fusl/src/misc/openpty.c

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

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

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

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

  pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);

  if (ioctl(m, TIOCSPTLCK, &n) || ioctl(m, TIOCGPTN, &n))
    goto fail;

  if (!name)
    name = buf;
  snprintf(name, sizeof buf, "/dev/pts/%d", n);
  if ((s = open(name, O_RDWR | O_NOCTTY)) < 0)
    goto fail;

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

  *pm = m;
  *ps = s;

  pthread_setcancelstate(cs, 0);
  return 0;
fail:
  close(m);
  pthread_setcancelstate(cs, 0);
  return -1;
}