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NAME

       console_ioctl - ioctl's for console terminal and virtual consoles

DESCRIPTION

       The  following  Linux-specific  ioctl(2)  requests are supported.  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
                  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: 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
              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 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 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 immediately.

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

                  struct unipair {
                      unsigned short unicode;
                      unsigned 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 {
                      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 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 {
                      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 1.1.63.)

       KDSETKEYCODE
              Write kernel keycode table  entry.   argp  points  to  a  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) */
                  };

              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 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 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 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 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 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[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 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.

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

       EINVAL The file descriptor or argp is invalid.

       EPERM  Insufficient permission.

NOTES

       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

       dumpkeys(1),   kbd_mode(1),    loadkeys(1),    mknod(1),    setleds(1),
       setmetamode(1), execve(2), fcntl(2), ioperm(2), termios(3), console(4),
       console_codes(4), mt(4), sd(4), tty(4), tty_ioctl(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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       description  of  the project, and information about reporting bugs, can
       be found at http://man7.org/linux/man-pages/.