示例#1
0
文件: server.py 项目: tardyp/Xpra
def create_sockets(opts, error_cb):
    from xpra.server.socket_util import (
        parse_bind_ip,
        parse_bind_vsock,
        get_network_logger,
        setup_tcp_socket,
        setup_udp_socket,
        setup_vsock_socket,
    )
    log = get_network_logger()

    bind_tcp = parse_bind_ip(opts.bind_tcp)
    bind_udp = parse_bind_ip(opts.bind_udp)
    bind_ssl = parse_bind_ip(opts.bind_ssl)
    bind_ssh = parse_bind_ip(opts.bind_ssh)
    bind_ws = parse_bind_ip(opts.bind_ws)
    bind_wss = parse_bind_ip(opts.bind_wss)
    bind_rfb = parse_bind_ip(opts.bind_rfb, 5900)
    bind_vsock = parse_bind_vsock(opts.bind_vsock)

    mdns_recs = {}
    sockets = []

    rfb_upgrades = int(opts.rfb_upgrade) > 0
    #SSL sockets:
    wrap_socket_fn = None
    need_ssl = False
    ssl_opt = opts.ssl.lower()
    if ssl_opt in TRUE_OPTIONS or bind_ssl or bind_wss:
        need_ssl = True
    if opts.bind_tcp or opts.bind_ws:
        if ssl_opt == "auto" and opts.ssl_cert:
            need_ssl = True
        elif ssl_opt == "tcp" and opts.bind_tcp:
            need_ssl = True
        elif ssl_opt == "www":
            need_ssl = True
    if need_ssl:
        from xpra.scripts.main import ssl_wrap_socket_fn
        try:
            wrap_socket_fn = ssl_wrap_socket_fn(opts, server_side=True)
            log("wrap_socket_fn=%s", wrap_socket_fn)
        except Exception as e:
            log("SSL error", exc_info=True)
            cpaths = csv("'%s'" % x for x in (opts.ssl_cert, opts.ssl_key)
                         if x)
            raise InitException(
                "cannot create SSL socket, check your certificate paths (%s): %s"
                % (cpaths, e))

    min_port = int(opts.min_port)

    def add_tcp_socket(socktype, host_str, iport):
        if iport != 0 and iport < min_port:
            error_cb("invalid %s port number %i (minimum value is %i)" %
                     (socktype, iport, min_port))
        for host in hosts(host_str):
            socket = setup_tcp_socket(host, iport, socktype)
            host, iport = socket[2]
            sockets.append(socket)
            add_mdns(mdns_recs, socktype, host, iport)

    def add_udp_socket(socktype, host_str, iport):
        if iport != 0 and iport < min_port:
            error_cb("invalid %s port number %i (minimum value is %i)" %
                     (socktype, iport, min_port))
        for host in hosts(host_str):
            socket = setup_udp_socket(host, iport, socktype)
            host, iport = socket[2]
            sockets.append(socket)
            add_mdns(mdns_recs, socktype, host, iport)

    # Initialize the TCP sockets before the display,
    # That way, errors won't make us kill the Xvfb
    # (which may not be ours to kill at that point)
    ws_upgrades = opts.html and (os.path.isabs(opts.html) or opts.html.lower()
                                 in list(TRUE_OPTIONS) + ["auto"])
    ssh_upgrades = opts.ssh_upgrade
    if ssh_upgrades:
        try:
            from xpra.net.ssh import nogssapi_context
            with nogssapi_context():
                import paramiko
            assert paramiko
        except ImportError as e:
            from xpra.log import Logger
            sshlog = Logger("ssh")
            sshlog("import paramiko", exc_info=True)
            sshlog.error("Error: cannot enable SSH socket upgrades:")
            sshlog.error(" %s", e)
    log("setting up SSL sockets: %s", csv(bind_ssl))
    for host, iport in bind_ssl:
        add_tcp_socket("ssl", host, iport)
        if ws_upgrades:
            add_tcp_socket("wss", host, iport)
    log("setting up SSH sockets: %s", csv(bind_ssh))
    for host, iport in bind_ssh:
        add_tcp_socket("ssh", host, iport)
    log("setting up https / wss (secure websockets): %s", csv(bind_wss))
    for host, iport in bind_wss:
        add_tcp_socket("wss", host, iport)
    tcp_ssl = ssl_opt in TRUE_OPTIONS or (ssl_opt == "auto" and opts.ssl_cert)
    log("setting up TCP sockets: %s", csv(bind_tcp))
    for host, iport in bind_tcp:
        add_tcp_socket("tcp", host, iport)
        if tcp_ssl:
            add_mdns(mdns_recs, "ssl", host, iport)
        if ws_upgrades:
            add_mdns(mdns_recs, "ws", host, iport)
        if ws_upgrades and tcp_ssl:
            add_mdns(mdns_recs, "wss", host, iport)
        if ssh_upgrades:
            add_mdns(mdns_recs, "ssh", host, iport)
        if rfb_upgrades:
            add_mdns(mdns_recs, "rfb", host, iport)
    log("setting up UDP sockets: %s", csv(bind_udp))
    for host, iport in bind_udp:
        add_udp_socket("udp", host, iport)
    log("setting up http / ws (websockets): %s", csv(bind_ws))
    for host, iport in bind_ws:
        add_tcp_socket("ws", host, iport)
        if tcp_ssl:
            add_mdns(mdns_recs, "wss", host, iport)
    log("setting up rfb sockets: %s", csv(bind_rfb))
    for host, iport in bind_rfb:
        add_tcp_socket("rfb", host, iport)
        add_mdns(mdns_recs, "rfb", host, iport)
    log("setting up vsock sockets: %s", csv(bind_vsock))
    for cid, iport in bind_vsock:
        socket = setup_vsock_socket(cid, iport)
        sockets.append(socket)
        #add_mdns(mdns_recs, "vsock", str(cid), iport)

    # systemd socket activation:
    if POSIX:
        try:
            from xpra.platform.xposix.sd_listen import get_sd_listen_sockets
        except ImportError:
            pass
        else:
            sd_sockets = get_sd_listen_sockets()
            log("systemd sockets: %s", sd_sockets)
            for stype, socket, addr in sd_sockets:
                sockets.append((stype, socket, addr))
                log("%s : %s", (stype, [addr]), socket)
                if stype == "tcp":
                    host, iport = addr
                    add_mdns(mdns_recs, "tcp", host, iport)
    return sockets, mdns_recs, wrap_socket_fn
示例#2
0
def run_server(error_cb,
               opts,
               mode,
               xpra_file,
               extra_args,
               desktop_display=None):
    try:
        cwd = os.getcwd()
    except:
        cwd = os.path.expanduser("~")
        warn("current working directory does not exist, using '%s'\n" % cwd)
    validate_encryption(opts)
    if opts.encoding == "help" or "help" in opts.encodings:
        return show_encoding_help(opts)

    from xpra.server.socket_util import parse_bind_ip, parse_bind_vsock, get_network_logger
    bind_tcp = parse_bind_ip(opts.bind_tcp)
    bind_udp = parse_bind_ip(opts.bind_udp)
    bind_ssl = parse_bind_ip(opts.bind_ssl)
    bind_ws = parse_bind_ip(opts.bind_ws)
    bind_wss = parse_bind_ip(opts.bind_wss)
    bind_rfb = parse_bind_ip(opts.bind_rfb, 5900)
    bind_vsock = parse_bind_vsock(opts.bind_vsock)

    assert mode in ("start", "start-desktop", "upgrade", "shadow", "proxy")
    starting = mode == "start"
    starting_desktop = mode == "start-desktop"
    upgrading = mode == "upgrade"
    shadowing = mode == "shadow"
    proxying = mode == "proxy"
    clobber = upgrading or opts.use_display
    start_vfb = not shadowing and not proxying and not clobber

    if upgrading or shadowing:
        #there should already be one running
        opts.pulseaudio = False

