crypto/external/bsd/heimdal/dist/lib/roken/get_default_username.c

   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
  45 ROKEN_LIB_FUNCTION const char * ROKEN_LIB_CALL
  46 get_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 }