static void
check_read_watch (DBusTransport *transport)
{
DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
dbus_bool_t need_read_watch;
_dbus_verbose ("fd = %" DBUS_SOCKET_FORMAT "\n",
_dbus_socket_printable (socket_transport->fd));
if (transport->connection == NULL)
return;
if (transport->disconnected)
{
_dbus_assert (socket_transport->read_watch == NULL);
return;
}
_dbus_transport_ref (transport);
if (_dbus_transport_try_to_authenticate (transport))
need_read_watch =
(_dbus_counter_get_size_value (transport->live_messages) < transport->max_live_messages_size) &&
(_dbus_counter_get_unix_fd_value (transport->live_messages) < transport->max_live_messages_unix_fds);
else
{
if (transport->receive_credentials_pending)
need_read_watch = TRUE;
else
{
/* The reason to disable need_read_watch when not WAITING_FOR_INPUT
* is to avoid spinning on the file descriptor when we're waiting
* to write or for some other part of the auth process
*/
DBusAuthState auth_state;
auth_state = _dbus_auth_do_work (transport->auth);
/* If we need memory we install the read watch just in case,
* if there's no need for it, it will get de-installed
* next time we try reading. If we're authenticated we
* install it since we normally have it installed while
* authenticated.
*/
if (auth_state == DBUS_AUTH_STATE_WAITING_FOR_INPUT ||
auth_state == DBUS_AUTH_STATE_WAITING_FOR_MEMORY ||
auth_state == DBUS_AUTH_STATE_AUTHENTICATED)
need_read_watch = TRUE;
else
need_read_watch = FALSE;
}
}
_dbus_verbose (" setting read watch enabled = %d\n", need_read_watch);
_dbus_connection_toggle_watch_unlocked (transport->connection,
socket_transport->read_watch,
need_read_watch);
_dbus_transport_unref (transport);
}
static void
check_write_watch (DBusTransport *transport)
{
DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
dbus_bool_t needed;
if (transport->connection == NULL)
return;
if (transport->disconnected)
{
_dbus_assert (socket_transport->write_watch == NULL);
return;
}
_dbus_transport_ref (transport);
if (_dbus_transport_try_to_authenticate (transport))
needed = _dbus_connection_has_messages_to_send_unlocked (transport->connection);
else
{
if (transport->send_credentials_pending)
needed = TRUE;
else
{
DBusAuthState auth_state;
auth_state = _dbus_auth_do_work (transport->auth);
/* If we need memory we install the write watch just in case,
* if there's no need for it, it will get de-installed
* next time we try reading.
*/
if (auth_state == DBUS_AUTH_STATE_HAVE_BYTES_TO_SEND ||
auth_state == DBUS_AUTH_STATE_WAITING_FOR_MEMORY)
needed = TRUE;
else
needed = FALSE;
}
}
_dbus_verbose ("check_write_watch(): needed = %d on connection %p watch %p fd = %" DBUS_SOCKET_FORMAT " outgoing messages exist %d\n",
needed, transport->connection, socket_transport->write_watch,
_dbus_socket_printable (socket_transport->fd),
_dbus_connection_has_messages_to_send_unlocked (transport->connection));
_dbus_connection_toggle_watch_unlocked (transport->connection,
socket_transport->write_watch,
needed);
_dbus_transport_unref (transport);
}
/**
* sends the nonce over a given socket. Blocks while doing so.
*
* @param fd the file descriptor to write the nonce data to (usually a socket)
* @param noncefile the noncefile location to read the nonce from
* @param error contains error details if FALSE is returned
* @return TRUE iff the nonce was successfully sent. Note that this does not
* indicate whether the server accepted the nonce.
