console_ioctl

IOCTL_CONSOLE(2)           Linux Programmer's Manual          IOCTL_CONSOLE(2)

NAME
       ioctl_console - ioctls for console terminal and virtual consoles

DESCRIPTION
       The  following  Linux-specific ioctl(2) requests are supported for con-
       sole 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  corre-
       sponding  keyboard  flags,  and KDGETLED/KDSETLED would also change the
       keyboard flags.  Since Linux 1.1.54 the LEDs can be made to display ar-
       bitrary  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 un-
              signed long integer in argp specify the period in clock  cycles,
              and  the  upper 16 bits give the duration in msec.  If the dura-
              tion is zero, the sound is turned off.  Control returns  immedi-
              ately.   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 spec-
              ify the period in clock cycles (that  is,  argp  =  1193180/fre-
              quency).  argp = 0 turns sound off.  In either case, control re-
              turns 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  cur-
              rently 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 SIG-
              WINCH sent to the appropriate processes.  This call also invali-
              dates 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  informa-
              tion 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

                  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 key-
              code  (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 {
                      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 kb-
              sentry.

       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==scan-
              code.)  (Since Linux 1.1.63.)

       KDSETKEYCODE
              Write kernel keycode table entry.  argp points to a struct  kbk-
              eycode.  (Since Linux 1.1.63.)

       KDSIGACCEPT
              The calling process indicates its willingness to accept the sig-
              nal 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 resize-
              cons(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  indi-
              cated  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 char-
              acter-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  moni-
              tors.   VESA  screen blanking mode is set to argp[1], which gov-
              erns 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 syn-
                 chronization 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 con-
       sole ioctls.  This is provided for the curious only, as an  alternative
       to  reading  the source.  Ioctl's are undocumented Linux internals, li-
       able 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), setmeta-
       mode(1), execve(2), fcntl(2), ioctl_tty(2), ioperm(2), termios(3), con-
       sole_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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       description  of  the project, information about reporting bugs, and the
       latest    version    of    this    page,    can     be     found     at
       https://www.kernel.org/doc/man-pages/.

Linux                             2017-09-15                  IOCTL_CONSOLE(2)
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