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man: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:
            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 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
     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:
            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 duration in msec.  If the
            duration  is  zero,  the  sound  is turned off.  Control returns
            immediately.  For example, argp = (125<<16) + 0x637 would  spec-
            ify  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
            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 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 ,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:
            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_ESCPRE-
            FIX    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
            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==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:
            l l.  VT_AUTO   auto vt  switching  VT_PROCESS     process  con-
            trols 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,
     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),  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

     This  page  is  part of release 4.16 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/.

Linux 2017-09-15 IOCTL_CONSOLE(2)

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