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

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