xref: /freebsd/lib/libutil/pty.c (revision 0b3105a37d7adcadcb720112fed4dc4e8040be99)
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 #include <unistd.h>
51 
52 int
53 openpty(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|O_NOCTTY);
60 	if (master == -1)
61 		return (-1);
62 
63 	if (grantpt(master) == -1)
64 		goto bad;
65 
66 	if (unlockpt(master) == -1)
67 		goto bad;
68 
69 	slavename = ptsname(master);
70 	if (slavename == NULL)
71 		goto bad;
72 
73 	slave = open(slavename, O_RDWR);
74 	if (slave == -1)
75 		goto bad;
76 
77 	*amaster = master;
78 	*aslave = slave;
79 
80 	if (name)
81 		strcpy(name, slavename);
82 	if (termp)
83 		tcsetattr(slave, TCSAFLUSH, termp);
84 	if (winp)
85 		ioctl(slave, TIOCSWINSZ, (char *)winp);
86 
87 	return (0);
88 
89 bad:	close(master);
90 	return (-1);
91 }
92 
93 int
94 forkpty(int *amaster, char *name, struct termios *termp, struct winsize *winp)
95 {
96 	int master, slave, pid;
97 
98 	if (openpty(&master, &slave, name, termp, winp) == -1)
99 		return (-1);
100 	switch (pid = fork()) {
101 	case -1:
102 		return (-1);
103 	case 0:
104 		/*
105 		 * child
106 		 */
107 		(void) close(master);
108 		login_tty(slave);
109 		return (0);
110 	}
111 	/*
112 	 * parent
113 	 */
114 	*amaster = master;
115 	(void) close(slave);
116 	return (pid);
117 }
118