src/odhcp6c.c

   1 /**
   2  * Copyright (C) 2012-2013 Steven Barth <steven@midlink.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License v2 as published by
   6  * the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  */
  14
  15 #include <time.h>
  16 #include <errno.h>
  17 #include <fcntl.h>
  18 #include <stdio.h>
  19 #include <stdlib.h>
  20 #include <stddef.h>
  21 #include <unistd.h>
  22 #include <syslog.h>
  23 #include <signal.h>
  24 #include <string.h>
  25 #include <stdbool.h>
  26
  27 #include <net/if.h>
  28 #include <sys/wait.h>
  29 #include <sys/syscall.h>
  30 #include <arpa/inet.h>
  31
  32 #include "odhcp6c.h"
  33 #include "ra.h"
  34
  35 #ifdef EXT_BFD_PING
  36 #include "bfd.h"
  37 #endif
  38
  39
  40 static void sighandler(int signal);
  41 static int usage(void);
  42
  43 static uint8_t *state_data[_STATE_MAX] = {NULL};
  44 static size_t state_len[_STATE_MAX] = {0};
  45
  46 static volatile bool signal_io = false;
  47 static volatile bool signal_usr1 = false;
  48 static volatile bool signal_usr2 = false;
  49 static volatile bool signal_term = false;
  50
  51 static int urandom_fd = -1, allow_slaac_only = 0;
  52 static bool bound = false, release = true;
  53 static time_t last_update = 0;
  54
  55 int main(_unused int argc, char* const argv[])
  56 {
  57         // Allocate ressources
  58         const char *pidfile = NULL;
  59         const char *script = "/usr/sbin/odhcp6c-update";
  60         ssize_t l;
  61         uint8_t buf[134];
  62         char *optpos;
  63         uint16_t opttype;
  64         enum odhcp6c_ia_mode ia_na_mode = IA_MODE_TRY;
  65         enum odhcp6c_ia_mode ia_pd_mode = IA_MODE_TRY;
  66         int ia_pd_iaid_index = 0;
  67         static struct in6_addr ifid = IN6ADDR_ANY_INIT;
  68         int sol_timeout = DHCPV6_SOL_MAX_RT;
  69
  70 #ifdef EXT_BFD_PING
  71         int bfd_interval = 0, bfd_loss = 3;
  72 #endif
  73
  74         bool help = false, daemonize = false;
  75         int logopt = LOG_PID;
  76         int c;
  77         unsigned int client_options = DHCPV6_CLIENT_FQDN | DHCPV6_ACCEPT_RECONFIGURE;
  78
  79         while ((c = getopt(argc, argv, "S::N:V:P:FB:c:i:r:Rs:kt:hedp:fa")) != -1) {
  80                 switch (c) {
  81                 case 'S':
  82                         allow_slaac_only = (optarg) ? atoi(optarg) : -1;
  83                         break;
  84
  85                 case 'N':
  86                         if (!strcmp(optarg, "force")) {
  87                                 ia_na_mode = IA_MODE_FORCE;
  88                                 allow_slaac_only = -1;
  89                         } else if (!strcmp(optarg, "none")) {
  90                                 ia_na_mode = IA_MODE_NONE;
  91                         } else if (!strcmp(optarg, "try")) {
  92                                 ia_na_mode = IA_MODE_TRY;
  93                         } else{
  94                                 help = true;
  95                         }
  96                         break;
  97
  98                 case 'V':
  99                         l = script_unhexlify(buf, sizeof(buf), optarg);
 100                         if (!l)
 101                                 help=true;
 102
 103                         odhcp6c_add_state(STATE_VENDORCLASS, buf, l);
 104
 105                         break;
 106                 case 'P':
 107                         if (allow_slaac_only >= 0 && allow_slaac_only < 10)
 108                                 allow_slaac_only = 10;
 109
 110                         char *iaid_begin;
 111                         int iaid_len = 0;
 112
 113                         int prefix_length = strtoul(optarg, &iaid_begin, 10);
 114
 115                         if (*iaid_begin != '\0' && *iaid_begin != ',') {
 116                                 syslog(LOG_ERR, "invalid argument: '%s'", optarg);
 117                                 return 1;
 118                         }
 119
 120                         struct odhcp6c_request_prefix prefix = { 0, prefix_length };
 121
 122                         if (*iaid_begin == ',' && (iaid_len = strlen(iaid_begin)) > 1)
 123                                 memcpy(&prefix.iaid, iaid_begin + 1, iaid_len > 4 ? 4 : iaid_len);
 124                         else
 125                                 prefix.iaid = ++ia_pd_iaid_index;
 126
 127                         odhcp6c_add_state(STATE_IA_PD_INIT, &prefix, sizeof(prefix));
 128
 129                         break;
 130
 131                 case 'F':
 132                         allow_slaac_only = -1;
 133                         ia_pd_mode = IA_MODE_FORCE;
