/*
 * lib/krb5/os/def_realm.c
 *
 * Copyright 1990,1991 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.
 * 
 *
 * krb5_get_default_realm() function.
 */


#include <krb5/krb5.h>
#include <krb5/ext-proto.h>

#include <stdio.h>

/*
 * Retrieves the default realm to be used if no user-specified realm is
 *  available.  [e.g. to interpret a user-typed principal name with the
 *  realm omitted for convenience]
 * 
 *  returns system errors, NOT_ENOUGH_SPACE
*/

/*
 * Implementation:  the default realm is stored in a configuration file,
 * named by krb5_config_file;  the first token in this file is taken as
 * the default local realm name.
 */

extern char *krb5_config_file;		/* extern so can be set at
					   load/runtime */

/*
 * In case the program wants to override this.
 */
extern char *krb5_override_default_realm;

char *krb5_override_default_realm = 0;

krb5_error_code
krb5_get_default_realm(context, lrealm)
    krb5_context context;
    char **lrealm;
{
    FILE *config_file;
    char realmbuf[BUFSIZ];
    static char *saved_realm = 0;
    char *realm;
    char *cp;

    if (krb5_override_default_realm)
	    realm = krb5_override_default_realm;
    else if (saved_realm)
	    realm = saved_realm;
    else {
	    if (!(config_file = fopen(krb5_config_file, "r")))
		    /* can't open */
		    return KRB5_CONFIG_CANTOPEN;

	    if (fgets(realmbuf, sizeof(realmbuf), config_file) == NULL) {
		    fclose(config_file);
		    return(KRB5_CONFIG_BADFORMAT);
	    }
	    fclose(config_file);
	    
	    realmbuf[BUFSIZ-1] = '0';
	    cp = strchr(realmbuf, '\n');
	    if (cp)
		    *cp = '\0';
	    cp = strchr(realmbuf, ' ');
	    if (cp)
		    *cp = '\0';

	    saved_realm = malloc(strlen (realmbuf) + 1);
	    if (!saved_realm)
		    return ENOMEM;

	    strcpy(saved_realm, realmbuf);

	    realm = saved_realm;
    }
    
    if (!(*lrealm = cp = malloc((unsigned int) strlen(realm) + 1)))
	    return ENOMEM;
    strcpy(cp, realm);
    return(0);
}