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
43 ROKEN_LIB_FUNCTION const char * ROKEN_LIB_CALL
get_default_username(void)44 get_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