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

NAME
       console  ioctl  - 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.

       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.   (Thus since 0.99pl1;
              broken in 2.1.49-50.)

       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_CMAP
              Get the current default  colour  map  from  kernel.
              argp points to a 48-byte array.  (Since 1.3.3.)

       PIO_CMAP
              Change  the  default  text-mode  colour  map.  argp
              points to a 48-byte array which contains, in order,
              the  Red,  Green, and Blue values for the 16 avail-
              able screen colours: 0 is  off,  and  255  is  full
              intensity.   The  default  colours  are,  in order:
              black, dark red, dark green, brown, dark blue, dark
              purple,  dark  cyan,  light grey, dark grey, bright
              red, bright green, yellow, bright blue, bright pur-
              ple, bright cyan and white.  (Since 1.3.3.)

       GIO_FONT
              Gets  256-character  screen  font in expanded form.
              argp points to an  8192  byte  array.   Fails  with
              error code EINVAL if the currently loaded font is a
              512-character font, or if the  console  is  not  in
              text mode.

       GIO_FONTX
              Gets  screen font and associated information.  argp
              points to a struct consolefontdesc (see PIO_FONTX).
              On  call,  the charcount field should be set to the
              maximum number of characters that would fit in  the
              buffer  pointed  to  by  chardata.   On return, the
              charcount  and  charheight  are  filled  with   the
              respective  data for the currently loaded font, and
              the chardata array contains the font  data  if  the
              initial  value  of charcount indicated enough space
              was available; otherwise the  buffer  is  untouched
              and errno is set to ENOMEM.  (Since 1.3.1.)

       PIO_FONT
              Sets 256-character 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).
              This call also invalidates the Unicode mapping.

       PIO_FONTX
              Sets  screen font and associated rendering informa-
              tion.  argp points to a

              struct consolefontdesc {
                      u_short charcount;      /* characters in font (256 or 512) */
                      u_short charheight;     /* scan lines per character (1-32) */
                      char *chardata;         /* font data in expanded form */
              };

              If necessary,  the  screen  will  be  appropriately
              resized,  and SIGWINCH sent to the appropriate pro-
              cesses.  This call  also  invalidates  the  Unicode
              mapping.  (Since 1.3.1.)

       PIO_FONTRESET
              Resets the screen font, size and Unicode mapping to
              the bootup defaults.  argp is unused, but should be
              set  to  NULL  to  ensure compatibility with future
              versions of Linux.  (Since 1.3.28.)

       GIO_SCRNMAP
              Get screen mapping from kernel.  argp points to  an
              area of size E_TABSZ, which is loaded with the font
              positions used to  display  each  character.   This
              call is likely to return useless information if the
              currently loaded font is more than 256  characters.

       GIO_UNISCRNMAP
              Get  full Unicode screen mapping from kernel.  argp
              points to an area of  size  E_TABSZ*sizeof(unsigned
              short),  which  is  loaded  with  the Unicodes each
              character represent.  A special  set  of  Unicodes,
              starting  at U+F000, are used to represent ``direct
              to font'' mappings.  (Since 1.3.1.)

       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.

       PIO_UNISCRNMAP
              Loads the ``user definable'' (fourth) table in  the
              kernel  which  maps  bytes into Unicodes, which are
              then translated into screen  symbols  according  to
              the  currently loaded Unicode-to-font map.  Special
              Unicodes starting at U+F000  can  be  used  to  map
              directly to the font symbols.  (Since 1.3.1.)

       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  the  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 */
              };

              Note that this does not change the videomode.   See
              resizecons(8).  (Since 1.1.54.)

       VT_RESIZEX
              Set the kernel's idea of various screen parameters.
              argp points to a

              struct vt_consize {
                      ushort v_rows;          /* number of rows */
                      ushort v_cols;          /* number of columns */
                      ushort v_vlin;          /* number of pixel rows on screen */
                      ushort v_clin;          /* number of pixel rows per character */
                      ushort v_vcol;          /* number of pixel columns on screen */
                      ushort v_ccol;          /* number of pixel columns per character */
              };

              Any parameter may be set to zero,  indicating  ``no
              change'',  but if multiple parameters are set, they
              must be self-consistent.  Note that this  does  not
              change  the  videomode.  See resizecons(8).  (Since
              1.3.3.)

       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[1],  which  governs  what  screen  blanking
              does:

                  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, hdparm, setserial,  tunelp,  loadkeys,  selection,
       setfont,  etc.),  and  their behavior will be changed when
       required by this particular program.

       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),   charsets(4),   console(4),   con-
       sole_codes(4),  mt(4),  sd(4),  tty(4),  ttys(4),  vcs(4),
       vcsa(4),    mapscrn(8),     setfont(8),     resizecons(8),
       /usr/include/linux/kd.h, /usr/include/linux/vt.h

Linux                   September 18, 1995                      1