getlogin.c revision 90039 
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 sccsid[] = "@(#)getlogin.c	8.1 (Berkeley) 6/4/93";
36#endif /* LIBC_SCCS and not lint */
37#include <sys/cdefs.h>
38__FBSDID("$FreeBSD: head/lib/libc/gen/getlogin.c 90039 2002-02-01 00:57:29Z obrien $");
39
40#include <sys/param.h>
41#include <errno.h>
42#include <pwd.h>
43#include <utmp.h>
44#include <stdio.h>
45#include <string.h>
46#include <unistd.h>
47#include "namespace.h"
48#include <pthread.h>
49#include "un-namespace.h"
50
51#include <libc_private.h>
52
53#define	THREAD_LOCK()	if (__isthreaded) _pthread_mutex_lock(&logname_mutex)
54#define	THREAD_UNLOCK()	if (__isthreaded) _pthread_mutex_unlock(&logname_mutex)
55
56extern int		_getlogin(char *, int);
57
58int			_logname_valid;		/* known to setlogin() */
59static pthread_mutex_t	logname_mutex = PTHREAD_MUTEX_INITIALIZER;
60
61static char *
62getlogin_basic(int *status)
63{
64	static char logname[MAXLOGNAME];
65
66	if (_logname_valid == 0) {
67#ifdef __NETBSD_SYSCALLS
68		if (_getlogin(logname, sizeof(logname) - 1) < 0) {
69#else
70		if (_getlogin(logname, sizeof(logname)) < 0) {
71#endif
72			*status = errno;
73			return (NULL);
74		}
75		_logname_valid = 1;
76	}
77	*status = 0;
78	return (*logname ? logname : NULL);
79}
80
81char *
82getlogin(void)
83{
84	char	*result;
85	int	status;
86
87	THREAD_LOCK();
88	result = getlogin_basic(&status);
89	THREAD_UNLOCK();
90	return (result);
91}
92
93int
94getlogin_r(char *logname, int namelen)
95{
96	char	*result;
97	int	len;
98	int	status;
99
100	THREAD_LOCK();
101	result = getlogin_basic(&status);
102	if (status == 0) {
103		if ((len = strlen(result) + 1) > namelen)
104			status = ERANGE;
105		else
106			strncpy(logname, result, len);
107	}
108	THREAD_UNLOCK();
109	return (status);
110}
111