/* openvt.c - Run a program on a new VT
 *
 * Copyright 2014 Vivek Kumar Bhagat <vivek.bhagat89@gmail.com>
 *
 * No Standard

USE_OPENVT(NEWTOY(openvt, "c#<1>63sw", TOYFLAG_BIN|TOYFLAG_NEEDROOT))

config OPENVT
  bool "openvt"
  default n
  help
    usage: openvt [-c N] [-s] [-w] [--] [command [command_options]]

    start a program on a new virtual terminal (VT)

    -c N  Use VT N
    -s    Switch to new VT
    -w    Wait for command to exit
          if -s and -w option used together, switch back
          to originating VT when command completes
*/

#define FOR_openvt
#include "toys.h"
#include <linux/vt.h>
#include <linux/kd.h>

GLOBALS(
	unsigned long vt_num;
)

int find_console_fd(void)
{
	char *console_name[] = {"/dev/tty", "/dev/tty0", "/dev/console"};
	int i;
	int fd;
	char arg;

	for (i = 0; i < 3; i++) {
		fd = open(console_name[i], O_RDWR);
		if (fd < 0 && errno == EACCES)
			fd = open(console_name[i], O_RDONLY);

		if (fd < 0 && errno == EACCES)
			fd = open(console_name[i], O_WRONLY);

		if (fd >= 0) {
			arg = 0;
			if (0 == ioctl(fd, KDGKBTYPE, &arg))
				return fd;
			else
				close(fd);
		}
	}

	/* check std fd 0, 1 and 2 */
	for (fd = 0; fd < 3; fd++) {
		arg = 0;
		if (0 == ioctl(fd, KDGKBTYPE, &arg))
			return fd;
	}

	return -1;
}

int xvtnum(int fd)
{
	int ret;

	ret = ioctl(fd, VT_OPENQRY, (int *)&TT.vt_num);
	if (ret != 0 || TT.vt_num <= 0) perror_exit("can't find open VT");

	return TT.vt_num;
}

void openvt_main(void)
{
	int fd = -1, vt_fd = -1, pid, ret = 0;
	struct vt_stat vstate;

	if (!(toys.optflags & FLAG_c)) {
		// check if fd 0,1 or 2 is already opened
		for (fd = 0; fd < 3; fd++)
			if (!ioctl(fd, VT_GETSTATE, &vstate)) {
				ret = xvtnum(fd);
				break;
			}

		// find VT number using /dev/console
		if (!ret) {
			fd = xopen("/dev/console", O_RDONLY | O_NONBLOCK);
			xioctl(fd, VT_GETSTATE, &vstate);
			xvtnum(fd);
		}
	}

	sprintf(toybuf, "/dev/tty%lu", TT.vt_num);
	fd = find_console_fd();
	xioctl(fd, VT_GETSTATE, &vstate);

	close(0);	//new vt becomes stdin
	vt_fd = xopen(toybuf, O_RDWR);
	if (toys.optflags & FLAG_s) {
		ioctl(vt_fd, VT_ACTIVATE, TT.vt_num);
		ioctl(vt_fd, VT_WAITACTIVE, TT.vt_num);
	}

	close(1);
	close(2);
	dup2(vt_fd, 1);
	dup2(vt_fd, 2);
	while (vt_fd > 2)
		close(vt_fd--);

	pid = vfork();
	if (pid < 0)	perror_exit("Fork failed");
	else if (!pid) {
		setsid();
		ioctl(vt_fd, TIOCSCTTY, 0);
		xexec(toys.optargs);
	}

	if (toys.optflags & FLAG_w) {
		while (-1 == waitpid(pid, NULL, 0) && errno == EINTR)
			;
		if (toys.optflags & FLAG_s) {
			ioctl(fd, VT_ACTIVATE, vstate.v_active);
			ioctl(fd, VT_WAITACTIVE, vstate.v_active);
			//check why deallocate isn't working here
			xioctl(fd, VT_DISALLOCATE, (void *)(ptrdiff_t)TT.vt_num); 
		}
	}
}