Κεφάλαιο 11 Το Σύστημα X Windows και οι Εικονικές Κονσόλες

The X Window System (commonly X11) is the most widely available windowing system capable of running on UNIX® or UNIX like systems, including FreeBSD. The X.Org Foundation administers the X protocol standards, with the current reference implementation, version 11 release 7.4, so you will often see references shortened to X11.

Many implementations are available for different architectures and operating systems. An implementation of the server-side code is properly known as an X server.

Historically, the default implementation of X on FreeBSD has been XFree86™ which is maintained by The XFree86 Project, Inc. This software was installed by default on FreeBSD versions up until 4.10 and 5.2. Although Xorg itself maintained an implementation during that time period, it was basically only provided as a reference platform, as it had suffered greatly from bitrot over the years.

However, early in 2004, some XFree86 developers left that project over issues including the pace of code changes, future directions, and interpersonal conflicts, and are now contributing code directly to Xorg instead. At that time, Xorg updated its source tree to the last XFree86 release before its subsequent licensing change (XFree86 version 4.3.99.903), incorporated many changes that had previously been maintained separately, and has released that software as X11R6.7.0. A separate but related project, freedesktop.org (or fd.o for short), is working on rearchitecting the original XFree86 code to offload more work onto the graphics cards (with the goal of increased performance) and make it more modular (with the goal of increased maintainability, and thus faster releases as well as easier configuration). Xorg intends to incorporate the freedesktop.org changes in its future releases.

As of July 2004, in FreeBSD-CURRENT, XFree86 has been replaced with Xorg as the default implementation. The XFree86 ports (x11/XFree86-4 and subports) remain in the ports collection. But Xorg is the default X11 implementation for FreeBSD 5.3 and later.

For further information, read the X11 section of the FreeBSD Handbook.

The Xorg software is written to the same X11R6 specification that XFree86 is, so basic applications should work unchanged. A few lesser-used protocols have been deprecated (XIE, PEX, and lbxproxy), but in the first two cases, the FreeBSD port of XFree86 did not support them either.

The answer to this question is outside the scope of this FAQ. Note that there are voluminous postings in various mailing list archives on the Internet; please use your favorite search engine to investigate the history instead of asking this question on the FreeBSD mailing lists. It may even be the case that only the participants will ever know for certain.

The Xorg developers claim that their goal is to release more often and incorporate new features more quickly. If they are able to do so, this will be very attractive. Also, their software still uses the traditional X license, while XFree86 is now using their modified one.

If you would like to add X to an existing installation, you should use the x11/xorg meta-port, which will build and install all the necessary components.

Then read and follow the documentation on the xorgconfig(1) tool, which assists you in configuring Xorg for your particular graphics card/mouse/etc. You may also wish to examine the xorgcfg(1) tool, which provides a graphical interface to the X configuration process.

For further information, read the X11 section of the FreeBSD Handbook.

You may also wish to investigate the Xaccel server. See the section on Xi Graphics for more details.

Your system is probably running at a raised securelevel. It is not possible to start X at a raised securelevel because X requires write access to /dev/io. For more information, see at the init(8) manual page.

So the question is what else you should do instead, and you basically have two choices: set your securelevel back down to zero (usually from /etc/rc.conf), or run xdm(1) at boot time (before the securelevel is raised).

See Ε: 11.14. for more information about running xdm(1) at boot time.

If you are using syscons (the default console driver), you can configure FreeBSD to support a mouse pointer on each virtual screen. In order to avoid conflicting with X, syscons supports a virtual device called /dev/sysmouse. All mouse events received from the real mouse device are written to the sysmouse device via moused. If you wish to use your mouse on one or more virtual consoles, and use X, see Ε: 4.4.4. and set up moused.

Then edit /etc/X11/xorg.conf and make sure you have the following lines:

Section "InputDevice"
   Option          "Protocol" "SysMouse"
   Option          "Device" "/dev/sysmouse"
.....

