git.sesse.net Git - cubemap/blob - main.cpp

   1 #include <assert.h>
   2 #include <errno.h>
   3 #include <fcntl.h>
   4 #include <getopt.h>
   5 #include <limits.h>
   6 #include <signal.h>
   7 #include <stddef.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <string.h>
  11 #include <sys/time.h>
  12 #include <sys/wait.h>
  13 #include <systemd/sd-daemon.h>
  14 #include <unistd.h>
  15 #include <algorithm>
  16 #include <map>
  17 #include <set>
  18 #include <string>
  19 #include <unordered_map>
  20 #include <utility>
  21 #include <vector>
  22
  23 #include "tlse.h"
  24
  25 #include "acceptor.h"
  26 #include "accesslog.h"
  27 #include "config.h"
  28 #include "input.h"
  29 #include "input_stats.h"
  30 #include "log.h"
  31 #include "sa_compare.h"
  32 #include "serverpool.h"
  33 #include "state.pb.h"
  34 #include "stats.h"
  35 #include "stream.h"
  36 #include "util.h"
  37 #include "version.h"
  38
  39 using namespace std;
  40
  41 AccessLogThread *access_log = nullptr;
  42 ServerPool *servers = nullptr;
  43 volatile bool hupped = false;
  44 volatile bool stopped = false;
  45
  46 typedef pair<string, Input::Encoding> InputKey;
  47
  48 namespace {
  49
  50 struct OrderByConnectionTime {
  51         bool operator() (const ClientProto &a, const ClientProto &b) const {
  52                 if (a.connect_time_sec() != b.connect_time_sec())
  53                         return a.connect_time_sec() < b.connect_time_sec();
  54                 return a.connect_time_nsec() < b.connect_time_nsec();
  55         }
  56 };
  57
  58 // An arbitrary ordering.
  59 struct AcceptorConfigCompare {
  60         bool operator() (const AcceptorConfig &a, const AcceptorConfig &b) const {
  61                 int cmp = a.certificate_chain.compare(b.certificate_chain);
  62                 if (cmp != 0) {
  63                         return cmp < 0;
  64                 }
  65
  66                 cmp = a.private_key.compare(b.private_key);
  67                 if (cmp != 0) {
  68                         return cmp < 0;
  69                 }
  70
  71                 return Sockaddr6Compare()(a.addr, b.addr);
  72         }
  73 };
  74
  75 }  // namespace
  76
  77 struct InputWithRefcount {
  78         Input *input;
  79         int refcount;
  80 };
  81
  82 void hup(int signum)
  83 {
  84         hupped = true;
  85         if (signum == SIGINT) {
  86                 stopped = true;
  87         }
  88 }
  89
  90 void do_nothing(int signum)
  91 {
  92 }
  93
  94 CubemapStateProto collect_state(const timespec &serialize_start,
  95                                 const vector<Acceptor *> acceptors,
  96                                 const multimap<InputKey, InputWithRefcount> inputs,
  97                                 ServerPool *servers)
  98 {
  99         CubemapStateProto state = servers->serialize();  // Fills streams() and clients().
 100         state.set_serialize_start_sec(serialize_start.tv_sec);
 101         state.set_serialize_start_usec(serialize_start.tv_nsec / 1000);
 102
 103         for (Acceptor *acceptor : acceptors) {
 104                 state.add_acceptors()->MergeFrom(acceptor->serialize());
 105         }
 106
 107         for (const auto &key_and_input_with_refcount : inputs) {
 108                 state.add_inputs()->MergeFrom(key_and_input_with_refcount.second.input->serialize());
 109         }
 110
 111         return state;
 112 }
 113
 114 // Find all port statements in the configuration file, and create acceptors for them.
