minix/lib/libutil/pty.c

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/* $NetBSD: pty.c,v 1.31 2009/02/20 16:44:06 christos Exp $ */
/*-
* Copyright (c) 1990, 1993, 1994
* 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/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)pty.c 8.3 (Berkeley) 5/16/94";
#else
__RCSID("$NetBSD: pty.c,v 1.31 2009/02/20 16:44:06 christos Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <stdio.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include <util.h>
/*
* XXX: `v' removed until no ports are using console devices which use ttyv0
*/
#define TTY_LETTERS "pqrstuwxyzPQRST"
#define TTY_OLD_SUFFIX "0123456789abcdef"
#define TTY_NEW_SUFFIX "ghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
int
openpty(int *amaster, int *aslave, char *name, struct termios *term,
struct winsize *winp)
{
char line[] = "/dev/XtyXX";
const char *cp1, *cp2, *cp, *linep;
int master, slave;
gid_t ttygid;
mode_t mode;
struct group grs, *grp;
char grbuf[1024];
_DIAGASSERT(amaster != NULL);
_DIAGASSERT(aslave != NULL);
/* name may be NULL */
/* term may be NULL */
/* winp may be NULL */
#ifndef __minix
if ((master = open("/dev/ptm", O_RDWR)) != -1) {
struct ptmget pt;
if (ioctl(master, TIOCPTMGET, &pt) != -1) {
(void)close(master);
master = pt.cfd;
slave = pt.sfd;
linep = pt.sn;
goto gotit;
}
(void)close(master);
}
#endif
(void)getgrnam_r("tty", &grs, grbuf, sizeof(grbuf), &grp);
if (grp != NULL) {
ttygid = grp->gr_gid;
mode = S_IRUSR|S_IWUSR|S_IWGRP;
} else {
ttygid = getgid();
mode = S_IRUSR|S_IWUSR;
}
for (cp1 = TTY_LETTERS; *cp1; cp1++) {
line[8] = *cp1;
for (cp = cp2 = TTY_OLD_SUFFIX TTY_NEW_SUFFIX; *cp2; cp2++) {
line[5] = 'p';
line[9] = *cp2;
if ((master = open(line, O_RDWR, 0)) == -1) {
if (errno != ENOENT)
continue; /* busy */
if ((size_t)(cp2 - cp + 1) < sizeof(TTY_OLD_SUFFIX))
return -1; /* out of ptys */
else
break; /* out of ptys in this group */
}
line[5] = 't';
linep = line;
if (chown(line, getuid(), ttygid) == 0 &&
chmod(line, mode) == 0 &&
revoke(line) == 0 &&
(slave = open(line, O_RDWR, 0)) != -1) {
gotit:
*amaster = master;
*aslave = slave;
if (name)
(void)strcpy(name, linep);
if (term)
(void)tcsetattr(slave, TCSAFLUSH, term);
if (winp)
(void)ioctl(slave, TIOCSWINSZ, winp);
return 0;
}
(void)close(master);
}
}
errno = ENOENT; /* out of ptys */
return -1;
}
pid_t
forkpty(int *amaster, char *name, struct termios *term, struct winsize *winp)
{
int master, slave;
pid_t pid;
_DIAGASSERT(amaster != NULL);
/* name may be NULL */
/* term may be NULL */
/* winp may be NULL */
if (openpty(&master, &slave, name, term, winp) == -1)
return -1;
switch (pid = fork()) {
case -1:
return -1;
case 0:
/*
* child
*/
(void)close(master);
login_tty(slave);
return 0;
}
/*
* parent
*/
*amaster = master;
(void)close(slave);
return pid;
}