xref: /freebsd/lib/libutil/pty.c (revision 4f52dfbb)
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 
35 #if defined(LIBC_SCCS) && !defined(lint)
36 #if 0
37 static char sccsid[] = "@(#)pty.c	8.3 (Berkeley) 5/16/94";
38 #endif
39 #endif /* LIBC_SCCS and not lint */
40 
41 #include <sys/types.h>
42 #include <sys/ioctl.h>
43 #include <sys/stat.h>
44 
45 #include <errno.h>
46 #include <fcntl.h>
47 #include <grp.h>
48 #include <libutil.h>
49 #include <stdlib.h>
50 #include <string.h>
51 #include <termios.h>
52 #include <unistd.h>
53 
54 int
55 openpty(int *amaster, int *aslave, char *name, struct termios *termp,
56     struct winsize *winp)
57 {
58 	const char *slavename;
59 	int master, slave;
60 
61 	master = posix_openpt(O_RDWR|O_NOCTTY);
62 	if (master == -1)
63 		return (-1);
64 
65 	if (grantpt(master) == -1)
66 		goto bad;
67 
68 	if (unlockpt(master) == -1)
69 		goto bad;
70 
71 	slavename = ptsname(master);
72 	if (slavename == NULL)
73 		goto bad;
74 
75 	slave = open(slavename, O_RDWR);
76 	if (slave == -1)
77 		goto bad;
78 
79 	*amaster = master;
80 	*aslave = slave;
81 
82 	if (name)
83 		strcpy(name, slavename);
84 	if (termp)
85 		tcsetattr(slave, TCSAFLUSH, termp);
86 	if (winp)
87 		ioctl(slave, TIOCSWINSZ, (char *)winp);
88 
89 	return (0);
90 
91 bad:	close(master);
92 	return (-1);
93 }
94 
95 int
96 forkpty(int *amaster, char *name, struct termios *termp, struct winsize *winp)
97 {
98 	int master, slave, pid;
99 
100 	if (openpty(&master, &slave, name, termp, winp) == -1)
101 		return (-1);
102 	switch (pid = fork()) {
103 	case -1:
104 		(void)close(slave);
105 		return (-1);
106 	case 0:
107 		/*
108 		 * child
109 		 */
110 		(void)close(master);
111 		login_tty(slave);
112 		return (0);
113 	}
114 	/*
115 	 * parent
116 	 */
117 	*amaster = master;
118 	(void) close(slave);
119 	return (pid);
120 }
121