musl/src/misc/openpty.c

#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <pty.h>
#include <stdio.h>

/* Nonstandard, but vastly superior to the standard functions */

int openpty(int *m, int *s, char *name, const struct termios *tio, const struct winsize *ws)
{
	int n=0;
	char buf[20];

	*m = open("/dev/ptmx", O_RDWR|O_NOCTTY);
	if (*m < 0) return -1;

	if (ioctl(*m, TIOCSPTLCK, &n) || ioctl (*m, TIOCGPTN, &n)) {
		close(*m);
		return -1;
	}

	if (!name) name = buf;
	snprintf(name, sizeof buf, "/dev/pts/%d", n);
	if ((*s = open(name, O_RDWR|O_NOCTTY)) < 0) {
		close(*m);
		return -1;
	}

	if (tio) tcsetattr(*s, TCSANOW, tio);
	if (ws) ioctl(*s, TIOCSWINSZ, ws);

	return 0;
}