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

NAME
       console_ioctl - ioctls for console terminal and virtual consoles

DESCRIPTION
       The following Linux-specific ioctl(2) requests are supported.  Each requires a third argu‐
       ment, 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 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 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 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  con‐
              tains,  in  order, the Red, Green, and Blue values for the 16 available screen col‐
              ors: 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-charac‐
              ter font, or if the console is not in text mode.

       GIO_FONTX
              Gets  screen font and associated information.  argp points to a struct consolefont‐
              desc (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 the first  N  of
              them  are  used for an 8xN font (0 < N <= 32).  This call also invalidates the Uni‐
              code 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 charac‐
              ters.

       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  con‐
              sole 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 Uni‐
              codes, 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 parame‐
              ters 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 terminal.

       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-charac‐
              ter 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_buf‐
              fer 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 moni‐
                 tor 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 synchro‐
                 nization 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 immedi‐
                 ately 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 spec‐
              ified 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  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), 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
       This  page  is  part of release 4.04 of the Linux man-pages project.  A description of the
       project, information about reporting bugs, and the latest version of  this  page,  can  be
       found at http://www.kernel.org/doc/man-pages/.

Linux                                       2009-02-28                           CONSOLE_IOCTL(4)

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