1 /* $OpenBSD: ttyname.c,v 1.20 2017/04/14 15:02:51 deraadt Exp $ */
2 /*
3 * Copyright (c) 1988, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 #include <sys/types.h>
32 #include <sys/stat.h>
33 #include <fcntl.h>
34 #include <dirent.h>
35 #include <db.h>
36 #include <string.h>
37 #include <unistd.h>
38 #include <paths.h>
39 #include <limits.h>
40 #include <errno.h>
41 #include "thread_private.h"
42
43 static char buf[TTY_NAME_MAX];
44 static int oldttyname(struct stat *, char *, size_t);
45
46 char *
ttyname(int fd)47 ttyname(int fd)
48 {
49 _THREAD_PRIVATE_KEY(ttyname);
50 char *bufp = (char *) _THREAD_PRIVATE(ttyname, buf, NULL);
51 int err;
52
53 if (bufp == NULL)
54 return NULL;
55
56 err = ttyname_r(fd, bufp, sizeof buf);
57 if (err) {
58 errno = err;
59 return NULL;
60 }
61
62 return bufp;
63 }
64 DEF_WEAK(ttyname);
65
66 int
ttyname_r(int fd,char * buf,size_t len)67 ttyname_r(int fd, char *buf, size_t len)
68 {
69 struct stat sb;
70 DB *db;
71 DBT data, key;
72 struct {
73 mode_t type;
74 dev_t dev;
75 } bkey;
76
77 /* Must be a terminal. */
78 if (!isatty(fd))
79 return (errno);
80 /* Must be a character device. */
81 if (fstat(fd, &sb))
82 return (errno);
83 if (!S_ISCHR(sb.st_mode))
84 return (ENOTTY);
85 if (len < sizeof(_PATH_DEV))
86 return (ERANGE);
87
88 memcpy(buf, _PATH_DEV, sizeof(_PATH_DEV));
89
90 if ((db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL))) {
91 memset(&bkey, 0, sizeof(bkey));
92 bkey.type = S_IFCHR;
93 bkey.dev = sb.st_rdev;
94 key.data = &bkey;
95 key.size = sizeof(bkey);
96 if (!(db->get)(db, &key, &data, 0)) {
97 if (data.size > len - (sizeof(_PATH_DEV) - 1)) {
98 (void)(db->close)(db);
99 return (ERANGE);
100 }
101 memcpy(buf + sizeof(_PATH_DEV) - 1, data.data,
102 data.size);
103 (void)(db->close)(db);
104 return (0);
105 }
106 (void)(db->close)(db);
107 }
108 return (oldttyname(&sb, buf, len));
109 }
110 DEF_WEAK(ttyname_r);
111
112 static int
oldttyname(struct stat * sb,char * buf,size_t len)113 oldttyname(struct stat *sb, char *buf, size_t len)
114 {
115 struct dirent *dirp;
116 DIR *dp;
117 struct stat dsb;
118 int error = ENOTTY;
119
120 if ((dp = opendir(_PATH_DEV)) == NULL)
121 return (errno);
122
123 while ((dirp = readdir(dp))) {
124 if (dirp->d_type != DT_CHR && dirp->d_type != DT_UNKNOWN)
125 continue;
126 if (fstatat(dirfd(dp), dirp->d_name, &dsb, AT_SYMLINK_NOFOLLOW)
127 || !S_ISCHR(dsb.st_mode) || sb->st_rdev != dsb.st_rdev)
128 continue;
129 if (dirp->d_namlen > len - sizeof(_PATH_DEV)) {
130 error = ERANGE;
131 } else {
132 memcpy(buf + sizeof(_PATH_DEV) - 1, dirp->d_name,
133 dirp->d_namlen + 1);
134 error = 0;
135 }
136 break;
137 }
138 (void)closedir(dp);
139 return (error);
140 }
141