xref: /openbsd-src/lib/libc/gen/ttyname.c (revision b2ea75c1b17e1a9a339660e7ed45cd24946b230e)
1 /*
2  * Copyright (c) 1988, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #if defined(LIBC_SCCS) && !defined(lint)
35 static char rcsid[] = "$OpenBSD: ttyname.c,v 1.7 2000/01/06 08:24:16 d Exp $";
36 #endif /* LIBC_SCCS and not lint */
37 
38 #include <sys/types.h>
39 #include <sys/stat.h>
40 #include <fcntl.h>
41 #include <dirent.h>
42 #include <termios.h>
43 #include <db.h>
44 #include <string.h>
45 #include <unistd.h>
46 #include <paths.h>
47 #include <limits.h>
48 #include <errno.h>
49 #include "thread_private.h"
50 
51 static char buf[TTY_NAME_MAX];
52 static int oldttyname __P((int, struct stat *, char *, size_t));
53 static int __ttyname_r_basic __P((int, char *, size_t));
54 
55 int
56 ttyname_r(int fd, char *buf, size_t buflen)
57 {
58 	int ret;
59 
60 	if ((ret = _FD_LOCK(fd, FD_READ, NULL)) == 0) {
61 		ret = __ttyname_r_basic(fd, buf, buflen);
62 		_FD_UNLOCK(fd, FD_READ);
63 	}
64 	return ret;
65 }
66 
67 char *
68 ttyname(int fd)
69 {
70 	_THREAD_PRIVATE_KEY(ttyname);
71 	char * bufp = (char*) _THREAD_PRIVATE(ttyname, buf, NULL);
72 	int err;
73 
74 	if (bufp == NULL)
75 		return NULL;
76 	err = ttyname_r(fd, bufp, sizeof buf);
77 	if (err) {
78 		errno = err;
79 		return NULL;
80 	}
81 	else
82 	return bufp;
83 }
84 
85 static int
86 __ttyname_r_basic(fd, buf, len)
87 	int fd;
88 	char *buf;
89 	size_t len;
90 {
91 	struct stat sb;
92 	struct termios ttyb;
93 	DB *db;
94 	DBT data, key;
95 	struct {
96 		mode_t type;
97 		dev_t dev;
98 	} bkey;
99 
100 	/* Must be a terminal. */
101 	if (tcgetattr(fd, &ttyb) < 0)
102 		return (errno);
103 	/* Must be a character device. */
104 	if (fstat(fd, &sb))
105 		return (errno);
106 	if (!S_ISCHR(sb.st_mode))
107 		return (ENOTTY);
108 	if (len < sizeof(_PATH_DEV))
109 		return (ERANGE);
110 
111 	memcpy(buf, _PATH_DEV, sizeof(_PATH_DEV));
112 
113 	if ((db = dbopen(_PATH_DEVDB, O_RDONLY, 0, DB_HASH, NULL))) {
114 		memset(&bkey, 0, sizeof(bkey));
115 		bkey.type = S_IFCHR;
116 		bkey.dev = sb.st_rdev;
117 		key.data = &bkey;
118 		key.size = sizeof(bkey);
119 		if (!(db->get)(db, &key, &data, 0)) {
120 			if (data.size > len - (sizeof(_PATH_DEV) - 1)) {
121 				(void)(db->close)(db);
122 				return (ERANGE);
123 			}
124 			memcpy(buf + sizeof(_PATH_DEV) - 1, data.data,
125 			    data.size);
126 			(void)(db->close)(db);
127 			return (0);
128 		}
129 		(void)(db->close)(db);
130 	}
131 	return (oldttyname(fd, &sb, buf, len));
132 }
133 
134 /* ARGSUSED */
135 static int
136 oldttyname(fd, sb, buf, len)
137 	int fd;
138 	struct stat *sb;
139 	char *buf;
140 	size_t len;
141 {
142 	register struct dirent *dirp;
143 	register DIR *dp;
144 	struct stat dsb;
145 
146 	if ((dp = opendir(_PATH_DEV)) == NULL)
147 		return (errno);
148 
149 	while ((dirp = readdir(dp))) {
150 		if (dirp->d_fileno != sb->st_ino)
151 			continue;
152 		if (dirp->d_namlen > len - sizeof(_PATH_DEV)) {
153 			(void)closedir(dp);
154 			return (ERANGE);
155 		}
156 		memcpy(buf + sizeof(_PATH_DEV) - 1, dirp->d_name,
157 		    dirp->d_namlen + 1);
158 		if (stat(buf, &dsb) || sb->st_dev != dsb.st_dev ||
159 		    sb->st_ino != dsb.st_ino)
160 			continue;
161 		(void)closedir(dp);
162 		return (0);
163 	}
164 	(void)closedir(dp);
165 	return (ENOTTY);
166 }
167