    #get the display name:
    if shadowing and len(extra_args) == 0:
        if WIN32 or OSX:
            #just a virtual name for the only display available:
            display_name = ":0"
        else:
            from xpra.scripts.main import guess_X11_display
            dotxpra = DotXpra(opts.socket_dir, opts.socket_dirs)
            display_name = guess_X11_display(dotxpra)
    elif upgrading and len(extra_args) == 0:
        display_name = guess_xpra_display(opts.socket_dir, opts.socket_dirs)
    else:
        if len(extra_args) > 1:
            error_cb(
                "too many extra arguments (%i): only expected a display number"
                % len(extra_args))
        if len(extra_args) == 1:
            display_name = extra_args[0]
            if not shadowing and not proxying and not opts.use_display:
                display_name_check(display_name)
        else:
            if proxying:
                #find a free display number:
                dotxpra = DotXpra(opts.socket_dir, opts.socket_dirs)
                all_displays = dotxpra.sockets()
                #ie: [("LIVE", ":100"), ("LIVE", ":200"), ...]
                displays = [v[1] for v in all_displays]
                display_name = None
                for x in range(1000, 20000):
                    v = ":%s" % x
                    if v not in displays:
                        display_name = v
                        break
                if not display_name:
                    error_cb(
                        "you must specify a free virtual display name to use with the proxy server"
                    )
            elif opts.use_display:
                #only use automatic guess for xpra displays and not X11 displays:
                display_name = guess_xpra_display(opts.socket_dir,
                                                  opts.socket_dirs)
            else:
                # We will try to find one automaticaly
                # Use the temporary magic value 'S' as marker:
                display_name = 'S' + str(os.getpid())

    if not shadowing and not proxying and not upgrading and opts.exit_with_children and not opts.start_child:
        error_cb(
            "--exit-with-children specified without any children to spawn; exiting immediately"
        )

    atexit.register(run_cleanups)

    # Generate the script text now, because os.getcwd() will
    # change if/when we daemonize:
    from xpra.server.server_util import xpra_runner_shell_script, write_runner_shell_scripts, write_pidfile, find_log_dir, create_input_devices
    script = xpra_runner_shell_script(xpra_file, cwd, opts.socket_dir)

    uid = int(opts.uid)
    gid = int(opts.gid)
    username = get_username_for_uid(uid)
    home = get_home_for_uid(uid)
    xauth_data = None
    if start_vfb:
        xauth_data = get_hex_uuid()
    ROOT = POSIX and getuid() == 0

    protected_fds = []
    protected_env = {}
    stdout = sys.stdout
    stderr = sys.stderr
    # Daemonize:
    if POSIX and opts.daemon:
        #daemonize will chdir to "/", so try to use an absolute path:
        if opts.password_file:
            opts.password_file = os.path.abspath(opts.password_file)
        from xpra.server.server_util import daemonize
        daemonize()

    displayfd = 0
    if POSIX and opts.displayfd:
        try:
            displayfd = int(opts.displayfd)
            if displayfd > 0:
                protected_fds.append(displayfd)
        except ValueError as e:
            stderr.write("Error: invalid displayfd '%s':\n" % opts.displayfd)
            stderr.write(" %s\n" % e)
            del e

    # if pam is present, try to create a new session:
    pam = None
    PAM_OPEN = POSIX and envbool("XPRA_PAM_OPEN", ROOT and uid != 0)
    if PAM_OPEN:
        try:
            from xpra.server.pam import pam_session  #@UnresolvedImport
        except ImportError as e:
            stderr.write("Error: failed to import pam module\n")
            stderr.write(" %s" % e)
            del e
            PAM_OPEN = False
    if PAM_OPEN:
        fdc = FDChangeCaptureContext()
        with fdc:
            pam = pam_session(username)
            env = {
                #"XDG_SEAT"               : "seat1",
                #"XDG_VTNR"               : "0",
                "XDG_SESSION_TYPE": "x11",
                #"XDG_SESSION_CLASS"      : "user",
                "XDG_SESSION_DESKTOP": "xpra",
            }
            #maybe we should just bail out instead?
            if pam.start():
                pam.set_env(env)
                items = {}
                if display_name.startswith(":"):
                    items["XDISPLAY"] = display_name
                if xauth_data:
                    items["XAUTHDATA"] = xauth_data
                pam.set_items(items)
                if pam.open():
                    #we can't close it, because we're not going to be root any more,
                    #but since we're the process leader for the session,
                    #terminating will also close the session
                    #add_cleanup(pam.close)
                    protected_env = pam.get_envlist()
                    os.environ.update(protected_env)
        #closing the pam fd causes the session to be closed,
        #and we don't want that!
        protected_fds += fdc.get_new_fds()

    #get XDG_RUNTIME_DIR from env options,
    #which may not be have updated os.environ yet when running as root with "--uid="
    xrd = os.path.abspath(parse_env(opts.env).get("XDG_RUNTIME_DIR", ""))
    if ROOT and (uid > 0 or gid > 0):
        #we're going to chown the directory if we create it,
        #ensure this cannot be abused, only use "safe" paths:
        if not any(x for x in ("/run/user/%i" % uid, "/tmp", "/var/tmp")
                   if xrd.startswith(x)):
            xrd = ""
        #these paths could cause problems if we were to create and chown them:
        if xrd.startswith("/tmp/.X11-unix") or xrd.startswith(
                "/tmp/.XIM-unix"):
            xrd = ""
    if not xrd:
        xrd = os.environ.get("XDG_RUNTIME_DIR")
    xrd = create_runtime_dir(xrd, uid, gid)
    if xrd:
        #this may override the value we get from pam
        #with the value supplied by the user:
        protected_env["XDG_RUNTIME_DIR"] = xrd

    if opts.pidfile:
        write_pidfile(opts.pidfile, uid, gid)

    if POSIX and not ROOT:
        # Write out a shell-script so that we can start our proxy in a clean
        # environment:
        write_runner_shell_scripts(script)

