static void
signal_handler (int sig)
{
DBusString str;
switch (sig)
{
#ifdef DBUS_BUS_ENABLE_DNOTIFY_ON_LINUX
case SIGIO:
/* explicit fall-through */
#endif /* DBUS_BUS_ENABLE_DNOTIFY_ON_LINUX */
case SIGHUP:
_dbus_string_init_const (&str, "foo");
if (!_dbus_write_socket (reload_pipe[RELOAD_WRITE_END], &str, 0, 1))
{
_dbus_warn ("Unable to write to reload pipe.\n");
exit (1);
}
break;
case SIGTERM:
_dbus_loop_quit (bus_context_get_loop (context));
break;
}
}
static void
signal_handler (int sig)
{
switch (sig)
{
#ifdef DBUS_BUS_ENABLE_DNOTIFY_ON_LINUX
case SIGIO:
/* explicit fall-through */
#endif /* DBUS_BUS_ENABLE_DNOTIFY_ON_LINUX */
#ifdef SIGHUP
case SIGHUP:
{
DBusString str;
_dbus_string_init_const (&str, "foo");
if ((reload_pipe[RELOAD_WRITE_END] > 0) &&
!_dbus_write_socket (reload_pipe[RELOAD_WRITE_END], &str, 0, 1))
{
_dbus_warn ("Unable to write to reload pipe.\n");
close_reload_pipe ();
}
}
break;
#endif
}
}
/**
* 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;
}
/* Return value is whether we successfully wrote any bytes */
static dbus_bool_t
write_data_from_auth (DBusTransport *transport)
{
DBusTransportSocket *socket_transport = (DBusTransportSocket*) transport;
int bytes_written;
int saved_errno;
const DBusString *buffer;
if (!_dbus_auth_get_bytes_to_send (transport->auth,
&buffer))
return FALSE;
bytes_written = _dbus_write_socket (socket_transport->fd,
buffer,
0, _dbus_string_get_length (buffer));
saved_errno = _dbus_save_socket_errno ();
if (bytes_written > 0)
{
_dbus_auth_bytes_sent (transport->auth, bytes_written);
return TRUE;
}
else if (bytes_written < 0)
{
/* EINTR already handled for us */
if (_dbus_get_is_errno_eagain_or_ewouldblock (saved_errno))
;
else
{
_dbus_verbose ("Error writing to remote app: %s\n",
_dbus_strerror (saved_errno));
do_io_error (transport);
}
}
return FALSE;
}
static void
signal_handler (int sig)
{
switch (sig)
{
case SIGHUP:
{
DBusString str;
char action[2] = { ACTION_RELOAD, '\0' };
_dbus_string_init_const (&str, action);
if ((reload_pipe[RELOAD_WRITE_END] > 0) &&
!_dbus_write_socket (reload_pipe[RELOAD_WRITE_END], &str, 0, 1))
{
/* If we receive SIGHUP often enough to fill the pipe buffer (4096
* times on old Linux, 65536 on modern Linux) before it can be
* drained, let's just warn and ignore. The configuration will be
* reloaded while draining the pipe buffer, which is what we
* wanted. It's harmless that it will be reloaded fewer times than
* we asked for, since the reload is delayed anyway, so new changes
* will be picked up.
*
* We use write() because _dbus_warn uses vfprintf, which isn't
* async-signal-safe.
