src/odhcp6c.c

   1 /**
   2  * Copyright (C) 2012-2014 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
  36
  37 static void sighandler(int signal);
  38 static int usage(void);
  39
  40 static uint8_t *state_data[_STATE_MAX] = {NULL};
  41 static size_t state_len[_STATE_MAX] = {0};
  42
  43 static volatile bool signal_io = false;
  44 static volatile bool signal_usr1 = false;
  45 static volatile bool signal_usr2 = false;
  46 static volatile bool signal_term = false;
  47
  48 static int urandom_fd = -1, allow_slaac_only = 0;
  49 static bool bound = false, release = true;
  50 static time_t last_update = 0;
  51
  52 static unsigned int min_update_interval = DEFAULT_MIN_UPDATE_INTERVAL;
  53
  54 int main(_unused int argc, char* const argv[])
  55 {
  56         // Allocate ressources
  57         const char *pidfile = NULL;
  58         const char *script = "/usr/sbin/odhcp6c-update";
  59         ssize_t l;
  60         uint8_t buf[134];
  61         char *optpos;
  62         uint16_t opttype;
  63         uint16_t optlen;
  64         enum odhcp6c_ia_mode ia_na_mode = IA_MODE_TRY;
  65         enum odhcp6c_ia_mode ia_pd_mode = IA_MODE_NONE;
  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
  71         bool help = false, daemonize = false;
  72         int logopt = LOG_PID;
  73         int c;
  74         unsigned int client_options = DHCPV6_CLIENT_FQDN | DHCPV6_ACCEPT_RECONFIGURE;
  75
  76         while ((c = getopt(argc, argv, "S::N:V:P:FB:c:i:r:Ru:s:kt:m:hedp:fa")) != -1) {
  77                 switch (c) {
  78                 case 'S':
  79                         allow_slaac_only = (optarg) ? atoi(optarg) : -1;
  80                         break;
  81
  82                 case 'N':
  83                         if (!strcmp(optarg, "force")) {
  84                                 ia_na_mode = IA_MODE_FORCE;
  85                                 allow_slaac_only = -1;
  86                         } else if (!strcmp(optarg, "none")) {
  87                                 ia_na_mode = IA_MODE_NONE;
  88                         } else if (!strcmp(optarg, "try")) {
  89                                 ia_na_mode = IA_MODE_TRY;
  90                         } else{
  91                                 help = true;
  92                         }
  93                         break;
  94
  95                 case 'V':
  96                         l = script_unhexlify(buf, sizeof(buf), optarg);
  97                         if (!l)
  98                                 help=true;
  99
 100                         odhcp6c_add_state(STATE_VENDORCLASS, buf, l);
 101
 102                         break;
 103                 case 'P':
 104                         if (ia_pd_mode == IA_MODE_NONE)
 105                                 ia_pd_mode = IA_MODE_TRY;
 106
 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 != ',' && *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 if (*iaid_begin == ':')
 125                                 prefix.iaid = htonl((uint32_t)strtoul(&iaid_begin[1], NULL, 16));
 126                         else
 127                                 prefix.iaid = htonl(++ia_pd_iaid_index);
 128
 129                         odhcp6c_add_state(STATE_IA_PD_INIT, &prefix, sizeof(prefix));
 130
 131                         break;
 132
 133                 case 'F':
 134                         allow_slaac_only = -1;
 135                         ia_pd_mode = IA_MODE_FORCE;
 136                         break;
 137
 138                 case 'c':
 139                         l = script_unhexlify(&buf[4], sizeof(buf) - 4, optarg);
 140                         if (l > 0) {
 141                                 buf[0] = 0;
 142                                 buf[1] = DHCPV6_OPT_CLIENTID;
 143                                 buf[2] = 0;
 144                                 buf[3] = l;
 145                                 odhcp6c_add_state(STATE_CLIENT_ID, buf, l + 4);
 146                         } else {
 147                                 help = true;
 148                         }
 149                         break;
 150
 151                 case 'i':
 152                         if (inet_pton(AF_INET6, optarg, &ifid) != 1)
 153                                 help = true;
 154                         break;
 155
 156                 case 'r':