    if start_vfb or opts.daemon:
        #we will probably need a log dir
        #either for the vfb, or for our own log file
        log_dir = opts.log_dir or ""
        if not log_dir or log_dir.lower() == "auto":
            log_dir = find_log_dir(username, uid=uid, gid=gid)
            if not log_dir:
                raise InitException(
                    "cannot find or create a logging directory")
        #expose the log-dir as "XPRA_LOG_DIR",
        #this is used by Xdummy for the Xorg log file
        if "XPRA_LOG_DIR" not in os.environ:
            os.environ["XPRA_LOG_DIR"] = log_dir

        if opts.daemon:
            from xpra.server.server_util import select_log_file, open_log_file, redirect_std_to_log
            log_filename0 = select_log_file(log_dir, opts.log_file,
                                            display_name)
            logfd = open_log_file(log_filename0)
            if ROOT and (uid > 0 or gid > 0):
                try:
                    os.fchown(logfd, uid, gid)
                except:
                    pass
            stdout, stderr = redirect_std_to_log(logfd, *protected_fds)
            try:
                stderr.write("Entering daemon mode; " +
                             "any further errors will be reported to:\n" +
                             ("  %s\n" % log_filename0))
            except:
                #we tried our best, logging another error won't help
                pass

    #warn early about this:
    if (starting or starting_desktop) and desktop_display:
        print_DE_warnings(desktop_display, opts.pulseaudio, opts.notifications,
                          opts.dbus_launch)

    log = get_util_logger()
    netlog = get_network_logger()

    mdns_recs = {}
    sockets = []

    #SSL sockets:
    wrap_socket_fn = None
    need_ssl = False
    ssl_opt = opts.ssl.lower()
    if ssl_opt in TRUE_OPTIONS or bind_ssl or bind_wss:
        need_ssl = True
    if opts.bind_tcp or opts.bind_ws:
        if ssl_opt == "auto" and opts.ssl_cert:
            need_ssl = True
        elif ssl_opt == "tcp" and opts.bind_tcp:
            need_ssl = True
        elif ssl_opt == "www":
            need_ssl = True
    if need_ssl:
        from xpra.scripts.main import ssl_wrap_socket_fn
        try:
            wrap_socket_fn = ssl_wrap_socket_fn(opts, server_side=True)
            netlog("wrap_socket_fn=%s", wrap_socket_fn)
        except Exception as e:
            netlog("SSL error", exc_info=True)
            cpaths = csv("'%s'" % x for x in (opts.ssl_cert, opts.ssl_key)
                         if x)
            raise InitException(
                "cannot create SSL socket, check your certificate paths (%s): %s"
                % (cpaths, e))

    from xpra.server.socket_util import setup_tcp_socket, setup_udp_socket, setup_vsock_socket, setup_local_sockets, has_dual_stack
    min_port = int(opts.min_port)

    def hosts(host_str):
        if host_str == "*":
            if has_dual_stack():
                #IPv6 will also listen for IPv4:
                return ["::"]
            #no dual stack, so we have to listen on both IPv4 and IPv6 explicitly:
            return ["0.0.0.0", "::"]
        return [host_str]

    def add_mdns(socktype, host_str, port):
        recs = mdns_recs.setdefault(socktype.lower(), [])
        for host in hosts(host_str):
            rec = (host, port)
            if rec not in recs:
                recs.append(rec)

    def add_tcp_socket(socktype, host_str, iport):
        if iport < min_port:
            error_cb("invalid %s port number %i (minimum value is %i)" %
                     (socktype, iport, min_port))
        for host in hosts(host_str):
            socket = setup_tcp_socket(host, iport, socktype)
            sockets.append(socket)
            add_mdns(socktype, host, iport)

    def add_udp_socket(socktype, host_str, iport):
        if iport < min_port:
            error_cb("invalid %s port number %i (minimum value is %i)" %
                     (socktype, iport, min_port))
        for host in hosts(host_str):
            socket = setup_udp_socket(host, iport, socktype)
            sockets.append(socket)
            add_mdns(socktype, host, iport)

    # Initialize the TCP sockets before the display,
    # That way, errors won't make us kill the Xvfb
    # (which may not be ours to kill at that point)
    netlog("setting up SSL sockets: %s", csv(bind_ssl))
    for host, iport in bind_ssl:
        add_tcp_socket("ssl", host, iport)
    netlog("setting up https / wss (secure websockets): %s", csv(bind_wss))
    for host, iport in bind_wss:
        add_tcp_socket("wss", host, iport)
    tcp_ssl = ssl_opt in TRUE_OPTIONS or (ssl_opt == "auto" and opts.ssl_cert)
    netlog("setting up TCP sockets: %s", csv(bind_tcp))
    for host, iport in bind_tcp:
        add_tcp_socket("tcp", host, iport)
        if tcp_ssl:
            add_mdns("ssl", host, iport)
    netlog("setting up UDP sockets: %s", csv(bind_udp))
    for host, iport in bind_udp:
        add_udp_socket("udp", host, iport)
    netlog("setting up http / ws (websockets): %s", csv(bind_ws))
    for host, iport in bind_ws:
        add_tcp_socket("ws", host, iport)
        if tcp_ssl:
            add_mdns("wss", host, iport)
    if bind_rfb and (proxying or starting):
        log.warn("Warning: bind-rfb sockets cannot be used with '%s' mode" %
                 mode)
    else:
        netlog("setting up rfb sockets: %s", csv(bind_rfb))
        for host, iport in bind_rfb:
            add_tcp_socket("rfb", host, iport)
    netlog("setting up vsock sockets: %s", csv(bind_vsock))
    for cid, iport in bind_vsock:
        socket = setup_vsock_socket(cid, iport)
        sockets.append(socket)
        #add_mdns("vsock", str(cid), iport)

    # systemd socket activation:
    try:
        from xpra.platform.xposix.sd_listen import get_sd_listen_sockets
    except ImportError:
        pass
    else:
        sd_sockets = get_sd_listen_sockets()
        netlog("systemd sockets: %s", sd_sockets)
        for stype, socket, addr in sd_sockets:
            sockets.append((stype, socket, addr))
            netlog("%s : %s", (stype, [addr]), socket)
            if stype == "tcp":
                host, iport = addr
                add_mdns("tcp", host, iport)

    sanitize_env()
    if POSIX:
        if xrd:
            os.environ["XDG_RUNTIME_DIR"] = xrd
        os.environ["XDG_SESSION_TYPE"] = "x11"
        if not starting_desktop:
            os.environ["XDG_CURRENT_DESKTOP"] = opts.wm_name
        configure_imsettings_env(opts.input_method)
    if display_name[0] != 'S':
        os.environ["DISPLAY"] = display_name
        os.environ["CKCON_X11_DISPLAY"] = display_name
    else:
        try:
            del os.environ["DISPLAY"]
        except:
            pass
    os.environ.update(protected_env)
    log("env=%s", os.environ)

