Beispiel #1
0
void AsyncServerSocket::handlerReady(uint16_t /* events */,
                                     int fd,
                                     sa_family_t addressFamily) noexcept {
  assert(!callbacks_.empty());
  DestructorGuard dg(this);

  // Only accept up to maxAcceptAtOnce_ connections at a time,
  // to avoid starving other I/O handlers using this EventBase.
  for (uint32_t n = 0; n < maxAcceptAtOnce_; ++n) {
    SocketAddress address;

    sockaddr_storage addrStorage;
    socklen_t addrLen = sizeof(addrStorage);
    sockaddr* saddr = reinterpret_cast<sockaddr*>(&addrStorage);

    // In some cases, accept() doesn't seem to update these correctly.
    saddr->sa_family = addressFamily;
    if (addressFamily == AF_UNIX) {
      addrLen = sizeof(struct sockaddr_un);
    }

    // Accept a new client socket
#ifdef SOCK_NONBLOCK
    int clientSocket = accept4(fd, saddr, &addrLen, SOCK_NONBLOCK);
#else
    int clientSocket = accept(fd, saddr, &addrLen);
#endif

    address.setFromSockaddr(saddr, addrLen);

    if (clientSocket >= 0 && connectionEventCallback_) {
      connectionEventCallback_->onConnectionAccepted(clientSocket, address);
    }

    std::chrono::time_point<std::chrono::steady_clock> nowMs =
      std::chrono::steady_clock::now();
    auto timeSinceLastAccept = std::max<int64_t>(
      0,
      nowMs.time_since_epoch().count() -
      lastAccepTimestamp_.time_since_epoch().count());
    lastAccepTimestamp_ = nowMs;
    if (acceptRate_ < 1) {
      acceptRate_ *= 1 + acceptRateAdjustSpeed_ * timeSinceLastAccept;
      if (acceptRate_ >= 1) {
        acceptRate_ = 1;
      } else if (rand() > acceptRate_ * RAND_MAX) {
        ++numDroppedConnections_;
        if (clientSocket >= 0) {
          closeNoInt(clientSocket);
          if (connectionEventCallback_) {
            connectionEventCallback_->onConnectionDropped(clientSocket,
                                                          address);
          }
        }
        continue;
      }
    }

    if (clientSocket < 0) {
      if (errno == EAGAIN) {
        // No more sockets to accept right now.
        // Check for this code first, since it's the most common.
        return;
      } else if (errno == EMFILE || errno == ENFILE) {
        // We're out of file descriptors.  Perhaps we're accepting connections
        // too quickly. Pause accepting briefly to back off and give the server
        // a chance to recover.
        LOG(ERROR) << "accept failed: out of file descriptors; entering accept "
                "back-off state";
        enterBackoff();

        // Dispatch the error message
        dispatchError("accept() failed", errno);
      } else {
        dispatchError("accept() failed", errno);
      }
      if (connectionEventCallback_) {
        connectionEventCallback_->onConnectionAcceptError(errno);
      }
      return;
    }

#ifndef SOCK_NONBLOCK
    // Explicitly set the new connection to non-blocking mode
    if (fcntl(clientSocket, F_SETFL, O_NONBLOCK) != 0) {
      closeNoInt(clientSocket);
      dispatchError("failed to set accepted socket to non-blocking mode",
                    errno);
      if (connectionEventCallback_) {
        connectionEventCallback_->onConnectionDropped(clientSocket, address);
      }
      return;
    }
#endif

    // Inform the callback about the new connection
    dispatchSocket(clientSocket, std::move(address));

    // If we aren't accepting any more, break out of the loop
    if (!accepting_ || callbacks_.empty()) {
      break;
    }
  }
}
Beispiel #2
0
void AsyncServerSocket::bind(uint16_t port) {
  struct addrinfo hints, *res0;
  char sport[sizeof("65536")];

  memset(&hints, 0, sizeof(hints));
  hints.ai_family = AF_UNSPEC;
  hints.ai_socktype = SOCK_STREAM;
  hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV;
  snprintf(sport, sizeof(sport), "%u", port);

  // On Windows the value we need to pass to bind to all available
  // addresses is an empty string. Everywhere else, it's nullptr.
  constexpr const char* kWildcardNode = kIsWindows ? "" : nullptr;
  if (getaddrinfo(kWildcardNode, sport, &hints, &res0)) {
    throw std::invalid_argument(
                              "Attempted to bind address to socket with "
                              "bad getaddrinfo");
  }