 157                         optpos = optarg;
 158                         while (optpos[0]) {
 159                                 opttype = htons(strtoul(optarg, &optpos, 10));
 160                                 if (optpos == optarg)
 161                                         break;
 162                                 else if (optpos[0])
 163                                         optarg = &optpos[1];
 164                                 odhcp6c_add_state(STATE_ORO, &opttype, 2);
 165                         }
 166                         break;
 167
 168                 case 'R':
 169                         client_options |= DHCPV6_STRICT_OPTIONS;
 170                         break;
 171
 172                 case 'u':
 173                         optlen = htons(strlen(optarg));
 174                         odhcp6c_add_state(STATE_USERCLASS, &optlen, 2);
 175                         odhcp6c_add_state(STATE_USERCLASS, optarg, strlen(optarg));
 176                         break;
 177
 178                 case 's':
 179                         script = optarg;
 180                         break;
 181
 182                 case 'k':
 183                         release = false;
 184                         break;
 185
 186                 case 't':
 187                         sol_timeout = atoi(optarg);
 188                         break;
 189
 190                 case 'm':
 191                         min_update_interval = atoi(optarg);
 192                         break;
 193
 194                 case 'e':
 195                         logopt |= LOG_PERROR;
 196                         break;
 197
 198                 case 'd':
 199                         daemonize = true;
 200                         break;
 201
 202                 case 'p':
 203                         pidfile = optarg;
 204                         break;
 205
 206                 case 'f':
 207                         client_options &= ~DHCPV6_CLIENT_FQDN;
 208                         break;
 209
 210                 case 'a':
 211                         client_options &= ~DHCPV6_ACCEPT_RECONFIGURE;
 212                         break;
 213
 214                 default:
 215                         help = true;
 216                         break;
 217                 }
 218         }
 219
 220         openlog("odhcp6c", logopt, LOG_DAEMON);
 221         const char *ifname = argv[optind];
 222
 223         if (help || !ifname)
 224                 return usage();
 225
 226         signal(SIGIO, sighandler);
 227         signal(SIGHUP, sighandler);
 228         signal(SIGINT, sighandler);
 229         signal(SIGCHLD, sighandler);
 230         signal(SIGTERM, sighandler);
 231         signal(SIGUSR1, sighandler);
 232         signal(SIGUSR2, sighandler);
 233
 234         if ((urandom_fd = open("/dev/urandom", O_CLOEXEC | O_RDONLY)) < 0 ||
 235                         init_dhcpv6(ifname, client_options, sol_timeout) ||
 236                         ra_init(ifname, &ifid) || script_init(script, ifname)) {
 237                 syslog(LOG_ERR, "failed to initialize: %s", strerror(errno));
 238                 return 3;
 239         }
 240
 241         if (daemonize) {
 242                 openlog("odhcp6c", LOG_PID, LOG_DAEMON); // Disable LOG_PERROR
 243                 if (daemon(0, 0)) {
 244                         syslog(LOG_ERR, "Failed to daemonize: %s",
 245                                         strerror(errno));
 246                         return 4;
 247                 }
 248
 249                 char pidbuf[128];
 250                 if (!pidfile) {
 251                         snprintf(pidbuf, sizeof(pidbuf),
 252                                         "/var/run/odhcp6c.%s.pid", ifname);
 253                         pidfile = pidbuf;
 254                 }
 255
 256                 int fd = open(pidfile, O_WRONLY | O_CREAT, 0644);
 257                 if (fd >= 0) {
 258                         char buf[8];
 259                         int len = snprintf(buf, sizeof(buf), "%i\n", getpid());
 260                         write(fd, buf, len);
 261                         close(fd);
 262                 }
 263         }
 264
 265         script_call("started");
 266
 267         while (!signal_term) { // Main logic
 268                 odhcp6c_clear_state(STATE_SERVER_ID);
 269                 odhcp6c_clear_state(STATE_SERVER_ADDR);