    UINPUT_UUID_LEN = 12
    UINPUT_UUID_MIN_LEN = 12
    UINPUT_UUID_MAX_LEN = 32
    # Start the Xvfb server first to get the display_name if needed
    odisplay_name = display_name
    xvfb = None
    xvfb_pid = None
    uinput_uuid = None
    if start_vfb:
        assert not proxying and xauth_data
        pixel_depth = validate_pixel_depth(opts.pixel_depth)
        from xpra.x11.vfb_util import start_Xvfb, check_xvfb_process
        from xpra.server.server_util import has_uinput
        uinput_uuid = None
        if has_uinput() and opts.input_devices.lower() in (
                "uinput", "auto") and not shadowing:
            from xpra.os_util import get_rand_chars
            uinput_uuid = get_rand_chars(UINPUT_UUID_LEN)
        xvfb, display_name, cleanups = start_Xvfb(opts.xvfb, pixel_depth,
                                                  display_name, cwd, uid, gid,
                                                  username, xauth_data,
                                                  uinput_uuid)
        for f in cleanups:
            add_cleanup(f)
        xvfb_pid = xvfb.pid
        #always update as we may now have the "real" display name:
        os.environ["DISPLAY"] = display_name
        os.environ["CKCON_X11_DISPLAY"] = display_name
        os.environ.update(protected_env)
        if display_name != odisplay_name and pam:
            pam.set_items({"XDISPLAY": display_name})

        def check_xvfb():
            return check_xvfb_process(xvfb)
    else:

        def check_xvfb():
            return True

    if POSIX and not OSX and displayfd > 0:
        from xpra.platform.displayfd import write_displayfd
        try:
            display = display_name[1:]
            log("writing display='%s' to displayfd=%i", display, displayfd)
            assert write_displayfd(displayfd, display), "timeout"
        except Exception as e:
            log.error("write_displayfd failed", exc_info=True)
            log.error("Error: failed to write '%s' to fd=%s", display_name,
                      displayfd)
            log.error(" %s", str(e) or type(e))
            del e
        try:
            os.close(displayfd)
        except:
            pass

    if not proxying:

        def close_display():
            close_gtk_display()
            kill_xvfb(xvfb_pid)

        add_cleanup(close_display)
    else:
        close_display = None

    if opts.daemon:

        def noerr(fn, *args):
            try:
                fn(*args)
            except:
                pass

        log_filename1 = select_log_file(log_dir, opts.log_file, display_name)
        if log_filename0 != log_filename1:
            # we now have the correct log filename, so use it:
            os.rename(log_filename0, log_filename1)
            if odisplay_name != display_name:
                #this may be used by scripts, let's try not to change it:
                noerr(stderr.write, "Actual display used: %s\n" % display_name)
            noerr(stderr.write,
                  "Actual log file name is now: %s\n" % log_filename1)
            noerr(stderr.flush)
        noerr(stdout.close)
        noerr(stderr.close)
    #we should not be using stdout or stderr from this point:
    del stdout
    del stderr

    if not check_xvfb():
        #xvfb problem: exit now
        return 1

    #create devices for vfb if needed:
    devices = {}
    if not start_vfb and not proxying and not shadowing:
        #try to find the existing uinput uuid:
        #use a subprocess to avoid polluting our current process
        #with X11 connections before we get a chance to change uid
        cmd = ["xprop", "-display", display_name, "-root", "_XPRA_UINPUT_ID"]
        try:
            code, out, err = get_status_output(cmd)
        except Exception as e:
            log("failed to get existing uinput id: %s", e)
            del e
        else:
            log("Popen(%s)=%s", cmd, (code, out, err))
            if code == 0 and out.find("=") > 0:
                uinput_uuid = out.split("=", 1)[1]
                log("raw uinput uuid=%s", uinput_uuid)
                uinput_uuid = strtobytes(uinput_uuid.strip('\n\r"\\ '))
                if uinput_uuid:
                    if len(uinput_uuid) > UINPUT_UUID_MAX_LEN or len(
                            uinput_uuid) < UINPUT_UUID_MIN_LEN:
                        log.warn("Warning: ignoring invalid uinput id:")
                        log.warn(" '%s'", uinput_uuid)
                        uinput_uuid = None
                    else:
                        log.info("retrieved existing uinput id: %s",
                                 bytestostr(uinput_uuid))
    if uinput_uuid:
        devices = create_input_devices(uinput_uuid, uid)

    if ROOT and (uid != 0 or gid != 0):
        log("root: switching to uid=%i, gid=%i", uid, gid)
        setuidgid(uid, gid)
        os.environ.update({
            "HOME": home,
            "USER": username,
            "LOGNAME": username,
        })
        shell = get_shell_for_uid(uid)
        if shell:
            os.environ["SHELL"] = shell
        #now we've changed uid, it is safe to honour all the env updates:
        configure_env(opts.env)
        os.environ.update(protected_env)

    if opts.chdir:
        os.chdir(opts.chdir)

    display = None
    if not proxying:
        no_gtk()
        if POSIX and not OSX and (starting or starting_desktop or shadowing):
            #check that we can access the X11 display:
            from xpra.x11.vfb_util import verify_display_ready
            if not verify_display_ready(xvfb, display_name, shadowing):
                return 1
            if not PYTHON3:
                from xpra.x11.gtk2.gdk_display_util import verify_gdk_display  #@UnusedImport
            else:
                from xpra.x11.gtk3.gdk_display_util import verify_gdk_display  #@Reimport
            display = verify_gdk_display(display_name)
            if not display:
                return 1
        #on win32, this ensures that we get the correct screen size to shadow:
        from xpra.platform.gui import init as gui_init
        gui_init()

    #setup unix domain socket:
    if not opts.socket_dir and not opts.socket_dirs:
        #we always need at least one valid socket dir
        from xpra.platform.paths import get_socket_dirs
        opts.socket_dirs = get_socket_dirs()
    local_sockets = setup_local_sockets(opts.bind, opts.socket_dir,
                                        opts.socket_dirs, display_name,
                                        clobber, opts.mmap_group,
                                        opts.socket_permissions, username, uid,
                                        gid)
    netlog("setting up local sockets: %s", local_sockets)
    for rec, cleanup_socket in local_sockets:
        socktype, socket, sockpath = rec
        #ie: ("unix-domain", sock, sockpath), cleanup_socket
        sockets.append(rec)
        netlog("%s %s : %s", socktype, sockpath, socket)
        add_cleanup(cleanup_socket)
        if opts.mdns:
            ssh_port = get_ssh_port()
            netlog("ssh %s:%s : %s", "", ssh_port, socket)
            if ssh_port:
                add_mdns("ssh", "", ssh_port)

    kill_dbus = None
    if shadowing:
        from xpra.platform.shadow_server import ShadowServer
        app = ShadowServer()
    elif proxying:
        from xpra.server.proxy.proxy_server import ProxyServer
        app = ProxyServer()
    else:
        if not check_xvfb():
            return 1
        assert starting or starting_desktop or upgrading
        from xpra.x11.gtk2.gdk_display_source import init_gdk_display_source
        init_gdk_display_source()
        #(now we can access the X11 server)

