text: /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
  /* dbus-server-socket.c Server implementation for sockets
   *
   * Copyright (C) 2002, 2003, 2004, 2006  Red Hat Inc.
   *
   * Licensed under the Academic Free License version 2.1
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
   *
   */
  
  #include <config.h>
  #include "dbus-internals.h"
  #include "dbus-server-socket.h"
  #include "dbus-transport-socket.h"
  #include "dbus-connection-internal.h"
  #include "dbus-memory.h"
  #include "dbus-nonce.h"
  #include "dbus-string.h"
  
  /**
   * @defgroup DBusServerSocket DBusServer implementations for SOCKET
   * @ingroup  DBusInternals
   * @brief Implementation details of DBusServer on SOCKET
   *
   * @{
   */
  /**
   *
   * Opaque object representing a Socket server implementation.
   */
  typedef struct DBusServerSocket DBusServerSocket;
  
  /**
   * Implementation details of DBusServerSocket. All members
   * are private.
   */
  struct DBusServerSocket
  {
    DBusServer base;   /**< Parent class members. */
    int n_fds;         /**< Number of active file handles */
    int *fds;          /**< File descriptor or -1 if disconnected. */
    DBusWatch **watch; /**< File descriptor watch. */
    char *socket_name; /**< Name of domain socket, to unlink if appropriate */
    DBusNonceFile *noncefile; /**< Nonce file used to authenticate clients */
  };
  
  static void
  socket_finalize (DBusServer *server)
  {
    DBusServerSocket *socket_server = (DBusServerSocket*) server;
    int i;
  
    _dbus_server_finalize_base (server);
  
    for (i = 0 ; i < socket_server->n_fds ; i++)
      if (socket_server->watch[i])
        {
          _dbus_watch_unref (socket_server->watch[i]);
          socket_server->watch[i] = NULL;
        }
  
    dbus_free (socket_server->fds);
    dbus_free (socket_server->watch);
    dbus_free (socket_server->socket_name);
    if (socket_server->noncefile)
  	_dbus_noncefile_delete (socket_server->noncefile, NULL);
    dbus_free (socket_server->noncefile);
    dbus_free (server);
  }
  
  /* Return value is just for memory, not other failures. */
  static dbus_bool_t
  handle_new_client_fd_and_unlock (DBusServer *server,
                                   int         client_fd)
  {
    DBusConnection *connection;
    DBusTransport *transport;
    DBusNewConnectionFunction new_connection_function;
    void *new_connection_data;
  
    _dbus_verbose ("Creating new client connection with fd %d\n", client_fd);
  
    HAVE_LOCK_CHECK (server);
  
    if (!_dbus_set_fd_nonblocking (client_fd, NULL))
      {
        SERVER_UNLOCK (server);
        return TRUE;
      }
  
    transport = _dbus_transport_new_for_socket (client_fd, &server->guid_hex, NULL);
    if (transport == NULL)
      {
        _dbus_close_socket (client_fd, NULL);
        SERVER_UNLOCK (server);
        return FALSE;
      }
  
    if (!_dbus_transport_set_auth_mechanisms (transport,
                                              (const char **) server->auth_mechanisms))
      {
        _dbus_transport_unref (transport);
        SERVER_UNLOCK (server);
        return FALSE;
      }
  
    /* note that client_fd is now owned by the transport, and will be
     * closed on transport disconnection/finalization
     */
  
    connection = _dbus_connection_new_for_transport (transport);
    _dbus_transport_unref (transport);
    transport = NULL; /* now under the connection lock */
  
    if (connection == NULL)
      {
        SERVER_UNLOCK (server);
        return FALSE;
      }
  
    /* See if someone wants to handle this new connection, self-referencing
     * for paranoia.
     */
    new_connection_function = server->new_connection_function;
    new_connection_data = server->new_connection_data;
  
    _dbus_server_ref_unlocked (server);
    SERVER_UNLOCK (server);
  
    if (new_connection_function)
      {
        (* new_connection_function) (server, connection,
                                     new_connection_data);
      }
    dbus_server_unref (server);
  