Some people prefer to use /dev/mouse under X. To make this work, /dev/mouse should be linked to /dev/sysmouse (see sysmouse(4)):

# cd /dev
# rm -f mouse
# ln -s sysmouse mouse

Yes.

You need to tell X that you have a 5 button mouse. To do this, simply add the lines Buttons 5 and ZAxisMapping 4 5 to the «InputDevice» section of /etc/X11/xorg.conf. For example, you might have the following «InputDevice» section in /etc/X11/xorg.conf.

Section "InputDevice"
   Identifier      "Mouse1"
   Driver          "mouse"
   Option          "Protocol" "auto"
   Option          "Device" "/dev/sysmouse"
   Option          "Buttons" "5"
   Option          "ZAxisMapping" "4 5"
EndSection

;; wheel mouse
(global-set-key [mouse-4] 'scroll-down)
(global-set-key [mouse-5] 'scroll-up)

For security reasons, the default setting is to not allow a machine to remotely open a window.

To enable this feature, simply start X with the optional -listen_tcp argument:

% startx -listen_tcp
       

Try turning off the Num Lock key.

If your Num Lock key is on by default at boot-time, you may add the following line in the Keyboard section of the /etc/X11/xorg.conf file.

# Let the server do the NumLock processing.  This should only be
# required when using pre-R6 clients
    ServerNumLock

Virtual consoles, put simply, enable you to have several simultaneous sessions on the same machine without doing anything complicated like setting up a network or running X.

When the system starts, it will display a login prompt on the monitor after displaying all the boot messages. You can then type in your login name and password and start working (or playing!) on the first virtual console.

At some point, you will probably wish to start another session, perhaps to look at documentation for a program you are running or to read your mail while waiting for an FTP transfer to finish. Just do Alt+F2 (hold down the Alt key and press the F2 key), and you will find a login prompt waiting for you on the second «virtual console»! When you want to go back to the original session, do Alt+F1.

The default FreeBSD installation has eight virtual consoles enabled. Alt+F1, Alt+F2, Alt+F3, and so on will switch between these virtual consoles.

To enable more of them, edit /etc/ttys (see ttys(5)) and add entries for ttyv4 to ttyvc after the comment on «Virtual terminals»:

# Edit the existing entry for ttyv3 in /etc/ttys and change
# "off" to "on".
ttyv3   "/usr/libexec/getty Pc"         cons25  on secure
ttyv4   "/usr/libexec/getty Pc"         cons25  on secure
ttyv5   "/usr/libexec/getty Pc"         cons25  on secure
ttyv6   "/usr/libexec/getty Pc"         cons25  on secure
ttyv7   "/usr/libexec/getty Pc"         cons25  on secure
ttyv8   "/usr/libexec/getty Pc"         cons25  on secure
ttyv9   "/usr/libexec/getty Pc"         cons25  on secure
ttyva   "/usr/libexec/getty Pc"         cons25  on secure
ttyvb   "/usr/libexec/getty Pc"         cons25  on secure

Use as many or as few as you want. The more virtual terminals you have, the more resources that are used; this can be important if you have 8MB RAM or less. You may also want to change the secure to insecure.

The easiest way to disable a console is by turning it off. For example, if you had the full 12 terminal allocation mentioned above and you wanted to run X, you would change settings for virtual terminal 12 from:

ttyvb   "/usr/libexec/getty Pc"         cons25  on  secure

to:

ttyvb   "/usr/libexec/getty Pc"         cons25  off secure

If your keyboard has only ten function keys, you would end up with:

ttyv9   "/usr/libexec/getty Pc"         cons25  off secure
ttyva   "/usr/libexec/getty Pc"         cons25  off secure
ttyvb   "/usr/libexec/getty Pc"         cons25  off secure

(You could also just delete these lines.)

Next, the easiest (and cleanest) way to activate the virtual consoles is to reboot. However, if you really do not want to reboot, you can just shut down the X Window system and execute (as root):

# kill -HUP 1

It is imperative that you completely shut down X Window if it is running, before running this command. If you do not, your system will probably appear to hang/lock up after executing the kill command.