 115 vector<Acceptor *> create_acceptors(
 116         const Config &config,
 117         map<AcceptorConfig, Acceptor *, AcceptorConfigCompare> *deserialized_acceptors)
 118 {
 119         vector<Acceptor *> acceptors;
 120         for (const AcceptorConfig &acceptor_config : config.acceptors) {
 121                 Acceptor *acceptor = nullptr;
 122                 const auto deserialized_acceptor_it = deserialized_acceptors->find(acceptor_config);
 123                 if (deserialized_acceptor_it != deserialized_acceptors->end()) {
 124                         acceptor = deserialized_acceptor_it->second;
 125                         deserialized_acceptors->erase(deserialized_acceptor_it);
 126                 } else {
 127                         int server_sock = create_server_socket(acceptor_config.addr, TCP_SOCKET);
 128                         acceptor = new Acceptor(server_sock, acceptor_config.addr,
 129                                                 acceptor_config.certificate_chain,
 130                                                 acceptor_config.private_key);
 131                 }
 132                 acceptor->run();
 133                 acceptors.push_back(acceptor);
 134         }
 135
 136         // Close all acceptors that are no longer in the configuration file.
 137         for (auto &config_and_acceptor : *deserialized_acceptors) {
 138                 config_and_acceptor.second->close_socket();
 139                 delete config_and_acceptor.second;
 140         }
 141
 142         return acceptors;
 143 }
 144
 145 void create_config_input(const string &src, Input::Encoding encoding, multimap<InputKey, InputWithRefcount> *inputs)
 146 {
 147         if (src.empty()) {
 148                 return;
 149         }
 150         InputKey key(src, encoding);
 151         if (inputs->count(key) != 0) {
 152                 return;
 153         }
 154
 155         InputWithRefcount iwr;
 156         iwr.input = create_input(src, encoding);
 157         if (iwr.input == nullptr) {
 158                 log(ERROR, "did not understand URL '%s' or source encoding was invalid, clients will not get any data.",
 159                         src.c_str());
 160                 return;
 161         }
 162         iwr.refcount = 0;
 163         inputs->insert(make_pair(key, iwr));
 164 }
 165
 166 // Find all streams in the configuration file, and create inputs for them.
 167 void create_config_inputs(const Config &config, multimap<InputKey, InputWithRefcount> *inputs)
 168 {
 169         for (const StreamConfig &stream_config : config.streams) {
 170                 if (stream_config.src == "delete") {
 171                         // Ignored for pre-1.4.0 configuration compatibility.
 172                         continue;
 173                 }
 174                 create_config_input(stream_config.src, Input::Encoding(stream_config.src_encoding), inputs);
 175         }
 176         for (const UDPStreamConfig &udpstream_config : config.udpstreams) {
 177                 create_config_input(udpstream_config.src, Input::INPUT_ENCODING_RAW, inputs);
 178         }
 179 }
 180
 181 void create_streams(const Config &config,
 182                     const set<string> &deserialized_urls,
 183                     multimap<InputKey, InputWithRefcount> *inputs)
 184 {
 185         // HTTP streams.
 186         set<string> expecting_urls = deserialized_urls;
 187         for (const StreamConfig &stream_config : config.streams) {
 188                 int stream_index;
 189
 190                 expecting_urls.erase(stream_config.url);
 191
 192                 if (stream_config.src == "delete") {
 193                         // Ignored for pre-1.4.0 configuration compatibility.