 270                 odhcp6c_clear_state(STATE_IA_NA);
 271                 odhcp6c_clear_state(STATE_IA_PD);
 272                 odhcp6c_clear_state(STATE_SNTP_IP);
 273                 odhcp6c_clear_state(STATE_NTP_IP);
 274                 odhcp6c_clear_state(STATE_NTP_FQDN);
 275                 odhcp6c_clear_state(STATE_SIP_IP);
 276                 odhcp6c_clear_state(STATE_SIP_FQDN);
 277                 dhcpv6_set_ia_mode(ia_na_mode, ia_pd_mode);
 278                 bound = false;
 279
 280                 syslog(LOG_NOTICE, "(re)starting transaction on %s", ifname);
 281
 282                 signal_usr1 = signal_usr2 = false;
 283                 int mode = dhcpv6_request(DHCPV6_MSG_SOLICIT);
 284                 odhcp6c_signal_process();
 285
 286                 if (mode < 0)
 287                         continue;
 288
 289                 do {
 290                         int res = dhcpv6_request(mode == DHCPV6_STATELESS ?
 291                                         DHCPV6_MSG_INFO_REQ : DHCPV6_MSG_REQUEST);
 292                         bool signalled = odhcp6c_signal_process();
 293
 294                         if (res > 0)
 295                                 break;
 296                         else if (signalled) {
 297                                 mode = -1;
 298                                 break;
 299                         }
 300
 301                         mode = dhcpv6_promote_server_cand();
 302                 } while (mode > DHCPV6_UNKNOWN);
 303
 304                 if (mode < 0)
 305                         continue;
 306
 307                 switch (mode) {
 308                 case DHCPV6_STATELESS:
 309                         bound = true;
 310                         syslog(LOG_NOTICE, "entering stateless-mode on %s", ifname);
 311
 312                         while (!signal_usr2 && !signal_term) {
 313                                 signal_usr1 = false;
 314                                 script_call("informed");
 315
 316                                 int res = dhcpv6_poll_reconfigure();
 317                                 odhcp6c_signal_process();
 318
 319                                 if (res > 0)
 320                                         continue;
 321
 322                                 if (signal_usr1) {
 323                                         signal_usr1 = false; // Acknowledged
 324                                         continue;
 325                                 }
 326                                 if (signal_usr2 || signal_term)
 327                                         break;
 328
 329                                 res = dhcpv6_request(DHCPV6_MSG_INFO_REQ);
 330                                 odhcp6c_signal_process();
 331                                 if (signal_usr1)
 332                                         continue;
 333                                 else if (res < 0)
 334                                         break;
 335                         }
 336                         break;
 337
 338                 case DHCPV6_STATEFUL:
 339                         bound = true;
 340                         script_call("bound");
 341                         syslog(LOG_NOTICE, "entering stateful-mode on %s", ifname);
 342
 343                         while (!signal_usr2 && !signal_term) {
 344                                 // Renew Cycle
 345                                 // Wait for T1 to expire or until we get a reconfigure
 346                                 int res = dhcpv6_poll_reconfigure();
 347                                 odhcp6c_signal_process();
 348                                 if (res > 0) {
 349                                         script_call("updated");
 350                                         continue;
 351                                 }
 352
 353                                 // Handle signal, if necessary
 354                                 if (signal_usr1)
 355                                         signal_usr1 = false; // Acknowledged
 356                                 if (signal_usr2 || signal_term)
 357                                         break; // Other signal type
 358
 359                                 // Send renew as T1 expired
 360                                 res = dhcpv6_request(DHCPV6_MSG_RENEW);