*
* This is necessarily Unix-specific, but so are POSIX signals,
* so... */
static const char message[] =
"Unable to write to reload pipe - buffer full?\n";
if (write (STDERR_FILENO, message, strlen (message)) != strlen (message))
{
/* ignore failure to write out a warning */
}
}
}
break;
case SIGTERM:
{
DBusString str;
char action[2] = { ACTION_QUIT, '\0' };
_dbus_string_init_const (&str, action);
if ((reload_pipe[RELOAD_WRITE_END] < 0) ||
!_dbus_write_socket (reload_pipe[RELOAD_WRITE_END], &str, 0, 1))
{
/* If we can't write to the socket, dying seems a more
* important response to SIGTERM than cleaning up sockets,
* so we exit. We'd use exit(), but that's not async-signal-safe,
* so we'll have to resort to _exit(). */
static const char message[] =
"Unable to write termination signal to pipe - buffer full?\n"
"Will exit instead.\n";
if (write (STDERR_FILENO, message, strlen (message)) != strlen (message))
{
/* ignore failure to write out a warning */
}
_exit (1);
}
}
break;
}
}
/* 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;
}
dbus_bool_t
_dbus_become_daemon (const DBusString *pidfile,
int print_pid_fd,
DBusError *error)
{
const char *s;
pid_t child_pid;
int dev_null_fd;
_dbus_verbose ("Becoming a daemon...\n");
_dbus_verbose ("chdir to /\n");
if (chdir ("/") < 0)
{
dbus_set_error (error, DBUS_ERROR_FAILED,
"Could not chdir() to root directory");
return FALSE;
}
_dbus_verbose ("forking...\n");
switch ((child_pid = fork ()))
{
case -1:
_dbus_verbose ("fork failed\n");
dbus_set_error (error, _dbus_error_from_errno (errno),
"Failed to fork daemon: %s", _dbus_strerror (errno));
return FALSE;
break;
case 0:
_dbus_verbose ("in child, closing std file descriptors\n");
/* silently ignore failures here, if someone
* doesn't have /dev/null we may as well try
* to continue anyhow
*/
dev_null_fd = open ("/dev/null", O_RDWR);
if (dev_null_fd >= 0)
{
dup2 (dev_null_fd, 0);
dup2 (dev_null_fd, 1);
s = _dbus_getenv ("DBUS_DEBUG_OUTPUT");
if (s == NULL || *s == '\0')
dup2 (dev_null_fd, 2);
else
_dbus_verbose ("keeping stderr open due to DBUS_DEBUG_OUTPUT\n");
}
/* Get a predictable umask */
_dbus_verbose ("setting umask\n");
umask (022);
break;
default:
if (pidfile)
{
_dbus_verbose ("parent writing pid file\n");
if (!_dbus_write_pid_file (pidfile,
child_pid,
error))
{
_dbus_verbose ("pid file write failed, killing child\n");
kill (child_pid, SIGTERM);
return FALSE;
}
}
/* Write PID if requested */
if (print_pid_fd >= 0)
{
DBusString pid;
int bytes;
if (!_dbus_string_init (&pid))
{
_DBUS_SET_OOM (error);
kill (child_pid, SIGTERM);
return FALSE;
}
if (!_dbus_string_append_int (&pid, child_pid) ||
!_dbus_string_append (&pid, "\n"))
{
_dbus_string_free (&pid);
_DBUS_SET_OOM (error);
kill (child_pid, SIGTERM);
return FALSE;
}
bytes = _dbus_string_get_length (&pid);
if (_dbus_write_socket (print_pid_fd, &pid, 0, bytes) != bytes)
{
dbus_set_error (error, DBUS_ERROR_FAILED,
"Printing message bus PID: %s\n",
_dbus_strerror (errno));
_dbus_string_free (&pid);
kill (child_pid, SIGTERM);
return FALSE;
}
_dbus_string_free (&pid);
}
_dbus_verbose ("parent exiting\n");
_exit (0);
break;
}
_dbus_verbose ("calling setsid()\n");
if (setsid () == -1)
_dbus_assert_not_reached ("setsid() failed");
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 = %d\n",
_dbus_connection_has_messages_to_send_unlocked (transport->connection),
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;
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);
}
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);
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));
}
}
}
if (bytes_written < 0)
{
/* EINTR already handled for us */
/* For some discussion of why we also ignore EPIPE here, see
* http://lists.freedesktop.org/archives/dbus/2008-March/009526.html
*/
if (_dbus_get_is_errno_eagain_or_ewouldblock () || _dbus_get_is_errno_epipe ())
goto out;
else
{
_dbus_verbose ("Error writing to remote app: %s\n",
_dbus_strerror_from_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;
}
