xref: /dragonfly/lib/libc/stdlib/ptsname.c (revision ae24b5e0)
1 /*
2  * Copyright (c) 2009 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Alex Hornung <ahornung@gmail.com>
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  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  * 3. Neither the name of The DragonFly Project nor the names of its
18  *    contributors may be used to endorse or promote products derived
19  *    from this software without specific, prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 #include "namespace.h"
35 #include <sys/types.h>
36 #include <fcntl.h>
37 #include <dirent.h>
38 #include <stdlib.h>
39 #include <termios.h>
40 #include <unistd.h>
41 #include <string.h>
42 #include <paths.h>
43 #include <errno.h>
44 #include <limits.h>
45 #include <machine/stdint.h>
46 #include <sys/stat.h>
47 #include <sys/ioctl.h>
48 #include "reentrant.h"
49 #include "un-namespace.h"
50 
51 #include "libc_private.h"
52 
53 #define TTYNAME_DEVFS_COMPAT 1
54 
55 static char ptsname_buf[sizeof(_PATH_DEV) + NAME_MAX];
56 
57 static once_t		ptsname_init_once = ONCE_INITIALIZER;
58 static thread_key_t	ptsname_key;
59 static int		ptsname_keycreated = 0;
60 
61 static int
62 __isptmaster(int fd)
63 {
64 	int error;
65 
66 	error = _ioctl(fd, TIOCISPTMASTER);
67 	if ((error) && (errno != EBADF))
68 		errno = EINVAL;
69 
70 	return error;
71 }
72 
73 static void
74 ptsname_keycreate(void)
75 {
76 	ptsname_keycreated = (thr_keycreate(&ptsname_key, free) == 0);
77 }
78 
79 char *
80 ptsname(int fd)
81 {
82 	int	error;
83 	size_t used;
84 	char	*buf;
85 
86 	error = __isptmaster(fd);
87 	if (error)
88 		return (NULL);
89 
90 	if (thr_main() != 0)
91 		buf = ptsname_buf;
92 	else {
93 		if (thr_once(&ptsname_init_once, ptsname_keycreate) != 0 ||
94 		    !ptsname_keycreated)
95 			return (NULL);
96 		if ((buf = thr_getspecific(ptsname_key)) == NULL) {
97 			if ((buf = malloc(sizeof ptsname_buf)) == NULL)
98 				return (NULL);
99 			if (thr_setspecific(ptsname_key, buf) != 0) {
100 				free(buf);
101 				return (NULL);
102 			}
103 		}
104 	}
105 
106 	strcpy(buf, "/dev/");
107 	used = strlen(buf);
108 
109 	if (((error = fdevname_r(fd, buf+used, sizeof(ptsname_buf)-used))) != 0) {
110 		errno = error;
111 		return (NULL);
112 	}
113 
114 	buf[used+2] = 's';
115 
116 	return (buf);
117 }
118 
119 int
120 posix_openpt(int oflag)
121 {
122 	return _open("/dev/ptmx", oflag);
123 }
124 
125 int
126 unlockpt(int fd)
127 {
128 	return __isptmaster(fd);
129 }
130 
131 int
132 grantpt(int fd)
133 {
134 	return __isptmaster(fd);
135 }
136