pty.c revision 175352 
1/*-
2 * Copyright (c) 1990, 1993, 1994
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31__FBSDID("$FreeBSD: head/lib/libutil/pty.c 175352 2008-01-15 15:36:23Z jhb $");
32
33#if defined(LIBC_SCCS) && !defined(lint)
34#if 0
35static char sccsid[] = "@(#)pty.c	8.3 (Berkeley) 5/16/94";
36#endif
37#endif /* LIBC_SCCS and not lint */
38
39#include <sys/types.h>
40#include <sys/ioctl.h>
41#include <sys/stat.h>
42
43#include <errno.h>
44#include <fcntl.h>
45#include <grp.h>
46#include <libutil.h>
47#include <stdlib.h>
48#include <string.h>
49#include <termios.h>
50#include <unistd.h>
51
52int
53openpty(int *amaster, int *aslave, char *name, struct termios *termp,
54    struct winsize *winp)
55{
56	const char *slavename;
57	int master, slave;
58
59	master = posix_openpt(O_RDWR);
60	if (master == -1)
61		return (-1);
62
63	if (grantpt(master) == -1) {
64		close(master);
65		return (-1);
66	}
67
68	slavename = ptsname(master);
69	if (slavename == NULL) {
70		close(master);
71		return (-1);
72	}
73
74	if (revoke(slavename) == -1) {
75		close(master);
76		return (-1);
77	}
78
79	slave = open(slavename, O_RDWR);
80	if (slave == -1) {
81		close(master);
82		return (-1);
83	}
84
85	if (unlockpt(master) == -1) {
86		close(master);
87		close(slave);
88		return (-1);
89	}
90
91	*amaster = master;
92	*aslave = slave;
93
94	if (name)
95		strcpy(name, slavename);
96	if (termp)
97		tcsetattr(slave, TCSAFLUSH, termp);
98	if (winp)
99		ioctl(slave, TIOCSWINSZ, (char *)winp);
100
101	return (0);
102}
103
104int
105forkpty(int *amaster, char *name, struct termios *termp, struct winsize *winp)
106{
107	int master, slave, pid;
108
109	if (openpty(&master, &slave, name, termp, winp) == -1)
110		return (-1);
111	switch (pid = fork()) {
112	case -1:
113		return (-1);
114	case 0:
115		/*
116		 * child
117		 */
118		(void) close(master);
119		login_tty(slave);
120		return (0);
121	}
122	/*
123	 * parent
124	 */
125	*amaster = master;
126	(void) close(slave);
127	return (pid);
128}
129