 361                                 odhcp6c_signal_process();
 362                                 if (res > 0) { // Renew was succesfull
 363                                         // Publish updates
 364                                         script_call("updated");
 365                                         continue; // Renew was successful
 366                                 }
 367
 368                                 odhcp6c_clear_state(STATE_SERVER_ID); // Remove binding
 369                                 odhcp6c_clear_state(STATE_SERVER_ADDR);
 370
 371                                 size_t ia_pd_len, ia_na_len;
 372                                 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 373                                 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 374
 375                                 if (ia_pd_len == 0 && ia_na_len == 0)
 376                                         break;
 377
 378                                 // If we have IAs, try rebind otherwise restart
 379                                 res = dhcpv6_request(DHCPV6_MSG_REBIND);
 380                                 odhcp6c_signal_process();
 381
 382                                 if (res > 0)
 383                                         script_call("rebound");
 384                                 else {
 385                                         break;
 386                                 }
 387                         }
 388                         break;
 389
 390                 default:
 391                         break;
 392                 }
 393
 394                 size_t ia_pd_len, ia_na_len, server_id_len;
 395                 odhcp6c_get_state(STATE_IA_PD, &ia_pd_len);
 396                 odhcp6c_get_state(STATE_IA_NA, &ia_na_len);
 397                 odhcp6c_get_state(STATE_SERVER_ID, &server_id_len);
 398
 399                 // Add all prefixes to lost prefixes
 400                 bound = false;
 401                 script_call("unbound");
 402
 403                 if (server_id_len > 0 && (ia_pd_len > 0 || ia_na_len > 0) && release)
 404                         dhcpv6_request(DHCPV6_MSG_RELEASE);
 405
 406                 odhcp6c_clear_state(STATE_IA_NA);
 407                 odhcp6c_clear_state(STATE_IA_PD);
 408         }
 409
 410         script_call("stopped");
 411         return 0;
 412 }
 413
 414
 415 static int usage(void)
 416 {
 417         const char buf[] =
 418         "Usage: odhcp6c [options] <interface>\n"
 419         "\nFeature options:\n"
 420         "       -S <time>       Wait at least <time> sec for a DHCP-server (0)\n"
 421         "       -N <mode>       Mode for requesting addresses [try|force|none]\n"
 422         "       -P <length>     Request IPv6-Prefix (0 = auto)\n"
 423         "       -F              Force IPv6-Prefix\n"
 424         "       -V <class>      Set vendor-class option (base-16 encoded)\n"
 425         "       -u <user-class> Set user-class option string\n"
 426         "       -c <clientid>   Override client-ID (base-16 encoded)\n"
 427         "       -i <iface-id>   Use a custom interface identifier for RA handling\n"
 428         "       -r <options>    Options to be requested (comma-separated)\n"
 429         "       -R              Do not request any options except those specified with -r\n"
 430         "       -s <script>     Status update script (/usr/sbin/odhcp6c-update)\n"
 431         "       -a              Don't send Accept Reconfigure option\n"
 432         "       -f              Don't send Client FQDN option\n"
 433         "       -k              Don't send a RELEASE when stopping\n"
 434         "       -t <seconds>    Maximum timeout for DHCPv6-SOLICIT (3600)\n"
 435         "       -m <seconds>    Minimum time between accepting updates (30)\n"
 436         "\nInvocation options:\n"
 437         "       -p <pidfile>    Set pidfile (/var/run/odhcp6c.pid)\n"
 438         "       -d              Daemonize\n"
 439         "       -e              Write logmessages to stderr\n"
 440         //"     -v              Increase logging verbosity\n"
 441         "       -h              Show this help\n\n";
 442         write(STDERR_FILENO, buf, sizeof(buf));
 443         return 1;
 444 }
 445
 446
 447 // Don't want to pull-in librt and libpthread just for a monotonic clock...
