ubase/vtallow.c

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/* See LICENSE file for copyright and license details. */
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include "util.h"
#define CONSOLE "/dev/console"
#define VT_LOCKSWITCH 0x560B /* disallow vt switching */
#define VT_UNLOCKSWITCH 0x560C /* allow vt switching */
static void
usage(void)
{
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eprintf("usage: %s n | y\n", argv0);
}
int
main(int argc, char *argv[])
{
int fd;
int allow;
ARGBEGIN {
default:
usage();
} ARGEND;
if (argc != 1)
usage();
if (!strcmp(argv[0], "y"))
allow = 1;
else if (!strcmp(argv[0], "n"))
allow = 0;
else
usage();
if ((fd = open(CONSOLE, O_WRONLY)) < 0)
eprintf("open %s:", CONSOLE);
if (ioctl(fd, allow ? VT_UNLOCKSWITCH : VT_LOCKSWITCH) < 0)
eprintf("cannot %s VT switch:",
allow ? "unlock" : "lock");
close(fd);
return 0;
}