1/*
2 * Copyright (c) 1997 - 1999 Kungliga Tekniska Högskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * 3. Neither the name of the Institute 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 INSTITUTE 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 INSTITUTE 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#include <config.h>
35
36#include "roken.h"
37
38/*
39 * Try to return what should be considered the default username or
40 * NULL if we can't guess at all.
41 */
42
43ROKEN_LIB_FUNCTION const char * ROKEN_LIB_CALL
44get_default_username (void)
45{
46    const char *user;
47
48    user = getenv ("USER");
49    if (user == NULL)
50	user = getenv ("LOGNAME");
51    if (user == NULL)
52	user = getenv ("USERNAME");
53
54#if defined(HAVE_GETLOGIN) && !defined(POSIX_GETLOGIN)
55    if (user == NULL) {
56	user = (const char *)getlogin ();
57	if (user != NULL)
58	    return user;
59    }
60#endif
61#ifdef HAVE_PWD_H
62    {
63	uid_t uid = getuid ();
64	struct passwd *pwd;
65
66	if (user != NULL) {
67	    pwd = k_getpwnam (user);
68	    if (pwd != NULL && pwd->pw_uid == uid)
69		return user;
70	}
71	pwd = k_getpwuid (uid);
72	if (pwd != NULL)
73	    return pwd->pw_name;
74    }
75#endif
76#ifdef _WIN32
77    /* TODO: We can call GetUserNameEx() and figure out a
78       username. However, callers do not free the return value of this
79       function. */
80#endif
81
82    return user;
83}
84