 194                         continue;
 195                 }
 196
 197                 if (deserialized_urls.count(stream_config.url) == 0) {
 198                         stream_index = servers->add_stream(stream_config.url,
 199                                                            stream_config.hls_url,
 200                                                            stream_config.backlog_size,
 201                                                            stream_config.prebuffering_bytes,
 202                                                            Stream::Encoding(stream_config.encoding),
 203                                                            Stream::Encoding(stream_config.src_encoding),
 204                                                            stream_config.hls_frag_duration,
 205                                                            stream_config.hls_backlog_margin,
 206                                                            stream_config.allow_origin);
 207                 } else {
 208                         stream_index = servers->lookup_stream_by_url(stream_config.url);
 209                         assert(stream_index != -1);
 210                         servers->set_backlog_size(stream_index, stream_config.backlog_size);
 211                         if (!stream_config.hls_url.empty()) {
 212                                 servers->register_hls_url(stream_index, stream_config.hls_url);
 213                         }
 214                         servers->set_prebuffering_bytes(stream_index, stream_config.prebuffering_bytes);
 215                         servers->set_encoding(stream_index,
 216                                               Stream::Encoding(stream_config.encoding));
 217                         servers->set_src_encoding(stream_index,
 218                                                   Stream::Encoding(stream_config.src_encoding));
 219                         servers->set_hls_frag_duration(stream_index, stream_config.hls_frag_duration);
 220                         servers->set_hls_backlog_margin(stream_index, stream_config.hls_backlog_margin);
 221                         servers->set_allow_origin(stream_index, stream_config.allow_origin);
 222                 }
 223
 224                 servers->set_pacing_rate(stream_index, stream_config.pacing_rate);
 225
 226                 string src = stream_config.src;
 227                 Input::Encoding src_encoding = Input::Encoding(stream_config.src_encoding);
 228                 if (!src.empty()) {
 229                         const auto input_it = inputs->find(make_pair(src, src_encoding));
 230                         if (input_it != inputs->end()) {
 231                                 input_it->second.input->add_destination(stream_index);
 232                                 ++input_it->second.refcount;
 233                         }
 234                 }
 235         }
 236
 237         // Warn about any streams servers we've lost.
 238         for (const string &url : expecting_urls) {
 239                 log(WARNING, "stream '%s' disappeared from the configuration file. "
 240                              "It will not be deleted, but clients will not get any new inputs. "
 241                              "If you really meant to delete it, set src=delete and reload.",
 242                              url.c_str());
 243         }
 244
 245         // UDP streams.
 246         for (const UDPStreamConfig &udpstream_config : config.udpstreams) {
 247                 int stream_index = servers->add_udpstream(
 248                         udpstream_config.dst,
 249                         udpstream_config.pacing_rate,
 250                         udpstream_config.ttl,
 251                         udpstream_config.multicast_iface_index);
 252
 253                 string src = udpstream_config.src;
 254                 if (!src.empty()) {
 255                         auto input_it = inputs->find(make_pair(src, Input::INPUT_ENCODING_RAW));
 256                         assert(input_it != inputs->end());
 257                         input_it->second.input->add_destination(stream_index);
 258                         ++input_it->second.refcount;
 259                 }
 260         }
 261
 262         // HTTP gen204 endpoints.
 263         for (const Gen204Config &ping_config : config.pings) {
 264                 servers->add_gen204(ping_config.url, ping_config.allow_origin);
 265         }
 266 }
 267
 268 void open_logs(const vector<LogConfig> &log_destinations)
 269 {
 270         for (const LogConfig &log_destination : log_destinations) {
 271                 if (log_destination.type == LogConfig::LOG_TYPE_FILE) {
 272                         add_log_destination_file(log_destination.filename);
 273                 } else if (log_destination.type == LogConfig::LOG_TYPE_CONSOLE) {
 274                         add_log_destination_console();
 275                 } else if (log_destination.type == LogConfig::LOG_TYPE_SYSLOG) {
 276                         add_log_destination_syslog();
 277                 } else {
 278                         assert(false);
 279                 }
 280         }
 281         start_logging();
 282 }
 283
 284 bool dry_run_config(const string &argv0, const string &config_filename)
 285 {
 286         char *argv0_copy = strdup(argv0.c_str());
 287         char *config_filename_copy = strdup(config_filename.c_str());
 288
 289         pid_t pid = fork();
 290         switch (pid) {
 291         case -1:
 292                 log_perror("fork()");
 293                 free(argv0_copy);
 294                 free(config_filename_copy);
 295                 return false;
 296         case 0:
 297                 // Child.
