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 <curl/curl.h>
   7 #include <sys/socket.h>
   8 #include <pthread.h>
   9 #include <sys/types.h>
  10 #include <sys/ioctl.h>
  11 #include <sys/epoll.h>
  12 #include <errno.h>
  13 #include <vector>
  14 #include <string>
  15 #include <map>
  16 #include <algorithm>
  17
  18 #include "metacube.h"
  19 #include "server.h"
  20 #include "mutexlock.h"
  21
  22 using namespace std;
  23
  24 Server::Server()
  25 {
  26         pthread_mutex_init(&mutex, NULL);
  27
  28         epoll_fd = epoll_create(1024);  // Size argument is ignored.
  29         if (epoll_fd == -1) {
  30                 perror("epoll_fd");
  31                 exit(1);
  32         }
  33 }
  34
  35 void Server::run()
  36 {
  37         pthread_t thread;
  38         pthread_create(&thread, NULL, Server::do_work_thunk, this);
  39 }
  40
  41 void *Server::do_work_thunk(void *arg)
  42 {
  43         Server *server = static_cast<Server *>(arg);
  44         server->do_work();
  45         return NULL;
  46 }
  47
  48 void Server::do_work()
  49 {
  50         for ( ;; ) {
  51                 int nfds = epoll_wait(epoll_fd, events, EPOLL_MAX_EVENTS, EPOLL_TIMEOUT_MS);
  52
  53                 MutexLock lock(&mutex);  // We release the mutex between iterations.
  54                 if (nfds == -1) {
  55                         perror("epoll_wait");
  56                         exit(1);
  57                 }
  58
  59                 for (int i = 0; i < nfds; ++i) {
  60                         int fd = events[i].data.fd;
  61                         assert(clients.count(fd) != 0);
  62                         Client *client = &clients[fd];
  63
  64                         if (events[i].events & (EPOLLERR | EPOLLRDHUP | EPOLLHUP)) {
  65                                 close_client(client);
  66                                 continue;
  67                         }
  68
  69                         process_client(client);
  70                 }
  71         }
  72 }
  73
  74 void Server::add_client(int sock)
  75 {
  76         MutexLock lock(&mutex);
  77         Client new_client;
  78         new_client.sock = sock;
  79         new_client.request.reserve(1024);
  80         new_client.state = Client::READING_REQUEST;
  81         new_client.header_bytes_sent = 0;
  82         new_client.bytes_sent = 0;
  83
  84         clients.insert(make_pair(sock, new_client));
  85
  86         // Start listening on data from this socket.
  87         epoll_event ev;
  88         ev.events = EPOLLIN | EPOLLRDHUP;
  89         ev.data.fd = sock;
  90         if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev) == -1) {
  91                 perror("epoll_ctl(EPOLL_CTL_ADD)");
  92                 exit(1);
  93         }
  94 }
  95
  96 void Server::add_stream(const string &stream_id)
  97 {
  98         MutexLock lock(&mutex);
  99         streams.insert(make_pair(stream_id, Stream()));
 100 }
 101
 102 void Server::set_header(const string &stream_id, const string &header)
 103 {
 104         MutexLock lock(&mutex);
 105         assert(streams.count(stream_id) != 0);
 106         streams[stream_id].header = header;
 107 }
 108
 109 void Server::add_data(const string &stream_id, const char *data, size_t bytes)
 110 {
 111         if (bytes == 0) {
 112                 return;
 113         }
 114
 115         MutexLock lock(&mutex);
 116         assert(streams.count(stream_id) != 0);
 117         Stream *stream = &streams[stream_id];
 118         size_t pos = stream->data_size % BACKLOG_SIZE;
 119         stream->data_size += bytes;
 120
 121         if (pos + bytes > BACKLOG_SIZE) {
 122                 size_t to_copy = BACKLOG_SIZE - pos;
 123                 memcpy(stream->data + pos, data, to_copy);
 124                 data += to_copy;
 125                 bytes -= to_copy;
 126                 pos = 0;
 127         }
 128
 129         memcpy(stream->data + pos, data, bytes);
 130         wake_up_all_clients();
 131 }
 132
 133 void Server::process_client(Client *client)
 134 {
 135         switch (client->state) {
 136         case Client::READING_REQUEST: {
 137                 // Try to read more of the request.
