CONSOLE_IOCTLS(4)   Linux Programmer's Manual   CONSOLE_IOCTLS(4)

NAME
       console  ioctl's- ioctl's for console terminal and virtual
       consoles

DESCRIPTION
       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 sup-
       ported.  Each requires a third argument, assumed  here  to
       be argp.

       KDGETLED
              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
              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: dis-
              playing 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
              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
              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
              Get  keyboard  type. This returns the value KB_101,
              defined as 0x02.

       KDADDIO
              Add  I/O  port  as  valid.   Equivalent   to   iop-
              erm(arg,1,1).

       KDDELIO
              Delete  I/O  port  as  valid.  Equivalent  to  iop-
              erm(arg,1,0).

       KDENABIO
              Enable I/O  to  video  board.  Equivalent  to  iop-
              erm(0x3b4, 0x3df-0x3b4+1, 1).

       KDDISABIO
              Disable  I/O  to  video  board.  Equivalent to iop-
              erm(0x3b4, 0x3df-0x3b4+1, 0).

       KDSETMODE
              Set text/graphics mode.  argp is one of these:

                  KD_TEXT       0x00
                  KD_GRAPHICS   0x01

       KDGETMODE
              Get text/graphics mode.   argp  points  to  a  long
              which is set to one of the above values.

       KDMKTONE
              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
              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 immedi-
              ately.

       GIO_FONT
              Gets  screen font in expanded form.  argp points to
              an 8192 byte array.

       PIO_FONT
              Sets screen font.  Load font into the EGA/VGA char-
              acter  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
              Get  screen mapping from kernel.  argp points to an
              area of size E_TABSZ.

       PIO_SCRNMAP
              Loads the "user definable" (fourth)  table  in  the
              kernel  which  maps  bytes into console screen sym-
              bols.  argp points to an area of size E_TABSZ.

       GIO_UNIMAP
              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
              Put unicode-to-font mapping in kernel.  argp points
              to a struct unimapdesc.  (Since 1.1.92)

       PIO_UNIMAPCLR
              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
              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
              Sets current keyboard mode.  argp is a  long  equal
              to one of the above values.

       KDGKBMETA
              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
              Sets meta key handling mode.  argp is a long  equal
              to one of the above values.

       KDGKBENT
              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 corre-
              sponding action code, or K_HOLE if there is no such
              key, or K_NOSUCHMAP if kb_table is invalid.

       KDSKBENT
              Sets  one  entry in translation table.  argp points
              to a struct kbentry.

       KDGKBSENT
              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
              Sets one function key string entry.  argp points to
              a struct kbsentry.

       KDGKBDIACR
              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
              Read kernel keycode table entry (scan code to  key-
              code).  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==scancode.)  (Since 1.1.63.)

       KDSETKEYCODE
              Write  kernel  keycode table entry.  argp points to
              struct kbkeycode.  (Since 1.1.63.)

       KDSIGACCEPT
              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
              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
              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
              Set mode of active vt.  argp  points  to  a  struct
              vt_mode.

       VT_GETSTATE
              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
              Release a display.

       VT_ACTIVATE
              Switch to vt argp (1 <= argp <= MAX_NR_CONSOLES).

       VT_WAITACTIVE
              Wait until vt argp has been activated.

       VT_DISALLOCATE
              Deallocate  the  memory  associated  with  vt argp.
              (Since 1.1.54.)

       VT_RESIZE
              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 cor-
              ner is row=column=1.)  sel_mode is 0 for character-
              by-character  selection,  1 for word-by-word selec-
              tion, or 2 for line-by-line selection.   The  indi-
              cated  screen  characters are highlighted and saved
              in the static array sel_buffer in devices/char/con-
              sole.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 genera-
              tion 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 mon-
              itor 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.)

RETURN VALUES
       -1 for error, and errno is set.

ERRORS
       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.

WARNING
       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),  setserial(8),   tunelp(8),   load-
       keys(1),  gpm(8), consolechars(8), etc.), and their behav-
       ior will be changed when required by these particular pro-
       grams.

       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.

SEE ALSO
       kbd_mode(1),     loadkeys(1),    dumpkeys(1),    mknod(1),
       setleds(1),   setmetamode(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                          1