getlogin.c revision 331722 
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: stable/11/lib/libc/gen/getlogin.c 331722 2018-03-29 02:50:57Z eadler $");
35
36#include <sys/param.h>
37#include <errno.h>
38#include <pwd.h>
39#include <stdio.h>
40#include <string.h>
41#include <unistd.h>
42#include "namespace.h"
43#include <pthread.h>
44#include "un-namespace.h"
45
46#include "libc_private.h"
47
48#define	THREAD_LOCK()	if (__isthreaded) _pthread_mutex_lock(&logname_mutex)
49#define	THREAD_UNLOCK()	if (__isthreaded) _pthread_mutex_unlock(&logname_mutex)
50
51extern int		_getlogin(char *, int);
52
53int			_logname_valid __hidden; /* known to setlogin() */
54static pthread_mutex_t	logname_mutex = PTHREAD_MUTEX_INITIALIZER;
55
56static char *
57getlogin_basic(int *status)
58{
59	static char logname[MAXLOGNAME];
60
61	if (_logname_valid == 0) {
62		if (_getlogin(logname, sizeof(logname)) < 0) {
63			*status = errno;
64			return (NULL);
65		}
66		_logname_valid = 1;
67	}
68	*status = 0;
69	return (*logname ? logname : NULL);
70}
71
72char *
73getlogin(void)
74{
75	char	*result;
76	int	status;
77
78	THREAD_LOCK();
79	result = getlogin_basic(&status);
80	THREAD_UNLOCK();
81	return (result);
82}
83
84int
85getlogin_r(char *logname, int namelen)
86{
87	char	*result;
88	int	len;
89	int	status;
90
91	if (namelen < 1)
92		return (ERANGE);
93	logname[0] = '\0';
94
95	THREAD_LOCK();
96	result = getlogin_basic(&status);
97	if (status == 0 && result != NULL) {
98		len = strlen(result) + 1;
99		if (len > namelen)
100			status = ERANGE;
101		else
102			strncpy(logname, result, len);
103	}
104	THREAD_UNLOCK();
105	return (status);
106}
107