 134                         break;
 135
 136 #ifdef EXT_BFD_PING
 137                 case 'B':
 138                         bfd_interval = atoi(optarg);
 139                         break;
 140 #endif
 141
 142                 case 'c':
 143                         l = script_unhexlify(&buf[4], sizeof(buf) - 4, optarg);
 144                         if (l > 0) {
 145                                 buf[0] = 0;
 146                                 buf[1] = DHCPV6_OPT_CLIENTID;
 147                                 buf[2] = 0;
 148                                 buf[3] = l;
 149                                 odhcp6c_add_state(STATE_CLIENT_ID, buf, l + 4);
 150                         } else {
 151                                 help = true;
 152                         }
 153                         break;
 154
 155                 case 'i':
 156                         if (inet_pton(AF_INET6, optarg, &ifid) != 1)
 157                                 help = true;
 158                         break;
 159
 160                 case 'r':
 161                         optpos = optarg;
 162                         while (optpos[0]) {
 163                                 opttype = htons(strtoul(optarg, &optpos, 10));
 164                                 if (optpos == optarg)
 165                                         break;
 166                                 else if (optpos[0])
 167                                         optarg = &optpos[1];
 168                                 odhcp6c_add_state(STATE_ORO, &opttype, 2);
 169                         }
 170                         break;
 171
 172                 case 'R':
 173                         client_options |= DHCPV6_STRICT_OPTIONS;
 174                         break;
 175
 176                 case 's':
 177                         script = optarg;
 178                         break;
 179
 180                 case 'k':
 181                         release = false;
 182                         break;
 183
 184                 case 't':
 185                         sol_timeout = atoi(optarg);
 186                         break;
 187
 188                 case 'e':
 189                         logopt |= LOG_PERROR;
 190                         break;
 191
 192                 case 'd':
 193                         daemonize = true;
 194                         break;
 195
 196                 case 'p':
 197                         pidfile = optarg;
 198                         break;
 199
 200                 case 'f':
 201                         client_options &= ~DHCPV6_CLIENT_FQDN;
 202                         break;
 203
 204                 case 'a':
 205                         client_options &= ~DHCPV6_ACCEPT_RECONFIGURE;
 206                         break;
 207
 208                 default:
 209                         help = true;
 210                         break;
 211                 }
 212         }
 213
 214         openlog("odhcp6c", logopt, LOG_DAEMON);
 215         const char *ifname = argv[optind];
 216
 217         if (help || !ifname)
 218                 return usage();
 219
 220         signal(SIGIO, sighandler);
 221         signal(SIGHUP, sighandler);
 222         signal(SIGINT, sighandler);
 223         signal(SIGCHLD, sighandler);
 224         signal(SIGTERM, sighandler);
 225         signal(SIGUSR1, sighandler);
 226         signal(SIGUSR2, sighandler);
 227
 228         if ((urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY)) < 0 ||
 229                         init_dhcpv6(ifname, client_options, sol_timeout) ||
 230                         ra_init(ifname, &ifid) || script_init(script, ifname)) {
 231                 syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
 232                 return 3;
 233         }
 234
 235         if (daemonize) {
 236                 openlog("odhcp6c", LOG_PID, LOG_DAEMON); // Disable LOG_PERROR
 237                 if (daemon(0, 0)) {
 238                         syslog(LOG_ERR, "Failed to daemonize: %s",
 239                                         strerror(errno));
 240                         return 4;
 241                 }
 242
 243                 char pidbuf[128];
 244                 if (!pidfile) {
 245                         snprintf(pidbuf, sizeof(pidbuf),
 246                                         "/var/run/odhcp6c.%s.pid", ifname);
 247                         pidfile = pidbuf;
 248                 }
 249
 250                 int fd = open(pidfile, O_WRONLY | O_CREAT);
 251                 if (fd >= 0) {
 252                         char buf[8];
 253                         int len = snprintf(buf, sizeof(buf), "%i\n", getpid());
