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dbus/dbus/dbus-server-socket.c
Simon McVittie 49646211f3 _dbus_server_init_base: raise a DBusError 
This can currently only fail from OOM, but I'm about to make
it possible to fail from insufficient entropy.

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=90414
Reviewed-by: Ralf Habacker <ralf.habacker@freenet.de>
[smcv: document @error]
Signed-off-by: Simon McVittie <simon.mcvittie@collabora.co.uk>
2015-05-14 14:30:30 +01:00

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/* -*- 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 */
DBusSocket *fds; /**< File descriptor or DBUS_SOCKET_INVALID 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,
DBusSocket client_fd)
{
DBusConnection *connection;
DBusTransport *transport;
DBusNewConnectionFunction new_connection_function;
void *new_connection_data;
_dbus_verbose ("Creating new client connection with fd %" DBUS_SOCKET_FORMAT "\n",
_dbus_socket_printable (client_fd));
HAVE_LOCK_CHECK (server);
if (!_dbus_set_socket_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)
{
DBusSocket client_fd;
DBusSocket listen_fd;
int saved_errno;
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);
saved_errno = _dbus_save_socket_errno ();
if (!_dbus_socket_is_valid (client_fd))
{
/* EINTR handled for us */
if (_dbus_get_is_errno_eagain_or_ewouldblock (saved_errno))
_dbus_verbose ("No client available to accept after all\n");
else
_dbus_verbose ("Failed to accept a client connection: %s\n",
_dbus_strerror (saved_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);
_dbus_socket_invalidate (&socket_server->fds[i]);
}
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)
* @param error location to store reason for failure
* @returns the new server, or #NULL on OOM or other error.
*
*/
DBusServer*
_dbus_server_new_for_socket (DBusSocket *fds,
int n_fds,
const DBusString *address,
DBusNonceFile *noncefile,
DBusError *error)
{
DBusServerSocket *socket_server;
DBusServer *server;
int i;
socket_server = dbus_new0 (DBusServerSocket, 1);
if (socket_server == NULL)
goto failed_0;
socket_server->noncefile = noncefile;
socket_server->fds = dbus_new (DBusSocket, 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 (_dbus_socket_get_pollable (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,
error))
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);
if (error != NULL && !dbus_error_is_set (error))
_DBUS_SET_OOM (error);
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;
DBusSocket *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, error);
if (server == 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;
}
/** @} */
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