1 /* $NetBSD: pty.c,v 1.31 2009/02/20 16:44:06 christos Exp $ */
2
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 #if defined(LIBC_SCCS) && !defined(lint)
34 #if 0
35 static char sccsid[] = "@(#)pty.c 8.3 (Berkeley) 5/16/94";
36 #else
37 __RCSID("$NetBSD: pty.c,v 1.31 2009/02/20 16:44:06 christos Exp $");
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 #if defined(__minix)
46 #include <stdlib.h>
47 #endif /* defined(__minix) */
48 #include <assert.h>
49 #include <errno.h>
50 #include <fcntl.h>
51 #include <grp.h>
52 #include <stdio.h>
53 #include <string.h>
54 #include <termios.h>
55 #include <unistd.h>
56 #include <util.h>
57
58 /*
59 * XXX: `v' removed until no ports are using console devices which use ttyv0
60 */
61 #define TTY_LETTERS "pqrstuwxyzPQRST"
62 #define TTY_OLD_SUFFIX "0123456789abcdef"
63 #define TTY_NEW_SUFFIX "ghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
64
65 int
openpty(int * amaster,int * aslave,char * name,struct termios * term,struct winsize * winp)66 openpty(int *amaster, int *aslave, char *name, struct termios *term,
67 struct winsize *winp)
68 {
69 char line[] = "/dev/XtyXX";
70 const char *cp1, *cp2, *cp, *linep;
71 int master, slave;
72 gid_t ttygid;
73 mode_t mode;
74 struct group grs, *grp;
75 char grbuf[1024];
76
77 _DIAGASSERT(amaster != NULL);
78 _DIAGASSERT(aslave != NULL);
79 /* name may be NULL */
80 /* term may be NULL */
81 /* winp may be NULL */
82
83 #if !defined(__minix)
84 if ((master = open("/dev/ptm", O_RDWR)) != -1) {
85 struct ptmget pt;
86 if (ioctl(master, TIOCPTMGET, &pt) != -1) {
87 (void)close(master);
88 master = pt.cfd;
89 slave = pt.sfd;
90 linep = pt.sn;
91 goto gotit;
92 }
93 (void)close(master);
94 }
95 #else
96 /*
97 * On MINIX3, we implement non-root openpty(3) using Unix98 PTYs.
98 * If this fails, the fallback code below works for root only.
99 */
100 if ((master = posix_openpt(O_RDWR | O_NOCTTY)) != -1) {
101 if (grantpt(master) != -1 && unlockpt(master) != -1 &&
102 (linep = ptsname(master)) != NULL &&
103 (slave = open(linep, O_RDWR | O_NOCTTY)) != -1)
104 goto gotit;
105 (void)close(master);
106 }
107 #endif /* !defined(__minix) */
108
109 (void)getgrnam_r("tty", &grs, grbuf, sizeof(grbuf), &grp);
110 if (grp != NULL) {
111 ttygid = grp->gr_gid;
112 mode = S_IRUSR|S_IWUSR|S_IWGRP;
113 } else {
114 ttygid = getgid();
115 mode = S_IRUSR|S_IWUSR;
116 }
117
118 for (cp1 = TTY_LETTERS; *cp1; cp1++) {
119 line[8] = *cp1;
120 for (cp = cp2 = TTY_OLD_SUFFIX TTY_NEW_SUFFIX; *cp2; cp2++) {
121 line[5] = 'p';
122 line[9] = *cp2;
123 #if defined(__minix)
124 if ((master = open(line, O_RDWR | O_NOCTTY, 0)) == -1) {
125 #else
126 if ((master = open(line, O_RDWR, 0)) == -1) {
127 #endif /* defined(__minix) */
128 if (errno != ENOENT)
129 continue; /* busy */
130 if ((size_t)(cp2 - cp + 1) < sizeof(TTY_OLD_SUFFIX))
131 return -1; /* out of ptys */
132 else
133 break; /* out of ptys in this group */
134 }
135 line[5] = 't';
136 linep = line;
137 if (chown(line, getuid(), ttygid) == 0 &&
138 chmod(line, mode) == 0 &&
139 #if !defined(__minix)
140 revoke(line) == 0 &&
141 #endif /* !defined(__minix) */
142 #if defined(__minix)
143 (slave = open(line, O_RDWR | O_NOCTTY, 0)) != -1) {
144 #else
145 (slave = open(line, O_RDWR, 0)) != -1) {
146 #endif /* defined(__minix) */
147 gotit:
148 *amaster = master;
149 *aslave = slave;
150 if (name)
151 (void)strcpy(name, linep);
152 if (term)
153 (void)tcsetattr(slave, TCSAFLUSH, term);
154 if (winp)
155 (void)ioctl(slave, TIOCSWINSZ, winp);
156 return 0;
157 }
158 (void)close(master);
159 }
160 }
161 errno = ENOENT; /* out of ptys */
162 return -1;
163 }
164
165 pid_t
166 forkpty(int *amaster, char *name, struct termios *term, struct winsize *winp)
167 {
168 int master, slave;
169 pid_t pid;
170
171 _DIAGASSERT(amaster != NULL);
172 /* name may be NULL */
173 /* term may be NULL */
174 /* winp may be NULL */
175
176 if (openpty(&master, &slave, name, term, winp) == -1)
177 return -1;
178 switch (pid = fork()) {
179 case -1:
180 return -1;
181 case 0:
182 /*
183 * child
184 */
185 (void)close(master);
186 login_tty(slave);
187 return 0;
188 }
189 /*
190 * parent
191 */
192 *amaster = master;
193 (void)close(slave);
194 return pid;
195 }
196