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NAME

       ioctl_console - ioctls for console terminal and virtual consoles

DESCRIPTION

       The  following  Linux-specific  ioctl(2)  requests are supported for console terminals and
       virtual consoles.  Each requires a third argument, assumed here to be argp.

       KDGETLED
              Get state of LEDs.  argp points to a char.  The lower three bits of *argp  are  set
              to the state of the LEDs, as follows:

              LED_CAP    0x04   caps lock led
              LED_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 the
              unsigned long integer in 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 Linux 1.1.54, the LEDs just reflected  the  state  of  the  corresponding  keyboard
       flags, and KDGETLED/KDSETLED would also change the keyboard flags.  Since Linux 1.1.54 the
       LEDs can be made to display  arbitrary  information,  but  by  default  they  display  the
       keyboard flags.  The following two ioctls 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 Linux 1.1.54.)

       KDSKBLED
              Set keyboard flags CapsLock, NumLock, ScrollLock (not lights).  argp is an unsigned
              long  integer that 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 Linux 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 ioperm(arg,1,1).

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

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

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

       KDSETMODE
              Set text/graphics mode.  argp is an unsigned integer containing one of:

              KD_TEXT       0x00
              KD_GRAPHICS   0x01

       KDGETMODE
              Get  text/graphics  mode.   argp points to an int which is set to one of the values
              shown above for KDSETMODE.

       KDMKTONE
              Generate tone of specified length.  The lower 16 bits of the unsigned long  integer
              in 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 Linux 0.99pl1; broken in Linux 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 immediately.

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

       PIO_CMAP
              Change  the  default  text-mode  color  map.   argp points to a 48-byte array which
              contains, in order, the Red, Green, and Blue values for  the  16  available  screen
              colors:  0  is  off,  and 255 is full intensity.  The default colors 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 purple, bright
              cyan and white.  (Since Linux 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 Linux 1.3.1.)

       PIO_FONT
              Sets 256-character screen font.  Load font into the  EGA/VGA  character  generator.
              argp  points to an 8192-byte map, with 32 bytes per character.  Only the 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 information.  argp points to a

                  struct consolefontdesc {
                      unsigned short charcount;  /* characters in font
                                                    (256 or 512) */
                      unsigned 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 processes.  This call also invalidates  the  Unicode  mapping.   (Since
              Linux 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 Linux 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 Linux 1.3.1.)

       PIO_SCRNMAP
              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.

       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 Linux 1.3.1.)

       GIO_UNIMAP
              Get Unicode-to-font mapping from kernel.  argp points to a

                  struct unimapdesc {
                      unsigned short  entry_ct;
                      struct unipair *entries;
                  };

              where entries points to an array of ,IP
                  struct unipair {
                      unsigned short unicode;
                      unsigned short fontpos;
                  };

              (Since Linux 1.1.92.)

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

       PIO_UNIMAPCLR
              Clear table, possibly advise hash algorithm.  argp points to a

                  struct unimapinit {
                      unsigned short advised_hashsize;  /* 0 if no opinion */
                      unsigned short advised_hashstep;  /* 0 if no opinion */
                      unsigned short advised_hashlevel; /* 0 if no opinion */
                  };

              (Since Linux 1.1.92.)

       KDGKBMODE
              Gets current keyboard mode.  argp points to a long which is set to one of these:

              K_RAW         0x00  /* Raw (scancode) mode */
              K_XLATE       0x01  /* Translate keycodes using keymap */
              K_MEDIUMRAW   0x02  /* Medium raw (scancode) mode */
              K_UNICODE     0x03  /* Unicode mode */
              K_OFF         0x04  /* Disabled mode; since Linux 2.6.39 */

       KDSKBMODE
              Sets current keyboard mode.  argp is a long equal to one of the  values  shown  for
              KDGKBMODE.

       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 values shown above
              for KDGKBMETA.

       KDGKBENT
              Gets one entry in key translation table (keycode to action code).  argp points to a

                  struct kbentry {
                      unsigned char  kb_table;
                      unsigned char  kb_index;
                      unsigned 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
              Sets one entry in translation table.  argp points to a struct kbentry.

       KDGKBSENT
              Gets one function key string.  argp points to a

                  struct kbsentry {
                      unsigned char kb_func;
                      unsigned 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 {
                      unsigned char diacr;
                      unsigned char base;
                      unsigned char result;
                  };

       KDGETKEYCODE
              Read kernel keycode table entry (scan code to keycode).  argp points to a

                  struct kbkeycode {
                      unsigned int scancode;
                      unsigned int keycode;
                  };

              keycode is set to correspond to the given scancode.  (89 <= scancode <=  255  only.
              For 1 <= scancode <= 88, keycode==scancode.)  (Since Linux 1.1.63.)

       KDSETKEYCODE
              Write kernel keycode table entry.  argp points to a struct kbkeycode.  (Since Linux
              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) */
                  };

              which is set to the mode of the active vt.  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 {
                      unsigned short v_active;  /* active vt */
                      unsigned short v_signal;  /* signal to send */
                      unsigned short v_state;   /* vt bit mask */
                  };

              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 Linux 1.1.54.)

       VT_RESIZE
              Set the kernel's idea of screensize.  argp points to a

                  struct vt_sizes {
                      unsigned short v_rows;       /* # rows */
                      unsigned short v_cols;       /* # columns */
                      unsigned short v_scrollsize; /* no longer used */
                  };

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

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

                  struct vt_consize {
                      unsigned short v_rows;  /* number of rows */
                      unsigned short v_cols;  /* number of columns */
                      unsigned short v_vlin;  /* number of pixel rows
                                                 on screen */
                      unsigned short v_clin;  /* number of pixel rows
                                                 per character */
                      unsigned short v_vcol;  /* number of pixel columns
                                                 on screen */
                      unsigned short 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 Linux 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 terminal.

       TIOCLINUX, subcode=0
              Dump  the screen.  Disappeared in Linux 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 Linux 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 word-by-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 Linux 1.1.32.)

       TIOCLINUX, subcode=6
              argp points to a char which is set to the value of the kernel variable shift_state.
              (Since Linux 1.1.32.)

       TIOCLINUX, subcode=7
              argp points  to  a  char  which  is  set  to  the  value  of  the  kernel  variable
              report_mouse.  (Since Linux 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[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 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 Linux
                 1.1.76.)

RETURN VALUE

       On success, 0 is returned.  On error, -1 is returned, and errno is set.

ERRORS

       errno may take on these values:

       EBADF  The file descriptor is invalid.

       EINVAL The file descriptor or argp is invalid.

       ENOTTY The file descriptor is not associated with  a  character  special  device,  or  the
              specified request does not apply to it.

       EPERM  Insufficient permission.

NOTES

       Warning:  Do  not regard this man page as documentation of the Linux console ioctls.  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, ioctls 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 ioctls 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

       dumpkeys(1), kbd_mode(1), loadkeys(1), mknod(1),  setleds(1),  setmetamode(1),  execve(2),
       fcntl(2),  ioctl_tty(2),  ioperm(2),  termios(3),  console_codes(4), mt(4), sd(4), tty(4),
       ttyS(4), vcs(4), vcsa(4), charsets(7), mapscrn(8), resizecons(8), setfont(8)

       /usr/include/linux/kd.h, /usr/include/linux/vt.h

COLOPHON

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       project,  information  about  reporting  bugs, and the latest version of this page, can be
       found at https://www.kernel.org/doc/man-pages/.