  SCOPE_EXIT { freeaddrinfo(res0); };

  auto setupAddress = [&] (struct addrinfo* res) {
    int s = fsp::socket(res->ai_family, res->ai_socktype, res->ai_protocol);
    // IPv6/IPv4 may not be supported by the kernel
    if (s < 0 && errno == EAFNOSUPPORT) {
      return;
    }
    CHECK_GE(s, 0);

    try {
      setupSocket(s, res->ai_family);
    } catch (...) {
      closeNoInt(s);
      throw;
    }

    if (res->ai_family == AF_INET6) {
      int v6only = 1;
      CHECK(0 == setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY,
                            &v6only, sizeof(v6only)));
    }

    // Bind to the socket
    if (fsp::bind(s, res->ai_addr, socklen_t(res->ai_addrlen)) != 0) {
      folly::throwSystemError(
          errno,
          "failed to bind to async server socket for port ",
          SocketAddress::getPortFrom(res->ai_addr),
          " family ",
          SocketAddress::getFamilyNameFrom(res->ai_addr, "<unknown>"));
    }

#if __linux__
    if (noTransparentTls_) {
      // Ignore return value, errors are ok
      setsockopt(s, SOL_SOCKET, SO_NO_TRANSPARENT_TLS, nullptr, 0);
    }
#endif

    SocketAddress address;
    address.setFromLocalAddress(s);

    sockets_.emplace_back(eventBase_, s, this, address.getFamily());
  };

  const int kNumTries = 25;
  for (int tries = 1; true; tries++) {
    // Prefer AF_INET6 addresses. RFC 3484 mandates that getaddrinfo
    // should return IPv6 first and then IPv4 addresses, but glibc's
    // getaddrinfo(nullptr) with AI_PASSIVE returns:
    // - 0.0.0.0 (IPv4-only)
    // - :: (IPv6+IPv4) in this order
    // See: https://sourceware.org/bugzilla/show_bug.cgi?id=9981
    for (struct addrinfo* res = res0; res; res = res->ai_next) {
      if (res->ai_family == AF_INET6) {
        setupAddress(res);
      }
    }

    // If port == 0, then we should try to bind to the same port on ipv4 and
    // ipv6.  So if we did bind to ipv6, figure out that port and use it.
    if (sockets_.size() == 1 && port == 0) {
      SocketAddress address;
      address.setFromLocalAddress(sockets_.back().socket_);
      snprintf(sport, sizeof(sport), "%u", address.getPort());
      freeaddrinfo(res0);
      CHECK_EQ(0, getaddrinfo(nullptr, sport, &hints, &res0));
    }

    try {
      for (struct addrinfo* res = res0; res; res = res->ai_next) {
        if (res->ai_family != AF_INET6) {
          setupAddress(res);
        }
      }
    } catch (const std::system_error&) {
      // If we can't bind to the same port on ipv4 as ipv6 when using
      // port=0 then we will retry again before giving up after
      // kNumTries attempts.  We do this by closing the sockets that
      // were opened, then restarting from scratch.
      if (port == 0 && !sockets_.empty() && tries != kNumTries) {
        for (const auto& socket : sockets_) {
          if (socket.socket_ <= 0) {
            continue;
          } else if (shutdownSocketSet_) {
            shutdownSocketSet_->close(socket.socket_);
          } else {
            closeNoInt(socket.socket_);
          }
        }
        sockets_.clear();
        snprintf(sport, sizeof(sport), "%u", port);
        freeaddrinfo(res0);
        CHECK_EQ(0, getaddrinfo(nullptr, sport, &hints, &res0));
        continue;
      }

      throw;
    }

    break;
  }

  if (sockets_.size() == 0) {
    throw std::runtime_error(
        "did not bind any async server socket for port");
  }
}
Beispiel #3
0
Symbolizer::Symbolizer(ElfCacheBase* cache)
  : cache_(cache ?: defaultElfCache()) {
}

void Symbolizer::symbolize(const uintptr_t* addresses,
                           SymbolizedFrame* frames,
                           size_t addressCount) {
  size_t remaining = 0;
  for (size_t i = 0; i < addressCount; ++i) {
    auto& frame = frames[i];
    if (!frame.found) {
      ++remaining;
      frame.clear();
    }
  }

  if (remaining == 0) {  // we're done
    return;
  }

  int fd = openNoInt("/proc/self/maps", O_RDONLY);
  if (fd == -1) {
    return;
  }

  char buf[PATH_MAX + 100];  // Long enough for any line
  LineReader reader(fd, buf, sizeof(buf));

  while (remaining != 0) {
    StringPiece line;
    if (reader.readLine(line) != LineReader::kReading) {
      break;
    }