 448 uint64_t odhcp6c_get_milli_time(void)
 449 {
 450         struct timespec t = {0, 0};
 451         syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &t);
 452         return ((uint64_t)t.tv_sec) * 1000 + ((uint64_t)t.tv_nsec) / 1000000;
 453 }
 454
 455
 456 static uint8_t* odhcp6c_resize_state(enum odhcp6c_state state, ssize_t len)
 457 {
 458         if (len == 0)
 459                 return state_data[state] + state_len[state];
 460         else if (state_len[state] + len > 1024)
 461                 return NULL;
 462
 463         uint8_t *n = realloc(state_data[state], state_len[state] + len);
 464         if (n || state_len[state] + len == 0) {
 465                 state_data[state] = n;
 466                 n += state_len[state];
 467                 state_len[state] += len;
 468         }
 469         return n;
 470 }
 471
 472
 473 bool odhcp6c_signal_process(void)
 474 {
 475         while (signal_io) {
 476                 signal_io = false;
 477
 478                 bool ra_updated = ra_process();
 479
 480                 if (ra_link_up())
 481                         signal_usr2 = true;
 482
 483                 if (ra_updated && (bound || allow_slaac_only >= 0))
 484                         script_call("ra-updated"); // Immediate process urgent events
 485         }
 486
 487         return signal_usr1 || signal_usr2 || signal_term;
 488 }
 489
 490
 491 void odhcp6c_clear_state(enum odhcp6c_state state)
 492 {
 493         state_len[state] = 0;
 494 }
 495
 496
 497 void odhcp6c_add_state(enum odhcp6c_state state, const void *data, size_t len)
 498 {
 499         uint8_t *n = odhcp6c_resize_state(state, len);
 500         if (n)
 501                 memcpy(n, data, len);
 502 }
 503
 504 void odhcp6c_insert_state(enum odhcp6c_state state, size_t offset, const void *data, size_t len)
 505 {
 506         ssize_t len_after = state_len[state] - offset;
 507         if (len_after < 0)
 508                 return;
 509
 510         uint8_t *n = odhcp6c_resize_state(state, len);
 511         if (n) {
 512                 uint8_t *sdata = state_data[state];
 513
 514                 memmove(sdata + offset + len, sdata + offset, len_after);
 515                 memcpy(sdata + offset, data, len);
 516         }
 517 }
 518
 519 size_t odhcp6c_remove_state(enum odhcp6c_state state, size_t offset, size_t len)
 520 {
 521         uint8_t *data = state_data[state];
 522         ssize_t len_after = state_len[state] - (offset + len);
 523         if (len_after < 0)
 524                 return state_len[state];
 525
 526         memmove(data + offset, data + offset + len, len_after);
 527         return state_len[state] -= len;
 528 }
 529
 530
 531 void* odhcp6c_move_state(enum odhcp6c_state state, size_t *len)
 532 {
 533         *len = state_len[state];
 534         void *data = state_data[state];
 535
 536         state_len[state] = 0;
 537         state_data[state] = NULL;
 538
 539         return data;
 540 }
 541
 542
 543 void* odhcp6c_get_state(enum odhcp6c_state state, size_t *len)
 544 {
 545         *len = state_len[state];
 546         return state_data[state];
 547 }
 548
 549
 550 struct odhcp6c_entry* odhcp6c_find_entry(enum odhcp6c_state state, const struct odhcp6c_entry *new)
 551 {
 552         size_t len, cmplen = offsetof(struct odhcp6c_entry, target) + new->length / 8;
 553         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 554         struct odhcp6c_entry *x = NULL;
 555
 556         for (struct odhcp6c_entry *c = start; !x && c < &start[len/sizeof(*c)]; ++c)
 557                 if (!memcmp(c, new, cmplen))
 558                         return c;
 559
 560         return NULL;
 561 }
 562
 563
 564 bool odhcp6c_update_entry_safe(enum odhcp6c_state state, struct odhcp6c_entry *new, uint32_t safe)
 565 {
 566         size_t len;
 567         struct odhcp6c_entry *x = odhcp6c_find_entry(state, new);
 568         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 569