 138                 char buf[1024];
 139                 int ret = read(client->sock, buf, sizeof(buf));
 140                 if (ret == -1) {
 141                         perror("read");
 142                         close_client(client);
 143                         return;
 144                 }
 145                 if (ret == 0) {
 146                         // No data? This really means that we were triggered for something else than
 147                         // POLLIN (which suggests a logic error in epoll).
 148                         fprintf(stderr, "WARNING: fd %d returned unexpectedly 0 bytes!\n", client->sock);
 149                         close_client(client);
 150                         return;
 151                 }
 152
 153                 // Guard against overlong requests gobbling up all of our space.
 154                 if (client->request.size() + ret > MAX_CLIENT_REQUEST) {
 155                         fprintf(stderr, "WARNING: fd %d sent overlong request!\n", client->sock);
 156                         close_client(client);
 157                         return;
 158                 }
 159
 160                 // See if we have \r\n\r\n anywhere in the request. We start three bytes
 161                 // before what we just appended, in case we just got the final character.
 162                 size_t existing_req_bytes = client->request.size();
 163                 client->request.append(string(buf, buf + ret));
 164
 165                 size_t start_at = (existing_req_bytes >= 3 ? existing_req_bytes - 3 : 0);
 166                 const char *ptr = reinterpret_cast<char *>(
 167                         memmem(client->request.data() + start_at, client->request.size() - start_at,
 168                                "\r\n\r\n", 4));
 169                 if (ptr == NULL) {
 170                         // OK, we don't have the entire header yet. Fine; we'll get it later.
 171                         return;
 172                 }
 173
 174                 if (ptr != client->request.data() + client->request.size() - 4) {
 175                         fprintf(stderr, "WARNING: fd %d had junk data after request!\n", client->sock);
 176                         close_client(client);
 177                         return;
 178                 }
 179
 180                 parse_request(client);
 181                 break;
 182         }
 183         case Client::SENDING_HEADER: {
 184                 int ret = write(client->sock,
 185                                 client->header.data() + client->header_bytes_sent,
 186                                 client->header.size() - client->header_bytes_sent);
 187                 if (ret == -1) {
 188                         perror("write");
 189                         close_client(client);
 190                         return;
 191                 }
 192
 193                 client->header_bytes_sent += ret;
 194                 assert(client->header_bytes_sent <= client->header.size());
 195
 196                 if (client->header_bytes_sent < client->header.size()) {
 197                         // We haven't sent all yet. Fine; we'll do that later.
 198                         return;
 199                 }
 200
 201                 // We're done sending the header! Clear the entire header to release some memory.
 202                 client->header.clear();
 203
 204                 // Start sending from the end. In other words, we won't send any of the backlog,
 205                 // but we'll start sending immediately as we get data.
 206                 client->state = Client::SENDING_DATA;
 207                 client->bytes_sent = streams[client->stream_id].data_size;
 208                 break;
 209         }
 210         case Client::SENDING_DATA: {
 211                 // See if there's some data we've lost. Ideally, we should drop to a block boundary,
 212                 // but resync will be the mux's problem.
 213                 const Stream &stream = streams[client->stream_id];
 214                 size_t bytes_to_send = stream.data_size - client->bytes_sent;
 215                 if (bytes_to_send > BACKLOG_SIZE) {
 216                         fprintf(stderr, "WARNING: fd %d lost %lld bytes, maybe too slow connection\n",
 217                                 client->sock,
 218                                 (long long int)(bytes_to_send - BACKLOG_SIZE));
 219                         client->bytes_sent = streams[client->stream_id].data_size - BACKLOG_SIZE;
 220                         bytes_to_send = BACKLOG_SIZE;
 221                 }
 222
 223                 // See if we need to split across the circular buffer.
