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CONSOLE_IOCTLS(4)
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console ioctl's- ioctl's for console terminal and virtual consoles
WARNING: If you use the following information you are going to burn
yourself.
WARNING: ioctl's are undocumented Linux internals, liable to be changed
without warning. Use POSIX functions where available.
The following Linux-peculiar ioctl() requests are supported. Each
requires a third argument, assumed here to be argp.
KDGETLED [Toc] [Back]
Get state of LEDs. argp points to a long int. The lower three
bits of *argp are set to the state of the LEDs, as follows:
LED_CAP 0x04 caps lock led
LEC_NUM 0x02 num lock led
LED_SCR 0x01 scroll lock led
KDSETLED [Toc] [Back]
Set the LEDs. The LEDs are set to correspond to the lower three
bits of argp. However, if a higher order bit is set, the LEDs
revert to normal: displaying the state of the keyboard functions
of caps lock, num lock, and scroll lock.
Before 1.1.54, the leds just reflected the state of the corresponding
keyboard flags, and KDGETLED/KDSETLED would also change
the keyboard flags. Since 1.1.54 the leds can be made to display
arbitrary information, but by default they display the keyboard
flags. The following two ioctl's are used to access the keyboard
flags.
KDGKBLED [Toc] [Back]
Get keyboard flags CapsLock, NumLock, ScrollLock (not lights).
argp points to a char which is set to the flag state. The low
order three bits (mask 0x7) get the current flag state, and the
low order bits of the next nibble (mask 0x70) get the default
flag state. (Since 1.1.54.)
KDSKBLED [Toc] [Back]
Set keyboard flags CapsLock, NumLock, ScrollLock (not lights).
argp has the desired flag state. The low order three bits (mask
0x7) have the flag state, and the low order bits of the next
nibble (mask 0x70) have the default flag state. (Since 1.1.54.)
KDGKBTYPE [Toc] [Back]
Get keyboard type. This returns the value KB_101, defined as
0x02.
KDADDIO [Toc] [Back]
Add I/O port as valid. Equivalent to ioperm(arg,1,1).
KDDELIO [Toc] [Back]
Delete I/O port as valid. Equivalent to ioperm(arg,1,0).
KDENABIO [Toc] [Back]
Enable I/O to video board. Equivalent to ioperm(0x3b4,
0x3df-0x3b4+1, 1).
KDDISABIO [Toc] [Back]
Disable I/O to video board. Equivalent to ioperm(0x3b4,
0x3df-0x3b4+1, 0).
KDSETMODE [Toc] [Back]
Set text/graphics mode. argp is one of these:
KD_TEXT 0x00
KD_GRAPHICS 0x01
KDGETMODE [Toc] [Back]
Get text/graphics mode. argp points to a long which is set to
one of the above values.
KDMKTONE [Toc] [Back]
Generate tone of specified length. The lower 16 bits of argp
specify the period in clock cycles, and the upper 16 bits give
the duration in msec. If the duration is zero, the sound is
turned off. Control returns immediately. For example, argp =
(125<<16) + 0x637 would specify the beep normally associated
with a ctrl-G.
KIOCSOUND [Toc] [Back]
Start or stop sound generation. The lower 16 bits of argp specify
the period in clock cycles (that is, argp = 1193180/frequency).
argp = 0 turns sound off. In either case, control
returns immediately.
GIO_FONT [Toc] [Back]
Gets screen font in expanded form. argp points to an 8192 byte
array.
PIO_FONT [Toc] [Back]
Sets screen font. Load font into the EGA/VGA character generator.
argp points to a 8192 byte map, with 32 bytes per character.
Only first N of them are used for an 8xN font (0 < N <=
32).
GIO_SCRNMAP [Toc] [Back]
Get screen mapping from kernel. argp points to an area of size
E_TABSZ.
PIO_SCRNMAP [Toc] [Back]
Loads the "user definable" (fourth) table in the kernel which
maps bytes into console screen symbols. argp points to an area
of size E_TABSZ.
GIO_UNIMAP [Toc] [Back]
Get unicode-to-font mapping from kernel. argp points to a
struct unimapdesc {
u_short entry_ct;
struct unipair *entries;
};
where entries points to an array of
struct unipair {
u_short unicode;
u_short fontpos;
};
(Since 1.1.92.)
