kbd_tty.c

嵌入式系统图形用户界面编程

/*
** $Id: kbd_tty.c,v 1.17 2003/09/26 08:45:14 snig Exp $
**
** kbd_tty.c: /dev/tty TTY Keyboard Driver
**
** Copyright (C) 2003 Feynman Software.
** Copyright (C) 2000 ~ 2002 Song Lixin and Wei Yongming.
*/

/*
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

/*
** TODO:
*/

#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <termios.h>

#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <linux/kd.h>

#include "common.h"
#include "ial.h"
#include "gal.h"
#include "native.h"

static const char* tty_dev;

static int  TTY_Open(void);
static void TTY_Close(void);
static void TTY_GetModifierInfo(int *modifiers);
static int  TTY_Read(unsigned char *buf, int *modifiers);
static void TTY_Suspend(void);
static int  TTY_Resume(void);

KBDDEVICE kbddev_tty = {
	TTY_Open,
	TTY_Close,
	TTY_GetModifierInfo,
	TTY_Read,
	TTY_Suspend,
	TTY_Resume
};

static int kbd_fd;		/* file descriptor for keyboard */
static	struct termios	startup_termios;		/* original terminal modes */
static	int	startup_kbdmode;
struct termios	work_termios;	/* startup_termios terminal modes */

/*
 * Open the keyboard.
 * This is real simple, we just use a special file handle
 * that allows blocking I/O, and put the terminal into
 * character mode.
 */
static int TTY_Open (void)
{
    if (geteuid() == 0) /* is a super user, try to open the active console */
        tty_dev = "/dev/tty0";
    else    /* not a super user, so try to open the control terminal */
        tty_dev = "/dev/tty";

	kbd_fd = open(tty_dev, O_RDONLY | O_NOCTTY);
	if (kbd_fd < 0)
		return -1;

	if (tcgetattr(kbd_fd, &startup_termios) < 0)
		goto err;

	work_termios = startup_termios;

	work_termios.c_lflag &= ~(ICANON | ECHO  | ISIG);
	work_termios.c_iflag &= ~(ISTRIP | IGNCR | ICRNL | INLCR | IXOFF | IXON);
	work_termios.c_iflag |= IGNBRK;
	work_termios.c_cc[VMIN] = 0;
	work_termios.c_cc[VTIME] = 0;

	if(tcsetattr(kbd_fd, TCSAFLUSH, &work_termios) < 0)
		goto err;

	/* Put the keyboard into MEDIUMRAW mode.  Despite the name, this
	 * is really "mostly raw", with the kernel just folding long
	 * scancode sequences (e.g. E0 XX) onto single keycodes.
	 */
	ioctl (kbd_fd, KDGKBMODE, &startup_kbdmode);
	if (ioctl(kbd_fd, KDSKBMODE, K_MEDIUMRAW) < 0) 
		goto err;
	return kbd_fd;

err:
	close(kbd_fd);
	kbd_fd = 0;
	return -1;
}

/*
 * Close the keyboard.
 * This resets the terminal modes.
 */
static void TTY_Close(void)
{
	ioctl(kbd_fd, KDSKBMODE, startup_kbdmode);
	tcsetattr(kbd_fd, TCSANOW, &startup_termios);
	close(kbd_fd);
	kbd_fd = -1;
}

/*
 * Return the possible modifiers for the keyboard.
 */
static  void TTY_GetModifierInfo(int *modifiers)
{
	*modifiers = 0;			/* no modifiers available */
}

/*
 * This reads one keystroke from the keyboard, and the current state of
 * the mode keys (ALT, SHIFT, CTRL).  Returns -1 on error, 0 if no data
 * is ready, and 1 if data was read.  This is a non-blocking call.
 */
static int TTY_Read(unsigned char *buf, int *modifiers)
{
	int	cc;			/* characters read */
	unsigned char buf1;

	*modifiers = 0;			/* no modifiers yet */
	cc = read(kbd_fd, &buf1, 1);
	*buf = buf1;
	if (cc > 0) {
		return 1;
	}
	if ((cc < 0) && (errno != EINTR) && (errno != EAGAIN))
		return -1;
	return 0;
}

/* activate_keyboard:
 *  Put keyboard into the mode we want.
 */
static void TTY_Suspend(void)
{
	TTY_Close();
}

/* deactivate_keyboard:
 *  Restore the original keyboard settings.
 */
static int TTY_Resume(void)
{
	kbd_fd = open (tty_dev, O_NONBLOCK);
	if (kbd_fd < 0)
		return -1;

	if(tcsetattr(kbd_fd, TCSANOW, &work_termios) < 0)
		goto err;

	/* Put the keyboard into MEDIUMRAW mode.  Despite the name, this
	 * is really "mostly raw", with the kernel just folding long
	 * scancode sequences (e.g. E0 XX) onto single keycodes.
	 */
	if (ioctl(kbd_fd, KDSKBMODE, K_MEDIUMRAW) < 0) 
		goto err;
	return kbd_fd;

err:
	close(kbd_fd);
	kbd_fd = 0;
	return -1;
}