 224                 ssize_t ret;
 225                 if ((client->bytes_sent % BACKLOG_SIZE) + bytes_to_send > BACKLOG_SIZE) {
 226                         size_t bytes_first_part = BACKLOG_SIZE - (client->bytes_sent % BACKLOG_SIZE);
 227
 228                         iovec iov[2];
 229                         iov[0].iov_base = const_cast<char *>(stream.data + (client->bytes_sent % BACKLOG_SIZE));
 230                         iov[0].iov_len = bytes_first_part;
 231
 232                         iov[1].iov_base = const_cast<char *>(stream.data);
 233                         iov[1].iov_len = bytes_to_send - bytes_first_part;
 234
 235                         ret = writev(client->sock, iov, 2);
 236                 } else {
 237                         ret = write(client->sock,
 238                                     stream.data + (client->bytes_sent % BACKLOG_SIZE),
 239                                     bytes_to_send);
 240                 }
 241                 if (ret == -1) {
 242                         perror("write/writev");
 243                         close_client(client);
 244                         return;
 245                 }
 246                 client->bytes_sent += ret;
 247
 248                 if (client->bytes_sent == stream.data_size) {
 249                         // We don't have any more data for this client, so put it to sleep.
 250                         put_client_to_sleep(client);
 251                 }
 252                 break;
 253         }
 254         default:
 255                 assert(false);
 256         }
 257 }
 258
 259 void Server::parse_request(Client *client)
 260 {
 261         // TODO: Actually parse the request. :-)
 262         client->stream_id = "stream";
 263         client->request.clear();
 264
 265         // Construct the header.
 266         client->header = "HTTP/1.0 200 OK\r\nContent-type: todo/fixme\r\n\r\n" +
 267                 streams[client->stream_id].header;
 268
 269         // Switch states.
 270         client->state = Client::SENDING_HEADER;
 271
 272         epoll_event ev;
 273         ev.events = EPOLLOUT | EPOLLRDHUP;
 274         ev.data.fd = client->sock;
 275
 276         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 277                 perror("epoll_ctl(EPOLL_CTL_MOD)");
 278                 exit(1);
 279         }
 280 }
 281
 282 void Server::close_client(Client *client)
 283 {
 284         if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->sock, NULL) == -1) {
 285                 perror("epoll_ctl(EPOLL_CTL_DEL)");
 286                 exit(1);
 287         }
 288
 289         // This client could be sleeping, so we'll need to fix that. (Argh, O(n).)
 290         vector<int>::iterator new_end =
 291                 remove(sleeping_clients.begin(), sleeping_clients.end(), client->sock);
 292         sleeping_clients.erase(new_end, sleeping_clients.end());
 293
 294         // Bye-bye!
 295         close(client->sock);
 296         clients.erase(client->sock);
 297 }
 298
 299 void Server::put_client_to_sleep(Client *client)
 300 {
 301         epoll_event ev;
 302         ev.events = EPOLLRDHUP;
 303         ev.data.fd = client->sock;
 304
 305         if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, client->sock, &ev) == -1) {
 306                 perror("epoll_ctl(EPOLL_CTL_MOD)");
 307                 exit(1);
 308         }
 309
 310         sleeping_clients.push_back(client->sock);
 311 }
 312
 313 void Server::wake_up_all_clients()
 314 {
 315         for (unsigned i = 0; i < sleeping_clients.size(); ++i) {
 316                 epoll_event ev;
 317                 ev.events = EPOLLOUT | EPOLLRDHUP;
 318                 ev.data.fd = sleeping_clients[i];
 319                 if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD, sleeping_clients[i], &ev) == -1) {
 320                         perror("epoll_ctl(EPOLL_CTL_MOD)");
 321                         exit(1);
 322                 }
 323         }
 324         sleeping_clients.clear();
 325 }