1 /* $NetBSD: pty.c,v 1.32 2018/06/24 09:30:26 kamil 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 1.32 2018/06/24 09:30:26 kamil 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 #include <assert.h>
46 #include <errno.h>
47 #include <fcntl.h>
48 #include <grp.h>
49 #include <stdio.h>
50 #include <string.h>
51 #include <termios.h>
52 #include <unistd.h>
53 #include <util.h>
54
55 /*
56 * XXX: `v' removed until no ports are using console devices which use ttyv0
57 */
58 #define TTY_LETTERS "pqrstuwxyzPQRST"
59 #define TTY_OLD_SUFFIX "0123456789abcdef"
60 #define TTY_NEW_SUFFIX "ghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
61
62 int
openpty(int * amaster,int * aslave,char * name,struct termios * term,struct winsize * winp)63 openpty(int *amaster, int *aslave, char *name, struct termios *term,
64 struct winsize *winp)
65 {
66 char line[] = "/dev/XtyXX";
67 const char *cp1, *cp2, *cp, *linep;
68 int master, slave;
69 gid_t ttygid;
70 mode_t mode;
71 struct group grs, *grp;
72 char grbuf[1024];
73 struct ptmget pt;
74
75 _DIAGASSERT(amaster != NULL);
76 _DIAGASSERT(aslave != NULL);
77 /* name may be NULL */
78 /* term may be NULL */
79 /* winp may be NULL */
80
81 if ((master = open("/dev/ptm", O_RDWR)) != -1) {
82 if (ioctl(master, TIOCPTMGET, &pt) != -1) {
83 (void)close(master);
84 master = pt.cfd;
85 slave = pt.sfd;
86 linep = pt.sn;
87 goto gotit;
88 }
89 (void)close(master);
90 }
91
92 (void)getgrnam_r("tty", &grs, grbuf, sizeof(grbuf), &grp);
93 if (grp != NULL) {
94 ttygid = grp->gr_gid;
95 mode = S_IRUSR|S_IWUSR|S_IWGRP;
96 } else {
97 ttygid = getgid();
98 mode = S_IRUSR|S_IWUSR;
99 }
100
101 for (cp1 = TTY_LETTERS; *cp1; cp1++) {
102 line[8] = *cp1;
103 for (cp = cp2 = TTY_OLD_SUFFIX TTY_NEW_SUFFIX; *cp2; cp2++) {
104 line[5] = 'p';
105 line[9] = *cp2;
106 if ((master = open(line, O_RDWR, 0)) == -1) {
107 if (errno != ENOENT)
108 continue; /* busy */
109 if ((size_t)(cp2 - cp + 1) < sizeof(TTY_OLD_SUFFIX))
110 return -1; /* out of ptys */
111 else
112 break; /* out of ptys in this group */
113 }
114 line[5] = 't';
115 linep = line;
116 if (chown(line, getuid(), ttygid) == 0 &&
117 chmod(line, mode) == 0 &&
118 revoke(line) == 0 &&
119 (slave = open(line, O_RDWR, 0)) != -1) {
120 gotit:
121 *amaster = master;
122 *aslave = slave;
123 if (name)
124 (void)strcpy(name, linep);
125 if (term)
126 (void)tcsetattr(slave, TCSAFLUSH, term);
127 if (winp)
128 (void)ioctl(slave, TIOCSWINSZ, winp);
129 return 0;
130 }
131 (void)close(master);
132 }
133 }
134 errno = ENOENT; /* out of ptys */
135 return -1;
136 }
137
138 pid_t
forkpty(int * amaster,char * name,struct termios * term,struct winsize * winp)139 forkpty(int *amaster, char *name, struct termios *term, struct winsize *winp)
140 {
141 int master, slave;
142 pid_t pid;
143
144 _DIAGASSERT(amaster != NULL);
145 /* name may be NULL */
146 /* term may be NULL */
147 /* winp may be NULL */
148
149 if (openpty(&master, &slave, name, term, winp) == -1)
150 return -1;
151 switch (pid = fork()) {
152 case -1:
153 return -1;
154 case 0:
155 /*
156 * child
157 */
158 (void)close(master);
159 login_tty(slave);
160 return 0;
161 }
162 /*
163 * parent
164 */
165 *amaster = master;
166 (void)close(slave);
167 return pid;
168 }
169