 254                         write(fd, buf, len);
 255                         close(fd);
 256                 }
 257         }
 258
 259         script_call("started");
 260
 261         while (!signal_term) { // Main logic
 262                 odhcp6c_clear_state(STATE_SERVER_ID);
 263                 odhcp6c_clear_state(STATE_IA_NA);
 264                 odhcp6c_clear_state(STATE_IA_PD);
 265                 odhcp6c_clear_state(STATE_SNTP_IP);
 266                 odhcp6c_clear_state(STATE_NTP_IP);
 267                 odhcp6c_clear_state(STATE_NTP_FQDN);
 268                 odhcp6c_clear_state(STATE_SIP_IP);
 269                 odhcp6c_clear_state(STATE_SIP_FQDN);
 270                 dhcpv6_set_ia_mode(ia_na_mode, ia_pd_mode);
 271                 bound = false;
 272
 273                 syslog(LOG_NOTICE, "(re)starting transaction on %s", ifname);
 274
 275                 signal_usr1 = signal_usr2 = false;
 276                 int mode = dhcpv6_request(DHCPV6_MSG_SOLICIT);
 277                 odhcp6c_signal_process();
 278
 279                 if (mode < 0)
 280                         continue;
 281
 282                 do {
 283                         int res = dhcpv6_request(mode == DHCPV6_STATELESS ?
 284                                         DHCPV6_MSG_INFO_REQ : DHCPV6_MSG_REQUEST);
 285                         bool signalled = odhcp6c_signal_process();
 286
 287                         if (res > 0)
 288                                 break;
 289                         else if (signalled) {
 290                                 mode = -1;
 291                                 break;
 292                         }
 293
 294                         mode = dhcpv6_promote_server_cand();
 295                 } while (mode > DHCPV6_UNKNOWN);
 296
 297                 if (mode < 0)
 298                         continue;
 299
 300                 switch (mode) {
 301                 case DHCPV6_STATELESS:
 302                         bound = true;
 303                         syslog(LOG_NOTICE, "entering stateless-mode on %s", ifname);
 304
 305                         while (!signal_usr2 && !signal_term) {
 306                                 signal_usr1 = false;
 307                                 script_call("informed");
 308
 309                                 int res = dhcpv6_poll_reconfigure();
 310                                 odhcp6c_signal_process();
 311
 312                                 if (res > 0)
 313                                         continue;
 314
 315                                 if (signal_usr1) {
 316                                         signal_usr1 = false; // Acknowledged
 317                                         continue;
 318                                 }
 319                                 if (signal_usr2 || signal_term)
 320                                         break;
 321
 322                                 res = dhcpv6_request(DHCPV6_MSG_INFO_REQ);
 323                                 odhcp6c_signal_process();
 324                                 if (signal_usr1)
 325                                         continue;
 326                                 else if (res < 0)
 327                                         break;
 328                         }
 329                         break;
 330
 331                 case DHCPV6_STATEFUL:
 332                         script_call("bound");
 333                         bound = true;
 334                         syslog(LOG_NOTICE, "entering stateful-mode on %s", ifname);
 335 #ifdef EXT_BFD_PING
 336                         if (bfd_interval > 0)
 337                                 bfd_start(ifname, bfd_loss, bfd_interval);
 338 #endif
 339
 340                         while (!signal_usr2 && !signal_term) {
 341                                 // Renew Cycle
 342                                 // Wait for T1 to expire or until we get a reconfigure
 343                                 int res = dhcpv6_poll_reconfigure();
 344                                 odhcp6c_signal_process();
 345                                 if (res > 0) {
 346                                         script_call("updated");
 347                                         continue;
 348                                 }
 349
 350                                 // Handle signal, if necessary
 351                                 if (signal_usr1)
 352                                         signal_usr1 = false; // Acknowledged
 353                                 if (signal_usr2 || signal_term)
 354                                         break; // Other signal type
 355
