GPM(1)
NAME
gpm - a cut and paste utility and mouse server for virtual
consoles
SYNOPSIS
gpm [ options ]
DESCRIPTION
This package tries to be a useful mouse server for appli-
cations running on the Linux console. It is based on the
"selection" package, and some of its code comes from
selection itself. This package is intended as a replace-
ment for "selection" as a cut-and-paste mechanism; it also
provides additional facilities. The "selection" package
offered the first cut-and-paste implementation for Linux
using two mouse buttons, and the cut buffer is still
called "selection buffer" or just "selection" throughout
this document. The information below is extracted from
the texinfo file, which is the preferred source of infor-
mation.
The gpm executable is meant to act like a daemon (thus,
gpmd would be a better name for it). This section is meant
to describe the command-line options for gpm, while its
internals are outlined in the next section. Gpm Inter-
nals.
Due to restrictions in the ioctl(TIOCLINUX) system call,
gpm must be run by the superuser. The restrictions have
been added in the last 1.1 kernels to fix a security hole
related to selection and screen dumping.
The server can be configured to match the user's taste,
and any application using the mouse will inherit the
server's attitude. Beginning from release 1.02, the mouse
`feeling' can be reconfigured by each user logging on the
system console. See the description of ``-q'' Server Invo-
cation.
As of 0.97 the server program puts itself in the back-
ground. To kill gpm you can just reinvoke it with the -k
cmdline switch, although killall gpm can be a better
choice.
SPECIAL COMMANDS
Version 1.10 adds the capability to execute special com-
mands on certain circumstances. Special commands default
to rebooting and halting the system, but the user can
specify his/her personal choice. The capability to invoke
commands using the mouse is a handy one for programmers,
because it allows to issue a clean shutdown when the key-
board is locked and no network is available to restore the
system to a sane state.
Special commands are toggled by triple-clicking the left
and right button -- an unlikely event during normal mouse
usage. The easiest way to triple-click is pressing one of
the buttons and triple-click the other one. When special
processing is toggled, a message appears on the console
(and the speaker beeps twice, if you have a speaker); if
the user releases all the buttons and presses one of them
again within three seconds, then the special command cor-
responding to the button is executed.
The default special commands are:
left button
Reboot the system by signalling the init process
middle button (if any)
Execute `/sbin/shutdown -h now'
right button
Execute `/sbin/shutdown -r now'
The -S commandline switch enables special command process-
ing and allows to change the three special commands. To
accept the default commands use `-S ""' (i.e., specify an
empty argument). To specify your own commands, use a
colon-separated list to specify commands associated to the
left, middle and right button. If any of the commands is
empty, it is interpreted as `send a signal to the init
process'. This particular operation is supported, in addi-
tion to executing external commands, because sometimes bad
bugs put the system to the impossibility to fork; in these
rare case the programmer should be able to shutdown the
system anyways, and killing init from a running process is
the only way to do it.
As an example, `-S ":telinit 1:/sbin/halt"', associates
killing init to the left button, going single user to the
middle one, and halting the system to the right button.
System administrators should obviously be careful about
special commands, as gpm runs with superuser permissions.
Special commands are best suited for computers whose mouse
can be physically accessed only by trusted people.
COMMAND LINE OPTIONS
Available command line options are the following:
-a accel
Set the acceleration value used when a single
motion event is longer than delta (see -d).
-b baud
Set the baud rate.
-B sequence
Set the button sequence. ``123'' is the normal
sequence, ``321'' can be used by left-handed peo-
ple, and ``132'' can be useful with two-button mice
(especially within Emacs). All the button permuta-
tions are allowable.
-d delta
Set the delta value. When a single motion event is
longer than delta, accel is used as a multiplying
factor. (Must be 2 or above)
-g number
With glidepoint devices, emulate the specified but-
ton with tapping. number must be 1, 2, or 3, and
refers to the button number before the -B button
remapping is performed. This option applies to the
mman and ps2 decoding. No button is emulated by
default because the ps2 tapping is incompatible
with some normal ps2 mice
-h Print a summary of command line options.
-i interval
Set interval to be used as an upper time limit for
multiple clicks. If the interval between button-up
and button-down events is less than limit, the
press is considered a double or triple click. Time
is in milliseconds.
-k Kill a running gpm. This can be used by busmouse
users to kill gpm before running X (unless they use
-R or the single-open limitation is removed from
the kernel).
-l charset
Choose the inword() look up table. The charset
argument is a list of characters. - is used to
specify a range and is used to escape the next
character or to provide octal codes. Only visible
character can appear in charset because control
characters can't appear in text-mode video memory,
whence selection is cut.
