/*	$OpenBSD: get_default_principal.c,v 1.2 1997/12/09 07:57:16 art Exp $	*/
/* $KTH: get_default_principal.c,v 1.10 1997/04/01 08:18:28 joda Exp $ */

/*
 * Copyright (c) 1995, 1996, 1997 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the Kungliga Tekniska
 *      Högskolan and its contributors.
 * 
 * 4. 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 "krb_locl.h"

int
krb_get_default_principal(char *name, char *instance, char *realm)
{
  char *file;
  int ret;

  char *p;

  if ((file = getenv("KRBTKFILE")) == NULL)
      file = TKT_FILE;  
  
  ret = krb_get_tf_fullname(file, name, instance, realm);
  if(ret == KSUCCESS)
      return 0;

  p = getenv("KRB4PRINCIPAL");
  if(p && kname_parse(name, instance, realm, p) == KSUCCESS)
      return 1;
      
  {
    struct passwd *pw;
    pw = getpwuid(getuid());
    if(pw == NULL){
      return -1;
    }

    strncpy(name, pw->pw_name, ANAME_SZ);
    name[ANAME_SZ-1] = '\0';
    strncpy(instance, "", 2);
    krb_get_lrealm(realm, 1);

    if(strcmp(name, "root") == 0){
      p = NULL;
      p = getlogin();
      if(p == NULL)
	p = getenv("USER");
      if(p == NULL)
	p = getenv("LOGNAME");
      if(p){
	strncpy (name, p, ANAME_SZ);
	name[ANAME_SZ - 1] = '\0';
	strncpy(instance, "root", 5);
      }
    }
    return 1;
  }
  return -1;
}