    /* If no one grabbed a reference, the connection will die. */
    _dbus_connection_close_if_only_one_ref (connection);
    dbus_connection_unref (connection);
  
    return TRUE;
  }
  
  static dbus_bool_t
  socket_handle_watch (DBusWatch    *watch,
                     unsigned int  flags,
                     void         *data)
  {
    DBusServer *server = data;
    DBusServerSocket *socket_server = data;
  
  #ifndef DBUS_DISABLE_ASSERT
    int i;
    dbus_bool_t found = FALSE;
  #endif
  
    SERVER_LOCK (server);
  
  #ifndef DBUS_DISABLE_ASSERT
    for (i = 0 ; i < socket_server->n_fds ; i++)
      {
        if (socket_server->watch[i] == watch)
          found = TRUE;
      }
    _dbus_assert (found);
  #endif
  
    _dbus_verbose ("Handling client connection, flags 0x%x\n", flags);
  
    if (flags & DBUS_WATCH_READABLE)
      {
        int client_fd;
        int listen_fd;
  
        listen_fd = dbus_watch_get_socket (watch);
  
        if (socket_server->noncefile)
            client_fd = _dbus_accept_with_noncefile (listen_fd, socket_server->noncefile);
        else 
            client_fd = _dbus_accept (listen_fd);
  
        if (client_fd < 0)
          {
            /* EINTR handled for us */
  
            if (_dbus_get_is_errno_eagain_or_ewouldblock ())
              _dbus_verbose ("No client available to accept after all\n");
            else
              _dbus_verbose ("Failed to accept a client connection: %s\n",
                             _dbus_strerror_from_errno ());
  
            SERVER_UNLOCK (server);
          }
        else
          {
            if (!handle_new_client_fd_and_unlock (server, client_fd))
              _dbus_verbose ("Rejected client connection due to lack of memory\n");
          }
      }
  
    if (flags & DBUS_WATCH_ERROR)
      _dbus_verbose ("Error on server listening socket\n");
  
    if (flags & DBUS_WATCH_HANGUP)
      _dbus_verbose ("Hangup on server listening socket\n");
  
    return TRUE;
  }
  
  static void
  socket_disconnect (DBusServer *server)
  {
    DBusServerSocket *socket_server = (DBusServerSocket*) server;
    int i;
  
    HAVE_LOCK_CHECK (server);
  
    for (i = 0 ; i < socket_server->n_fds ; i++)
      {
        if (socket_server->watch[i])
          {
            _dbus_server_remove_watch (server,
                                       socket_server->watch[i]);
            _dbus_watch_invalidate (socket_server->watch[i]);
            _dbus_watch_unref (socket_server->watch[i]);
            socket_server->watch[i] = NULL;
          }
  
        _dbus_close_socket (socket_server->fds[i], NULL);
        socket_server->fds[i] = -1;
      }
  
    if (socket_server->socket_name != NULL)
      {
        DBusString tmp;
        _dbus_string_init_const (&tmp, socket_server->socket_name);
        _dbus_delete_file (&tmp, NULL);
      }
  
    if (server->published_address)
        _dbus_daemon_unpublish_session_bus_address();
  
    HAVE_LOCK_CHECK (server);
  }
  
  static const DBusServerVTable socket_vtable = {
    socket_finalize,
    socket_disconnect
  };
  
  /**
   * Creates a new server listening on the given file descriptor.  The
   * file descriptor should be nonblocking (use
   * _dbus_set_fd_nonblocking() to make it so). The file descriptor
   * should be listening for connections, that is, listen() should have
   * been successfully invoked on it. The server will use accept() to
   * accept new client connections.
   *
   * @param fds list of file descriptors.
   * @param n_fds number of file descriptors
   * @param address the server's address
   * @param noncefile to be used for authentication (NULL if not needed)
   * @returns the new server, or #NULL if no memory.
   *
   */
  DBusServer*
  _dbus_server_new_for_socket (int              *fds,
                               int               n_fds,
                               const DBusString *address,
                               DBusNonceFile    *noncefile)
  {
    DBusServerSocket *socket_server;
    DBusServer *server;
    int i;
  
    socket_server = dbus_new0 (DBusServerSocket, 1);
    if (socket_server == NULL)
      return NULL;
  