*/
dbus_bool_t
_dbus_send_nonce (DBusSocket fd,
const DBusString *noncefile,
DBusError *error)
{
dbus_bool_t read_result;
int send_result;
DBusString nonce;
_DBUS_ASSERT_ERROR_IS_CLEAR (error);
if (_dbus_string_get_length (noncefile) == 0)
return FALSE;
if (!_dbus_string_init (&nonce))
{
dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
return FALSE;
}
read_result = _dbus_read_nonce (noncefile, &nonce, error);
if (!read_result)
{
_DBUS_ASSERT_ERROR_IS_SET (error);
_dbus_string_free (&nonce);
return FALSE;
}
_DBUS_ASSERT_ERROR_IS_CLEAR (error);
send_result = _dbus_write_socket (fd, &nonce, 0, _dbus_string_get_length (&nonce));
_dbus_string_free (&nonce);
if (send_result == -1)
{
dbus_set_error (error,
_dbus_error_from_system_errno (),
"Failed to send nonce (fd=%" DBUS_SOCKET_FORMAT "): %s",
_dbus_socket_printable (fd),
_dbus_strerror_from_errno ());
return FALSE;
}
return TRUE;
}
/* returns false on out-of-memory */
static dbus_bool_t
do_reading (DBusTransport *transport)
{
DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
DBusString *buffer;
int bytes_read;
int total;
dbus_bool_t oom;
int saved_errno;
_dbus_verbose ("fd = %" DBUS_SOCKET_FORMAT "\n",
_dbus_socket_printable (socket_transport->fd));
/* No messages without authentication! */
if (!_dbus_transport_try_to_authenticate (transport))
return TRUE;
oom = FALSE;
total = 0;
again:
/* See if we've exceeded max messages and need to disable reading */
check_read_watch (transport);
if (total > socket_transport->max_bytes_read_per_iteration)
{
_dbus_verbose ("%d bytes exceeds %d bytes read per iteration, returning\n",
total, socket_transport->max_bytes_read_per_iteration);
goto out;
}
_dbus_assert (socket_transport->read_watch != NULL ||
transport->disconnected);
if (transport->disconnected)
goto out;
if (!dbus_watch_get_enabled (socket_transport->read_watch))
return TRUE;
if (_dbus_auth_needs_decoding (transport->auth))
{
/* Does fd passing even make sense with encoded data? */
_dbus_assert(!DBUS_TRANSPORT_CAN_SEND_UNIX_FD(transport));
if (_dbus_string_get_length (&socket_transport->encoded_incoming) > 0)
bytes_read = _dbus_string_get_length (&socket_transport->encoded_incoming);
else
bytes_read = _dbus_read_socket (socket_transport->fd,
&socket_transport->encoded_incoming,
socket_transport->max_bytes_read_per_iteration);
saved_errno = _dbus_save_socket_errno ();
_dbus_assert (_dbus_string_get_length (&socket_transport->encoded_incoming) ==
bytes_read);
if (bytes_read > 0)
{
_dbus_message_loader_get_buffer (transport->loader,
&buffer);
if (!_dbus_auth_decode_data (transport->auth,
&socket_transport->encoded_incoming,
buffer))
{
_dbus_verbose ("Out of memory decoding incoming data\n");
_dbus_message_loader_return_buffer (transport->loader,
buffer);
oom = TRUE;
goto out;
}
_dbus_message_loader_return_buffer (transport->loader,
buffer);
_dbus_string_set_length (&socket_transport->encoded_incoming, 0);
_dbus_string_compact (&socket_transport->encoded_incoming, 2048);
}
}
else
{
_dbus_message_loader_get_buffer (transport->loader,
&buffer);
#ifdef HAVE_UNIX_FD_PASSING
if (DBUS_TRANSPORT_CAN_SEND_UNIX_FD(transport))
{
int *fds;
unsigned int n_fds;
if (!_dbus_message_loader_get_unix_fds(transport->loader, &fds, &n_fds))
{
_dbus_verbose ("Out of memory reading file descriptors\n");
_dbus_message_loader_return_buffer (transport->loader, buffer);
oom = TRUE;
goto out;
}
bytes_read = _dbus_read_socket_with_unix_fds(socket_transport->fd,
buffer,
socket_transport->max_bytes_read_per_iteration,
fds, &n_fds);
saved_errno = _dbus_save_socket_errno ();
if (bytes_read >= 0 && n_fds > 0)
_dbus_verbose("Read %i unix fds\n", n_fds);
