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

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <stdint.h>
   4 #include <assert.h>
   5 #include <arpa/inet.h>
   6 #include <sys/socket.h>
   7 #include <pthread.h>
   8 #include <sys/types.h>
   9 #include <sys/ioctl.h>
  10 #include <sys/epoll.h>
  11 #include <errno.h>
  12 #include <vector>
  13 #include <string>
  14 #include <map>
  15 #include <algorithm>
  16
  17 #include "metacube.h"
  18 #include "server.h"
  19 #include "mutexlock.h"
  20 #include "parse.h"
  21 #include "state.pb.h"
  22
  23 using namespace std;
  24
  25 Client::Client(int sock)
  26         : sock(sock),
  27           state(Client::READING_REQUEST),
  28           stream(NULL),
  29           header_or_error_bytes_sent(0),
  30           bytes_sent(0)
  31 {
  32         request.reserve(1024);
  33 }
  34
  35 Client::Client(const ClientProto &serialized, Stream *stream)
  36         : sock(serialized.sock()),
  37           state(State(serialized.state())),
  38           request(serialized.request()),
  39           stream_id(serialized.stream_id()),
  40           stream(stream),
  41           header_or_error(serialized.header_or_error()),
  42           header_or_error_bytes_sent(serialized.header_or_error_bytes_sent()),
  43           bytes_sent(serialized.bytes_sent())
  44 {
  45 }
  46
  47 ClientProto Client::serialize() const
  48 {
  49         ClientProto serialized;
  50         serialized.set_sock(sock);
  51         serialized.set_state(state);
  52         serialized.set_request(request);
  53         serialized.set_stream_id(stream_id);
  54         serialized.set_header_or_error(header_or_error);
  55         serialized.set_header_or_error_bytes_sent(serialized.header_or_error_bytes_sent());
  56         serialized.set_bytes_sent(bytes_sent);
  57         return serialized;
  58 }
  59
  60 Stream::Stream(const string &stream_id)
  61         : stream_id(stream_id),
  62           data(new char[BACKLOG_SIZE]),
  63           data_size(0)
  64 {
  65         memset(data, 0, BACKLOG_SIZE);
  66 }
  67
  68 Stream::~Stream()
  69 {
  70         delete[] data;
  71 }
  72
  73 Stream::Stream(const StreamProto &serialized)
  74         : stream_id(serialized.stream_id()),
  75           header(serialized.header()),
  76           data(new char[BACKLOG_SIZE]),
  77           data_size(serialized.data_size())
  78 {
  79         assert(serialized.data().size() == BACKLOG_SIZE);
  80         memcpy(data, serialized.data().data(), BACKLOG_SIZE);
  81 }
  82
  83 StreamProto Stream::serialize() const
  84 {
  85         StreamProto serialized;
  86         serialized.set_header(header);
  87         serialized.set_data(string(data, data + BACKLOG_SIZE));
  88         serialized.set_data_size(data_size);
  89         serialized.set_stream_id(stream_id);
  90         return serialized;
  91 }
  92
  93 void Stream::put_client_to_sleep(Client *client)
  94 {
  95         sleeping_clients.push_back(client);
  96 }
  97
  98 void Stream::wake_up_all_clients()
  99 {
 100         if (to_process.empty()) {
 101                 swap(sleeping_clients, to_process);
 102         } else {
 103                 to_process.insert(to_process.end(), sleeping_clients.begin(), sleeping_clients.end());
 104                 sleeping_clients.clear();
 105         }
 106 }
 107
 108 Server::Server()
 109 {
 110         pthread_mutex_init(&mutex, NULL);
 111         pthread_mutex_init(&queued_data_mutex, NULL);
 112
 113         epoll_fd = epoll_create(1024);  // Size argument is ignored.
 114         if (epoll_fd == -1) {
 115                 perror("epoll_fd");
 116                 exit(1);
 117         }
 118 }
 119
 120 Server::~Server()
 121 {
 122         int ret;
 123         do {
 124                 ret = close(epoll_fd);
 125         } while (ret == -1 && errno == EINTR);
 126
 127         if (ret == -1) {
 128                 perror("close(epoll_fd)");
 129         }
 130 }
 131
 132 void Server::run()
 133 {
 134         should_stop = false;
 135
 136         // Joinable is already the default, but it's good to be certain.
