cosmopolitan/libc/calls/posix_openpt.c

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2020-06-15 14:18:57 +00:00
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi
Copyright 2020 Justine Alexandra Roberts Tunney
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include "libc/calls/internal.h"
#include "libc/calls/termios.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/consts/pty.h"
#include "libc/sysv/consts/termios.h"
#include "libc/sysv/errfuns.h"
/**
* Opens new pseudo teletypewriter.
*
* @params flags is usually O_RDWR|O_NOCTTY
* @return file descriptor, or -1 w/ errno
*/
int posix_openpt(int flags) {
int fd, ilduce;
struct IoctlPtmGet ptm;
if ((flags & O_ACCMODE) != O_RDWR) return einval();
if (SupportsFreebsd() &&
((fd = posix_openpt$sysv(flags)) != -1 || errno != ENOSYS)) {
return fd;
} else if ((fd = open("/dev/ptmx", flags)) != -1 || errno != ENOENT) {
return fd;
} else if (SupportsOpenbsd() &&
((fd = open("/dev/ptm", flags)) != -1 || errno != ENOENT)) {
if (ioctl(fd, PTMGET, &ptm) != -1) {
close(ptm.workerfd);
ilduce = ptm.theduxfd;
} else {
ilduce = -1;
}
close(fd);
return ilduce;
} else {
return enosys();
}
}