        #make sure the pid we save is the real one:
        if not check_xvfb():
            return 1
        if xvfb_pid is not None:
            #save the new pid (we should have one):
            save_xvfb_pid(xvfb_pid)

        if POSIX:
            save_uinput_id(uinput_uuid or "")
            dbus_pid = -1
            dbus_env = {}
            if clobber:
                #get the saved pids and env
                dbus_pid = get_dbus_pid()
                dbus_env = get_dbus_env()
                log("retrieved existing dbus attributes")
            else:
                assert starting or starting_desktop
                if xvfb_pid is not None:
                    #save the new pid (we should have one):
                    save_xvfb_pid(xvfb_pid)
                bus_address = protected_env.get("DBUS_SESSION_BUS_ADDRESS")
                log("dbus_launch=%s, current DBUS_SESSION_BUS_ADDRESS=%s",
                    opts.dbus_launch, bus_address)
                if opts.dbus_launch and not bus_address:
                    #start a dbus server:
                    def kill_dbus():
                        log("kill_dbus: dbus_pid=%s" % dbus_pid)
                        if dbus_pid <= 0:
                            return
                        try:
                            os.kill(dbus_pid, signal.SIGINT)
                        except Exception as e:
                            log.warn(
                                "Warning: error trying to stop dbus with pid %i:",
                                dbus_pid)
                            log.warn(" %s", e)

                    add_cleanup(kill_dbus)
                    #this also updates os.environ with the dbus attributes:
                    dbus_pid, dbus_env = start_dbus(opts.dbus_launch)
                    if dbus_pid > 0:
                        save_dbus_pid(dbus_pid)
                    if dbus_env:
                        save_dbus_env(dbus_env)
            log("dbus attributes: pid=%s, env=%s", dbus_pid, dbus_env)
            if dbus_env:
                os.environ.update(dbus_env)
                os.environ.update(protected_env)

        log("env=%s", os.environ)
        try:
            # This import is delayed because the module depends on gtk:
            from xpra.x11.bindings.window_bindings import X11WindowBindings
            X11Window = X11WindowBindings()
            if (starting or
                    starting_desktop) and not clobber and opts.resize_display:
                from xpra.x11.vfb_util import set_initial_resolution
                set_initial_resolution(starting_desktop)
        except ImportError as e:
            log.error(
                "Failed to load Xpra server components, check your installation: %s"
                % e)
            return 1
        if starting or upgrading:
            if not X11Window.displayHasXComposite():
                log.error(
                    "Xpra 'start' subcommand runs as a compositing manager")
                log.error(
                    " it cannot use a display which lacks the XComposite extension!"
                )
                return 1
            if starting:
                #check for an existing window manager:
                from xpra.x11.gtk2.wm import wm_check
                if not wm_check(display, opts.wm_name, upgrading):
                    return 1
            log("XShape=%s", X11Window.displayHasXShape())
            from xpra.x11.server import XpraServer
            app = XpraServer(clobber)
        else:
            assert starting_desktop
            from xpra.x11.desktop_server import XpraDesktopServer
            app = XpraDesktopServer()
        app.init_virtual_devices(devices)

    #publish mdns records:
    if opts.mdns:
        from xpra.platform.info import get_username
        from xpra.server.socket_util import mdns_publish
        mdns_info = {
            "display": display_name,
            "username": get_username(),
            "uuid": strtobytes(app.uuid),
            "platform": sys.platform,
            "type": app.session_type,
        }
        if opts.session_name:
            mdns_info["session"] = opts.session_name
        for mode, listen_on in mdns_recs.items():
            mdns_publish(display_name, mode, listen_on, mdns_info)

    try:
        app._ssl_wrap_socket = wrap_socket_fn
        app.original_desktop_display = desktop_display
        app.exec_cwd = opts.chdir or cwd
        app.init(opts)
        app.init_components(opts)
    except InitException as e:
        log.error("xpra server initialization error:")
        log.error(" %s", e)
        return 1
    except Exception as e:
        log.error("Error: cannot start the %s server",
                  app.session_type,
                  exc_info=True)
        log.error(str(e))
        log.info("")
        return 1

    #honour start child, html webserver, and setup child reaper
    if not proxying and not upgrading:
        if opts.exit_with_children:
            assert opts.start_child, "exit-with-children was specified but start-child is missing!"
        app.start_commands = opts.start
        app.start_child_commands = opts.start_child
        app.start_after_connect = opts.start_after_connect
        app.start_child_after_connect = opts.start_child_after_connect
        app.start_on_connect = opts.start_on_connect
        app.start_child_on_connect = opts.start_child_on_connect
        app.exec_start_commands()
    del opts

    log("%s(%s)", app.init_sockets, sockets)
    app.init_sockets(sockets)
    log("%s(%s)", app.init_when_ready, _when_ready)
    app.init_when_ready(_when_ready)

    try:
        #from here on, we own the vfb, even if we inherited one:
        if (starting or starting_desktop or upgrading) and clobber:
            #and it will be killed if exit cleanly:
            xvfb_pid = get_xvfb_pid()

        log("running %s", app.run)
        r = app.run()
        log("%s()=%s", app.run, r)
    except KeyboardInterrupt:
        log.info("stopping on KeyboardInterrupt")
        r = 0
    except Exception:
        log.error("server error", exc_info=True)
        r = -128
    if r > 0:
        # Upgrading/exiting, so leave X and dbus servers running
        if close_display:
            _cleanups.remove(close_display)
        if kill_dbus:
            _cleanups.remove(kill_dbus)
        from xpra.server.server_core import ServerCore
        if r == ServerCore.EXITING_CODE:
            log.info("exiting: not cleaning up Xvfb")
        else:
            log.info("upgrading: not cleaning up Xvfb")
        log("cleanups=%s", _cleanups)
        r = 0
    return r
示例#3
0
def run_server(error_cb,
               opts,
               mode,
               xpra_file,
               extra_args,
               desktop_display=None):
    try:
        cwd = os.getcwd()
    except:
        cwd = os.path.expanduser("~")
        warn("current working directory does not exist, using '%s'\n" % cwd)
    validate_encryption(opts)
    if opts.encoding == "help" or "help" in opts.encodings:
        return show_encoding_help(opts)

    from xpra.server.socket_util import parse_bind_tcp, parse_bind_vsock
    bind_tcp = parse_bind_tcp(opts.bind_tcp)
    bind_ssl = parse_bind_tcp(opts.bind_ssl)
    bind_vsock = parse_bind_vsock(opts.bind_vsock)

    assert mode in ("start", "start-desktop", "upgrade", "shadow", "proxy")
    starting = mode == "start"
    starting_desktop = mode == "start-desktop"
    upgrading = mode == "upgrade"
    shadowing = mode == "shadow"
    proxying = mode == "proxy"
    clobber = upgrading or opts.use_display
    start_vfb = not shadowing and not proxying and not clobber

    if upgrading or shadowing:
        #there should already be one running
        opts.pulseaudio = False

