xref: /freebsd/lib/libutil/pty.c (revision 6c6c03be2ddb04c54e455122799923deaefa4114)
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("$FreeBSD$");
32 
33 #if defined(LIBC_SCCS) && !defined(lint)
34 #if 0
35 static 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 
51 int
52 openpty(int *amaster, int *aslave, char *name, struct termios *termp,
53     struct winsize *winp)
54 {
55 	const char *slavename;
56 	int master, slave;
57 
58 	master = posix_openpt(O_RDWR|O_NOCTTY);
59 	if (master == -1)
60 		return (-1);
61 
62 	if (grantpt(master) == -1)
63 		goto bad;
64 
65 	if (unlockpt(master) == -1)
66 		goto bad;
67 
68 	slavename = ptsname(master);
69 	if (slavename == NULL)
70 		goto bad;
71 
72 	slave = open(slavename, O_RDWR);
73 	if (slave == -1)
74 		goto bad;
75 
76 	*amaster = master;
77 	*aslave = slave;
78 
79 	if (name)
80 		strcpy(name, slavename);
81 	if (termp)
82 		tcsetattr(slave, TCSAFLUSH, termp);
83 	if (winp)
84 		ioctl(slave, TIOCSWINSZ, (char *)winp);
85 
86 	return (0);
87 
88 bad:	close(master);
89 	return (-1);
90 }
91 
92 int
93 forkpty(int *amaster, char *name, struct termios *termp, struct winsize *winp)
94 {
95 	int master, slave, pid;
96 
97 	if (openpty(&master, &slave, name, termp, winp) == -1)
98 		return (-1);
99 	switch (pid = fork()) {
100 	case -1:
101 		return (-1);
102 	case 0:
103 		/*
104 		 * child
105 		 */
106 		(void) close(master);
107 		login_tty(slave);
108 		return (0);
109 	}
110 	/*
111 	 * parent
112 	 */
113 	*amaster = master;
114 	(void) close(slave);
115 	return (pid);
116 }
117