getlogin.c revision 165903 
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 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#if defined(LIBC_SCCS) && !defined(lint)
31static char sccsid[] = "@(#)getlogin.c	8.1 (Berkeley) 6/4/93";
32#endif /* LIBC_SCCS and not lint */
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD: head/lib/libc/gen/getlogin.c 165903 2007-01-09 00:28:16Z imp $");
35
36#include <sys/param.h>
37#include <errno.h>
38#include <pwd.h>
39#include <utmp.h>
40#include <stdio.h>
41#include <string.h>
42#include <unistd.h>
43#include "namespace.h"
44#include <pthread.h>
45#include "un-namespace.h"
46
47#include "libc_private.h"
48
49#define	THREAD_LOCK()	if (__isthreaded) _pthread_mutex_lock(&logname_mutex)
50#define	THREAD_UNLOCK()	if (__isthreaded) _pthread_mutex_unlock(&logname_mutex)
51
52extern int		_getlogin(char *, int);
53
54int			_logname_valid;		/* known to setlogin() */
55static pthread_mutex_t	logname_mutex = PTHREAD_MUTEX_INITIALIZER;
56
57static char *
58getlogin_basic(int *status)
59{
60	static char logname[MAXLOGNAME];
61
62	if (_logname_valid == 0) {
63		if (_getlogin(logname, sizeof(logname)) < 0) {
64			*status = errno;
65			return (NULL);
66		}
67		_logname_valid = 1;
68	}
69	*status = 0;
70	return (*logname ? logname : NULL);
71}
72
73char *
74getlogin(void)
75{
76	char	*result;
77	int	status;
78
79	THREAD_LOCK();
80	result = getlogin_basic(&status);
81	THREAD_UNLOCK();
82	return (result);
83}
84
85int
86getlogin_r(char *logname, int namelen)
87{
88	char	*result;
89	int	len;
90	int	status;
91
92	THREAD_LOCK();
93	result = getlogin_basic(&status);
94	if (status == 0) {
95		if ((len = strlen(result) + 1) > namelen)
96			status = ERANGE;
97		else
98			strncpy(logname, result, len);
99	}
100	THREAD_UNLOCK();
101	return (status);
102}
103