static dbus_bool_t
do_check_nonce (int fd, const DBusString *nonce, DBusError *error)
{
DBusString buffer;
DBusString p;
size_t nleft;
dbus_bool_t result;
int n;
_DBUS_ASSERT_ERROR_IS_CLEAR (error);
nleft = 16;
if ( !_dbus_string_init (&buffer)
|| !_dbus_string_init (&p) ) {
dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
_dbus_string_free (&p);
_dbus_string_free (&buffer);
return FALSE;
}
while (nleft)
{
n = _dbus_read_socket (fd, &p, nleft);
if (n == -1 && _dbus_get_is_errno_eintr())
;
else if (n == -1 && _dbus_get_is_errno_eagain_or_ewouldblock())
_dbus_sleep_milliseconds (100);
else if (n==-1)
{
dbus_set_error (error, DBUS_ERROR_IO_ERROR, "Could not read nonce from socket (fd=%d)", fd );
_dbus_string_free (&p);
_dbus_string_free (&buffer);
return FALSE;
}
else if (!n)
{
_dbus_string_free (&p);
_dbus_string_free (&buffer);
dbus_set_error (error, DBUS_ERROR_IO_ERROR, "Could not read nonce from socket (fd=%d)", fd );
return FALSE;
}
else
{
_dbus_string_append_len(&buffer, _dbus_string_get_const_data (&p), n);
nleft -= n;
}
}
result = _dbus_string_equal_len (&buffer, nonce, 16);
if (!result)
dbus_set_error (error, DBUS_ERROR_ACCESS_DENIED, "Nonces do not match, access denied (fd=%d)", fd );
_dbus_string_free (&p);
_dbus_string_free (&buffer);
return result;
}
/**
* @todo We need to have a way to wake up the select sleep if
* a new iteration request comes in with a flag (read/write) that
* we're not currently serving. Otherwise a call that just reads
* could block a write call forever (if there are no incoming
* messages).
*/
static void
socket_do_iteration (DBusTransport *transport,
unsigned int flags,
int timeout_milliseconds)
{
DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
DBusPollFD poll_fd;
int poll_res;
int poll_timeout;
_dbus_verbose (" iteration flags = %s%s timeout = %d read_watch = %p write_watch = %p fd = %" DBUS_SOCKET_FORMAT "\n",
flags & DBUS_ITERATION_DO_READING ? "read" : "",
flags & DBUS_ITERATION_DO_WRITING ? "write" : "",
timeout_milliseconds,
socket_transport->read_watch,
socket_transport->write_watch,
_dbus_socket_printable (socket_transport->fd));
/* the passed in DO_READING/DO_WRITING flags indicate whether to
* read/write messages, but regardless of those we may need to block
* for reading/writing to do auth. But if we do reading for auth,
* we don't want to read any messages yet if not given DO_READING.
*/
poll_fd.fd = _dbus_socket_get_pollable (socket_transport->fd);
poll_fd.events = 0;
if (_dbus_transport_try_to_authenticate (transport))
{
/* This is kind of a hack; if we have stuff to write, then try
* to avoid the poll. This is probably about a 5% speedup on an
* echo client/server.
*
* If both reading and writing were requested, we want to avoid this
* since it could have funky effects:
* - both ends spinning waiting for the other one to read
* data so they can finish writing
* - prioritizing all writing ahead of reading
*/
if ((flags & DBUS_ITERATION_DO_WRITING) &&
!(flags & (DBUS_ITERATION_DO_READING | DBUS_ITERATION_BLOCK)) &&
!transport->disconnected &&
_dbus_connection_has_messages_to_send_unlocked (transport->connection))
{
do_writing (transport);
if (transport->disconnected ||
!_dbus_connection_has_messages_to_send_unlocked (transport->connection))
goto out;
}
/* If we get here, we decided to do the poll() after all */
_dbus_assert (socket_transport->read_watch);
if (flags & DBUS_ITERATION_DO_READING)
poll_fd.events |= _DBUS_POLLIN;
_dbus_assert (socket_transport->write_watch);
if (flags & DBUS_ITERATION_DO_WRITING)
poll_fd.events |= _DBUS_POLLOUT;
}
else
{
DBusAuthState auth_state;
auth_state = _dbus_auth_do_work (transport->auth);
if (transport->receive_credentials_pending ||
auth_state == DBUS_AUTH_STATE_WAITING_FOR_INPUT)
poll_fd.events |= _DBUS_POLLIN;
if (transport->send_credentials_pending ||
auth_state == DBUS_AUTH_STATE_HAVE_BYTES_TO_SEND)
poll_fd.events |= _DBUS_POLLOUT;
}
if (poll_fd.events)
{
int saved_errno;
if (flags & DBUS_ITERATION_BLOCK)
poll_timeout = timeout_milliseconds;
else
poll_timeout = 0;
/* For blocking selects we drop the connection lock here
* to avoid blocking out connection access during a potentially
* indefinite blocking call. The io path is still protected
* by the io_path_cond condvar, so we won't reenter this.