    socket_server->noncefile = noncefile;
  
    socket_server->fds = dbus_new (int, n_fds);
    if (!socket_server->fds)
      goto failed_0;
  
    socket_server->watch = dbus_new0 (DBusWatch *, n_fds);
    if (!socket_server->watch)
      goto failed_1;
  
    for (i = 0 ; i < n_fds ; i++)
      {
        DBusWatch *watch;
  
        watch = _dbus_watch_new (fds[i],
                                 DBUS_WATCH_READABLE,
                                 TRUE,
                                 socket_handle_watch, socket_server,
                                 NULL);
        if (watch == NULL)
          goto failed_2;
  
        socket_server->n_fds++;
        socket_server->fds[i] = fds[i];
        socket_server->watch[i] = watch;
      }
  
    if (!_dbus_server_init_base (&socket_server->base,
                                 &socket_vtable, address))
      goto failed_2;
  
    server = (DBusServer*)socket_server;
  
    SERVER_LOCK (server);
  
    for (i = 0 ; i < n_fds ; i++)
      {
        if (!_dbus_server_add_watch (&socket_server->base,
                                     socket_server->watch[i]))
          {
            int j;
            for (j = 0 ; j < i ; j++)
              _dbus_server_remove_watch (server,
                                         socket_server->watch[j]);
  
            SERVER_UNLOCK (server);
            _dbus_server_finalize_base (&socket_server->base);
            goto failed_2;
          }
      }
  
    SERVER_UNLOCK (server);
  
    _dbus_server_trace_ref (&socket_server->base, 0, 1, "new_for_socket");
    return (DBusServer*) socket_server;
  
   failed_2:
    for (i = 0 ; i < n_fds ; i++)
      {
        if (socket_server->watch[i] != NULL)
          {
            _dbus_watch_unref (socket_server->watch[i]);
            socket_server->watch[i] = NULL;
          }
      }
    dbus_free (socket_server->watch);
  
   failed_1:
    dbus_free (socket_server->fds);
  
   failed_0:
    dbus_free (socket_server);
    return NULL;
  }
  
  /**
   * Creates a new server listening on TCP.
   * If host is NULL, it will default to localhost.
   * If bind is NULL, it will default to the value for the host
   * parameter, and if that is NULL, then localhost
   * If bind is a hostname, it will be resolved and will listen
   * on all returned addresses.
   * If family is NULL, hostname resolution will try all address
   * families, otherwise it can be ipv4 or ipv6 to restrict the
   * addresses considered.
   *
   * @param host the hostname to report for the listen address
   * @param bind the hostname to listen on
   * @param port the port to listen on or 0 to let the OS choose
   * @param family
   * @param error location to store reason for failure.
   * @param use_nonce whether to use a nonce for low-level authentication (nonce-tcp transport) or not (tcp transport)
   * @returns the new server, or #NULL on failure.
   */
  DBusServer*
  _dbus_server_new_for_tcp_socket (const char     *host,
                                   const char     *bind,
                                   const char     *port,
                                   const char     *family,
                                   DBusError      *error,
                                   dbus_bool_t    use_nonce)
  {
    DBusServer *server;
    int *listen_fds = NULL;
    int nlisten_fds = 0, i;
    DBusString address;
    DBusString host_str;
    DBusString port_str;
    DBusNonceFile *noncefile;
    
    _DBUS_ASSERT_ERROR_IS_CLEAR (error);
  
    noncefile = NULL;
  
    if (!_dbus_string_init (&address))
      {
        dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
        return NULL;
      }
  
    if (!_dbus_string_init (&port_str))
      {
        dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
        goto failed_0;
      }
  
    if (host == NULL)
      host = "localhost";
  
    if (port == NULL)
      port = "0";
  
    if (bind == NULL)
      bind = host;
    else if (strcmp (bind, "*") == 0)
      bind = NULL;
  
    nlisten_fds =_dbus_listen_tcp_socket (bind, port, family,
                                          &port_str,
                                          &listen_fds, error);
    if (nlisten_fds <= 0)
      {
        _DBUS_ASSERT_ERROR_IS_SET(error);
        goto failed_1;
      }
  