    // Parse line
    uintptr_t from;
    uintptr_t to;
    StringPiece fileName;
    if (!parseProcMapsLine(line, from, to, fileName)) {
      continue;
    }

    bool first = true;
    std::shared_ptr<ElfFile> elfFile;

    // See if any addresses are here
    for (size_t i = 0; i < addressCount; ++i) {
      auto& frame = frames[i];
      if (frame.found) {
        continue;
      }

      uintptr_t address = addresses[i];

      if (from > address || address >= to) {
        continue;
      }

      // Found
      frame.found = true;
      --remaining;

      // Open the file on first use
      if (first) {
        first = false;
        elfFile = cache_->getFile(fileName);
      }

      if (!elfFile) {
        continue;
      }

      // Undo relocation
      frame.set(elfFile, address - from);
    }
  }

  closeNoInt(fd);
}
Beispiel #4
0
void Symbolizer::symbolize(const uintptr_t* addresses,
                           SymbolizedFrame* frames,
                           size_t addressCount) {
  size_t remaining = 0;
  for (size_t i = 0; i < addressCount; ++i) {
    auto& frame = frames[i];
    if (!frame.found) {
      ++remaining;
      frame.name.clear();
      frame.location = Dwarf::LocationInfo();
    }
  }

  if (remaining == 0) {  // we're done
    return;
  }

  int fd = openNoInt("/proc/self/maps", O_RDONLY);
  if (fd == -1) {
    return;
  }

  char buf[PATH_MAX + 100];  // Long enough for any line
  LineReader reader(fd, buf, sizeof(buf));

  char fileNameBuf[PATH_MAX];

  while (remaining != 0) {
    StringPiece line;
    if (reader.readLine(line) != LineReader::kReading) {
      break;
    }

    // Parse line
    uintptr_t from;
    uintptr_t to;
    StringPiece fileName;
    if (!parseProcMapsLine(line, from, to, fileName)) {
      continue;
    }

    bool first = true;
    ElfFile* elfFile = nullptr;

    // See if any addresses are here
    for (size_t i = 0; i < addressCount; ++i) {
      auto& frame = frames[i];
      if (frame.found) {
        continue;
      }

      uintptr_t address = addresses[i];

      if (from > address || address >= to) {
        continue;
      }

      // Found
      frame.found = true;
      --remaining;

      // Open the file on first use
      if (first) {
        first = false;
        if (fileCount_ < kMaxFiles &&
            !fileName.empty() &&
            fileName.size() < sizeof(fileNameBuf)) {
          memcpy(fileNameBuf, fileName.data(), fileName.size());
          fileNameBuf[fileName.size()] = '\0';
          auto& f = files_[fileCount_++];
          if (f.openNoThrow(fileNameBuf) != -1) {
            elfFile = &f;
          }
        }
      }

      if (!elfFile) {
        continue;
      }

      // Undo relocation
      uintptr_t fileAddress = address - from + elfFile->getBaseAddress();
      auto sym = elfFile->getDefinitionByAddress(fileAddress);
      if (!sym.first) {
        continue;
      }
      auto name = elfFile->getSymbolName(sym);
      if (name) {
        frame.name = name;
      }

      Dwarf(elfFile).findAddress(fileAddress, frame.location);
    }
  }

  closeNoInt(fd);
}
Beispiel #5
0
void AsyncServerSocket::dispatchSocket(int socket,
                                        SocketAddress&& address) {
  uint32_t startingIndex = callbackIndex_;

  // Short circuit if the callback is in the primary EventBase thread

  CallbackInfo *info = nextCallback();
  if (info->eventBase == nullptr) {
    info->callback->connectionAccepted(socket, address);
    return;
  }

  const SocketAddress addr(address);
  // Create a message to send over the notification queue
  QueueMessage msg;
  msg.type = MessageType::MSG_NEW_CONN;
  msg.address = std::move(address);
  msg.fd = socket;

  // Loop until we find a free queue to write to
  while (true) {
    if (info->consumer->getQueue()->tryPutMessageNoThrow(std::move(msg))) {
      if (connectionEventCallback_) {
        connectionEventCallback_->onConnectionEnqueuedForAcceptorCallback(
            socket,
            addr);
      }
      // Success! return.
      return;
    }

