1/*
2 * Copyright (c) 1997 - 2001 Kungliga Tekniska H�gskolan
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 "krb5_locl.h"
35
36RCSID("$Id: get_default_principal.c 14870 2005-04-20 20:53:29Z lha $");
37
38/*
39 * Try to find out what's a reasonable default principal.
40 */
41
42static const char*
43get_env_user(void)
44{
45    const char *user = getenv("USER");
46    if(user == NULL)
47	user = getenv("LOGNAME");
48    if(user == NULL)
49	user = getenv("USERNAME");
50    return user;
51}
52
53/*
54 * Will only use operating-system dependant operation to get the
55 * default principal, for use of functions that in ccache layer to
56 * avoid recursive calls.
57 */
58
59krb5_error_code
60_krb5_get_default_principal_local (krb5_context context,
61				   krb5_principal *princ)
62{
63    krb5_error_code ret;
64    const char *user;
65    uid_t uid;
66
67    *princ = NULL;
68
69    uid = getuid();
70    if(uid == 0) {
71	user = getlogin();
72	if(user == NULL)
73	    user = get_env_user();
74	if(user != NULL && strcmp(user, "root") != 0)
75	    ret = krb5_make_principal(context, princ, NULL, user, "root", NULL);
76	else
77	    ret = krb5_make_principal(context, princ, NULL, "root", NULL);
78    } else {
79	struct passwd *pw = getpwuid(uid);
80	if(pw != NULL)
81	    user = pw->pw_name;
82	else {
83	    user = get_env_user();
84	    if(user == NULL)
85		user = getlogin();
86	}
87	if(user == NULL) {
88	    krb5_set_error_string(context,
89				  "unable to figure out current principal");
90	    return ENOTTY; /* XXX */
91	}
92	ret = krb5_make_principal(context, princ, NULL, user, NULL);
93    }
94    return ret;
95}
96
97krb5_error_code KRB5_LIB_FUNCTION
98krb5_get_default_principal (krb5_context context,
99			    krb5_principal *princ)
100{
101    krb5_error_code ret;
102    krb5_ccache id;
103
104    *princ = NULL;
105
106    ret = krb5_cc_default (context, &id);
107    if (ret == 0) {
108	ret = krb5_cc_get_principal (context, id, princ);
109	krb5_cc_close (context, id);
110	if (ret == 0)
111	    return 0;
112    }
113
114    return _krb5_get_default_principal_local(context, princ);
115}
116