XLOCK(1) Irix (06 Jun 1991) XLOCK(1)
NAME
xlock - Locks the local X display until a password is
entered.
SYNOPSIS
xlock [ -display dsp ] [ -help ] [ -resources ]
[ -blankthresh num ] [ -/+remote ] [ -/+mono ]
[ -/+nolock ] [ -/+allowroot ] [ -/+besaver ]
[ -/+allowaccess ] [ -/+echokeys ] [ -/+v ]
[ -/+usefirst ] [ -delay usecs ] [ -batchcount num ]
[ -colorcount num ] [ -nice level ]
[ -timeout seconds ] [ -saturation value ]
[ -font fontname ] [ -bg color ] [ -fg color ]
[ -mode mode ] [ -name textstring ]
[ -password textstring ] [ -info textstring ]
[ -validate textstring ] [ -invalid textstring ]
DESCRIPTION
xlock blanks (or otherwise saves) the screen and possibly
locks the X server till the user enters their password at
the keyboard. While xlock is has the screen locked, all new
server connections are refused. The screen saver is
disabled. The mouse cursor is turned off. The screen is
blanked and a changing pattern is put on the screen. If a
key or a mouse button is pressed then the user is prompted
for the password of the user who started xlock.
If the correct password is typed, then the screen is
unlocked and the X server is restored. When typing the
password Control-U and Control-H are active as kill and
erase respectively. To return to the locked screen, click
in the small icon version of the changing pattern.
If the screen is merely saved, but not locked, or if the
user who started the program does not have a password, then
no password is required.
OPTIONS
-display dsp
The display option sets the X11 display to lock. xlock
locks all available screens on a given server, and
restricts you to locking only a local server such as
unix:0, localhost:0, or :0 unless you set the -remote
option.
-mode modename
As of this writing there are ten display modes
supported (plus one more for random selection of one of
the ten).
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blank Blank mode shows nothing but a black screen.
rotor Rotor mode shows a swirling rotorlike thing.
pyro Pyro mode shows lots of small fireworks.
flame Flame mode shows wierd but cool cosmic flame
fractals.
hop Hop mode shows the "real plane fractals" from the
September 1986 issue of Scientific American.
image Image mode shows several sgi logos randomly
appearing on the screen.
life Life mode shows Conway's game of life.
pop Pop mode shows single large fireworks exploding on
the screen.
qix Qix mode shows the spinning lines similar to the old
video game by the same name.
swarm Swarm mode shows a swarm of bees following a wasp.
random Selects one of the above modes randomly.
-delay usecs
The delay option sets the speed at which a mode will
operate. It simply sets the number of microseconds to
delay between batches of "hopalong pixels", "qix
lines", "life generations", "image blits", and "pop or
swarm motions". In blank mode, it is important to set
this to some small number of seconds, because the
keyboard and mouse are only checked after each delay,
so you cannot set the delay too high, but a delay of
zero would needlessly consume cpu checking for mouse
and keyboard input in a tight loop, since blank mode
has no work to do.
-batchcount num
The batchcount option sets the number of things to do
per batch to num . In qix mode this refers to the
number of lines rendered in the same color. In life
mode it is the number of generations to let each
species live. In hop mode this refers to the number of
pixels rendered in the same color. In image mode this
refers to the number of sgilogos on screen at once. In
swarm mode this refers to the number of bees. In rotor
mode it is the number of rotor thingys which whirr...
In pyro mode it is the maximum number flying rockets at
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one time. In flame mode it is the number of levels to
recurse (larger = more complex). In pop mode this sets
the maximum number of sparks in a burst (the actual
number of sparts in any one burst is chosen randomly).
In blank mode it means nothing.
-colorcount num
The colorcount option sets the number of colors to use
to num .
-nice nicelevel
The nice option sets system nicelevel of the xlock
process to nicelevel .
-timeout seconds
The timeout option sets the number of seconds before
the password screen will time out.
-saturation value
The saturation option sets saturation of the color ramp
used to value . 0 is grayscale and 1 is very rich
color. 0.4 is a nice pastel.
-font fontname
The font option sets the font to be used on the prompt
screen.
-fg color
The fg option sets the color of the text on the
password screen to color .
-bg color
The bg option sets the color of the background on the
password screen to color .