 356                                 // Send renew as T1 expired
 357                                 size_t ia_pd_len, ia_na_len;
 358                                 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 359                                 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 360
 361                                 // If we have any IAs, send renew, otherwise request
 362                                 if (ia_pd_len == 0 && ia_na_len == 0)
 363                                         res = dhcpv6_request(DHCPV6_MSG_REQUEST);
 364                                 else
 365                                         res = dhcpv6_request(DHCPV6_MSG_RENEW);
 366
 367                                 odhcp6c_signal_process();
 368                                 if (res > 0) { // Renew was succesfull
 369                                         // Publish updates
 370                                         script_call("updated");
 371                                         continue; // Renew was successful
 372                                 }
 373
 374                                 odhcp6c_clear_state(STATE_SERVER_ID); // Remove binding
 375
 376                                 // If we have IAs, try rebind otherwise restart
 377                                 res = dhcpv6_request(DHCPV6_MSG_REBIND);
 378                                 odhcp6c_signal_process();
 379
 380                                 if (res > 0)
 381                                         script_call("rebound");
 382                                 else {
 383 #ifdef EXT_BFD_PING
 384                                         bfd_stop();
 385 #endif
 386                                         break;
 387                                 }
 388                         }
 389                         break;
 390
 391                 default:
 392                         break;
 393                 }
 394
 395                 size_t ia_pd_len, ia_na_len, server_id_len;
 396                 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 397                 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 398                 odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 399
 400                 // Add all prefixes to lost prefixes
 401                 bound = false;
 402                 script_call("unbound");
 403
 404                 if (server_id_len > 0 && (ia_pd_len > 0 || ia_na_len > 0) && release)
 405                         dhcpv6_request(DHCPV6_MSG_RELEASE);
 406
 407                 odhcp6c_clear_state(STATE_IA_NA);
 408                 odhcp6c_clear_state(STATE_IA_PD);
 409         }
 410
 411         script_call("stopped");
 412         return 0;
 413 }
 414
 415
 416 static int usage(void)
 417 {
 418         const char buf[] =
 419         "Usage: odhcp6c [options] <interface>\n"
 420         "\nFeature options:\n"
 421         "       -S <time>       Wait at least <time> sec for a DHCP-server (0)\n"
 422         "       -N <mode>       Mode for requesting addresses [try|force|none]\n"
 423         "       -P <length>     Request IPv6-Prefix (0 = auto)\n"
 424         "       -F              Force IPv6-Prefix\n"
 425         "       -V <hex-string> Set vendor-class option. string length must be a multiple of 2\n"
 426 #ifdef EXT_BFD_PING
 427         "       -B <interval>   Enable BFD ping check\n"
 428 #endif
 429         "       -c <clientid>   Override client-ID (base-16 encoded)\n"
 430         "       -i <iface-id>   Use a custom interface identifier for RA handling\n"
 431         "       -r <options>    Options to be requested (comma-separated)\n"
 432         "       -R              Do not request any options except those specified with -r\n"
 433         "       -s <script>     Status update script (/usr/sbin/odhcp6c-update)\n"
 434         "       -a              Don't send Accept Reconfigure option\n"
 435         "       -f              Don't send Client FQDN option\n"
 436         "       -k              Don't send a RELEASE when stopping\n"
 437         "       -t <seconds>    Maximum timeout for DHCPv6-SOLICIT (120)\n"
 438         "\nInvocation options:\n"
 439         "       -p <pidfile>    Set pidfile (/var/run/6relayd.pid)\n"
 440         "       -d              Daemonize\n"
 441         "       -e              Write logmessages to stderr\n"
 442         //"     -v              Increase logging verbosity\n"
 443         "       -h              Show this help\n\n";
 444         write(STDERR_FILENO, buf, sizeof(buf));
 445         return 1;
 446 }
 447
 448
 449 // Don't want to pull-in librt and libpthread just for a monotonic clock...
