1/*	$NetBSD: getlogin.c,v 1.17 2024/01/20 14:52:47 christos Exp $	*/
2
3/*-
4 * Copyright (c) 2008 The NetBSD Foundation, Inc.
5 * All rights reserved.
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 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/*
30 * Copyright (c) 1988, 1993
31 *	The Regents of the University of California.  All rights reserved.
32 *
33 * Redistribution and use in source and binary forms, with or without
34 * modification, are permitted provided that the following conditions
35 * are met:
36 * 1. Redistributions of source code must retain the above copyright
37 *    notice, this list of conditions and the following disclaimer.
38 * 2. Redistributions in binary form must reproduce the above copyright
39 *    notice, this list of conditions and the following disclaimer in the
40 *    documentation and/or other materials provided with the distribution.
41 * 3. Neither the name of the University nor the names of its contributors
42 *    may be used to endorse or promote products derived from this software
43 *    without specific prior written permission.
44 *
45 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
46 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
47 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
48 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
49 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
50 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
51 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
52 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
53 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
54 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
55 * SUCH DAMAGE.
56 */
57
58#include <sys/cdefs.h>
59#if defined(LIBC_SCCS) && !defined(lint)
60#if 0
61static char sccsid[] = "@(#)getlogin.c	8.1 (Berkeley) 6/4/93";
62#else
63__RCSID("$NetBSD: getlogin.c,v 1.17 2024/01/20 14:52:47 christos Exp $");
64#endif
65#endif /* LIBC_SCCS and not lint */
66
67#include "namespace.h"
68#include <sys/param.h>
69#include <pwd.h>
70#include <utmp.h>
71#include <stdio.h>
72#include <string.h>
73#include <unistd.h>
74#include <errno.h>
75#include "reentrant.h"
76#include "extern.h"
77
78#ifdef __weak_alias
79__weak_alias(getlogin,_getlogin)
80__weak_alias(getlogin_r,_getlogin_r)
81__weak_alias(setlogin,_setlogin)
82#endif
83
84static int	__logname_valid;		/* known to setlogin() */
85static char logname[MAXLOGNAME + 1];
86
87#ifdef _REENTRANT
88static mutex_t	logname_mutex = MUTEX_INITIALIZER;
89#endif
90
91char *
92getlogin(void)
93{
94	char *rv;
95
96	mutex_lock(&logname_mutex);
97	if (__logname_valid == 0) {
98		if (__getlogin(logname, sizeof(logname) - 1) < 0) {
99			mutex_unlock(&logname_mutex);
100			return ((char *)NULL);
101		}
102		__logname_valid = 1;
103	}
104	rv = (*logname ? logname : (char *)NULL);
105	mutex_unlock(&logname_mutex);
106
107	return rv;
108}
109
110int
111getlogin_r(char *name, size_t namelen)
112{
113	size_t len;
114	int rv;
115
116	mutex_lock(&logname_mutex);
117	if (__logname_valid == 0) {
118		if (__getlogin(logname, sizeof(logname) - 1) < 0) {
119			rv = errno;
120			mutex_unlock(&logname_mutex);
121			return (rv);
122		}
123		__logname_valid = 1;
124	}
125	len = strlen(logname) + 1;
126	if (len > namelen) {
127		rv = ERANGE;
128	} else {
129		strcpy(name, logname);
130		rv = 0;
131	}
132	mutex_unlock(&logname_mutex);
133
134	return (rv);
135}
136
137int
138setlogin(const char *name)
139{
140	int retval;
141
142	retval = __setlogin(name);
143	__logname_valid = 0;
144
145	return (retval);
146}
147