 298                 execlp(argv0_copy, argv0_copy, "--test-config", config_filename_copy, nullptr);
 299                 log_perror(argv0_copy);
 300                 _exit(1);
 301         default:
 302                 // Parent.
 303                 break;
 304         }
 305
 306         free(argv0_copy);
 307         free(config_filename_copy);
 308
 309         int status;
 310         pid_t err;
 311         do {
 312                 err = waitpid(pid, &status, 0);
 313         } while (err == -1 && errno == EINTR);
 314
 315         if (err == -1) {
 316                 log_perror("waitpid()");
 317                 return false;
 318         }
 319
 320         return (WIFEXITED(status) && WEXITSTATUS(status) == 0);
 321 }
 322
 323 void find_all_streams(const Config &config, set<string> *all_urls)
 324 {
 325         for (const StreamConfig &stream_config : config.streams) {
 326                 if (stream_config.src == "delete") {
 327                         log(WARNING, "stream '%s' has src=delete; ignoring it. Since Cubemap 1.4.0, you do not "
 328                                      "need to set src=delete to delete streams anymore; just delete them from "
 329                                      "the configuration file.",
 330                                      stream_config.url.c_str());
 331                 } else {
 332                         all_urls->insert(stream_config.url);
 333                 }
 334         }
 335 }
 336
 337 int main(int argc, char **argv)
 338 {
 339         signal(SIGHUP, hup);
 340         signal(SIGINT, hup);
 341         signal(SIGUSR1, do_nothing);  // Used in internal signalling.
 342         signal(SIGPIPE, SIG_IGN);
 343
 344         tls_init();
 345
 346         // Parse options.
 347         int state_fd = -1;
 348         bool test_config = false;
 349         for ( ;; ) {
 350                 static const option long_options[] = {
 351                         { "state", required_argument, 0, 's' },
 352                         { "test-config", no_argument, 0, 't' },
 353                         { 0, 0, 0, 0 }
 354                 };
 355                 int option_index = 0;
 356                 int c = getopt_long(argc, argv, "s:t", long_options, &option_index);
 357
 358                 if (c == -1) {
 359                         break;
 360                 }
 361                 switch (c) {
 362                 case 's':
 363                         state_fd = atoi(optarg);
 364                         break;
 365                 case 't':
 366                         test_config = true;
 367                         break;
 368                 default:
 369                         fprintf(stderr, "Unknown option '%s'\n", argv[option_index]);
 370                         exit(1);
 371                 }
 372         }
 373
 374         string config_filename = "cubemap.config";
 375         if (optind < argc) {
 376                 config_filename = argv[optind++];
 377         }
 378
 379         // Canonicalize argv[0] and config_filename.
 380         char argv0_canon[PATH_MAX];
 381         char config_filename_canon[PATH_MAX];
 382
 383         if (realpath("/proc/self/exe", argv0_canon) == nullptr) {
 384                 log_perror(argv[0]);
 385                 exit(1);
 386         }
 387         if (realpath(config_filename.c_str(), config_filename_canon) == nullptr) {
 388                 log_perror(config_filename.c_str());
 389                 exit(1);
 390         }
 391
 392         // Now parse the configuration file.
 393         Config config;
 394         if (!parse_config(config_filename_canon, &config)) {
 395                 exit(1);
 396         }
 397         if (test_config) {
 398                 exit(0);
 399         }
 400
 401         // Ideally we'd like to daemonize only when we've started up all threads etc.,
 402         // but daemon() forks, which is not good in multithreaded software, so we'll
 403         // have to do it here.
 404         if (config.daemonize) {
 405                 if (daemon(0, 0) == -1) {
 406                         log_perror("daemon");
 407                         exit(1);
 408                 }
 409         }
 410
 411 start:
 412         // Open logs as soon as possible.