*/
if (flags & DBUS_ITERATION_BLOCK)
{
_dbus_verbose ("unlock pre poll\n");
_dbus_connection_unlock (transport->connection);
}
again:
poll_res = _dbus_poll (&poll_fd, 1, poll_timeout);
saved_errno = _dbus_save_socket_errno ();
if (poll_res < 0 && _dbus_get_is_errno_eintr (saved_errno))
goto again;
if (flags & DBUS_ITERATION_BLOCK)
{
_dbus_verbose ("lock post poll\n");
_dbus_connection_lock (transport->connection);
}
if (poll_res >= 0)
{
if (poll_res == 0)
poll_fd.revents = 0; /* some concern that posix does not guarantee this;
* valgrind flags it as an error. though it probably
* is guaranteed on linux at least.
*/
if (poll_fd.revents & _DBUS_POLLERR)
do_io_error (transport);
else
{
dbus_bool_t need_read = (poll_fd.revents & _DBUS_POLLIN) > 0;
dbus_bool_t need_write = (poll_fd.revents & _DBUS_POLLOUT) > 0;
dbus_bool_t authentication_completed;
_dbus_verbose ("in iteration, need_read=%d need_write=%d\n",
need_read, need_write);
do_authentication (transport, need_read, need_write,
&authentication_completed);
/* See comment in socket_handle_watch. */
if (authentication_completed)
goto out;
if (need_read && (flags & DBUS_ITERATION_DO_READING))
do_reading (transport);
if (need_write && (flags & DBUS_ITERATION_DO_WRITING))
do_writing (transport);
}
}
else
{
_dbus_verbose ("Error from _dbus_poll(): %s\n",
_dbus_strerror (saved_errno));
}
}
out:
/* We need to install the write watch only if we did not
* successfully write everything. Note we need to be careful that we
* don't call check_write_watch *before* do_writing, since it's
* inefficient to add the write watch, and we can avoid it most of
* the time since we can write immediately.
*
* However, we MUST always call check_write_watch(); DBusConnection code
* relies on the fact that running an iteration will notice that
* messages are pending.
*/
check_write_watch (transport);
_dbus_verbose (" ... leaving do_iteration()\n");
}
static dbus_bool_t
do_check_nonce (DBusSocket fd, const DBusString *nonce, DBusError *error)
{
DBusString buffer;
DBusString p;
size_t nleft;
dbus_bool_t result;
int n;
_DBUS_ASSERT_ERROR_IS_CLEAR (error);
nleft = 16;
/* This is a trick to make it safe to call _dbus_string_free on these
* strings during error unwinding, even if allocating memory for them
* fails. A constant DBusString is considered to be valid to "free",
* even though there is nothing to free (of course the free operation
* is trivial, because it does not own its own buffer); but
* unlike a mutable DBusString, initializing a constant DBusString
* cannot fail.
*
* We must successfully re-initialize the strings to be mutable before
* writing to them, of course.
*/
_dbus_string_init_const (&buffer, "");
_dbus_string_init_const (&p, "");
if ( !_dbus_string_init (&buffer)
|| !_dbus_string_init (&p) ) {
dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
_dbus_string_free (&p);
_dbus_string_free (&buffer);
return FALSE;
}
while (nleft)
{
int saved_errno;
n = _dbus_read_socket (fd, &p, nleft);
saved_errno = _dbus_save_socket_errno ();
if (n == -1 && _dbus_get_is_errno_eintr (saved_errno))
;
else if (n == -1 && _dbus_get_is_errno_eagain_or_ewouldblock (saved_errno))
_dbus_sleep_milliseconds (100);
else if (n==-1)
{
dbus_set_error (error, DBUS_ERROR_IO_ERROR, "Could not read nonce from socket (fd=%" DBUS_SOCKET_FORMAT ")", _dbus_socket_printable (fd));
_dbus_string_free (&p);
_dbus_string_free (&buffer);
return FALSE;
}
else if (!n)
{
_dbus_string_free (&p);
_dbus_string_free (&buffer);
dbus_set_error (error, DBUS_ERROR_IO_ERROR, "Could not read nonce from socket (fd=%" DBUS_SOCKET_FORMAT ")", _dbus_socket_printable (fd));
return FALSE;
}
else
{
if (!_dbus_string_append_len (&buffer, _dbus_string_get_const_data (&p), n))
{
dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
_dbus_string_free (&p);
_dbus_string_free (&buffer);
return FALSE;
}
nleft -= n;
}
}
result = _dbus_string_equal_len (&buffer, nonce, 16);
if (!result)
dbus_set_error (error, DBUS_ERROR_ACCESS_DENIED, "Nonces do not match, access denied (fd=%" DBUS_SOCKET_FORMAT ")", _dbus_socket_printable (fd));
_dbus_string_free (&p);
_dbus_string_free (&buffer);
return result;
}