 137         pthread_attr_t attr;
 138         pthread_attr_init(&attr);
 139         pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
 140         pthread_create(&worker_thread, &attr, Server::do_work_thunk, this);
 141 }
 142
 143 void Server::stop()
 144 {
 145         {
 146                 MutexLock lock(&mutex);
 147                 should_stop = true;
 148         }
 149
 150         if (pthread_join(worker_thread, NULL) == -1) {
 151                 perror("pthread_join");
 152                 exit(1);
 153         }
 154 }
 155
 156 void *Server::do_work_thunk(void *arg)
 157 {
 158         Server *server = static_cast<Server *>(arg);
 159         server->do_work();
 160         return NULL;
 161 }
 162
 163 void Server::do_work()
 164 {
 165         for ( ;; ) {
 166                 int nfds = epoll_wait(epoll_fd, events, EPOLL_MAX_EVENTS, EPOLL_TIMEOUT_MS);
 167                 if (nfds == -1 && errno == EINTR) {
 168                         continue;
 169                 }
 170                 if (nfds == -1) {
 171                         perror("epoll_wait");
 172                         exit(1);
 173                 }
 174
 175                 MutexLock lock(&mutex);  // We release the mutex between iterations.
 176
 177                 if (should_stop) {
 178                         return;
 179                 }
 180
 181                 process_queued_data();
 182
 183                 for (int i = 0; i < nfds; ++i) {
 184                         int fd = events[i].data.fd;
 185                         assert(clients.count(fd) != 0);
 186                         Client *client = &clients[fd];
 187
 188                         if (events[i].events & (EPOLLERR | EPOLLRDHUP | EPOLLHUP)) {
 189                                 close_client(client);
 190                                 continue;
 191                         }
 192
 193                         process_client(client);
 194                 }
 195
 196                 for (map<string, Stream *>::iterator stream_it = streams.begin();
 197                      stream_it != streams.end();
 198                      ++stream_it) {
 199                         vector<Client *> to_process;
 200                         swap(stream_it->second->to_process, to_process);
 201                         for (size_t i = 0; i < to_process.size(); ++i) {
 202                                 process_client(to_process[i]);
 203                         }
 204                 }
 205         }
 206 }
 207
 208 CubemapStateProto Server::serialize()
 209 {
 210         // We don't serialize anything queued, so empty the queues.
 211         process_queued_data();
 212
 213         CubemapStateProto serialized;
 214         for (map<int, Client>::const_iterator client_it = clients.begin();
 215              client_it != clients.end();
 216              ++client_it) {
 217                 serialized.add_clients()->MergeFrom(client_it->second.serialize());
 218         }
 219         for (map<string, Stream *>::const_iterator stream_it = streams.begin();
 220              stream_it != streams.end();
 221              ++stream_it) {
 222                 serialized.add_streams()->MergeFrom(stream_it->second->serialize());
 223         }
 224         return serialized;
 225 }
 226
 227 void Server::add_client_deferred(int sock)
 228 {
 229         MutexLock lock(&queued_data_mutex);
 230         queued_add_clients.push_back(sock);
 231 }
 232
 233 void Server::add_client(int sock)
 234 {
 235         clients.insert(make_pair(sock, Client(sock)));
 236
 237         // Start listening on data from this socket.
 238         epoll_event ev;
 239         ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 240         ev.data.u64 = 0;  // Keep Valgrind happy.
 241         ev.data.fd = sock;
 242         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
 243                 perror("epoll_ctl(EPOLL_CTL_ADD)");
 244                 exit(1);
 245         }
 246
 247         process_client(&clients[sock]);
 248 }
 249
 250 void Server::add_client_from_serialized(const ClientProto &client)
 251 {
 252         MutexLock lock(&mutex);
 253         Stream *stream = find_stream(client.stream_id());
 254         clients.insert(make_pair(client.sock(), Client(client, stream)));
 255         Client *client_ptr = &clients[client.sock()];
 256
 257         // Start listening on data from this socket.
 258         epoll_event ev;
 259         if (client.state() == Client::READING_REQUEST) {
 260                 ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
 261         } else {
 262                 // If we don't have more data for this client, we'll be putting it into
 263                 // the sleeping array again soon.
 264                 ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 265         }
 266         ev.data.u64 = 0;  // Keep Valgrind happy.
