src/lib/libutil/pty.c

145 lines
3.6 KiB
C

/* $OpenBSD: pty.c,v 1.22 2022/04/20 14:00:19 millert Exp $ */
/*-
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <termios.h>
#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <grp.h>
#include <sys/tty.h>
#include "util.h"
int
getptmfd(void)
{
return (open(PATH_PTMDEV, O_RDWR|O_CLOEXEC));
}
int
openpty(int *amaster, int *aslave, char *name, const struct termios *termp,
const struct winsize *winp)
{
int ptmfd;
if ((ptmfd = getptmfd()) == -1)
return (-1);
if (fdopenpty(ptmfd, amaster, aslave, name, termp, winp) == -1) {
close(ptmfd);
return (-1);
}
close(ptmfd);
return (0);
}
int
fdopenpty(int ptmfd, int *amaster, int *aslave, char *name,
const struct termios *termp, const struct winsize *winp)
{
int master, slave;
struct ptmget ptm;
/*
* Use /dev/ptm and the PTMGET ioctl to get a properly set up and
* owned pty/tty pair.
*/
if (ioctl(ptmfd, PTMGET, &ptm) == -1)
return (-1);
master = ptm.cfd;
slave = ptm.sfd;
if (name) {
/*
* Manual page says "at least 16 characters".
*/
strlcpy(name, ptm.sn, 16);
}
*amaster = master;
*aslave = slave;
if (termp)
(void) tcsetattr(slave, TCSAFLUSH, termp);
if (winp)
(void) ioctl(slave, TIOCSWINSZ, winp);
return (0);
}
pid_t
forkpty(int *amaster, char *name, const struct termios *termp,
const struct winsize *winp)
{
int ptmfd;
pid_t pid;
if ((ptmfd = getptmfd()) == -1)
return (-1);
if ((pid = fdforkpty(ptmfd, amaster, name, termp, winp)) == -1) {
close(ptmfd);
return (-1);
}
close(ptmfd);
return (pid);
}
pid_t
fdforkpty(int ptmfd, int *amaster, char *name, const struct termios *termp,
const struct winsize *winp)
{
int master, slave;
pid_t pid;
if (fdopenpty(ptmfd, &master, &slave, name, termp, winp) == -1)
return (-1);
switch (pid = fork()) {
case -1:
(void) close(master);
(void) close(slave);
return (-1);
case 0:
/*
* child
*/
(void) close(master);
login_tty(slave);
return (0);
}
/*
* parent
*/
*amaster = master;
(void) close(slave);
return (pid);
}