| LED_CAP | 0x04 | caps lock led |
| LED_NUM | 0x02 | num lock led |
| LED_SCR | 0x01 | scroll lock led |
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.
| KD_TEXT | 0x00 |
| KD_GRAPHICS | 0x01 |
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.)
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.)
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.)
| 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 */ |
| K_METABIT | 0x03 | set high order bit |
| K_ESCPREFIX | 0x04 | escape prefix |
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.
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.
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;
};
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.)
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 |
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.)
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.)
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.
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.
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.
/usr/include/linux/kd.h, /usr/include/linux/vt.h