1 /* $NetBSD: tty_bsdpty.c,v 1.20 2014/04/04 18:11:58 christos Exp $ */
2
3 /*-
4 * Copyright (c) 2004 The NetBSD Foundation, Inc.
5 * 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 *
16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __KERNEL_RCSID(0, "$NetBSD: tty_bsdpty.c,v 1.20 2014/04/04 18:11:58 christos Exp $");
31
32 #include "opt_ptm.h"
33
34 #ifndef NO_DEV_PTM
35 #ifdef COMPAT_BSDPTY
36 /* bsd tty implementation for pty multiplexor driver /dev/ptm{,x} */
37
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/ioctl.h>
41 #include <sys/lwp.h>
42 #include <sys/tty.h>
43 #include <sys/stat.h>
44 #include <sys/file.h>
45 #include <sys/uio.h>
46 #include <sys/kernel.h>
47 #include <sys/vnode.h>
48 #include <sys/namei.h>
49 #include <sys/signalvar.h>
50 #include <sys/filedesc.h>
51 #include <sys/conf.h>
52 #include <sys/poll.h>
53 #include <sys/pty.h>
54 #include <sys/kauth.h>
55
56 /*
57 * pts == /dev/tty[pqrs]?
58 * ptc == /dev/pty[pqrs]?
59 */
60
61 /*
62 * All this hard-coding is really evil.
63 */
64 #define TTY_GID 4
65 #define TTY_PERM (S_IRUSR|S_IWUSR|S_IWGRP)
66 #define TTY_TEMPLATE "/dev/XtyXX"
67 #define TTY_NAMESIZE sizeof(TTY_TEMPLATE)
68 #define TTY_LETTERS "pqrstuvwxyzPQRST"
69 #define TTY_OLD_SUFFIX "0123456789abcdef"
70 #define TTY_NEW_SUFFIX "ghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
71
72 static int pty_makename(struct mount *, struct lwp *, char *, size_t, dev_t,
73 char);
74 static int pty_allocvp(struct mount *, struct lwp *, struct vnode **,
75 dev_t, char);
76 static void pty_getvattr(struct mount *, struct lwp *, struct vattr *);
77 static int pty__getmp(struct lwp *, struct mount **);
78
79 struct ptm_pty ptm_bsdpty = {
80 pty_allocvp,
81 pty_makename,
82 pty_getvattr,
83 pty__getmp,
84 };
85
86 static int
87 /*ARGSUSED*/
pty_makename(struct mount * mp,struct lwp * l,char * bf,size_t bufsiz,dev_t dev,char c)88 pty_makename(struct mount *mp, struct lwp *l, char *bf,
89 size_t bufsiz, dev_t dev, char c)
90 {
91 size_t nt;
92 dev_t minor = minor(dev);
93 const char *suffix;
94
95 if (bufsiz < TTY_NAMESIZE)
96 return EINVAL;
97
98 (void)memcpy(bf, TTY_TEMPLATE, TTY_NAMESIZE);
99
100 if (minor < 256) {
101 suffix = TTY_OLD_SUFFIX;
102 nt = sizeof(TTY_OLD_SUFFIX) - 1;
103 } else {
104 minor -= 256;
105 suffix = TTY_NEW_SUFFIX;
106 nt = sizeof(TTY_NEW_SUFFIX) - 1;
107 }
108
109 bf[5] = c;
110 bf[8] = TTY_LETTERS[minor / nt];
111 bf[9] = suffix[minor % nt];
112 return 0;
113 }
114
115
116 static int
117 /*ARGSUSED*/
pty_allocvp(struct mount * mp,struct lwp * l,struct vnode ** vp,dev_t dev,char ms)118 pty_allocvp(struct mount *mp, struct lwp *l, struct vnode **vp, dev_t dev,
119 char ms)
120 {
121 int error;
122 struct pathbuf *pb;
123 struct nameidata nd;
124 char name[TTY_NAMESIZE];
125
126 error = pty_makename(NULL, l, name, sizeof(name), dev, ms);
127 if (error)
128 return error;
129
130 pb = pathbuf_create(name);
131 if (pb == NULL) {
132 return ENOMEM;
133 }
134
135 NDINIT(&nd, LOOKUP, NOFOLLOW|LOCKLEAF, pb);
136 if ((error = namei(&nd)) != 0) {
137 pathbuf_destroy(pb);
138 return error;
139 }
140 *vp = nd.ni_vp;
141 pathbuf_destroy(pb);
142 return 0;
143 }
144
145
146 static void
147 /*ARGSUSED*/
pty_getvattr(struct mount * mp,struct lwp * l,struct vattr * vattr)148 pty_getvattr(struct mount *mp, struct lwp *l, struct vattr *vattr)
149 {
150 vattr_null(vattr);
151 /* get real uid */
152 vattr->va_uid = kauth_cred_getuid(l->l_cred);
153 vattr->va_gid = TTY_GID;
154 vattr->va_mode = TTY_PERM;
155 }
156
157 static int
pty__getmp(struct lwp * l __unused,struct mount ** mpp)158 pty__getmp(struct lwp *l __unused, struct mount **mpp)
159 {
160 *mpp = 0;
161 return 0;
162 }
163
164 #endif /* COMPAT_BSDPTY */
165 #endif /* NO_DEV_PTM */
166