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/*
* consoletype.c
* simple app to figure out whether the current terminal
* is serial, console (vt), or remote (pty).
*
* Copyright 1999-2020 Gentoo Authors
* Distributed under the terms of the GNU General Public License v2
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#if defined(__linux__)
#include <sys/sysmacros.h>
#endif
enum termtype {
IS_VT = 0,
IS_SERIAL = 1,
IS_PTY = 2,
IS_UNK = 3
};
const char * const tty_names[] = {
"vt",
"serial",
"pty",
"unknown"
};
static inline int check_ttyname(void)
{
char *tty = ttyname(0);
if (tty == NULL)
return IS_UNK;
if (strncmp(tty, "/dev/", 5) == 0)
tty += 5;
if (!strncmp (tty, "ttyS", 4) || !strncmp (tty, "cuaa", 4))
return IS_SERIAL;
else if (!strncmp (tty, "pts/", 4) || !strncmp (tty, "ttyp", 4))
return IS_PTY;
else if (!strncmp (tty, "tty", 3))
return IS_VT;
else
return IS_UNK;
}
static inline int check_devnode(void)
{
#if defined(__linux__)
int maj;
struct stat sb;
fstat(0, &sb);
maj = major(sb.st_rdev);
if (maj != 3 && (maj < 136 || maj > 143)) {
#if defined(TIOCLINUX)
unsigned char twelve = 12;
if (ioctl (0, TIOCLINUX, &twelve) < 0)
return IS_SERIAL;
#endif
return IS_VT;
} else
return IS_PTY;
#endif
return IS_UNK;
}
int main(int argc, char *argv[])
{
int rc;
int type = check_ttyname();
if (type == IS_UNK)
type = check_devnode();
puts(tty_names[type]);
if (argc > 1 && strcmp(argv[1], "stdout") == 0)
rc = 0;
else
rc = type;
return rc;
}
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