text: /*
   * Copyright (c) 1997 - 2001 Kungliga Tekniska Högskolan
   * (Royal Institute of Technology, Stockholm, Sweden).
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * 3. Neither the name of the Institute nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  #include "krb5_locl.h"
  
  /*
   * Try to find out what's a reasonable default principal.
   */
  
  static const char*
  get_env_user(void)
  {
      const char *user = getenv("USER");
      if(user == NULL)
  	user = getenv("LOGNAME");
      if(user == NULL)
  	user = getenv("USERNAME");
      return user;
  }
  
  #ifndef _WIN32
  
  /*
   * Will only use operating-system dependant operation to get the
   * default principal, for use of functions that in ccache layer to
   * avoid recursive calls.
   */
  
  krb5_error_code
  _krb5_get_default_principal_local (krb5_context context,
  				   krb5_principal *princ)
  {
      krb5_error_code ret;
      const char *user;
      uid_t uid;
  
      *princ = NULL;
  
      uid = getuid();
      if(uid == 0) {
  	user = getlogin();
  	if(user == NULL)
  	    user = get_env_user();
  	if(user != NULL && strcmp(user, "root") != 0)
  	    ret = krb5_make_principal(context, princ, NULL, user, "root", NULL);
  	else
  	    ret = krb5_make_principal(context, princ, NULL, "root", NULL);
      } else {
  	struct passwd *pw = getpwuid(uid);
  	if(pw != NULL)
  	    user = pw->pw_name;
  	else {
  	    user = get_env_user();
  	    if(user == NULL)
  		user = getlogin();
  	}
  	if(user == NULL) {
  	    krb5_set_error_message(context, ENOTTY,
  				   N_("unable to figure out current "
  				      "principal", ""));
  	    return ENOTTY; /* XXX */
  	}
  	ret = krb5_make_principal(context, princ, NULL, user, NULL);
      }
      return ret;
  }
  
  #else  /* _WIN32 */
  
  #define SECURITY_WIN32
  #include <security.h>
  
  krb5_error_code
  _krb5_get_default_principal_local(krb5_context context,
  				  krb5_principal *princ)
  {
      /* See if we can get the principal first.  We only expect this to
         work if logged into a domain. */
      {
  	char username[1024];
  	ULONG sz = sizeof(username);
  
  	if (GetUserNameEx(NameUserPrincipal, username, &sz)) {
  	    return krb5_parse_name_flags(context, username,
  					 KRB5_PRINCIPAL_PARSE_ENTERPRISE,
  					 princ);
  	}
      }
  
      /* Just get the Windows username.  This should pretty much always
         work. */
      {
  	char username[1024];
  	DWORD dsz = sizeof(username);
  
  	if (GetUserName(username, &dsz)) {
  	    return krb5_make_principal(context, princ, NULL, username, NULL);
  	}
      }
  
      /* Failing that, we look at the environment */
      {
  	const char * username = get_env_user();
  
  	if (username == NULL) {
  	    krb5_set_error_string(context,
  				  "unable to figure out current principal");
  	    return ENOTTY;	/* Really? */
  	}
  
  	return krb5_make_principal(context, princ, NULL, username, NULL);
      }
  }
  
  #endif
  
  KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
  krb5_get_default_principal (krb5_context context,
  			    krb5_principal *princ)
  {
      krb5_error_code ret;
      krb5_ccache id;
  
      *princ = NULL;
  
      ret = krb5_cc_default (context, &id);
      if (ret == 0) {
  	ret = krb5_cc_get_principal (context, id, princ);
  	krb5_cc_close (context, id);
  	if (ret == 0)
  	    return 0;
      }
  
      return _krb5_get_default_principal_local(context, princ);
  }
  