 267         ev.data.fd = client.sock();
 268         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client.sock(), &ev) == -1) {
 269                 perror("epoll_ctl(EPOLL_CTL_ADD)");
 270                 exit(1);
 271         }
 272
 273         if (client_ptr->state == Client::SENDING_DATA &&
 274             client_ptr->bytes_sent == client_ptr->stream->data_size) {
 275                 client_ptr->stream->put_client_to_sleep(client_ptr);
 276         } else {
 277                 process_client(client_ptr);
 278         }
 279 }
 280
 281 void Server::add_stream(const string &stream_id)
 282 {
 283         MutexLock lock(&mutex);
 284         streams.insert(make_pair(stream_id, new Stream(stream_id)));
 285 }
 286
 287 void Server::add_stream_from_serialized(const StreamProto &stream)
 288 {
 289         MutexLock lock(&mutex);
 290         streams.insert(make_pair(stream.stream_id(), new Stream(stream)));
 291 }
 292
 293 void Server::set_header(const string &stream_id, const string &header)
 294 {
 295         MutexLock lock(&mutex);
 296         find_stream(stream_id)->header = header;
 297
 298         // If there are clients we haven't sent anything to yet, we should give
 299         // them the header, so push back into the SENDING_HEADER state.
 300         for (map<int, Client>::iterator client_it = clients.begin();
 301              client_it != clients.end();
 302              ++client_it) {
 303                 Client *client = &client_it->second;
 304                 if (client->state == Client::SENDING_DATA &&
 305                     client->bytes_sent == 0) {
 306                         construct_header(client);
 307                 }
 308         }
 309 }
 310
 311 void Server::add_data_deferred(const string &stream_id, const char *data, size_t bytes)
 312 {
 313         MutexLock lock(&queued_data_mutex);
 314         queued_data[stream_id].append(string(data, data + bytes));
 315 }
 316
 317 void Server::add_data(const string &stream_id, const char *data, size_t bytes)
 318 {
 319         Stream *stream = find_stream(stream_id);
 320         size_t pos = stream->data_size % BACKLOG_SIZE;
 321         stream->data_size += bytes;
 322
 323         if (pos + bytes > BACKLOG_SIZE) {
 324                 size_t to_copy = BACKLOG_SIZE - pos;
 325                 memcpy(stream->data + pos, data, to_copy);
 326                 data += to_copy;
 327                 bytes -= to_copy;
 328                 pos = 0;
 329         }
 330
 331         memcpy(stream->data + pos, data, bytes);
 332         stream->wake_up_all_clients();
 333 }
 334
 335 // See the .h file for postconditions after this function.
 336 void Server::process_client(Client *client)
 337 {
 338         switch (client->state) {
 339         case Client::READING_REQUEST: {
 340 read_request_again:
 341                 // Try to read more of the request.
 342                 char buf[1024];
 343                 int ret;
 344                 do {
 345                         ret = read(client->sock, buf, sizeof(buf));
 346                 } while (ret == -1 && errno == EINTR);
 347
 348                 if (ret == -1 && errno == EAGAIN) {
 349                         // No more data right now. Nothing to do.
 350                         // This is postcondition #2.
 351                         return;
 352                 }
 353                 if (ret == -1) {
 354                         perror("read");
 355                         close_client(client);
 356                         return;
 357                 }
 358                 if (ret == 0) {
 359                         // OK, the socket is closed.
 360                         close_client(client);
 361                         return;
 362                 }
 363
 364                 RequestParseStatus status = wait_for_double_newline(&client->request, buf, ret);
 365
 366                 switch (status) {
 367                 case RP_OUT_OF_SPACE:
 368                         fprintf(stderr, "WARNING: fd %d sent overlong request!\n", client->sock);
 369                         close_client(client);
 370                         return;
 371                 case RP_NOT_FINISHED_YET:
 372                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 373                         // See if there's more data for us.
 374                         goto read_request_again;
 375                 case RP_EXTRA_DATA:
 376                         fprintf(stderr, "WARNING: fd %d had junk data after request!\n", client->sock);
 377                         close_client(client);
 378                         return;
 379                 case RP_FINISHED:
 380                         break;
 381                 }
 382
 383                 assert(status == RP_FINISHED);
 384
 385                 int error_code = parse_request(client);
 386                 if (error_code == 200) {
 387                         construct_header(client);
 388                 } else {
 389                         construct_error(client, error_code);
 390                 }
 391
 392                 // We've changed states, so fall through.