 450 uint64_t odhcp6c_get_milli_time(void)
 451 {
 452         struct timespec t = {0, 0};
 453         syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &t);
 454         return t.tv_sec * 1000 + t.tv_nsec / 1000000;
 455 }
 456
 457
 458 static uint8_t* odhcp6c_resize_state(enum odhcp6c_state state, ssize_t len)
 459 {
 460         if (len == 0)
 461                 return state_data[state] + state_len[state];
 462         else if (state_len[state] + len > 1024)
 463                 return NULL;
 464
 465         uint8_t *n = realloc(state_data[state], state_len[state] + len);
 466         if (n || state_len[state] + len == 0) {
 467                 state_data[state] = n;
 468                 n += state_len[state];
 469                 state_len[state] += len;
 470         }
 471         return n;
 472 }
 473
 474
 475 bool odhcp6c_signal_process(void)
 476 {
 477         while (signal_io) {
 478                 signal_io = false;
 479
 480                 bool ra_updated = ra_process();
 481
 482                 if (ra_link_up())
 483                         signal_usr2 = true;
 484
 485                 if (ra_updated && (bound || allow_slaac_only == 0))
 486                         script_call("ra-updated"); // Immediate process urgent events
 487                 else if (ra_updated && !bound && allow_slaac_only > 0)
 488                         script_delay_call("ra-updated", allow_slaac_only);
 489
 490 #ifdef EXT_BFD_PING
 491                 bfd_receive();
 492 #endif
 493         }
 494
 495         return signal_usr1 || signal_usr2 || signal_term;
 496 }
 497
 498
 499 void odhcp6c_clear_state(enum odhcp6c_state state)
 500 {
 501         state_len[state] = 0;
 502 }
 503
 504
 505 void odhcp6c_add_state(enum odhcp6c_state state, const void *data, size_t len)
 506 {
 507         uint8_t *n = odhcp6c_resize_state(state, len);
 508         if (n)
 509                 memcpy(n, data, len);
 510 }
 511
 512 void odhcp6c_insert_state(enum odhcp6c_state state, size_t offset, const void *data, size_t len)
 513 {
 514         ssize_t len_after = state_len[state] - offset;
 515         if (len_after < 0)
 516                 return;
 517
 518         uint8_t *n = odhcp6c_resize_state(state, len);
 519         if (n) {
 520                 uint8_t *sdata = state_data[state];
 521
 522                 memmove(sdata + offset + len, sdata + offset, len_after);
 523                 memcpy(sdata + offset, data, len);
 524         }
 525 }
 526
 527 size_t odhcp6c_remove_state(enum odhcp6c_state state, size_t offset, size_t len)
 528 {
 529         uint8_t *data = state_data[state];
 530         ssize_t len_after = state_len[state] - (offset + len);
 531         if (len_after < 0)
 532                 return state_len[state];
 533
 534         memmove(data + offset, data + offset + len, len_after);
 535         return state_len[state] -= len;
 536 }
 537
 538
 539 void* odhcp6c_move_state(enum odhcp6c_state state, size_t *len)
 540 {
 541         *len = state_len[state];
 542         void *data = state_data[state];
 543
 544         state_len[state] = 0;
 545         state_data[state] = NULL;
 546
 547         return data;
 548 }
 549
 550
 551 void* odhcp6c_get_state(enum odhcp6c_state state, size_t *len)
 552 {
 553         *len = state_len[state];
 554         return state_data[state];
 555 }
 556
 557
 558 struct odhcp6c_entry* odhcp6c_find_entry(enum odhcp6c_state state, const struct odhcp6c_entry *new)
 559 {
 560         size_t len, cmplen = offsetof(struct odhcp6c_entry, target) + new->length / 8;
 561         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 562         struct odhcp6c_entry *x = NULL;
 563
 564         for (struct odhcp6c_entry *c = start; !x && c < &start[len/sizeof(*c)]; ++c)
 565                 if (!memcmp(c, new, cmplen))
 566                         return c;
 567
 568         return NULL;
 569 }
 570
 571
 572 bool odhcp6c_update_entry_safe(enum odhcp6c_state state, struct odhcp6c_entry *new, uint32_t safe)
