidfilename) {
 337                                 fprintf(stderr, "Only one pidfile can be given.\n");
 338                                 usage(true);
 339                                 return false;
 340                         }
 341
 342                         pidfilename = xstrdup(optarg);
 343                         break;
 344
 345                 case '?':
 346                         usage(true);
 347                         return false;
 348
 349                 default:
 350                         break;
 351                 }
 352         }
 353
 354         if(optind < argc) {
 355                 fprintf(stderr, "%s: unrecognized argument '%s'\n", argv[0], argv[optind]);
 356                 usage(true);
 357                 return false;
 358         }
 359
 360         return true;
 361 }
 362
 363 /* This function prettyprints the key generation process */
 364
 365 static int indicator(int a, int b, BN_GENCB *cb) {
 366         switch(a) {
 367         case 0:
 368                 fprintf(stderr, ".");
 369                 break;
 370
 371         case 1:
 372                 fprintf(stderr, "+");
 373                 break;
 374
 375         case 2:
 376                 fprintf(stderr, "-");
 377                 break;
 378
 379         case 3:
 380                 switch(b) {
 381                 case 0:
 382                         fprintf(stderr, " p\n");
 383                         break;
 384
 385                 case 1:
 386                         fprintf(stderr, " q\n");
 387                         break;
 388
 389                 default:
 390                         fprintf(stderr, "?");
 391                 }
 392
 393                 break;
 394
 395         default:
 396                 fprintf(stderr, "?");
 397         }
 398
 399         return 1;
 400 }
 401
 402 #ifndef HAVE_BN_GENCB_NEW
 403 BN_GENCB *BN_GENCB_new(void) {
 404         return xmalloc_and_zero(sizeof(BN_GENCB));
 405 }
 406
 407 void BN_GENCB_free(BN_GENCB *cb) {
 408         free(cb);
 409 }
 410 #endif
 411
 412 /*
 413   Generate a public/private RSA keypair, and ask for a file to store
 414   them in.
 415 */
 416 static bool keygen(int bits) {
 417         BIGNUM *e = NULL;
 418         RSA *rsa_key;
 419         FILE *f;
 420         char filename[PATH_MAX];
 421         BN_GENCB *cb;
 422         int result;
 423
 424         fprintf(stderr, "Generating %d bits keys:\n", bits);
 425
 426         cb = BN_GENCB_new();
 427
 428         if(!cb) {
 429                 abort();
 430         }
 431
 432         BN_GENCB_set(cb, indicator, NULL);
 433
 434         rsa_key = RSA_new();
 435         BN_hex2bn(&e, "10001");
 436
 437         if(!rsa_key || !e) {
 438                 abort();
 439         }
 440
 441         result = RSA_generate_key_ex(rsa_key, bits, e, cb);
 442
 443         BN_free(e);
 444         BN_GENCB_free(cb);
 445
 446         if(!result) {
 447                 fprintf(stderr, "Error during key generation!\n");
 448                 RSA_free(rsa_key);
 449                 return false;
 450         } else {
 451                 fprintf(stderr, "Done.\n");
 452         }
 453
 454         snprintf(filename, sizeof(filename), "%s/rsa_key.priv", confbase);
 455         f = ask_and_open(filename, "private RSA key");
 456
 457         if(!f) {
 458                 RSA_free(rsa_key);
 459                 return false;
 460         }
 461
 462 #ifdef HAVE_FCHMOD
 463         /* Make it unreadable for others. */
 464         fchmod(fileno(f), 0600);
 465 #endif
 466
 467         fputc('\n', f);
 468         PEM_write_RSAPrivateKey(f, rsa_key, NULL, NULL, 0, NULL, NULL);
 469         fclose(f);
 470
 471         char *name = get_name();
 472
 473         if(name) {
 474                 snprintf(filename, sizeof(filename), "%s/hosts/%s", confbase, name);
 475                 free(name);
 476         } else {
 477                 snprintf(filename, sizeof(filename), "%s/rsa_key.pub", confbase);
 478         }
 479
 480         f = ask_and_open(filename, "public RSA key");
 481
 482         if(!f) {
 483                 RSA_free(rsa_key);
 484                 return false;
 485         }
 486
 487         fputc('\n', f);
 488         PEM_write_RSAPublicKey(f, rsa_key);
 489         fclose(f);
 490
 491         RSA_free(rsa_key);
 492
 493         return true;
 494 }
 495
 496 /*
 497   Set all files and paths according to netname
 498 */
 499 static void make_names(void) {
 500 #ifdef HAVE_MINGW
 501         HKEY key;
 502         char installdir[1024] = "";
 503         DWORD len = sizeof(installdir);
 504 #endif
 505
 506         if(netname) {
 507                 xasprintf(&identname, "tinc.%s", netname);
 508         } else {
 509                 identname = xstrdup("tinc");
 510         }
 511
 512 #ifdef HAVE_MINGW
 513
 514         if(!RegOpenKeyEx(HKEY_LOCAL_MACHINE, "SOFTWARE\\tinc", 0, KEY_READ, &key)) {
 515                 if(!RegQueryValueEx(key, NULL, 0, 0, (LPBYTE)installdir, &len)) {
 516                         if(!confbase) {
 517                                 if(netname) {