    #get the display name:
    if shadowing and len(extra_args) == 0:
        if WIN32 or OSX:
            #just a virtual name for the only display available:
            display_name = ":0"
        else:
            from xpra.scripts.main import guess_X11_display
            dotxpra = DotXpra(opts.socket_dir, opts.socket_dirs)
            display_name = guess_X11_display(dotxpra)
    elif upgrading and len(extra_args) == 0:
        display_name = guess_xpra_display(opts.socket_dir, opts.socket_dirs)
    else:
        if len(extra_args) > 1:
            error_cb(
                "too many extra arguments (%i): only expected a display number"
                % len(extra_args))
        if len(extra_args) == 1:
            display_name = extra_args[0]
            if not shadowing and not proxying and not opts.use_display:
                display_name_check(display_name)
        else:
            if proxying:
                #find a free display number:
                dotxpra = DotXpra(opts.socket_dir, opts.socket_dirs)
                all_displays = dotxpra.sockets()
                #ie: [("LIVE", ":100"), ("LIVE", ":200"), ...]
                displays = [v[1] for v in all_displays]
                display_name = None
                for x in range(1000, 20000):
                    v = ":%s" % x
                    if v not in displays:
                        display_name = v
                        break
                if not display_name:
                    error_cb(
                        "you must specify a free virtual display name to use with the proxy server"
                    )
            elif opts.use_display:
                #only use automatic guess for xpra displays and not X11 displays:
                display_name = guess_xpra_display(opts.socket_dir,
                                                  opts.socket_dirs)
            else:
                # We will try to find one automaticaly
                # Use the temporary magic value 'S' as marker:
                display_name = 'S' + str(os.getpid())

    if not shadowing and not proxying and not upgrading and opts.exit_with_children and not opts.start_child:
        error_cb(
            "--exit-with-children specified without any children to spawn; exiting immediately"
        )

    atexit.register(run_cleanups)

    # Generate the script text now, because os.getcwd() will
    # change if/when we daemonize:
    from xpra.server.server_util import xpra_runner_shell_script, write_runner_shell_scripts, write_pidfile, find_log_dir
    script = xpra_runner_shell_script(xpra_file, cwd, opts.socket_dir)

    uid = int(opts.uid)
    gid = int(opts.gid)
    username = get_username_for_uid(uid)
    home = get_home_for_uid(uid)
    xauth_data = None
    if start_vfb:
        xauth_data = get_hex_uuid()
    ROOT = POSIX and getuid() == 0

    stdout = sys.stdout
    stderr = sys.stderr
    # Daemonize:
    if POSIX and opts.daemon:
        #daemonize will chdir to "/", so try to use an absolute path:
        if opts.password_file:
            opts.password_file = os.path.abspath(opts.password_file)
        from xpra.server.server_util import daemonize
        daemonize()

    # if pam is present, try to create a new session:
    pam = None
    protected_fds = []
    protected_env = {}
    PAM_OPEN = POSIX and envbool("XPRA_PAM_OPEN", ROOT and uid != 0)
    if PAM_OPEN:
        try:
            from xpra.server.pam import pam_session  #@UnresolvedImport
        except ImportError as e:
            stderr.write("Error: failed to import pam module\n")
            stderr.write(" %s" % e)
            PAM_OPEN = False
    if PAM_OPEN:
        fdc = FDChangeCaptureContext()
        with fdc:
            pam = pam_session(username)
            env = {
                #"XDG_SEAT"               : "seat1",
                #"XDG_VTNR"               : "0",
                "XDG_SESSION_TYPE": "x11",
                #"XDG_SESSION_CLASS"      : "user",
                "XDG_SESSION_DESKTOP": "xpra",
            }
            #maybe we should just bail out instead?
            if pam.start():
                pam.set_env(env)
                items = {}
                if display_name.startswith(":"):
                    items["XDISPLAY"] = display_name
                if xauth_data:
                    items["XAUTHDATA"] = xauth_data
                pam.set_items(items)
                if pam.open():
                    #we can't close it, because we're not going to be root any more,
                    #but since we're the process leader for the session,
                    #terminating will also close the session
                    #add_cleanup(pam.close)
                    protected_env = pam.get_envlist()
                    os.environ.update(protected_env)
        #closing the pam fd causes the session to be closed,
        #and we don't want that!
        protected_fds = fdc.get_new_fds()

    xrd = create_runtime_dir(uid, gid)

    if opts.pidfile:
        write_pidfile(opts.pidfile, uid, gid)

    if POSIX and not ROOT:
        # Write out a shell-script so that we can start our proxy in a clean
        # environment:
        write_runner_shell_scripts(script)

    if start_vfb or opts.daemon:
        #we will probably need a log dir
        #either for the vfb, or for our own log file
        log_dir = opts.log_dir or ""
        if not log_dir or log_dir.lower() == "auto":
            log_dir = find_log_dir(username, uid=uid, gid=gid)
            if not log_dir:
                raise InitException(
                    "cannot find or create a logging directory")
        #expose the log-dir as "XPRA_LOG_DIR",
        #this is used by Xdummy for the Xorg log file
        if "XPRA_LOG_DIR" not in os.environ:
            os.environ["XPRA_LOG_DIR"] = log_dir

        if opts.daemon:
            from xpra.server.server_util import select_log_file, open_log_file, redirect_std_to_log
            log_filename0 = select_log_file(log_dir, opts.log_file,
                                            display_name)
            logfd = open_log_file(log_filename0)
            if ROOT and (uid > 0 or gid > 0):
                try:
                    os.fchown(logfd, uid, gid)
                except:
                    pass
            stdout, stderr = redirect_std_to_log(logfd, *protected_fds)
            stderr.write("Entering daemon mode; " +
                         "any further errors will be reported to:\n" +
                         ("  %s\n" % log_filename0))

    #warn early about this:
    if (starting or starting_desktop) and desktop_display:
        print_DE_warnings(desktop_display, opts.pulseaudio, opts.notifications,
                          opts.dbus_launch)

    from xpra.log import Logger
    log = Logger("server")
    netlog = Logger("network")

    mdns_recs = []
    sockets = []