 413         open_logs(config.log_destinations);
 414
 415         log(INFO, "Cubemap " SERVER_VERSION " starting.");
 416         if (config.access_log_file.empty()) {
 417                 // Create a dummy logger.
 418                 access_log = new AccessLogThread();
 419         } else {
 420                 access_log = new AccessLogThread(config.access_log_file);
 421         }
 422         access_log->run();
 423
 424         servers = new ServerPool(config.num_servers);
 425
 426         // Find all the streams that are to be kept.
 427         set<string> all_urls;
 428         find_all_streams(config, &all_urls);
 429
 430         CubemapStateProto loaded_state;
 431         timespec serialize_start;
 432         set<string> deserialized_urls;
 433         map<AcceptorConfig, Acceptor *, AcceptorConfigCompare> deserialized_acceptors;
 434         multimap<InputKey, InputWithRefcount> inputs;  // multimap due to older versions without deduplication.
 435         if (state_fd != -1) {
 436                 log(INFO, "Deserializing state from previous process...");
 437                 string serialized;
 438                 if (!read_tempfile_and_close(state_fd, &serialized)) {
 439                         exit(1);
 440                 }
 441                 if (!loaded_state.ParseFromString(serialized)) {
 442                         log(ERROR, "Failed deserialization of state.");
 443                         exit(1);
 444                 }
 445
 446                 serialize_start.tv_sec = loaded_state.serialize_start_sec();
 447                 serialize_start.tv_nsec = loaded_state.serialize_start_usec() * 1000ull;
 448
 449                 // Deserialize the streams.
 450                 unordered_map<string, string> stream_headers_for_url;  // See below.
 451                 for (const StreamProto &stream : loaded_state.streams()) {
 452                         if (all_urls.count(stream.url()) == 0) {
 453                                 // Delete the stream backlogs.
 454                                 log(INFO, "Deleting stream '%s'.", stream.url().c_str());
 455                                 for (const int fd : stream.data_fds()) {
 456                                         safe_close(fd);
 457                                 }
 458                         } else {
 459                                 vector<int> data_fds;
 460                                 for (const int fd : stream.data_fds()) {
 461                                         data_fds.push_back(fd);
 462                                 }
 463
 464                                 servers->add_stream_from_serialized(stream, data_fds);
 465                                 deserialized_urls.insert(stream.url());
 466
 467                                 stream_headers_for_url.insert(make_pair(stream.url(), stream.stream_header()));
 468                         }
 469                 }
 470
 471                 // Deserialize the inputs. Note that we don't actually add them to any stream yet.
 472                 for (const InputProto &serialized_input : loaded_state.inputs()) {
 473                         InputWithRefcount iwr;
 474                         iwr.input = create_input(serialized_input);
 475                         iwr.refcount = 0;
 476
 477                         Input::Encoding src_encoding = serialized_input.is_metacube_encoded() ?
 478                                 Input::INPUT_ENCODING_METACUBE :
 479                                 Input::INPUT_ENCODING_RAW;
 480                         InputKey key(serialized_input.url(), src_encoding);
 481                         inputs.insert(make_pair(key, iwr));
 482                 }
 483
 484                 // Deserialize the acceptors.
 485                 for (const AcceptorProto &serialized_acceptor : loaded_state.acceptors()) {
 486                         AcceptorConfig config;
 487                         config.addr = extract_address_from_acceptor_proto(serialized_acceptor);
 488                         config.certificate_chain = serialized_acceptor.certificate_chain();
 489                         config.private_key = serialized_acceptor.private_key();
 490                         deserialized_acceptors.insert(make_pair(
 491                                 config,
 492                                 new Acceptor(serialized_acceptor)));
 493                 }
 494
 495                 log(INFO, "Deserialization done.");
 496         }
 497
 498         // Add any new inputs coming from the config.