 518                                         xasprintf(&confbase, "%s/%s", installdir, netname);
 519                                 } else {
 520                                         xasprintf(&confbase, "%s", installdir);
 521                                 }
 522                         }
 523
 524                         if(!logfilename) {
 525                                 xasprintf(&logfilename, "%s/tinc.log", confbase);
 526                         }
 527                 }
 528
 529                 RegCloseKey(key);
 530
 531                 if(*installdir) {
 532                         return;
 533                 }
 534         }
 535
 536 #endif
 537
 538         if(!pidfilename) {
 539                 xasprintf(&pidfilename, LOCALSTATEDIR "/run/%s.pid", identname);
 540         }
 541
 542         if(!logfilename) {
 543                 xasprintf(&logfilename, LOCALSTATEDIR "/log/%s.log", identname);
 544         }
 545
 546         if(netname) {
 547                 if(!confbase) {
 548                         xasprintf(&confbase, CONFDIR "/tinc/%s", netname);
 549                 } else {
 550                         logger(LOG_INFO, "Both netname and configuration directory given, using the latter...");
 551                 }
 552         } else {
 553                 if(!confbase) {
 554                         xasprintf(&confbase, CONFDIR "/tinc");
 555                 }
 556         }
 557 }
 558
 559 static void free_names() {
 560         if(identname) {
 561                 free(identname);
 562         }
 563
 564         if(netname) {
 565                 free(netname);
 566         }
 567
 568         if(pidfilename) {
 569                 free(pidfilename);
 570         }
 571
 572         if(logfilename) {
 573                 free(logfilename);
 574         }
 575
 576         if(confbase) {
 577                 free(confbase);
 578         }
 579 }
 580
 581 static bool drop_privs() {
 582 #ifdef HAVE_MINGW
 583
 584         if(switchuser) {
 585                 logger(LOG_ERR, "%s not supported on this platform", "-U");
 586                 return false;
 587         }
 588
 589         if(do_chroot) {
 590                 logger(LOG_ERR, "%s not supported on this platform", "-R");
 591                 return false;
 592         }
 593
 594 #else
 595         uid_t uid = 0;
 596
 597         if(switchuser) {
 598                 struct passwd *pw = getpwnam(switchuser);
 599
 600                 if(!pw) {
 601                         logger(LOG_ERR, "unknown user `%s'", switchuser);
 602                         return false;
 603                 }
 604
 605                 uid = pw->pw_uid;
 606
 607                 if(initgroups(switchuser, pw->pw_gid) != 0 ||
 608                                 setgid(pw->pw_gid) != 0) {
 609                         logger(LOG_ERR, "System call `%s' failed: %s",
 610                                "initgroups", strerror(errno));
 611                         return false;
 612                 }
 613
 614 #ifndef ANDROID
 615 // Not supported in android NDK
 616                 endgrent();
 617                 endpwent();
 618 #endif
 619         }
 620
 621         if(do_chroot) {
 622                 tzset();        /* for proper timestamps in logs */
 623
 624                 if(chroot(confbase) != 0 || chdir("/") != 0) {
 625                         logger(LOG_ERR, "System call `%s' failed: %s",
 626                                "chroot", strerror(errno));
 627                         return false;
 628                 }
 629
 630                 free(confbase);
 631                 confbase = xstrdup("");
 632         }
 633
 634         if(switchuser)
 635                 if(setuid(uid) != 0) {
 636                         logger(LOG_ERR, "System call `%s' failed: %s",
 637                                "setuid", strerror(errno));
 638                         return false;
 639                 }
 640
 641 #endif
 642         return true;
 643 }
 644
 645 #ifdef HAVE_MINGW
 646 # define setpriority(level) !SetPriorityClass(GetCurrentProcess(), (level))
 647 #else
 648 # define NORMAL_PRIORITY_CLASS 0
 649 # define BELOW_NORMAL_PRIORITY_CLASS 10
 650 # define HIGH_PRIORITY_CLASS -10
 651 # define setpriority(level) (setpriority(PRIO_PROCESS, 0, (level)))
 652 #endif
 653
 654 int main(int argc, char **argv) {
 655         program_name = argv[0];
 656
 657         if(!parse_options(argc, argv)) {
 658                 return 1;
 659         }
 660
 661         make_names();
 662
 663         if(show_version) {
 664                 printf("%s version %s\n", PACKAGE, VERSION);
 665                 printf("Copyright (C) 1998-2017 Ivo Timmermans, Guus Sliepen and others.\n"
 666                        "See the AUTHORS file for a complete list.\n\n"
 667                        "tinc comes with ABSOLUTELY NO WARRANTY.  This is free software,\n"
 668                        "and you are welcome to redistribute it under certain conditions;\n"
 669                        "see the file COPYING for details.\n");
 670
