1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1988, 1993
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 __SCCSID("@(#)ttyname.c 8.2 (Berkeley) 1/27/94");
34 #include "namespace.h"
35 #include <sys/types.h>
36 #include <sys/ioctl.h>
37 #include <sys/filio.h>
38 #include <fcntl.h>
39 #include <dirent.h>
40 #include <stdlib.h>
41 #include <termios.h>
42 #include <unistd.h>
43 #include <string.h>
44 #include <paths.h>
45 #include <errno.h>
46 #include "reentrant.h"
47 #include "un-namespace.h"
48
49 #include "libc_private.h"
50
51 static char ttyname_buf[sizeof(_PATH_DEV) + MAXNAMLEN];
52
53 static once_t ttyname_init_once = ONCE_INITIALIZER;
54 static thread_key_t ttyname_key;
55 static int ttyname_keycreated = 0;
56
57 int
ttyname_r(int fd,char * buf,size_t len)58 ttyname_r(int fd, char *buf, size_t len)
59 {
60 size_t used;
61
62 /* Don't write off the end of a zero-length buffer. */
63 if (len < 1)
64 return (ERANGE);
65
66 *buf = '\0';
67
68 /* Must be a terminal. */
69 if (!isatty(fd))
70 return (errno);
71 /* Must have enough room */
72 if (len <= sizeof(_PATH_DEV))
73 return (ERANGE);
74
75 strcpy(buf, _PATH_DEV);
76 used = strlen(buf);
77 if (fdevname_r(fd, buf + used, len - used) == NULL)
78 return (errno == EINVAL ? ERANGE : errno);
79 return (0);
80 }
81
82 static void
ttyname_keycreate(void)83 ttyname_keycreate(void)
84 {
85 ttyname_keycreated = (thr_keycreate(&ttyname_key, free) == 0);
86 }
87
88 char *
ttyname(int fd)89 ttyname(int fd)
90 {
91 char *buf;
92
93 if (thr_main() != 0)
94 buf = ttyname_buf;
95 else {
96 if (thr_once(&ttyname_init_once, ttyname_keycreate) != 0 ||
97 !ttyname_keycreated)
98 return (NULL);
99 if ((buf = thr_getspecific(ttyname_key)) == NULL) {
100 if ((buf = malloc(sizeof ttyname_buf)) == NULL)
101 return (NULL);
102 if (thr_setspecific(ttyname_key, buf) != 0) {
103 free(buf);
104 return (NULL);
105 }
106 }
107 }
108
109 if (ttyname_r(fd, buf, sizeof ttyname_buf) != 0)
110 return (NULL);
111 return (buf);
112 }
113