/*
 *	$Source: /afs/sipb.mit.edu/project/sipb-athena/repository/src/kerberos/appl/tftp/resolve_host.c,v $
 *	$Author: ghudson $
 *	$Locker:  $
 *	$Log: resolve_host.c,v $
 *	Revision 1.4  1996/06/02 07:36:04  ghudson
 *	Initial checkin.
 *
 * Revision 1.4  1993/10/17  17:38:03  raeburn
 * include string.h
 *
 * Revision 1.3  1993/03/17  00:36:48  eichin
 * NULL is not a char, 0 is. (-Wall cleanup)
 * '-' is not a string, "-" is. (real bug, tftp.c)
 *
 * Revision 1.2  1993/01/07  21:05:55  eichin
 * punt extraneous declaration of index
 * change index to strchr
 * change bcopy to memcpy
 *
 * Revision 1.1.1.2  1991/12/03  18:47:29  eichin
 * Athena Kerberos 4 patch 9
 *
 * Revision 4.2  89/01/24  14:24:22  root
 * add notie
 * 
 * Revision 4.1  87/09/01  16:33:15  steiner
 * No change; starting version 4.
 * 
 * Revision 2.2  87/03/11  10:18:28  jtkohl
 * add PrincipalHostname function
 * 
 * Revision 2.1  85/12/12  10:55:25  bcn
 * change majore revision to 2.
 * 
 * Revision 1.1  85/06/07  21:44:10  martillo
 * Initial revision
 * 
 */

#ifndef lint
static char *rcsid_resolve_host_c = "$Header: /afs/sipb.mit.edu/project/sipb-athena/repository/src/kerberos/appl/tftp/resolve_host.c,v 1.4 1996/06/02 07:36:04 ghudson Exp $";
#endif	lint

/* $Header: /afs/sipb.mit.edu/project/sipb-athena/repository/src/kerberos/appl/tftp/resolve_host.c,v 1.4 1996/06/02 07:36:04 ghudson Exp $ */

/*  Copyright 1984 by the Massachusetts Institute of Technology  */
/*  See permission and disclaimer notice in file "notice.h"  */
#include	"notice.h"

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <errno.h>
#include <signal.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <ctype.h>

struct sockaddr_in *
resolve_host(name)

/* Resolve the specified host name into an internet address.  The "name" may
 * be either a character string name, or an address in the form a.b.c.d where
 * the pieces are octal, decimal, or hex numbers.  Returns a pointer to a
 * sockaddr_in struct (note this structure is statically allocated and must
 * be copied), or NULL if the name is unknown.
 */

register char *name;
{
	register struct hostent *fhost;
	static struct sockaddr_in sa;

	
	if ((sa.sin_addr.s_addr = inet_addr(name)) != -1) {
		sa.sin_family = AF_INET;	/* grot */
		sa.sin_port = 0;
	} else if ((fhost = gethostbyname(name)) != NULL) {
		sa.sin_family = fhost->h_addrtype;
		sa.sin_port = 0;
		memcpy(&sa.sin_addr, fhost->h_addr, fhost->h_length);
	} else
			return(NULL);
	return(&sa);
}


/*
 * The convention established by the Kerberos-authenticated
 * services is that the principal host name is
 * all lower case characters.  Therefore, we can get this name from
 * an alias by taking the official, fully qualified hostname, stripping off
 * the domain info (ie, take everything up to but excluding the
 * '.') and translating it to lower case.  For example, if "menel" is an
 * alias for host officially named "menelaus" (in /etc/hosts), for 
 * the host whose official name is "MENELAUS.MIT.EDU", the user could
 * give the command "menel echo foo" and we will resolve it to "menelaus".
 */

char *
PrincipalHostname( alias )
char *alias;
{
    struct hostent *h;
    char *phost = alias;
    if ( (h=gethostbyname(alias)) != (struct hostent *)NULL ) {
	char *p = strchr( h->h_name, '.' );
	if (p) *p = 0;
	p = phost = h->h_name;
	do {
	    if (isupper(*p)) *p=tolower(*p);
	} while (*p++);
    }
    return( phost );
}