VT(7I)VT(7I)NAMEvt - Solaris virtual console interface
SYNOPSIS
#include <sys/kd.h>
#include <sys/vt.h>
DESCRIPTION
The virtual console device driver — also known as virtual terminal (VT)
— is a layer of management functions that provides facilities to sup‐
port and switch between multiple screen faces on a single physical
device.
VT's are accessed in the same way as other devices. The open(2) system
call is used to open the virtual console and read(2), write(2) and
ioctl(2) are used in the normal way and support the functionality of
the underlying device. In addition, some virtual console-specific
ioctls are provided and described below.
The VT provides a link between different screen faces and the device.
The active virtual console corresponds to the currently visible screen
face. Device input is directed to the active console and any device-
specific modes that change on a per virtual terminal basis are set to
the characteristics associated with the active console.
You manage VT's by intercepting keyboard sequences ("hot key"). To
maintain consistency with Xserver, the virtual console device driver
supports the Ctrl, Alt, F# and arrow keys.
The sequence AltL + F# (where AltL represents the Alt key and F# repre‐
sents function keys 1 through 12) is used to select virtual console
1-12. The sequence AltGraph + F# (where AltGraph represents the right
Alt key and F# represent function keys 1 through 12) is for virtual
console 13-24. Alt + F1 chooses the system console (also known as vir‐
tual console 1). The sequence Alt + -> (where ">" represents the right
directional arrow) selects the next VT in a circular ring fashion and
Alt + <- ( where "<" represents the left directional arrow) changes to
the previous console in a circular fashion. The sequence Alt + ^
(where "^" represents the up directional arrow) is for the last used
console.
Virtual console switching can be done automatically (VT_AUTO) on
receipt of a ``hot-key'' or by the process owning the VT (VT_PROCESS).
When performed automatically, the process associated with the virtual
console is unaware of the switch. Saving and restoring the device are
handled by the underlying device driver and the virtual console man‐
ager. Note that automatic switching is the default mode.
When a ``hot-key'' is sent when in process-controlled switch mode, the
process owning the VT is sent a signal (relsig) it has specified to the
virtual console manager (see signal(3C)) requesting the process to
release the physical device. At this point, the virtual console manager
awaits the VT_RELDISP ioctl from the process. If the process refuses to
release the device (meaning the switch does not occur), it performs a
VT_RELDISP ioctl with an argument of 0 (zero). If the process desires
to release the device, it saves the device state (keyboard, display,
and I/O registers) and then performs a VT_RELDISP with an argument of 1
to complete the switch.
A ring of VT's can contain intermixed auto mode and process control
mode consoles. When an auto mode process becomes active, the underly‐
ing device driver and the virtual console manager handle the restoring
of the device. Process control mode processes are sent a specified
signal (acqsig) when they become the active console. The process then
restores the device state (keyboard, display, and I/O registers) and
performs VT_RELDISP ioctl with an argument of VT_ACKACQ to complete the
switching protocol.
The modify-operations ioctls (VT_SETMODE, VT_RELDISP, VT_WAITACTIVE,
KDSETMODE) check if the VT is the controlling tty of the calling
process. If not, the sys_devices privilege is enforced. VT_ACTIVATE
requires the sys_devices privilege. Note that there is no controlling
tty and privilege check for query/view operations.
IOCTLS
The following ioctls apply to devices that support virtual consoles:
VT_ENABLED
Queries to determine if VT functionality is available on the sys‐
tem. The argument is a pointer to an integer. If VT functionality
is available, the integer is 1, otherwise it is 0.
VT_OPENQRY
Finds an available VT. The argument is a pointer to an integer. The
integer is filled in with the number of the first available console
that no other process has open (and hence, is available to be
opened). If there are no available VT's, -1 is filled in.
VT_GETMODE
Determines the VT's current mode, either VT_AUTO or VT_PROCESS. The
argument is the address of the following structure, as defined in
<sys/vt.h>
struct vt_mode {
char mode; /* VT mode */
char waitv; /* not used */
short relsig;/* signal to use for release request */
short acqsig;/* signal to use for display acquired */
short frsig;/* not used */
}
/* Virtual console Modes */
#define VT_AUTO 0 /* automatic VT switching */
#define VT_PROCESS 1 /* process controls switching */
The structure will be filled in with the current value
for each field.