 393                 assert(client->state == Client::SENDING_ERROR ||
 394                        client->state == Client::SENDING_HEADER);
 395         }
 396         case Client::SENDING_ERROR:
 397         case Client::SENDING_HEADER: {
 398 sending_header_or_error_again:
 399                 int ret;
 400                 do {
 401                         ret = write(client->sock,
 402                                     client->header_or_error.data() + client->header_or_error_bytes_sent,
 403                                     client->header_or_error.size() - client->header_or_error_bytes_sent);
 404                 } while (ret == -1 && errno == EINTR);
 405
 406                 if (ret == -1 && errno == EAGAIN) {
 407                         // We're out of socket space, so now we're at the “low edge” of epoll's
 408                         // edge triggering. epoll will tell us when there is more room, so for now,
 409                         // just return.
 410                         // This is postcondition #4.
 411                         return;
 412                 }
 413
 414                 if (ret == -1) {
 415                         // Error! Postcondition #1.
 416                         perror("write");
 417                         close_client(client);
 418                         return;
 419                 }
 420
 421                 client->header_or_error_bytes_sent += ret;
 422                 assert(client->header_or_error_bytes_sent <= client->header_or_error.size());
 423
 424                 if (client->header_or_error_bytes_sent < client->header_or_error.size()) {
 425                         // We haven't sent all yet. Fine; go another round.
 426                         goto sending_header_or_error_again;
 427                 }
 428
 429                 // We're done sending the header or error! Clear it to release some memory.
 430                 client->header_or_error.clear();
 431
 432                 if (client->state == Client::SENDING_ERROR) {
 433                         // We're done sending the error, so now close.
 434                         // This is postcondition #1.
 435                         close_client(client);
 436                         return;
 437                 }
 438
 439                 // Start sending from the end. In other words, we won't send any of the backlog,
 440                 // but we'll start sending immediately as we get data.
 441                 // This is postcondition #3.
 442                 client->state = Client::SENDING_DATA;
 443                 client->bytes_sent = client->stream->data_size;
 444                 client->stream->put_client_to_sleep(client);
 445                 return;
 446         }
 447         case Client::SENDING_DATA: {
 448                 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 449                 // but resync will be the mux's problem.
 450                 Stream *stream = client->stream;
 451                 size_t bytes_to_send = stream->data_size - client->bytes_sent;
 452                 if (bytes_to_send == 0) {
 453                         return;
 454                 }
 455                 if (bytes_to_send > BACKLOG_SIZE) {
 456                         fprintf(stderr, "WARNING: fd %d lost %lld bytes, maybe too slow connection\n",
 457                                 client->sock,
 458                                 (long long int)(bytes_to_send - BACKLOG_SIZE));
 459                         client->bytes_sent = stream->data_size - BACKLOG_SIZE;
 460                         bytes_to_send = BACKLOG_SIZE;
 461                 }
 462
 463                 // See if we need to split across the circular buffer.
 464                 ssize_t ret;
 465                 if ((client->bytes_sent % BACKLOG_SIZE) + bytes_to_send > BACKLOG_SIZE) {
 466                         size_t bytes_first_part = BACKLOG_SIZE - (client->bytes_sent % BACKLOG_SIZE);
 467
 468                         iovec iov[2];
 469                         iov[0].iov_base = const_cast<char *>(stream->data + (client->bytes_sent % BACKLOG_SIZE));
 470                         iov[0].iov_len = bytes_first_part;
 471
 472                         iov[1].iov_base = const_cast<char *>(stream->data);
 473                         iov[1].iov_len = bytes_to_send - bytes_first_part;
 474
 475                         do {
 476                                 ret = writev(client->sock, iov, 2);
 477                         } while (ret == -1 && errno == EINTR);
 478                 } else {
 479                         do {
 480                                 ret = write(client->sock,
 481                                             stream->data + (client->bytes_sent % BACKLOG_SIZE),
 482                                             bytes_to_send);
 483                         } while (ret == -1 && errno == EINTR);
 484                 }
 485                 if (ret == -1 && errno == EAGAIN) {
 486                         // We're out of socket space, so return; epoll will wake us up
 487                         // when there is more room.
 488                         // This is postcondition #4.
 489                         return;
 490                 }
 491                 if (ret == -1) {
 492                         // Error, close; postcondition #1.