 499         create_config_inputs(config, &inputs);
 500
 501         // Find all streams in the configuration file, create them, and connect to the inputs.
 502         create_streams(config, deserialized_urls, &inputs);
 503         vector<Acceptor *> acceptors = create_acceptors(config, &deserialized_acceptors);
 504
 505         // Make all the servers create TLS contexts for every TLS keypair we have.
 506         for (Acceptor *acceptor : acceptors) {
 507                 if (acceptor->is_tls()) {
 508                         servers->create_tls_context_for_acceptor(acceptor);
 509                 }
 510         }
 511
 512         // Allocate strings for the short responses.
 513         vector<shared_ptr<const string>> short_response_pool;
 514         for (const ShortResponsePool &str : loaded_state.short_response_pool()) {
 515                 short_response_pool.emplace_back(new string(str.header_or_short_response()));
 516         }
 517
 518         // Put back the existing clients. It doesn't matter which server we
 519         // allocate them to, so just do round-robin. However, we need to sort them
 520         // by connection time first, since add_client_serialized() expects that.
 521         sort(loaded_state.mutable_clients()->begin(),
 522              loaded_state.mutable_clients()->end(),
 523              OrderByConnectionTime());
 524         for (int i = 0; i < loaded_state.clients_size(); ++i) {
 525                 if (!loaded_state.clients(i).url().empty() &&
 526                     all_urls.count(loaded_state.clients(i).url()) == 0) {
 527                         // Belongs to a dead stream (not keepalive), so we just have to close.
 528                         safe_close(loaded_state.clients(i).sock());
 529                 } else {
 530                         servers->add_client_from_serialized(loaded_state.clients(i), short_response_pool);
 531                 }
 532         }
 533
 534         short_response_pool.clear();  // No longer needed; the clients have their own refcounts now.
 535
 536         // Put back the HLS zombies. There's no really good allocation here
 537         // except round-robin; it would be marginally more efficient to match it
 538         // to the client (since that would have them deleted immediately when
 539         // the client requests the next fragment, instead of being later weeded
 540         // out during statistics collection), but it's not a big deal.
 541         for (const HLSZombieProto &zombie_proto : loaded_state.hls_zombies()) {
 542                 servers->add_hls_zombie_from_serialized(zombie_proto);
 543         }
 544
 545         servers->run();
 546
 547         // Now delete all inputs that are longer in use, and start the others.
 548         for (auto input_it = inputs.begin(); input_it != inputs.end(); ) {
 549                 if (input_it->second.refcount == 0) {
 550                         if (input_it->first.second == Input::INPUT_ENCODING_RAW) {
 551                                 log(WARNING, "Raw input '%s' no longer in use, closing.",
 552                                     input_it->first.first.c_str());
 553                         } else {
 554                                 assert(input_it->first.second == Input::INPUT_ENCODING_METACUBE);
 555                                 log(WARNING, "Metacube input '%s' no longer in use, closing.",
 556                                     input_it->first.first.c_str());
 557                         }
 558                         input_it->second.input->close_socket();
 559                         delete input_it->second.input;
 560                         inputs.erase(input_it++);
 561                 } else {
 562                         input_it->second.input->run();
 563                         ++input_it;
 564                 }
 565         }
 566
 567         // Start writing statistics.
 568         unique_ptr<StatsThread> stats_thread;
 569         if (!config.stats_file.empty()) {
 570                 stats_thread.reset(new StatsThread(config.stats_file, config.stats_interval));
 571                 stats_thread->run();
 572         }
 573
 574         unique_ptr<InputStatsThread> input_stats_thread;
 575         if (!config.input_stats_file.empty()) {
 576                 vector<Input*> inputs_no_refcount;
 577                 for (const auto &key_and_input_with_refcount : inputs) {
 578                         inputs_no_refcount.push_back(key_and_input_with_refcount.second.input);
 579                 }
 580
 581                 input_stats_thread.reset(new InputStatsThread(config.input_stats_file, config.input_stats_interval, inputs_no_refcount));
 582                 input_stats_thread->run();
 583         }
 584
 585         timespec server_start;
 586         int err = clock_gettime(CLOCK_MONOTONIC, &server_start);
 587         assert(err != -1);
 588         if (state_fd != -1) {
 589                 // Measure time from we started deserializing (below) to now, when basically everything
 590                 // is up and running. This is, in other words, a conservative estimate of how long our
 591                 // “glitch” period was, not counting of course reconnects if the configuration changed.