 570         if (x && x->valid > new->valid && new->valid < safe)
 571                 new->valid = safe;
 572
 573         if (new->valid > 0) {
 574                 if (x) {
 575                         if (new->valid >= x->valid && new->valid != UINT32_MAX &&
 576                                         new->valid - x->valid < min_update_interval &&
 577                                         new->preferred >= x->preferred &&
 578                                         new->preferred != UINT32_MAX &&
 579                                         new->preferred - x->preferred < min_update_interval &&
 580                                         x->class == new->class)
 581                                 return false;
 582                         x->valid = new->valid;
 583                         x->preferred = new->preferred;
 584                         x->t1 = new->t1;
 585                         x->t2 = new->t2;
 586                         x->class = new->class;
 587                         x->iaid = new->iaid;
 588                 } else {
 589                         odhcp6c_add_state(state, new, sizeof(*new));
 590                 }
 591         } else if (x) {
 592                 odhcp6c_remove_state(state, (x - start) * sizeof(*x), sizeof(*x));
 593         }
 594         return true;
 595 }
 596
 597
 598 bool odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new)
 599 {
 600         return odhcp6c_update_entry_safe(state, new, 0);
 601 }
 602
 603
 604 static void odhcp6c_expire_list(enum odhcp6c_state state, uint32_t elapsed)
 605 {
 606         size_t len;
 607         struct odhcp6c_entry *start = odhcp6c_get_state(state, &len);
 608         for (struct odhcp6c_entry *c = start; c < &start[len / sizeof(*c)]; ++c) {
 609                 if (c->t1 < elapsed)
 610                         c->t1 = 0;
 611                 else if (c->t1 != UINT32_MAX)
 612                         c->t1 -= elapsed;
 613
 614                 if (c->t2 < elapsed)
 615                         c->t2 = 0;
 616                 else if (c->t2 != UINT32_MAX)
 617                         c->t2 -= elapsed;
 618
 619                 if (c->preferred < elapsed)
 620                         c->preferred = 0;
 621                 else if (c->preferred != UINT32_MAX)
 622                         c->preferred -= elapsed;
 623
 624                 if (c->valid < elapsed)
 625                         c->valid = 0;
 626                 else if (c->valid != UINT32_MAX)
 627                         c->valid -= elapsed;
 628
 629                 if (!c->valid)
 630                         odhcp6c_remove_state(state, (c - start) * sizeof(*c), sizeof(*c));
 631         }
 632 }
 633
 634
 635 void odhcp6c_expire(void)
 636 {
 637         time_t now = odhcp6c_get_milli_time() / 1000;
 638         uint32_t elapsed = (last_update > 0) ? now - last_update : 0;
 639         last_update = now;
 640
 641         odhcp6c_expire_list(STATE_RA_PREFIX, elapsed);
 642         odhcp6c_expire_list(STATE_RA_ROUTE, elapsed);
 643         odhcp6c_expire_list(STATE_RA_DNS, elapsed);
 644         odhcp6c_expire_list(STATE_IA_NA, elapsed);
 645         odhcp6c_expire_list(STATE_IA_PD, elapsed);
 646 }
 647
 648
 649 uint32_t odhcp6c_elapsed(void)
 650 {
 651         return odhcp6c_get_milli_time() / 1000 - last_update;
 652 }
 653
 654
 655 void odhcp6c_random(void *buf, size_t len)
 656 {
 657         read(urandom_fd, buf, len);
 658 }
 659
 660 bool odhcp6c_is_bound(void)
 661 {
 662         return bound;
 663 }
 664
 665 static void sighandler(int signal)
 666 {
 667         if (signal == SIGCHLD)
 668                 while (waitpid(-1, NULL, WNOHANG) > 0);
 669         else if (signal == SIGUSR1)
 670                 signal_usr1 = true;
 671         else if (signal == SIGUSR2)
 672                 signal_usr2 = true;
 673         else if (signal == SIGIO)
 674                 signal_io = true;
 675         else
 676                 signal_term = true;
 677 }