 493                         perror("write/writev");
 494                         close_client(client);
 495                         return;
 496                 }
 497                 client->bytes_sent += ret;
 498
 499                 if (client->bytes_sent == stream->data_size) {
 500                         // We don't have any more data for this client, so put it to sleep.
 501                         // This is postcondition #3.
 502                         stream->put_client_to_sleep(client);
 503                 } else {
 504                         // XXX: Do we need to go another round here to explicitly
 505                         // get the EAGAIN?
 506                 }
 507                 break;
 508         }
 509         default:
 510                 assert(false);
 511         }
 512 }
 513
 514 int Server::parse_request(Client *client)
 515 {
 516         vector<string> lines = split_lines(client->request);
 517         if (lines.empty()) {
 518                 return 400;  // Bad request (empty).
 519         }
 520
 521         vector<string> request_tokens = split_tokens(lines[0]);
 522         if (request_tokens.size() < 2) {
 523                 return 400;  // Bad request (empty).
 524         }
 525         if (request_tokens[0] != "GET") {
 526                 return 400;  // Should maybe be 405 instead?
 527         }
 528         if (streams.count(request_tokens[1]) == 0) {
 529                 return 404;  // Not found.
 530         }
 531
 532         client->stream_id = request_tokens[1];
 533         client->stream = find_stream(client->stream_id);
 534         client->request.clear();
 535
 536         return 200;  // OK!
 537 }
 538
 539 void Server::construct_header(Client *client)
 540 {
 541         client->header_or_error = find_stream(client->stream_id)->header;
 542
 543         // Switch states.
 544         client->state = Client::SENDING_HEADER;
 545
 546         epoll_event ev;
 547         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 548         ev.data.u64 = 0;  // Keep Valgrind happy.
 549         ev.data.fd = client->sock;
 550
 551         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 552                 perror("epoll_ctl(EPOLL_CTL_MOD)");
 553                 exit(1);
 554         }
 555 }
 556
 557 void Server::construct_error(Client *client, int error_code)
 558 {
 559         char error[256];
 560         snprintf(error, 256, "HTTP/1.0 %d Error\r\nContent-type: text/plain\r\n\r\nSomething went wrong. Sorry.\r\n",
 561                 error_code);
 562         client->header_or_error = error;
 563
 564         // Switch states.
 565         client->state = Client::SENDING_ERROR;
 566
 567         epoll_event ev;
 568         ev.events = EPOLLOUT | EPOLLET | EPOLLRDHUP;
 569         ev.data.u64 = 0;  // Keep Valgrind happy.
 570         ev.data.fd = client->sock;
 571
 572         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 573                 perror("epoll_ctl(EPOLL_CTL_MOD)");
 574                 exit(1);
 575         }
 576 }
 577
 578 template<class T>
 579 void delete_from(vector<T> *v, T elem)
 580 {
 581         typename vector<T>::iterator new_end = remove(v->begin(), v->end(), elem);
 582         v->erase(new_end, v->end());
 583 }
 584
 585 void Server::close_client(Client *client)
 586 {
 587         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 588                 perror("epoll_ctl(EPOLL_CTL_DEL)");
 589                 exit(1);
 590         }
 591
 592         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 593         if (client->stream != NULL) {
 594                 delete_from(&client->stream->sleeping_clients, client);
 595                 delete_from(&client->stream->to_process, client);
 596         }
 597
 598         // Bye-bye!
 599         int ret;
 600         do {
 601                 ret = close(client->sock);
 602         } while (ret == -1 && errno == EINTR);
 603
 604         if (ret == -1) {
 605                 perror("close");
 606         }
 607
 608         clients.erase(client->sock);
 609 }
 610
 611 Stream *Server::find_stream(const string &stream_id)
 612 {
 613         map<string, Stream *>::iterator it = streams.find(stream_id);
 614         assert(it != streams.end());
 615         return it->second;
 616 }
 617
 618 void Server::process_queued_data()
 619 {
 620         MutexLock lock(&queued_data_mutex);
 621
 622         for (size_t i = 0; i < queued_add_clients.size(); ++i) {
 623                 add_client(queued_add_clients[i]);
 624         }
 625         queued_add_clients.clear();
 626
 627         for (map<string, string>::iterator queued_it = queued_data.begin();
 628              queued_it != queued_data.end();
 629              ++queued_it) {
 630                 add_data(queued_it->first, queued_it->second.data(), queued_it->second.size());
 631         }
 632         queued_data.clear();
 633 }