PIO_UNIMAP [Toc] [Back]
Put unicode-to-font mapping in kernel. argp points to a struct
unimapdesc. (Since 1.1.92)
PIO_UNIMAPCLR [Toc] [Back]
Clear table, possibly advise hash algorithm. argp points to a
struct unimapinit {
u_short advised_hashsize; /* 0 if no opinion */
u_short advised_hashstep; /* 0 if no opinion */
u_short advised_hashlevel; /* 0 if no opinion */
};
(Since 1.1.92.)
KDGKBMODE [Toc] [Back]
Gets current keyboard mode. argp points to a long which is set
to one of these:
K_RAW 0x00
K_XLATE 0x01
K_MEDIUMRAW 0x02
K_UNICODE 0x03
KDSKBMODE [Toc] [Back]
Sets current keyboard mode. argp is a long equal to one of the
above values.
KDGKBMETA [Toc] [Back]
Gets meta key handling mode. argp points to a long which is set
to one of these:
K_METABIT 0x03 set high order bit
K_ESCPREFIX 0x04 escape prefix
KDSKBMETA [Toc] [Back]
Sets meta key handling mode. argp is a long equal to one of the
above values.
KDGKBENT [Toc] [Back]
Gets one entry in key translation table (keycode to action
code). argp points to a
struct kbentry {
u_char kb_table;
u_char kb_index;
u_short kb_value;
};
with the first two members filled in: kb_table selects the key
table (0 <= kb_table < MAX_NR_KEYMAPS), and kb_index is the keycode
(0 <= kb_index < NR_KEYS). kb_value is set to the corresponding
action code, or K_HOLE if there is no such key, or
K_NOSUCHMAP if kb_table is invalid.
KDSKBENT [Toc] [Back]
Sets one entry in translation table. argp points to a struct
kbentry.
KDGKBSENT [Toc] [Back]
Gets one function key string. argp points to a
struct kbsentry {
u_char kb_func;
u_char kb_string[512];
};
kb_string is set to the (NULL terminated) string corresponding
to the kb_functh function key action code.
KDSKBSENT [Toc] [Back]
Sets one function key string entry. argp points to a struct
kbsentry.
KDGKBDIACR [Toc] [Back]
Read kernel accent table. argp points to a
struct kbdiacrs {
unsigned int kb_cnt;
struct kbdiacr kbdiacr[256];
};
where kb_cnt is the number of entries in the array, each of
which is a
struct kbdiacr { u_char diacr, base, result; };
KDGETKEYCODE [Toc] [Back]
Read kernel keycode table entry (scan code to keycode). argp
points to a
struct kbkeycode { unsigned int scancode, keycode; };
keycode is set to correspond to the given scancode. (89 <=
scancode <= 255 only. For 1 <= scancode <= 88, keycode==scan-
code.) (Since 1.1.63.)
KDSETKEYCODE [Toc] [Back]
Write kernel keycode table entry. argp points to struct kbkeycode.
(Since 1.1.63.)
KDSIGACCEPT [Toc] [Back]
The calling process indicates its willingness to accept the signal
argp when it is generated by pressing an appropriate key
combination. (1 <= argp <= NSIG). (See spawn_console() in
linux/drivers/char/keyboard.c.)
VT_OPENQRY [Toc] [Back]
Returns the first available (non-opened) console. argp points
to an int which is set to the number of the vt (1 <= *argp <=
MAX_NR_CONSOLES).
VT_GETMODE [Toc] [Back]
Get mode of active vt. argp points to a
struct vt_mode {
char mode; /* vt mode */
char waitv; /* if set, hang on writes if not active */
short relsig; /* signal to raise on release req */
short acqsig; /* signal to raise on acquisition */
short frsig; /* unused (set to 0) */
};
mode is set to one of these values:
VT_AUTO auto vt switching
VT_PROCESS process controls switching
VT_ACKACQ acknowledge switch
VT_SETMODE [Toc] [Back]
Set mode of active vt. argp points to a struct vt_mode.
VT_GETSTATE [Toc] [Back]
Get global vt state info. argp points to a
struct vt_stat {
ushort v_active; /* active vt */
ushort v_signal; /* signal to send */
ushort v_state; /* vt bitmask */
};
For each vt in use, the corresponding bit in the v_state member
is set. (Kernels 1.0 through 1.1.92.)
VT_RELDISP [Toc] [Back]
Release a display.
VT_ACTIVATE [Toc] [Back]
Switch to vt argp (1 <= argp <= MAX_NR_CONSOLES).
VT_WAITACTIVE [Toc] [Back]
Wait until vt argp has been activated.
VT_DISALLOCATE [Toc] [Back]
Deallocate the memory associated with vt argp. (Since 1.1.54.)