_dbus_message_loader_return_unix_fds(transport->loader, fds, bytes_read < 0 ? 0 : n_fds);
}
else
#endif
{
bytes_read = _dbus_read_socket (socket_transport->fd,
buffer, socket_transport->max_bytes_read_per_iteration);
saved_errno = _dbus_save_socket_errno ();
}
_dbus_message_loader_return_buffer (transport->loader,
buffer);
}
if (bytes_read < 0)
{
/* EINTR already handled for us */
if (_dbus_get_is_errno_enomem (saved_errno))
{
_dbus_verbose ("Out of memory in read()/do_reading()\n");
oom = TRUE;
goto out;
}
else if (_dbus_get_is_errno_eagain_or_ewouldblock (saved_errno))
goto out;
else
{
_dbus_verbose ("Error reading from remote app: %s\n",
_dbus_strerror (saved_errno));
do_io_error (transport);
goto out;
}
}
else if (bytes_read == 0)
{
_dbus_verbose ("Disconnected from remote app\n");
do_io_error (transport);
goto out;
}
else
{
_dbus_verbose (" read %d bytes\n", bytes_read);
total += bytes_read;
if (!_dbus_transport_queue_messages (transport))
{
oom = TRUE;
_dbus_verbose (" out of memory when queueing messages we just read in the transport\n");
goto out;
}
/* Try reading more data until we get EAGAIN and return, or
* exceed max bytes per iteration. If in blocking mode of
* course we'll block instead of returning.
*/
goto again;
}
out:
if (oom)
return FALSE;
else
return TRUE;
}
/* returns false on oom */
static dbus_bool_t
do_writing (DBusTransport *transport)
{
int total;
DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
dbus_bool_t oom;
/* No messages without authentication! */
if (!_dbus_transport_try_to_authenticate (transport))
{
_dbus_verbose ("Not authenticated, not writing anything\n");
return TRUE;
}
if (transport->disconnected)
{
_dbus_verbose ("Not connected, not writing anything\n");
return TRUE;
}
#if 1
_dbus_verbose ("do_writing(), have_messages = %d, fd = %" DBUS_SOCKET_FORMAT "\n",
_dbus_connection_has_messages_to_send_unlocked (transport->connection),
_dbus_socket_printable (socket_transport->fd));
#endif
oom = FALSE;
total = 0;
while (!transport->disconnected &&
_dbus_connection_has_messages_to_send_unlocked (transport->connection))
{
int bytes_written;
DBusMessage *message;
const DBusString *header;
const DBusString *body;
int header_len, body_len;
int total_bytes_to_write;
int saved_errno;
if (total > socket_transport->max_bytes_written_per_iteration)
{
_dbus_verbose ("%d bytes exceeds %d bytes written per iteration, returning\n",
total, socket_transport->max_bytes_written_per_iteration);
goto out;
}
message = _dbus_connection_get_message_to_send (transport->connection);
_dbus_assert (message != NULL);
dbus_message_lock (message);
#if 0
_dbus_verbose ("writing message %p\n", message);
#endif
_dbus_message_get_network_data (message,
&header, &body);
header_len = _dbus_string_get_length (header);
body_len = _dbus_string_get_length (body);
if (_dbus_auth_needs_encoding (transport->auth))
{
/* Does fd passing even make sense with encoded data? */
_dbus_assert(!DBUS_TRANSPORT_CAN_SEND_UNIX_FD(transport));
if (_dbus_string_get_length (&socket_transport->encoded_outgoing) == 0)
{
if (!_dbus_auth_encode_data (transport->auth,
header, &socket_transport->encoded_outgoing))
{
oom = TRUE;
goto out;
}
if (!_dbus_auth_encode_data (transport->auth,
body, &socket_transport->encoded_outgoing))
{
_dbus_string_set_length (&socket_transport->encoded_outgoing, 0);
oom = TRUE;
goto out;
}
}
total_bytes_to_write = _dbus_string_get_length (&socket_transport->encoded_outgoing);
#if 0
_dbus_verbose ("encoded message is %d bytes\n",
total_bytes_to_write);
#endif
bytes_written =
_dbus_write_socket (socket_transport->fd,
&socket_transport->encoded_outgoing,
socket_transport->message_bytes_written,