    _dbus_string_init_const (&host_str, host);
    if (!_dbus_string_append (&address, use_nonce ? "nonce-tcp:host=" : "tcp:host=") ||
        !_dbus_address_append_escaped (&address, &host_str) ||
        !_dbus_string_append (&address, ",port=") ||
        !_dbus_string_append (&address, _dbus_string_get_const_data(&port_str)))
      {
        dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
        goto failed_2;
      }
    if (family &&
        (!_dbus_string_append (&address, ",family=") ||
         !_dbus_string_append (&address, family)))
      {
        dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
        goto failed_2;
      }
  
    if (use_nonce)
      {
        noncefile = dbus_new0 (DBusNonceFile, 1);
        if (noncefile == NULL)
          {
            dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
            goto failed_2;
          }
  
        if (!_dbus_noncefile_create (noncefile, error))
            goto failed_3;
  
        if (!_dbus_string_append (&address, ",noncefile=") ||
            !_dbus_address_append_escaped (&address, _dbus_noncefile_get_path (noncefile)))
          {
            dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
            goto failed_4;
          }
  
      }
  
    server = _dbus_server_new_for_socket (listen_fds, nlisten_fds, &address, noncefile);
    if (server == NULL)
      {
        dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
        if (noncefile != NULL)
          goto failed_4;
        else
          goto failed_2;
      }
  
    _dbus_string_free (&port_str);
    _dbus_string_free (&address);
    dbus_free(listen_fds);
  
    return server;
  
   failed_4:
    _dbus_noncefile_delete (noncefile, NULL);
  
   failed_3:
    dbus_free (noncefile);
  
   failed_2:
    for (i = 0 ; i < nlisten_fds ; i++)
      _dbus_close_socket (listen_fds[i], NULL);
    dbus_free(listen_fds);
  
   failed_1:
    _dbus_string_free (&port_str);
  
   failed_0:
    _dbus_string_free (&address);
  
    return NULL;
  }
  
  /**
   * Tries to interpret the address entry for various socket-related
   * addresses (well, currently only tcp and nonce-tcp).
   *
   * Sets error if the result is not OK.
   *
   * @param entry an address entry
   * @param server_p a new DBusServer, or #NULL on failure.
   * @param error location to store rationale for failure on bad address
   * @returns the outcome
   *
   */
  DBusServerListenResult
  _dbus_server_listen_socket (DBusAddressEntry *entry,
                              DBusServer      **server_p,
                              DBusError        *error)
  {
    const char *method;
  
    *server_p = NULL;
  
    method = dbus_address_entry_get_method (entry);
  
    if (strcmp (method, "tcp") == 0 || strcmp (method, "nonce-tcp") == 0)
      {
        const char *host;
        const char *port;
        const char *bind;
        const char *family;
  
        host = dbus_address_entry_get_value (entry, "host");
        bind = dbus_address_entry_get_value (entry, "bind");
        port = dbus_address_entry_get_value (entry, "port");
        family = dbus_address_entry_get_value (entry, "family");
  
        *server_p = _dbus_server_new_for_tcp_socket (host, bind, port,
                                                     family, error, strcmp (method, "nonce-tcp") == 0 ? TRUE : FALSE);
  
        if (*server_p)
          {
            _DBUS_ASSERT_ERROR_IS_CLEAR(error);
            return DBUS_SERVER_LISTEN_OK;
          }
        else
          {
            _DBUS_ASSERT_ERROR_IS_SET(error);
            return DBUS_SERVER_LISTEN_DID_NOT_CONNECT;
          }
      }
    else
      {
        _DBUS_ASSERT_ERROR_IS_CLEAR(error);
        return DBUS_SERVER_LISTEN_NOT_HANDLED;
      }
  }
  
  /**
   * This is a bad hack since it's really unix domain socket
   * specific. Also, the function weirdly adopts ownership
   * of the passed-in string.
   *
   * @param server a socket server
   * @param filename socket filename to report/delete
   *
   */
  void
  _dbus_server_socket_own_filename (DBusServer *server,
                                    char       *filename)
  {
    DBusServerSocket *socket_server = (DBusServerSocket*) server;
  
    socket_server->socket_name = filename;
  }
  
  
  /** @} */
  
  