1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2008 Ed Schouten <ed@FreeBSD.org>
5 * All rights reserved.
6 *
7 * Portions of this software were developed under sponsorship from Snow
8 * B.V., the Netherlands.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 "namespace.h"
33 #include <sys/param.h>
34 #include <sys/ioctl.h>
35
36 #include <errno.h>
37 #include <paths.h>
38 #include <stdlib.h>
39 #include <string.h>
40 #include "un-namespace.h"
41
42 /*
43 * __isptmaster(): return whether the file descriptor refers to a
44 * pseudo-terminal master device.
45 */
46 static int
__isptmaster(int fildes)47 __isptmaster(int fildes)
48 {
49
50 if (_ioctl(fildes, TIOCPTMASTER) == 0)
51 return (0);
52
53 if (errno != EBADF)
54 errno = EINVAL;
55
56 return (-1);
57 }
58
59 /*
60 * In our implementation, grantpt() and unlockpt() don't actually have
61 * any use, because PTY's are created on the fly and already have proper
62 * permissions upon creation.
63 *
64 * Just make sure `fildes' actually points to a real PTY master device.
65 */
66 __strong_reference(__isptmaster, grantpt);
67 __strong_reference(__isptmaster, unlockpt);
68
69 /*
70 * ptsname_r(): return the pathname of the slave pseudo-terminal device
71 * associated with the specified master.
72 */
73 int
__ptsname_r(int fildes,char * buffer,size_t buflen)74 __ptsname_r(int fildes, char *buffer, size_t buflen)
75 {
76
77 if (buflen <= sizeof(_PATH_DEV)) {
78 errno = ERANGE;
79 return (-1);
80 }
81
82 /* Make sure fildes points to a master device. */
83 if (__isptmaster(fildes) != 0)
84 return (-1);
85
86 memcpy(buffer, _PATH_DEV, sizeof(_PATH_DEV));
87 buffer += sizeof(_PATH_DEV) - 1;
88 buflen -= sizeof(_PATH_DEV) - 1;
89
90 if (fdevname_r(fildes, buffer, buflen) == NULL) {
91 if (errno == EINVAL)
92 errno = ERANGE;
93 return (-1);
94 }
95
96 return (0);
97 }
98
99 __strong_reference(__ptsname_r, ptsname_r);
100
101 /*
102 * ptsname(): return the pathname of the slave pseudo-terminal device
103 * associated with the specified master.
104 */
105 char *
ptsname(int fildes)106 ptsname(int fildes)
107 {
108 static char pt_slave[sizeof(_PATH_DEV) + SPECNAMELEN];
109
110 if (__ptsname_r(fildes, pt_slave, sizeof(pt_slave)) == 0)
111 return (pt_slave);
112
113 return (NULL);
114 }
115