-m filename
Choose the mouse file to open. It defaults to
/dev/mouse.
-M Enable multiple mode. The daemon will read two dif-
ferent mouse devices. Any subsequent option will
refer to the second device, while any preceding
option will be used for the first device. This
option automatically forces the ``repeater'' (-R)
option on.
-o lines
Toggle modem lines. The lines argument can be
``dtr'', ``rts'' or ``both''. This is needed for
some strange serial mice.
-p Forces the pointer to be visible while selecting.
This is the behaviour of selection-1.7, but it is
sometimes confusing. The default is not to show
the pointer, which can be confusing as well.
-q Quit after changing mouse behaviour. This is
intended to allow users to change the mouse ``feel-
ing'' (-a, -B, -d, -i, -l, -p, -r) without restart-
ing the server. Since this needs root permissions,
the system administrators can use the `set-uid'
bits to enable/disable such capability. Changing
mouse parameters is nonetheless only allowed from
one of the virtual consoles. Options are trans-
ferred only for the first mouse.
-r number
Set the responsiveness. A higher responsiveness is
used for a faster cursor motion.
-R Causes gpm to act as a repeater: any mouse data
received while in graphic mode will be produced on
the fifo /dev/gpmdata in mouse-system protocol.
This means that you can configure the X server to
use that fifo as a mouse device. This option is
useful for bus-mouse owners to override the single-
open limitation. It is also an easy way to manage
those stupid dual-mode mice which force you to keep
the middle button down while changing video mode.
The option is forced on by the -M option.
-s number
Set the sample rate for the mouse device.
-S commands
Enable special-command processing, and optionally
specify custom commands as a colon-separated list.
See above for a detailed description of special
commands.
-t name
Set the mouse type. Use -t help to get a list of
allowable types. Mouse Types.
-v Print version information and exit.
-2 Force two buttons. This means that the middle but-
ton, if any, will be taken as it was the right one.
-3 Force three buttons. By default the mouse is con-
sidered to be a 2-buttons one, until the middle
button is pressed. If three buttons are there, the
right one is used to extend the selection, and the
middle one is used to paste it. Beware: if you use
the -3 option with a 2-buttons mouse, you won't be
able to paste the selection.
OPERATION
To select text press the left mouse button and drag the
mouse. To paste text in the same or another console,
press the middle button. The right button is used to
extend the selection, like in `xterm'.
Two-button mice use the right button to paste text.
Double and triple clicks select whole wird and whole
lines. Use of the `-P' option is recommended for best
visual feedback.
If a trailing space after the contents of a line is high-
lighted, and if there is no other text on the remainder of
the line, the rest of the line will be selected automati-
cally. If a number of lines are selected, highlighted
trailing spaces on each line will be removed from the
selection buffer.
Any output on the virtual console holding the selection
will clear the highlighted selection from the screen, to
maintain integrity of the display, although the contents
of the paste buffer will be unaffected.
The selection mechanism is disabled if the controlling
virtual console is placed in graphics mode, for example
when running X11, and is re-enabled when text mode is
resumed. (But see BUGS section below.)
BUGS
The gpm server may have problems interacting with X: if
your mouse is a single-open device (i.e. a bus mouse), you
should kill gpm before strating X, or use the ``-R''
option (see above). To kill gpm just invoke gpm -k. This
problem doesn't apply to serial mice.
Two instances of gpm can't run on the same system. If you
have two mice use the ``-M'' option (see above).
While the current console is in graphic mode, gpm sleeps
until text mode is back (unless -R is used). Thus, it
won't reply to clients. Anyways, it is unlikely that
mouse-eager clients will spur out in hidden consoles.
pre-1.0 gpm releases have problems with kernel 1.2.9 and
later, because the clients must have write permission on
the node /var/run/gpmctl. You should invoke chmod on the
node or install gpm-1.0 or later (you have this docs, you
have the updated software).
AUTHORS
Andrew Haylett lt;ajh@gec-mrc.co.uk (the original selection code)
Alessandro Rubini lt;rubini@ipvvis.unipv.it (all the new features)
Many many contributors, to both selection and gpm.
FILES
/dev/mouse The default mouse device
/var/run/gpmpid The PID of the running gpm
/var/run/gpmctl A control socket for clients
/dev/gpmdata The fifo written to by a `repeater' (-R) daemon.
SEE ALSO
mev(1) A sample client for the gpm daemon.
gpm-root(1) An handler for Control-Mouse events.
The info file about `gpm', which gives more complete
information and explains how to write a gpm client.