total_bytes_to_write - socket_transport->message_bytes_written);
saved_errno = _dbus_save_socket_errno ();
}
else
{
total_bytes_to_write = header_len + body_len;
#if 0
_dbus_verbose ("message is %d bytes\n",
total_bytes_to_write);
#endif
#ifdef HAVE_UNIX_FD_PASSING
if (socket_transport->message_bytes_written <= 0 && DBUS_TRANSPORT_CAN_SEND_UNIX_FD(transport))
{
/* Send the fds along with the first byte of the message */
const int *unix_fds;
unsigned n;
_dbus_message_get_unix_fds(message, &unix_fds, &n);
bytes_written =
_dbus_write_socket_with_unix_fds_two (socket_transport->fd,
header,
socket_transport->message_bytes_written,
header_len - socket_transport->message_bytes_written,
body,
0, body_len,
unix_fds,
n);
saved_errno = _dbus_save_socket_errno ();
if (bytes_written > 0 && n > 0)
_dbus_verbose("Wrote %i unix fds\n", n);
}
else
#endif
{
if (socket_transport->message_bytes_written < header_len)
{
bytes_written =
_dbus_write_socket_two (socket_transport->fd,
header,
socket_transport->message_bytes_written,
header_len - socket_transport->message_bytes_written,
body,
0, body_len);
}
else
{
bytes_written =
_dbus_write_socket (socket_transport->fd,
body,
(socket_transport->message_bytes_written - header_len),
body_len -
(socket_transport->message_bytes_written - header_len));
}
saved_errno = _dbus_save_socket_errno ();
}
}
if (bytes_written < 0)
{
/* EINTR already handled for us */
/* If the other end closed the socket with close() or shutdown(), we
* receive EPIPE here but we must not close the socket yet: there
* might still be some data to read. See:
* http://lists.freedesktop.org/archives/dbus/2008-March/009526.html
*/
if (_dbus_get_is_errno_eagain_or_ewouldblock (saved_errno) || _dbus_get_is_errno_epipe (saved_errno))
goto out;
/* Since Linux commit 25888e (from 2.6.37-rc4, Nov 2010), sendmsg()
* on Unix sockets returns -1 errno=ETOOMANYREFS when the passfd
* mechanism (SCM_RIGHTS) is used recursively with a recursion level
* of maximum 4. The kernel does not have an API to check whether
* the passed fds can be forwarded and it can change asynchronously.
* See:
* https://bugs.freedesktop.org/show_bug.cgi?id=80163
*/
else if (_dbus_get_is_errno_etoomanyrefs (saved_errno))
{
/* We only send fds in the first byte of the message.
* ETOOMANYREFS cannot happen after.
*/
_dbus_assert (socket_transport->message_bytes_written == 0);
_dbus_verbose (" discard message of %d bytes due to ETOOMANYREFS\n",
total_bytes_to_write);
socket_transport->message_bytes_written = 0;
_dbus_string_set_length (&socket_transport->encoded_outgoing, 0);
_dbus_string_compact (&socket_transport->encoded_outgoing, 2048);
/* The message was not actually sent but it needs to be removed
* from the outgoing queue
*/
_dbus_connection_message_sent_unlocked (transport->connection,
message);
}
else
{
_dbus_verbose ("Error writing to remote app: %s\n",
_dbus_strerror (saved_errno));
do_io_error (transport);
goto out;
}
}
else
{
_dbus_verbose (" wrote %d bytes of %d\n", bytes_written,
total_bytes_to_write);
total += bytes_written;
socket_transport->message_bytes_written += bytes_written;
_dbus_assert (socket_transport->message_bytes_written <=
total_bytes_to_write);
if (socket_transport->message_bytes_written == total_bytes_to_write)
{
socket_transport->message_bytes_written = 0;
_dbus_string_set_length (&socket_transport->encoded_outgoing, 0);
_dbus_string_compact (&socket_transport->encoded_outgoing, 2048);
_dbus_connection_message_sent_unlocked (transport->connection,
message);
}
}
}
out:
if (oom)
return FALSE;
else
return TRUE;
}
/**
* @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;
}