-name textstring
textstring is shown in front of user name, defaults to
"Name: ".
-password textstring
textstring is the password prompt string, defaults to
"Password: ".
-info textstring
textstring is an informational message to tell the user
what to do, defaults to "Enter password to unlock;
select icon to lock.".
-validate textstring
textstring -validate message shown while validating the
password, defaults to "Validating login..."
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-invalid textstring
textstring -invalid message shown when password is
invalid, defaults to "Invalid login."
-resources
The resources option prints the default resource file
for xlock to standard output.
-/+remote
The remote option tells xlock to not stop you from
locking remote X11 servers. This option should be used
with care and is intended mainly to lock X11 terminals
which cannot run xlock locally. If you lock someone
else's workstation, they will have to know your
password to unlock it.
-/+mono
The mono option causes xlock to display monochrome,
(black and white) pixels rather than the default
colored ones on color displays
-/+nolock
The nolock option causes xlock to only draw the
patterns and not lock the display. A keypress or a
mouse click will terminate the screen saver or send it
back into the background (with -besaver).
-/+allowroot
The allowroot option allows the root password to unlock
the server as well as the user who started xlock.
-/+enablesaver
By default xlock will disable the normal X server's
screen saver since it is in effect a replacement for
it. Since it is possible to set delay parameters long
enough to cause phosphor burn on some displays, this
option will turn back on the default screensaver which
is very careful to keep most of the screen black.
-/+besaver
If your X server supports the SCREEN-SAVER protocol,
then this option will tell xlock to act as the screen
saver. When you use xlock in this mode, it will not
lock the screen immediately. Instead, when the server
decides the screen should be blanked, it will notify
xlock instead of merely blanking the screen. Xlock
will then display whatever display mode you have
selected.
In this mode, xlock will not exit when you type in a
password. Instead, its window will disappear, and it
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will wait for the next screen saver time out.
This option forces -enablesaver.
-blankthresh num
Whenever xlock is displaying some graphic mode and the
system load rises over this value, xlock will switch to
blank mode. Since blank mode is much less expensive
than many of the graphic modes, this will allow time
for other system activity.
-/+allowaccess
This option is required for servers which do not allow
clients to modify the host access control list. It is
also useful if you need to run x clients on a server
which is locked for some reason... When allowaccess is
true, the X11 server is left open for clients to attach
and thus lowers the inherent security of this
lockscreen. A side effect of using this option is that
if xlock is killed -KILL, the access control list is
not lost.
-/+echokeys
The echokeys option causes xlock to echo '?' characters
for each key typed into the password prompt. Some
consider this a security risk, so the default is to not
echo anything.
-/+usefirst
The usefirst option causes xlock to use the keystroke
which got you to the password screen as the first
character in the password. The default is to ignore
the first key pressed.
-v Verbose mode, tells what options it is going to use.
BUGS
"kill -KILL xlock " causes the server that was locked to be
unusable, since all hosts (including localhost) were removed
from the access control list to lock out new X clients, and
since xlock couldn't catch SIGKILL, it terminated before
restoring the access control list. This will leave the X
server in a state where "you can no longer connect to that
server, and this operation cannot be reversed unless you
reset the server." -From the X11R4 Xlib
Documentation, Chapter 7.
On some kernel and hardware combinations, pop mode will
cause trashy flickering at the top of the screen. This is a
bug in the graphics library/kernel/hardware (depending on
how you look at it) and is out of xlock's control.
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NOTE
If you run xlock on a machine not running the kernel in
/unix, you can potentially confuse xlock since it will not
be able to measure the load correctly. If the load appears
too far out of range, xlock will print a message to that
affect and disable the load threshold checking.
SEE ALSO
X(1), xset(1), Xlib Documentation.
AUTHOR
Patrick J. Naughton (naughton@eng.sun.com)
Mailstop 10-20
Sun Laboratories, Inc.
Mountain View, CA 94043
415/336-1080
COPYRIGHT
Copyright (c) 1988-91 by Patrick J. Naughton
Permission to use, copy, modify, and distribute this
software and its documentation for any purpose and without
fee is hereby granted, provided that the above copyright
notice appear in all copies and that both that copyright
notice and this permission notice appear in supporting
documentation.
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