VT_RESIZE [Toc] [Back]
Set kernel's idea of screensize. argp points to a
struct vt_sizes {
ushort v_rows; /* # rows */
ushort v_cols; /* # columns */
ushort v_scrollsize; /* no longer used */
};
(Since 1.1.54.) Note that this does not change the videomode.
See resizecons(8).
The action of the following ioctls depends on the first byte in the
struct pointed to by argp, referred to here as the subcode. These are
legal only for the superuser or the owner of the current tty.
TIOCLINUX, subcode=0
Dump the screen. Disappeared in 1.1.92. (With kernel 1.1.92 or
later, read from /dev/vcsN or /dev/vcsaN instead.)
TIOCLINUX, subcode=1
Get task information. Disappeared in 1.1.92.
TIOCLINUX, subcode=2
Set selection. argp points to a
struct {char subcode;
short xs, ys, xe, ye;
short sel_mode;
}
xs and ys are the starting column and row. xe and ye are the
ending column and row. (Upper left corner is row=column=1.)
sel_mode is 0 for character-by-character selection, 1 for wordby-word
selection, or 2 for line-by-line selection. The indicated
screen characters are highlighted and saved in the static
array sel_buffer in devices/char/console.c.
TIOCLINUX, subcode=3
Paste selection. The characters in the selection buffer are
written to fd.
TIOCLINUX, subcode=4
Unblank the screen.
TIOCLINUX, subcode=5
Sets contents of a 256-bit look up table defining characters in
a "word", for word-by-word selection. (Since 1.1.32.)
TIOCLINUX, subcode=6
argp points to a char which is set to the value of the kernel
variable shift_state. (Since 1.1.32.)
TIOCLINUX, subcode=7
argp points to a char which is set to the value of the kernel
variable report_mouse. (Since 1.1.33.)
TIOCLINUX, subcode=8
Dump screen width and height, cursor position, and all the character-attribute
pairs. (Kernels 1.1.67 through 1.1.91 only.
With kernel 1.1.92 or later, read from /dev/vcsa* instead.)
TIOCLINUX, subcode=9
Restore screen width and height, cursor position, and all the
character-attribute pairs. (Kernels 1.1.67 through 1.1.91 only.
With kernel 1.1.92 or later, write to /dev/vcsa* instead.)
TIOCLINUX, subcode=10
Handles the Power Saving feature of the new generation of monitors.
VESA screen blanking mode is set to argp, which is one
of:
0: Screen blanking is disabled.
1: The current video adapter register settings are saved,
then the controller is programmed to turn off the vertical synchronization
pulses. This puts the monitor into "standby" mode.
If your monitor has an Off_Mode timer, then it will eventually
power down by itself.
2: The current settings are saved, then both the vertical
and horizontal synchronization pulses are turned off. This puts
the monitor into "off" mode. If your monitor has no Off_Mode
timer, or if you want your monitor to power down immediately
when the blank_timer times out, then you choose this option.
(Caution: Powering down frequently will damage the monitor.)
(Since 1.1.76.)
-1 for error, and errno is set.
errno may take on these values:
EBADF file descriptor is invalid.
ENOTTY file descriptor is not associated with a character
special device, or the specified request does not
apply to it.
EINVAL file descriptor or argp is invalid.
EPERM permission violation.
Do not regard this man page as documentation of the Linux console
ioctl's. This is provided for the curious only, as an alternative to
reading the source. Ioctl's are undocumented Linux internals, liable to
be changed without warning. (And indeed, this page more or less
describes the situation as of kernel version 1.1.94; there are many
minor and not-so-minor differences with earlier versions.)
Very often, ioctl's are introduced for communication between the kernel
and one particular well-known program (fdisk(8), hdparm(8), setse-
rial(8), tunelp(8), loadkeys(1), gpm(8), consolechars(8), etc.), and
their behavior will be changed when required by these particular programs.
Programs using these ioctl's will not be portable to other versions of
Unix, will not work on older versions of Linux, and will not work on
future versions of Linux.
Use POSIX functions.
kbd_mode(1), loadkeys(1), dumpkeys(1), mknod(1), setleds(1), setmeta-
mode(1), ioperm(2), termios(2), execve(2), fcntl(2), mt(4), sd(4),
tty(4), ttys(4), vcs(4), vcsa(4), mapscrn(8), consolechars(8), resize-
cons(8), /usr/include/linux/kd.h, /usr/include/linux/vt.h.
Linux 28 Oct 1997 CONSOLE_IOCTLS(4)
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