    #SSL sockets:
    wrap_socket_fn = None
    need_ssl = False
    ssl_opt = opts.ssl.lower()
    if ssl_opt in TRUE_OPTIONS or bind_ssl:
        need_ssl = True
    if opts.bind_tcp:
        if ssl_opt == "auto" and opts.ssl_cert:
            need_ssl = True
        elif ssl_opt == "tcp":
            need_ssl = True
        elif ssl_opt == "www":
            need_ssl = True
    if need_ssl:
        from xpra.scripts.main import ssl_wrap_socket_fn
        try:
            wrap_socket_fn = ssl_wrap_socket_fn(opts, server_side=True)
            netlog("wrap_socket_fn=%s", wrap_socket_fn)
        except Exception as e:
            netlog("SSL error", exc_info=True)
            cpaths = csv("'%s'" % x for x in (opts.ssl_cert, opts.ssl_key)
                         if x)
            raise InitException(
                "cannot create SSL socket, check your certificate paths (%s): %s"
                % (cpaths, e))

    from xpra.server.socket_util import setup_tcp_socket, setup_vsock_socket, setup_local_sockets
    min_port = int(opts.min_port)
    netlog("setting up SSL sockets: %s", bind_ssl)
    for host, iport in bind_ssl:
        if iport < min_port:
            error_cb("invalid %s port number %i (minimum value is %i)" %
                     (socktype, iport, min_port))
        _, tcp_socket, host_port = setup_tcp_socket(host, iport, "SSL")
        socket = ("SSL", wrap_socket_fn(tcp_socket), host_port)
        sockets.append(socket)
        rec = "ssl", [(host, iport)]
        netlog("%s : %s", rec, socket)
        mdns_recs.append(rec)

    # Initialize the TCP sockets before the display,
    # That way, errors won't make us kill the Xvfb
    # (which may not be ours to kill at that point)
    tcp_ssl = ssl_opt in TRUE_OPTIONS or (ssl_opt == "auto" and opts.ssl_cert)

    def add_tcp_mdns_rec(host, iport):
        rec = "tcp", [(host, iport)]
        netlog("%s : %s", rec, socket)
        mdns_recs.append(rec)
        if tcp_ssl:
            #SSL is also available on this TCP socket:
            rec = "ssl", [(host, iport)]
            netlog("%s : %s", rec, socket)
            mdns_recs.append(rec)

    netlog("setting up TCP sockets: %s", bind_tcp)
    for host, iport in bind_tcp:
        if iport < min_port:
            error_cb("invalid %s port number %i (minimum value is %i)" %
                     (socktype, iport, min_port))
        socket = setup_tcp_socket(host, iport)
        sockets.append(socket)
        add_tcp_mdns_rec(host, iport)

    # VSOCK:
    netlog("setting up vsock sockets: %s", bind_vsock)
    for cid, iport in bind_vsock:
        socket = setup_vsock_socket(cid, iport)
        sockets.append(socket)
        rec = "vsock", [("", iport)]
        netlog("%s : %s", rec, socket)
        mdns_recs.append(rec)

    # systemd socket activation:
    try:
        from xpra.server.sd_listen import get_sd_listen_sockets
    except ImportError:
        pass
    else:
        sd_sockets = get_sd_listen_sockets()
        netlog("systemd sockets: %s", sd_sockets)
        for stype, socket, addr in sd_sockets:
            sockets.append((stype, socket, addr))
            netlog("%s : %s", (stype, [addr]), socket)
            if stype == "tcp":
                host, iport = addr
                add_tcp_mdns_rec(host, iport)

    sanitize_env()
    if POSIX:
        if xrd:
            os.environ["XDG_RUNTIME_DIR"] = xrd
        os.environ["XDG_SESSION_TYPE"] = "x11"
        if not starting_desktop:
            os.environ["XDG_CURRENT_DESKTOP"] = opts.wm_name
        configure_imsettings_env(opts.input_method)
    if display_name[0] != 'S':
        os.environ["DISPLAY"] = display_name
        os.environ["CKCON_X11_DISPLAY"] = display_name
    else:
        try:
            del os.environ["DISPLAY"]
        except:
            pass
    os.environ.update(protected_env)
    log("env=%s", os.environ)

    # Start the Xvfb server first to get the display_name if needed
    from xpra.server.vfb_util import start_Xvfb, check_xvfb_process, verify_display_ready, verify_gdk_display, set_initial_resolution
    odisplay_name = display_name
    xvfb = None
    xvfb_pid = None
    if start_vfb:
        assert not proxying and xauth_data
        pixel_depth = validate_pixel_depth(opts.pixel_depth)
        xvfb, display_name = start_Xvfb(opts.xvfb, pixel_depth, display_name,
                                        cwd, uid, gid, xauth_data)
        xvfb_pid = xvfb.pid
        #always update as we may now have the "real" display name:
        os.environ["DISPLAY"] = display_name
        os.environ["CKCON_X11_DISPLAY"] = display_name
        os.environ.update(protected_env)
        if display_name != odisplay_name and pam:
            pam.set_items({"XDISPLAY": display_name})

    close_display = None
    if not proxying:

        def close_display():
            # Close our display(s) first, so the server dying won't kill us.
            # (if gtk has been loaded)
            gtk_mod = sys.modules.get("gtk")
            if gtk_mod:
                for d in gtk_mod.gdk.display_manager_get().list_displays():
                    d.close()
            if xvfb_pid:
                log.info("killing xvfb with pid %s", xvfb_pid)
                try:
                    os.kill(xvfb_pid, signal.SIGTERM)
                except OSError as e:
                    log.info("failed to kill xvfb process with pid %s:",
                             xvfb_pid)
                    log.info(" %s", e)

        add_cleanup(close_display)

    if opts.daemon:

        def noerr(fn, *args):
            try:
                fn(*args)
            except:
                pass

        log_filename1 = select_log_file(log_dir, opts.log_file, display_name)
        if log_filename0 != log_filename1:
            # we now have the correct log filename, so use it:
            os.rename(log_filename0, log_filename1)
            if odisplay_name != display_name:
                #this may be used by scripts, let's try not to change it:
                noerr(stderr.write, "Actual display used: %s\n" % display_name)
            noerr(stderr.write,
                  "Actual log file name is now: %s\n" % log_filename1)
            noerr(stderr.flush)
        noerr(stdout.close)
        noerr(stderr.close)
    #we should not be using stdout or stderr from this point:
    del stdout
    del stderr

    if not check_xvfb_process(xvfb):
        #xvfb problem: exit now
        return 1

    if ROOT and (uid != 0 or gid != 0):
        log("root: switching to uid=%i, gid=%i", uid, gid)
        setuidgid(uid, gid)
        os.environ.update({
            "HOME": home,
            "USER": username,
            "LOGNAME": username,
        })
        shell = get_shell_for_uid(uid)
        if shell:
            os.environ["SHELL"] = shell
        os.environ.update(protected_env)

    if opts.chdir:
        os.chdir(opts.chdir)

    display = None
    if not proxying:
        no_gtk()
        if POSIX and (starting or starting_desktop or shadowing):
            #check that we can access the X11 display:
            if not verify_display_ready(xvfb, display_name, shadowing):
                return 1
            display = verify_gdk_display(display_name)
            if not display:
                return 1
            import gtk  #@Reimport
            assert gtk
        #on win32, this ensures that we get the correct screen size to shadow:
        from xpra.platform.gui import init as gui_init
        gui_init()