 573 {
 574         size_t len;
 575         struct odhcp6c_entry *x = odhcp6c_find_entry(state, new);
 576         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 577
 578         if (x && x->valid > new->valid && new->valid < safe)
 579                 new->valid = safe;
 580
 581         if (new->valid > 0) {
 582                 if (x) {
 583                         if (new->valid >= x->valid && new->valid - x->valid < 60 &&
 584                                         new->preferred >= x->preferred &&
 585                                         new->preferred - x->preferred < 60 &&
 586                                         x->class == new->class)
 587                                 return false;
 588                         x->valid = new->valid;
 589                         x->preferred = new->preferred;
 590                         x->t1 = new->t1;
 591                         x->t2 = new->t2;
 592                         x->class = new->class;
 593                         x->iaid = new->iaid;
 594                 } else {
 595                         odhcp6c_add_state(state, new, sizeof(*new));
 596                 }
 597         } else if (x) {
 598                 odhcp6c_remove_state(state, (x - start) * sizeof(*x), sizeof(*x));
 599         }
 600         return true;
 601 }
 602
 603
 604 bool odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new)
 605 {
 606         return odhcp6c_update_entry_safe(state, new, 0);
 607 }
 608
 609
 610 static void odhcp6c_expire_list(enum odhcp6c_state state, uint32_t elapsed)
 611 {
 612         size_t len;
 613         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 614         for (struct odhcp6c_entry *c = start; c < &start[len / sizeof(*c)]; ++c) {
 615                 if (c->t1 < elapsed)
 616                         c->t1 = 0;
 617                 else if (c->t1 != UINT32_MAX)
 618                         c->t1 -= elapsed;
 619
 620                 if (c->t2 < elapsed)
 621                         c->t2 = 0;
 622                 else if (c->t2 != UINT32_MAX)
 623                         c->t2 -= elapsed;
 624
 625                 if (c->preferred < elapsed)
 626                         c->preferred = 0;
 627                 else if (c->preferred != UINT32_MAX)
 628                         c->preferred -= elapsed;
 629
 630                 if (c->valid < elapsed)
 631                         c->valid = 0;
 632                 else if (c->valid != UINT32_MAX)
 633                         c->valid -= elapsed;
 634
 635                 if (!c->valid)
 636                         odhcp6c_remove_state(state, (c - start) * sizeof(*c), sizeof(*c));
 637         }
 638 }
 639
 640
 641 void odhcp6c_expire(void)
 642 {
 643         time_t now = odhcp6c_get_milli_time() / 1000;
 644         uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 645         last_update = now;
 646
 647         odhcp6c_expire_list(STATE_RA_PREFIX, elapsed);
 648         odhcp6c_expire_list(STATE_RA_ROUTE, elapsed);
 649         odhcp6c_expire_list(STATE_RA_DNS, elapsed);
 650         odhcp6c_expire_list(STATE_IA_NA, elapsed);
 651         odhcp6c_expire_list(STATE_IA_PD, elapsed);
 652 }
 653
 654
 655 uint32_t odhcp6c_elapsed(void)
 656 {
 657         return odhcp6c_get_milli_time() / 1000 - last_update;
 658 }
 659
 660
 661 void odhcp6c_random(void *buf, size_t len)
 662 {
 663         read(urandom_fd, buf, len);
 664 }
 665
 666 bool odhcp6c_is_bound(void)
 667 {
 668         return bound;
 669 }
 670
 671 static void sighandler(int signal)
 672 {
 673         if (signal == SIGCHLD)
 674                 while (waitpid(-1, NULL, WNOHANG) > 0);
 675         else if (signal == SIGUSR1)
 676                 signal_usr1 = true;
 677         else if (signal == SIGUSR2)
 678                 signal_usr2 = true;
 679         else if (signal == SIGIO)
 680                 signal_io = true;
 681         else
 682                 signal_term = true;
 683 }