text: /*
   * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *
   * 1. Redistributions of source code must retain the above copyright notice, this
   *    list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright notice,
   *    this list of conditions and the following disclaimer in the documentation
   *    and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #include <LibCore/LocalSocket.h>
  #include <errno.h>
  #include <stdio.h>
  #include <sys/socket.h>
  #include <sys/stat.h>
  
  #ifndef SOCK_NONBLOCK
  #    include <sys/ioctl.h>
  #endif
  
  namespace Core {
  
  LocalSocket::LocalSocket(int fd, Object* parent)
      : Socket(Socket::Type::Local, parent)
  {
      // NOTE: This constructor is used by LocalServer::accept(), so the socket is already connected.
      m_connected = true;
      set_fd(fd);
      set_mode(IODevice::ReadWrite);
      set_error(0);
  }
  
  LocalSocket::LocalSocket(Object* parent)
      : Socket(Socket::Type::Local, parent)
  {
  
  #ifdef SOCK_NONBLOCK
      int fd = socket(AF_LOCAL, SOCK_STREAM | SOCK_NONBLOCK | SOCK_CLOEXEC, 0);
  #else
      int fd = socket(AF_LOCAL, SOCK_STREAM, 0);
      int option = 1;
      ioctl(fd, FIONBIO, &option);
      fcntl(fd, F_SETFD, FD_CLOEXEC);
  #endif
  
      if (fd < 0) {
          set_error(errno);
      } else {
          set_fd(fd);
          set_mode(IODevice::ReadWrite);
          set_error(0);
      }
  }
  
  LocalSocket::~LocalSocket()
  {
  }
  
  RefPtr<LocalSocket> LocalSocket::take_over_accepted_socket_from_system_server()
  {
      constexpr auto socket_takeover = "SOCKET_TAKEOVER";
      if (!getenv(socket_takeover))
          return nullptr;
  
      // The SystemServer has passed us the socket as fd 3,
      // so use that instead of creating our own.
      constexpr int fd = 3;
  
      // Sanity check: it has to be a socket.
      struct stat stat;
      int rc = fstat(fd, &stat);
      if (rc < 0 || !S_ISSOCK(stat.st_mode)) {
          if (rc != 0)
              perror("fstat");
          dbgln("ERROR: The fd we got from SystemServer is not a socket");
          return nullptr;
      }
  
      auto socket = LocalSocket::construct(fd);
  
      // It had to be !CLOEXEC for obvious reasons, but we
      // don't need it to be !CLOEXEC anymore, so set the
      // CLOEXEC flag now.
      fcntl(fd, F_SETFD, FD_CLOEXEC);
      // We wouldn't want our children to think we're passing
      // them a socket either, so unset the env variable.
      unsetenv(socket_takeover);
      return socket;
  }
  
  }
  