Use Ctrl+Alt+Fn to switch back to a virtual console. Ctrl+Alt+F1 would return you to the first virtual console.

Once you are back to a text console, you can then use Alt+Fn as normal to move between them.

To return to the X session, you must switch to the virtual console running X. If you invoked X from the command line, (e.g., using startx) then the X session will attach to the next unused virtual console, not the text console from which it was invoked. If you have eight active virtual terminals then X will be running on the ninth, and you would use Alt+F9 to return.

There are two schools of thought on how to start xdm(1). One school starts xdm from /etc/ttys (see ttys(5)) using the supplied example, while the other simply runs xdm from rc.local (see rc(8)) or from a X.sh script in /usr/local/etc/rc.d. Both are equally valid, and one may work in situations where the other does not. In both cases the result is the same: X will pop up a graphical login: prompt.

The ttys method has the advantage of documenting which vty X will start on and passing the responsibility of restarting the X server on logout to init. The rc.local method makes it easy to kill xdm if there is a problem starting the X server.

If loaded from rc.local, xdm should be started without any arguments (i.e., as a daemon). xdm must start AFTER getty runs, or else getty and xdm will conflict, locking out the console. The best way around this is to have the script sleep 10 seconds or so then launch xdm.

If you are to start xdm from /etc/ttys, there still is a chance of conflict between xdm and getty(8). One way to avoid this is to add the vt number in the /usr/local/lib/X11/xdm/Xservers file.

:0 local /usr/local/bin/X vt4

The above example will direct the X server to run in /dev/ttyv3. Note the number is offset by one. The X server counts the vty from one, whereas the FreeBSD kernel numbers the vty from zero.

If you start X with startx, the permissions on /dev/console will not get changed, resulting in things like xterm -C and xconsole not working.

This is because of the way console permissions are set by default. On a multi-user system, one does not necessarily want just any user to be able to write on the system console. For users who are logging directly onto a machine with a VTY, the fbtab(5) file exists to solve such problems.

In a nutshell, make sure an uncommented line of the form

/dev/ttyv0 0600 /dev/console

is in /etc/fbtab (see fbtab(5)) and it will ensure that whomever logs in on /dev/ttyv0 will own the console.

All X servers need to be run as root in order to get direct access to your video hardware. Older versions of XFree86 (<= 3.3.6) installed all bundled servers to be automatically run as root (setuid to root). This is obviously a security hazard because X servers are large, complicated programs. Newer versions of XFree86 do not install the servers setuid to root for just this reason.

Obviously, running an X server as the root user is not acceptable, nor a good idea security-wise. There are two ways to be able to use X as a regular user. The first is to use xdm or another display manager (e.g., kdm); the second is to use the Xwrapper.

xdm is a daemon that handles graphical logins. It is usually started at boot time, and is responsible for authenticating users and starting their sessions; it is essentially the graphical counterpart of getty(8) and login(1). For more information on xdm see the XFree86 documentation, and the the FAQ entry on it.

Xwrapper is the X server wrapper; it is a small utility to enable one to manually run an X server while maintaining reasonable safety. It performs some sanity checks on the command line arguments given, and if they pass, runs the appropriate X server. If you do not want to run a display manager for whatever reason, this is for you. If you have installed the complete ports collection, you can find the port in /usr/ports/x11/wrapper.

Your mouse and the mouse driver may have somewhat become out of synchronization.

In rare cases the driver may erroneously report synchronization problem and you may see the kernel message:

psmintr: out of sync (xxxx != yyyy)

and notice that your mouse does not work properly.

If this happens, disable the synchronization check code by setting the driver flags for the PS/2 mouse driver to 0x100. Enter UserConfig by giving the -c option at the boot prompt:

boot: -c

Then, in the UserConfig command line, type:

UserConfig> flags psm0 0x100
UserConfig> quit

There have been some reports that certain model of PS/2 mouse from MouseSystems works only if it is put into the «high resolution» mode. Otherwise, the mouse cursor may jump to the upper-left corner of the screen every so often.

