getlogin.c revision 1.5 
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)
35static char rcsid[] = "$OpenBSD: getlogin.c,v 1.5 2000/01/06 08:24:16 d Exp $";
36#endif /* LIBC_SCCS and not lint */
37
38#include <sys/param.h>
39#include <pwd.h>
40#include <utmp.h>
41#include <stdio.h>
42#include <string.h>
43#include <unistd.h>
44#include <errno.h>
45#include "thread_private.h"
46
47_THREAD_PRIVATE_MUTEX(logname);
48static int  logname_valid = 0;
49static char logname[MAXLOGNAME + 1];
50
51int	_getlogin __P((char *, size_t));
52int	_setlogin __P((const char *));
53
54char *
55getlogin()
56{
57	_THREAD_PRIVATE_KEY(getlogin);
58	char * name = (char *)_THREAD_PRIVATE(getlogin, logname, NULL);
59
60	if ((errno = getlogin_r(name, sizeof logname)) != 0)
61		return NULL;
62	if (*name == '\0') {
63		errno = ENOENT;  /* well? */
64		return NULL;
65	}
66	return name;
67}
68
69int
70getlogin_r(name, namelen)
71	char *name;
72	size_t namelen;
73{
74	int logname_size;
75
76	if (name == NULL)
77		return EFAULT;
78
79	_THREAD_PRIVATE_MUTEX_LOCK(logname);
80	if (!logname_valid) {
81		if (_getlogin(logname, sizeof(logname) - 1) < 0) {
82			_THREAD_PRIVATE_MUTEX_UNLOCK(logname);
83			return errno;
84		}
85		logname_valid = 1;
86		logname[MAXLOGNAME] = '\0';	/* paranoia */
87	}
88	logname_size = strlen(logname) + 1;
89	if (namelen < logname_size)
90		return ERANGE;
91	memcpy(name, logname, logname_size);
92	_THREAD_PRIVATE_MUTEX_UNLOCK(logname);
93	return 0;
94}
95
96int
97setlogin(name)
98	const char *name;
99{
100	int ret;
101
102	_THREAD_PRIVATE_MUTEX_LOCK(logname);
103	ret = _setlogin(name);
104	if (ret == 0)
105		logname_valid = 0;
106	_THREAD_PRIVATE_MUTEX_UNLOCK(logname);
107	return ret;
108}
109