 592                 double glitch_time = server_start.tv_sec - serialize_start.tv_sec +
 593                         1e-9 * (server_start.tv_nsec - serialize_start.tv_nsec);
 594                 log(INFO, "Re-exec happened in approx. %.0f ms.", glitch_time * 1000.0);
 595         }
 596
 597         sd_notify(0, "READY=1");
 598
 599         while (!hupped) {
 600                 usleep(100000);
 601         }
 602
 603         if (stopped) {
 604                 sd_notify(0, "STOPPING=1");
 605         } else {
 606                 sd_notify(0, "RELOADING=1");
 607         }
 608
 609         // OK, we've been HUPed. Time to shut down everything, serialize, and re-exec.
 610         err = clock_gettime(CLOCK_MONOTONIC, &serialize_start);
 611         assert(err != -1);
 612
 613         if (input_stats_thread != nullptr) {
 614                 input_stats_thread->stop();
 615                 input_stats_thread.reset();
 616         }
 617         if (stats_thread != nullptr) {
 618                 stats_thread->stop();
 619                 stats_thread.reset();
 620         }
 621         for (Acceptor *acceptor : acceptors) {
 622                 acceptor->stop();
 623         }
 624         for (const auto &key_and_input_with_refcount : inputs) {
 625                 key_and_input_with_refcount.second.input->stop();
 626                 if (stopped) {
 627                         key_and_input_with_refcount.second.input->close_socket();
 628                 }
 629         }
 630         servers->stop();
 631
 632         CubemapStateProto state;
 633         if (stopped) {
 634                 log(INFO, "Shutting down.");
 635         } else {
 636                 log(INFO, "Serializing state and re-execing...");
 637                 state = collect_state(
 638                         serialize_start, acceptors, inputs, servers);
 639                 string serialized;
 640                 state.SerializeToString(&serialized);
 641                 state_fd = make_tempfile(serialized);
 642                 if (state_fd == -1) {
 643                         exit(1);
 644                 }
 645         }
 646         delete servers;
 647
 648         access_log->stop();
 649         delete access_log;
 650         shut_down_logging();
 651
 652         if (stopped) {
 653                 exit(0);
 654         }
 655
 656         // OK, so the signal was SIGHUP. Check that the new config is okay, then exec the new binary.
 657         if (!dry_run_config(argv0_canon, config_filename_canon)) {
 658                 open_logs(config.log_destinations);
 659                 log(ERROR, "%s --test-config failed. Restarting old version instead of new.", argv[0]);
 660                 hupped = false;
 661                 shut_down_logging();
 662                 goto start;
 663         }
 664
 665         char buf[16];
 666         sprintf(buf, "%d", state_fd);
 667
 668         // Unset the close-on-exec flag for the state fd.
 669         // (This can't leak into a child, since there's only one thread left.)
 670         fcntl(state_fd, F_SETFD, 0);
 671
 672         for ( ;; ) {
 673                 execlp(argv0_canon, argv0_canon, config_filename_canon, "--state", buf, nullptr);
 674                 open_logs(config.log_destinations);
 675                 log_perror("execlp");
 676                 log(ERROR, "re-exec of %s failed. Waiting 0.2 seconds and trying again...", argv0_canon);
 677                 shut_down_logging();
 678                 usleep(200000);
 679         }
 680 }