VT_SETMODE
Sets the VT mode. The argument is a pointer to a vt_mode structure
as defined above. The structure should be filled in with the
desired mode. If process-control mode is specified, the signals
used to communicate with the process should be specified. If any
signals are not specified (value is zero), the signal default is
SIGUSR1 (for relsig and acqsig).
VT_RELDISP
Tells the VT manager if the process releases (or refuses to
release) the display. An argument of 1 indicates the VT is
released. An argument of 0 indicates refusal to release. The
VT_ACKACQ argument indicates if acquisition of the VT has been com‐
pleted.
VT_ACTIVATE
Makes the VT specified in the argument the active VT (in the same
manner as if a hotkey initiated the switch). If the specified VT
is not open or does not exist, the call fails and errno is set to
ENXIO.
VT_WAITACTIVE
If the specified VT is currently active, this call returns immedi‐
ately. Otherwise, it sleeps until the specified VT becomes active,
at which point it returns.
VT_GETSTATE
Obtains the active VT number and a list of open VTs. The argument
is an address to the following structure:
struct vt_stat {
unsigned short v_active, /* number of the active VT */
v_signal, /* not used */
v_state; /* count of open VTs. For every 1 in this
field, there is an open VT */
}
With VT_GETSTATE, the VT manager first gets the number of the
active VT, then determines the number of open VTs in the system and
sets a 1 for each open VT in v_state. Next, the VT manager trans‐
fers the information in structure vt_stat passed by the user
process.
KDGETMODE
Obtains the text/graphics mode associated with the VT.
#define KD_TEXT 0
#define KD_GRAPHICS 1
KDSETMODE
Sets the text/graphics mode to the VT.
KD_TEXT indicates that console text is displayed on the screen.
Normally KD_TEXT is combined with VT_AUTO mode for text console
terminals, so that the console text display automatically is saved
and restored on the hot key screen switches.
KD_GRAPHICS indicates that the user/application (usually Xserver)
has direct control of the display for this VT in graphics mode.
Normally KD_GRAPHICS is combined with VT_PROCESS mode for this VT
indicating direct control of the display in graphics mode. In this
mode, all writes to the VT using the write system call are ignored,
and you must save and restore the display on the hot key screen
switches.
When the mode of the active VT is changed from KD_TEXT to KD_GRAPH‐
ICS or a VT of KD_GRAPHICS mode is made active from a previous
active VT of KD_TEXT mode, the virtual console manager initiates a
KDSETMODE ioctl with KD_GRAPHICS as the argument to the underlying
console frame buffer device indicating that current display is run‐
ning into graphics mode.
When the mode of the active VT is changed from KD_GRAPHICS to
KD_TEXT or a VT of KD_TEXT mode is actived from a previous active
VT of KD_GRAPHICS mode, the virtual console manager initiates a
KDSETMODE ioctl with KD_TEXT as the argument to the underlying con‐
sole frame buffer device indicating that current display is running
into console text mode.
FILES
/dev/vt/#
VT devices.
SEE ALSOioctl(2), signal(3C), wscons(7D)NOTES
By default, there are only five virtual console instance login prompts
running on /dev/vt/# (where "#" represents 2 to 6) in addition to the
system console running on /dev/console. Normally Xorg uses the seventh
virtual console (/dev/vt/7.) To switch from consoles to Xserver (which
normally picks up the first available virtual console), use [ Ctrl + ]
Alt + F7 .
# svcs | grep login
online 17:49:11 svc:/system/console-login:default
online 17:49:11 svc:/system/console-login:vt2
online 17:49:11 svc:/system/console-login:vt3
online 17:49:11 svc:/system/console-login:vt4
online 17:49:11 svc:/system/console-login:vt5
online 17:49:11 svc:/system/console-login:vt6
console-login:default is for the system console, others for
virtual consoles.
You can modify properties/disable/enable and remove/add
virtual consoles using smf(5):
# svccfg -s console-login add vt8
# svccfg -s console-login:vt8 setprop ttymon/device=astring: "/dev/vt/8"
# svcadm enable console-login:vt8
Sep 22, 2008 VT(7I)