    // We couldn't add to queue.  Fall through to below

    ++numDroppedConnections_;
    if (acceptRateAdjustSpeed_ > 0) {
      // aggressively decrease accept rate when in trouble
      static const double kAcceptRateDecreaseSpeed = 0.1;
      acceptRate_ *= 1 - kAcceptRateDecreaseSpeed;
    }


    if (callbackIndex_ == startingIndex) {
      // The notification queue was full
      // We can't really do anything at this point other than close the socket.
      //
      // This should only happen if a user's service is behaving extremely
      // badly and none of the EventBase threads are looping fast enough to
      // process the incoming connections.  If the service is overloaded, it
      // should use pauseAccepting() to temporarily back off accepting new
      // connections, before they reach the point where their threads can't
      // even accept new messages.
      LOG(ERROR) << "failed to dispatch newly accepted socket:"
                 << " all accept callback queues are full";
      closeNoInt(socket);
      if (connectionEventCallback_) {
        connectionEventCallback_->onConnectionDropped(socket, addr);
      }
      return;
    }

    info = nextCallback();
  }
}
Beispiel #6
0
void AsyncServerSocket::bind(uint16_t port) {
  struct addrinfo hints, *res, *res0;
  char sport[sizeof("65536")];

  memset(&hints, 0, sizeof(hints));
  hints.ai_family = AF_UNSPEC;
  hints.ai_socktype = SOCK_STREAM;
  hints.ai_flags = AI_PASSIVE;
  snprintf(sport, sizeof(sport), "%u", port);

  if (getaddrinfo(nullptr, sport, &hints, &res0)) {
    throw std::invalid_argument(
                              "Attempted to bind address to socket with "
                              "bad getaddrinfo");
  }

  SCOPE_EXIT { freeaddrinfo(res0); };

  auto setupAddress = [&] (struct addrinfo* res) {
    int s = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
    // IPv6/IPv4 may not be supported by the kernel
    if (s < 0 && errno == EAFNOSUPPORT) {
      return;
    }
    CHECK_GE(s, 0);

    try {
      setupSocket(s);
    } catch (...) {
      closeNoInt(s);
      throw;
    }

    if (res->ai_family == AF_INET6) {
      int v6only = 1;
      CHECK(0 == setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY,
                            &v6only, sizeof(v6only)));
    }

    SocketAddress address;
    address.setFromLocalAddress(s);

    sockets_.emplace_back(eventBase_, s, this, address.getFamily());

    // Bind to the socket
    if (::bind(s, res->ai_addr, res->ai_addrlen) != 0) {
      folly::throwSystemError(
        errno,
        "failed to bind to async server socket for port");
    }
  };

  const int kNumTries = 25;
  for (int tries = 1; true; tries++) {
    // Prefer AF_INET6 addresses. RFC 3484 mandates that getaddrinfo
    // should return IPv6 first and then IPv4 addresses, but glibc's
    // getaddrinfo(nullptr) with AI_PASSIVE returns:
    // - 0.0.0.0 (IPv4-only)
    // - :: (IPv6+IPv4) in this order
    // See: https://sourceware.org/bugzilla/show_bug.cgi?id=9981
    for (res = res0; res; res = res->ai_next) {
      if (res->ai_family == AF_INET6) {
        setupAddress(res);
      }
    }

    // If port == 0, then we should try to bind to the same port on ipv4 and
    // ipv6.  So if we did bind to ipv6, figure out that port and use it,
    // except for the last attempt when we just use any port available.
    if (sockets_.size() == 1 && port == 0) {
      SocketAddress address;
      address.setFromLocalAddress(sockets_.back().socket_);
      snprintf(sport, sizeof(sport), "%u", address.getPort());
      freeaddrinfo(res0);
      CHECK_EQ(0, getaddrinfo(nullptr, sport, &hints, &res0));
    }

    try {
      for (res = res0; res; res = res->ai_next) {
        if (res->ai_family != AF_INET6) {
          setupAddress(res);
        }
      }
    } catch (const std::system_error& e) {
      // if we can't bind to the same port on ipv4 as ipv6 when using port=0
      // then we will try again another 2 times before giving up.  We do this
      // by closing the sockets that were opened, then redoing the whole thing
      if (port == 0 && !sockets_.empty() && tries != kNumTries) {
        for (const auto& socket : sockets_) {
          if (socket.socket_ <= 0) {
            continue;
          } else if (shutdownSocketSet_) {
            shutdownSocketSet_->close(socket.socket_);
          } else {
            closeNoInt(socket.socket_);
          }
        }
        sockets_.clear();
        snprintf(sport, sizeof(sport), "%u", port);
        freeaddrinfo(res0);
        CHECK_EQ(0, getaddrinfo(nullptr, sport, &hints, &res0));
        continue;
      }
      throw;
    }

    break;
  }

  if (sockets_.size() == 0) {
    throw std::runtime_error(
        "did not bind any async server socket for port");
  }
}