IOCTL_CONSOLE(2)          (2017-09-15)           IOCTL_CONSOLE(2)

     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: l l l.  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 func-
               tions 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.

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          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: l l.  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 dura-
               tion 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 nor-
               mally 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 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

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               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 indi-
               cated 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.)

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          GIO_SCRNMAP
               Get screen mapping from kernel.  argp points to an area
               of size E_TABSZ, which is loaded with the font posi-
               tions 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 charac-
               ter represent.  A special set of Unicodes, starting at
               U+F000, are used to represent "direct to font" map-
               pings.  (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 trans-
               lated 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 sym-
               bols.  (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

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               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: l l.  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: l l l.
               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

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               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 corre-
               sponding 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

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               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: l l.  VT_AUTO   auto vt switch-
               ing 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

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               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

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                   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 char-
               acters 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 char-
               acters 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.

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               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 verti-
                  cal 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.

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          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
          This page is part of release 5.10 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 https://www.kernel.org/doc/man-pages/.

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