/*
 * lib/krb5/keytab/file/ktf_get_en.c
 *
 * Copyright 1990 by the Massachusetts Institute of Technology.
 * All Rights Reserved.
 *
 * Export of this software from the United States of America may
 *   require a specific license from the United States Government.
 *   It is the responsibility of any person or organization contemplating
 *   export to obtain such a license before exporting.
 * 
 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
 * distribute this software and its documentation for any purpose and
 * without fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation, and that
 * the name of M.I.T. not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior
 * permission.  M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without express
 * or implied warranty.
 * 
 *
 * This is the get_entry routine for the file based keytab implementation.
 * It opens the keytab file, and either retrieves the entry or returns
 * an error.
 */

#include "k5-int.h"
#include "ktfile.h"

krb5_error_code
krb5_ktfile_get_entry(context, id, principal, kvno, enctype, entry)
   krb5_context context;
   krb5_keytab id;
   krb5_principal principal;
   krb5_kvno kvno;
   krb5_enctype enctype;
   krb5_keytab_entry * entry;
{
    krb5_keytab_entry cur_entry, new_entry;
    krb5_error_code kerror = 0;
    int found_wrong_kvno = 0;

    /* Open the keyfile for reading */
    if ((kerror = krb5_ktfileint_openr(context, id)))
	return(kerror);
    
    /* 
     * For efficiency and simplicity, we'll use a while true that 
     * is exited with a break statement.
     */
    cur_entry.principal = 0;
    cur_entry.vno = 0;
    cur_entry.key.contents = 0;
    while (TRUE) {
	krb5_enctype entry_type;
	
	if ((kerror = krb5_ktfileint_read_entry(context, id, &new_entry)))
	    break;

	switch (enctype) {
	case ENCTYPE_DES_CBC_CRC:
	case ENCTYPE_DES_CBC_MD5:
	case ENCTYPE_DES_CBC_MD4:
	case ENCTYPE_DES_CBC_RAW:
	    enctype = ENCTYPE_DES_CBC_CRC;
	    break;
	}

	entry_type = new_entry.key.enctype;
	switch(entry_type) {
	case ENCTYPE_DES_CBC_CRC:
	case ENCTYPE_DES_CBC_MD5:
	case ENCTYPE_DES_CBC_MD4:
	case ENCTYPE_DES_CBC_RAW:
	    entry_type = ENCTYPE_DES_CBC_CRC;
	    break;
	}

	if (((enctype == IGNORE_ENCTYPE)||
	    (entry_type == enctype))&&
	    krb5_principal_compare(context, principal, new_entry.principal)) {
		if (kvno == IGNORE_VNO) {
			if (! cur_entry.principal ||
			    (cur_entry.vno < new_entry.vno))
			{
			    krb5_kt_free_entry(context, &cur_entry);
			    cur_entry = new_entry;
			}
		} else {
			if (new_entry.vno == kvno) {
			    krb5_kt_free_entry(context, &cur_entry);
			    cur_entry = new_entry;
			    break;
			} else
			     found_wrong_kvno++;
		}
	} else {
		krb5_kt_free_entry(context, &new_entry);
	}
    }
    if (kerror == KRB5_KT_END) {
	 if (cur_entry.principal)
	      kerror = 0;
	 else if (found_wrong_kvno)
	      kerror = KRB5_KT_KVNONOTFOUND;
	 else
	      kerror = KRB5_KT_NOTFOUND;
    }
    if (kerror) {
	(void) krb5_ktfileint_close(context, id);
	krb5_kt_free_entry(context, &cur_entry);
	return kerror;
    }
    if ((kerror = krb5_ktfileint_close(context, id)) != 0) {
	krb5_kt_free_entry(context, &cur_entry);
	return kerror;
    }
    *entry = cur_entry;
    return 0;
}