 671                 return 0;
 672         }
 673
 674         if(show_help) {
 675                 usage(false);
 676                 return 0;
 677         }
 678
 679         if(kill_tincd) {
 680                 return !kill_other(kill_tincd);
 681         }
 682
 683         openlogger("tinc", use_logfile ? LOGMODE_FILE : LOGMODE_STDERR);
 684
 685         g_argv = argv;
 686
 687         if(getenv("LISTEN_PID") && atoi(getenv("LISTEN_PID")) == getpid()) {
 688                 do_detach = false;
 689         }
 690
 691 #ifdef HAVE_UNSETENV
 692         unsetenv("LISTEN_PID");
 693 #endif
 694
 695         init_configuration(&config_tree);
 696
 697         /* Slllluuuuuuurrrrp! */
 698
 699         RAND_load_file("/dev/urandom", 1024);
 700
 701         ENGINE_load_builtin_engines();
 702         ENGINE_register_all_complete();
 703
 704         OpenSSL_add_all_algorithms();
 705
 706         if(generate_keys) {
 707                 read_server_config();
 708                 return !keygen(generate_keys);
 709         }
 710
 711         if(!read_server_config()) {
 712                 return 1;
 713         }
 714
 715 #ifdef HAVE_LZO
 716
 717         if(lzo_init() != LZO_E_OK) {
 718                 logger(LOG_ERR, "Error initializing LZO compressor!");
 719                 return 1;
 720         }
 721
 722 #endif
 723
 724 #ifdef HAVE_MINGW
 725
 726         if(WSAStartup(MAKEWORD(2, 2), &wsa_state)) {
 727                 logger(LOG_ERR, "System call `%s' failed: %s", "WSAStartup", winerror(GetLastError()));
 728                 return 1;
 729         }
 730
 731         if(!do_detach || !init_service()) {
 732                 return main2(argc, argv);
 733         } else {
 734                 return 1;
 735         }
 736 }
 737
 738 int main2(int argc, char **argv) {
 739         InitializeCriticalSection(&mutex);
 740         EnterCriticalSection(&mutex);
 741 #endif
 742         char *priority = NULL;
 743
 744         if(!detach()) {
 745                 return 1;
 746         }
 747
 748 #ifdef HAVE_MLOCKALL
 749
 750         /* Lock all pages into memory if requested.
 751          * This has to be done after daemon()/fork() so it works for child.
 752          * No need to do that in parent as it's very short-lived. */
 753         if(do_mlock && mlockall(MCL_CURRENT | MCL_FUTURE) != 0) {
 754                 logger(LOG_ERR, "System call `%s' failed: %s", "mlockall",
 755                        strerror(errno));
 756                 return 1;
 757         }
 758
 759 #endif
 760
 761         /* Setup sockets and open device. */
 762
 763         if(!setup_network()) {
 764                 goto end;
 765         }
 766
 767         /* Initiate all outgoing connections. */
 768
 769         try_outgoing_connections();
 770
 771         /* Change process priority */
 772
 773         if(get_config_string(lookup_config(config_tree, "ProcessPriority"), &priority)) {
 774                 if(!strcasecmp(priority, "Normal")) {
 775                         if(setpriority(NORMAL_PRIORITY_CLASS) != 0) {
 776                                 logger(LOG_ERR, "System call `%s' failed: %s",
 777                                        "setpriority", strerror(errno));
 778                                 goto end;
 779                         }
 780                 } else if(!strcasecmp(priority, "Low")) {
 781                         if(setpriority(BELOW_NORMAL_PRIORITY_CLASS) != 0) {
 782                                 logger(LOG_ERR, "System call `%s' failed: %s",
 783                                        "setpriority", strerror(errno));
 784                                 goto end;
 785                         }
 786                 } else if(!strcasecmp(priority, "High")) {
 787                         if(setpriority(HIGH_PRIORITY_CLASS) != 0) {
 788                                 logger(LOG_ERR, "System call `%s' failed: %s",
 789                                        "setpriority", strerror(errno));
 790                                 goto end;
 791                         }
 792                 } else {
 793                         logger(LOG_ERR, "Invalid priority `%s`!", priority);
 794                         goto end;
 795                 }
 796         }
 797
 798         /* drop privileges */
 799         if(!drop_privs()) {
 800                 goto end;
 801         }
 802
 803         /* Start main loop. It only exits when tinc is killed. */
 804
 805         status = main_loop();
 806
 807         /* Shutdown properly. */
 808
 809         ifdebug(CONNECTIONS)
 810         devops.dump_stats();
 811
 812         close_network_connections();
 813
 814 end:
 815         logger(LOG_NOTICE, "Terminating");
 816
 817 #ifndef HAVE_MINGW
 818         remove_pid(pidfilename);
 819 #endif
 820
 821         free(priority);
 822
 823         EVP_cleanup();
 824         ERR_free_strings();
 825         ENGINE_cleanup();
 826
 827         exit_configuration(&config_tree);
 828         list_delete_list(cmdline_conf);
 829         free_names();
 830
 831         return status;
 832 }