1/*	$NetBSD: get_default_username.c,v 1.1.1.1 2011/04/13 18:15:41 elric Exp $	*/
2
3/*
4 * Copyright (c) 1997 - 1999 Kungliga Tekniska Högskolan
5 * (Royal Institute of Technology, Stockholm, Sweden).
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * 3. Neither the name of the Institute nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include <config.h>
37
38#include <krb5/roken.h>
39
40/*
41 * Try to return what should be considered the default username or
42 * NULL if we can't guess at all.
43 */
44
45ROKEN_LIB_FUNCTION const char * ROKEN_LIB_CALL
46get_default_username (void)
47{
48    const char *user;
49
50    user = getenv ("USER");
51    if (user == NULL)
52	user = getenv ("LOGNAME");
53    if (user == NULL)
54	user = getenv ("USERNAME");
55
56#if defined(HAVE_GETLOGIN) && !defined(POSIX_GETLOGIN)
57    if (user == NULL) {
58	user = (const char *)getlogin ();
59	if (user != NULL)
60	    return user;
61    }
62#endif
63#ifdef HAVE_PWD_H
64    {
65	uid_t uid = getuid ();
66	struct passwd *pwd;
67
68	if (user != NULL) {
69	    pwd = k_getpwnam (user);
70	    if (pwd != NULL && pwd->pw_uid == uid)
71		return user;
72	}
73	pwd = k_getpwuid (uid);
74	if (pwd != NULL)
75	    return pwd->pw_name;
76    }
77#endif
78#ifdef _WIN32
79    /* TODO: We can call GetUserNameEx() and figure out a
80       username. However, callers do not free the return value of this
81       function. */
82#endif
83
84    return user;
85}
86