xref: /freebsd/lib/libutil/pty.c (revision 3078531de10dcae44b253a35125c949ff4235284)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1990, 1993, 1994
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 __SCCSID("@(#)pty.c	8.3 (Berkeley) 5/16/94");
35 
36 #include <sys/types.h>
37 #include <sys/ioctl.h>
38 #include <sys/stat.h>
39 
40 #include <errno.h>
41 #include <fcntl.h>
42 #include <grp.h>
43 #include <libutil.h>
44 #include <stdlib.h>
45 #include <string.h>
46 #include <termios.h>
47 #include <unistd.h>
48 
49 int
50 openpty(int *amaster, int *aslave, char *name, struct termios *termp,
51     struct winsize *winp)
52 {
53 	const char *slavename;
54 	int master, slave;
55 
56 	master = posix_openpt(O_RDWR|O_NOCTTY);
57 	if (master == -1)
58 		return (-1);
59 
60 	if (grantpt(master) == -1)
61 		goto bad;
62 
63 	if (unlockpt(master) == -1)
64 		goto bad;
65 
66 	slavename = ptsname(master);
67 	if (slavename == NULL)
68 		goto bad;
69 
70 	slave = open(slavename, O_RDWR);
71 	if (slave == -1)
72 		goto bad;
73 
74 	*amaster = master;
75 	*aslave = slave;
76 
77 	if (name)
78 		strcpy(name, slavename);
79 	if (termp)
80 		tcsetattr(slave, TCSAFLUSH, termp);
81 	if (winp)
82 		ioctl(slave, TIOCSWINSZ, (char *)winp);
83 
84 	return (0);
85 
86 bad:	close(master);
87 	return (-1);
88 }
89 
90 int
91 forkpty(int *amaster, char *name, struct termios *termp, struct winsize *winp)
92 {
93 	int master, slave, pid;
94 
95 	if (openpty(&master, &slave, name, termp, winp) == -1)
96 		return (-1);
97 	switch (pid = fork()) {
98 	case -1:
99 		(void)close(slave);
100 		return (-1);
101 	case 0:
102 		/*
103 		 * child
104 		 */
105 		(void)close(master);
106 		login_tty(slave);
107 		return (0);
108 	}
109 	/*
110 	 * parent
111 	 */
112 	*amaster = master;
113 	(void) close(slave);
114 	return (pid);
115 }
116