Specify the flags 0x04 to the PS/2 mouse driver to put the mouse into the high resolution mode. Enter UserConfig by giving the -c option at the boot prompt:

boot: -c

Then, in the UserConfig command line, type:

UserConfig> flags psm0 0x04
UserConfig> quit

See the previous section for another possible cause of mouse problems.

FreeBSD versions prior 5.3 will use the default XFree86 4.X, while latter versions will default to Xorg. If you want to run a different X11 implementation than the default one, add the following line to /etc/make.conf, (if you do not have this file, create it):

X_WINDOW_SYSTEM=        xorg

This variable may be set to xorg, xfree86-4, or xfree86-3.

Run the command xmodmap -e "pointer = 3 2 1" from your .xinitrc or .xsession.

FreeBSD have a feature to allow the display of «splash» screens during the boot messages. The splash screens currently must be a 256 color bitmap (*.BMP) or ZSoft PCX (*.PCX) file. In addition, they must have a resolution of 320x200 or less to work on standard VGA adapters. If you compile VESA support into your kernel, then you can use larger bitmaps up to 1024x768. The actual VESA support can either be compiled directly into the kernel with the VESA kernel config option or by loading the VESA kld module during bootup.

To use a splash screen, you need to modify the startup files that control the boot process for FreeBSD.

You need to create a /boot/loader.rc file that contains the following lines:

include /boot/loader.4th
start

and a /boot/loader.conf that contains the following:

splash_bmp_load="YES"
bitmap_load="YES"

This assumes you are using /boot/splash.bmp for your splash screen. If you would rather use a PCX file, copy it to /boot/splash.pcx, create a /boot/loader.rc as instructed above, and create a /boot/loader.conf that contains:

splash_pcx_load="YES"
bitmap_load="YES"
bitmap_name="/boot/splash.pcx"

Now all you need is a splash screen. For that you can surf on over to the gallery at http://www.baldwin.cx/splash/.

Yes. All you need to do is use xmodmap(1) to define what function you wish them to perform.

Assuming all «Windows» keyboards are standard then the keycodes for the 3 keys are

• 115 - Windows key, between the left-hand Ctrl and Alt keys

• 116 - Windows key, to the right of the AltGr key

• 117 - Menu key, to the left of the right-hand Ctrl key

To have the left Windows key print a comma, try this.

# xmodmap -e "keycode 115 = comma"

You will probably have to re-start your window manager to see the result.

To have the Windows key-mappings enabled automatically every time you start X either put the xmodmap commands in your ~/.xinitrc file or, preferably, create a file ~/.xmodmaprc and include the xmodmap options, one per line, then add the line

xmodmap $HOME/.xmodmaprc

to your ~/.xinitrc.

For example, you could map the 3 keys to be F13, F14, and F15, respectively. This would make it easy to map them to useful functions within applications or your window manager, as demonstrated further down.

To do this put the following in ~/.xmodmaprc.

keycode 115 = F13
keycode 116 = F14
keycode 117 = F15

If you use fvwm2, for example, you could map the keys so that F13 iconifies (or de-iconifies) the window the cursor is in, F14 brings the window the cursor is in to the front or, if it is already at the front, pushes it to the back, and F15 pops up the main Workplace (application) menu even if the cursor is not on the desktop, which is useful if you do not have any part of the desktop visible (and the logo on the key matches its functionality).

The following entries in ~/.fvwmrc implement the aforementioned setup:

Key F13        FTIWS    A        Iconify
Key F14        FTIWS    A        RaiseLower
Key F15        A        A        Menu Workplace Nop

The availability of 3D acceleration depends on the version of XFree86 or Xorg that you are using and the type of video chip you have. If you have an NVIDIA chip, you can use the binary drivers provided for FreeBSD on the Drivers section of their website. For other cards with XFree86-4 or Xorg, including the Matrox G200/G400, ATI Rage 128/Radeon, and 3dfx Voodoo 3, 4, 5, and Banshee, information on hardware acceleration is available on the XFree86-4 Direct Rendering on FreeBSD page.