    #setup unix domain socket:
    if not opts.socket_dir and not opts.socket_dirs:
        #we always need at least one valid socket dir
        from xpra.platform.paths import get_socket_dirs
        opts.socket_dirs = get_socket_dirs()
    local_sockets = setup_local_sockets(opts.bind, opts.socket_dir,
                                        opts.socket_dirs, display_name,
                                        clobber, opts.mmap_group,
                                        opts.socket_permissions, username, uid,
                                        gid)
    netlog("setting up local sockets: %s", local_sockets)
    for rec, cleanup_socket in local_sockets:
        socktype, socket, sockpath = rec
        #ie: ("unix-domain", sock, sockpath), cleanup_socket
        sockets.append(rec)
        netlog("%s : %s", (socktype, [sockpath]), socket)
        add_cleanup(cleanup_socket)
        if opts.mdns:
            ssh_port = get_ssh_port()
            rec = "ssh", [("", ssh_port)]
            netlog("%s : %s", rec, socket)
            if ssh_port and rec not in mdns_recs:
                mdns_recs.append(rec)

    kill_dbus = None
    if shadowing:
        from xpra.platform.shadow_server import ShadowServer
        app = ShadowServer()
        server_type_info = "shadow"
    elif proxying:
        from xpra.server.proxy.proxy_server import ProxyServer
        app = ProxyServer()
        server_type_info = "proxy"
    else:
        assert starting or starting_desktop or upgrading
        from xpra.x11.gtk2.gdk_display_source import init_gdk_display_source
        init_gdk_display_source()
        #(now we can access the X11 server)

        if xvfb_pid is not None:
            #save the new pid (we should have one):
            save_xvfb_pid(xvfb_pid)

        if POSIX:
            dbus_pid = -1
            dbus_env = {}
            if clobber:
                #get the saved pids and env
                dbus_pid = get_dbus_pid()
                dbus_env = get_dbus_env()
                log("retrieved existing dbus attributes")
            else:
                assert starting or starting_desktop
                if xvfb_pid is not None:
                    #save the new pid (we should have one):
                    save_xvfb_pid(xvfb_pid)
                bus_address = protected_env.get("DBUS_SESSION_BUS_ADDRESS")
                log("dbus_launch=%s, current DBUS_SESSION_BUS_ADDRESS=%s",
                    opts.dbus_launch, bus_address)
                if opts.dbus_launch and not bus_address:
                    #start a dbus server:
                    def kill_dbus():
                        log("kill_dbus: dbus_pid=%s" % dbus_pid)
                        if dbus_pid <= 0:
                            return
                        try:
                            os.kill(dbus_pid, signal.SIGINT)
                        except Exception as e:
                            log.warn(
                                "Warning: error trying to stop dbus with pid %i:",
                                dbus_pid)
                            log.warn(" %s", e)

                    add_cleanup(kill_dbus)
                    #this also updates os.environ with the dbus attributes:
                    dbus_pid, dbus_env = start_dbus(opts.dbus_launch)
                    if dbus_pid > 0:
                        save_dbus_pid(dbus_pid)
                    if dbus_env:
                        save_dbus_env(dbus_env)
            log("dbus attributes: pid=%s, env=%s", dbus_pid, dbus_env)
            if dbus_env:
                os.environ.update(dbus_env)
                os.environ.update(protected_env)

        log("env=%s", os.environ)
        try:
            # This import is delayed because the module depends on gtk:
            from xpra.x11.bindings.window_bindings import X11WindowBindings
            X11Window = X11WindowBindings()
            if (starting or
                    starting_desktop) and not clobber and opts.resize_display:
                set_initial_resolution(starting_desktop)
        except ImportError as e:
            log.error(
                "Failed to load Xpra server components, check your installation: %s"
                % e)
            return 1
        if starting or upgrading:
            if not X11Window.displayHasXComposite():
                log.error(
                    "Xpra 'start' subcommand runs as a compositing manager")
                log.error(
                    " it cannot use a display which lacks the XComposite extension!"
                )
                return 1
            if starting:
                #check for an existing window manager:
                from xpra.x11.gtk2.wm import wm_check
                if not wm_check(display, opts.wm_name, upgrading):
                    return 1
            log("XShape=%s", X11Window.displayHasXShape())
            from xpra.x11.server import XpraServer
            app = XpraServer(clobber)
            server_type_info = "xpra"
        else:
            assert starting_desktop
            from xpra.x11.desktop_server import XpraDesktopServer
            app = XpraDesktopServer()
            server_type_info = "xpra desktop"

    #publish mdns records:
    if opts.mdns:
        from xpra.os_util import strtobytes
        from xpra.platform.info import get_username
        from xpra.server.socket_util import mdns_publish
        mdns_info = {
            "display": display_name,
            "username": get_username(),
            "uuid": strtobytes(app.uuid),
            "platform": sys.platform,
            "type": {
                "xpra": "seamless",
                "xpra desktop": "desktop"
            }.get(server_type_info, server_type_info),
        }
        if opts.session_name:
            mdns_info["session"] = opts.session_name
        for mode, listen_on in mdns_recs:
            mdns_publish(display_name, mode, listen_on, mdns_info)

    try:
        app._ssl_wrap_socket = wrap_socket_fn
        app.original_desktop_display = desktop_display
        app.exec_cwd = opts.chdir or cwd
        app.init(opts)
        app.init_components(opts)
    except InitException as e:
        log.error("xpra server initialization error:")
        log.error(" %s", e)
        return 1
    except Exception as e:
        log.error("Error: cannot start the %s server",
                  server_type_info,
                  exc_info=True)
        log.error(str(e))
        log.info("")
        return 1

    #honour start child, html webserver, and setup child reaper
    if not proxying and not upgrading:
        if opts.exit_with_children:
            assert opts.start_child, "exit-with-children was specified but start-child is missing!"
        app.start_commands = opts.start
        app.start_child_commands = opts.start_child
        app.start_after_connect = opts.start_after_connect
        app.start_child_after_connect = opts.start_child_after_connect
        app.start_on_connect = opts.start_on_connect
        app.start_child_on_connect = opts.start_child_on_connect
        app.exec_start_commands()
    del opts

    log("%s(%s)", app.init_sockets, sockets)
    app.init_sockets(sockets)
    log("%s(%s)", app.init_when_ready, _when_ready)
    app.init_when_ready(_when_ready)

    try:
        #from here on, we own the vfb, even if we inherited one:
        if (starting or starting_desktop or upgrading) and clobber:
            #and it will be killed if exit cleanly:
            xvfb_pid = get_xvfb_pid()

        log("running %s", app.run)
        e = app.run()
        log("%s()=%s", app.run, e)
    except KeyboardInterrupt:
        log.info("stopping on KeyboardInterrupt")
        e = 0
    except Exception as e:
        log.error("server error", exc_info=True)
        e = -128
    if e > 0:
        # Upgrading/exiting, so leave X and dbus servers running
        if close_display:
            _cleanups.remove(close_display)
        if kill_dbus:
            _cleanups.remove(kill_dbus)
        from xpra.server.server_core import ServerCore
        if e == ServerCore.EXITING_CODE:
            log.info("exiting: not cleaning up Xvfb")
        else:
            log.info("upgrading: not cleaning up Xvfb")
        log("cleanups=%s", _cleanups)
        e = 0
    return e