xref: /freebsd/lib/libutil/pty.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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);
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 
104 int
105 forkpty(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