netname.c

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2009, Sun Microsystems, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met:
 * - Redistributions of source code must retain the above copyright notice, 
 *   this list of conditions and the following disclaimer.
 * - 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.
 * - Neither the name of Sun Microsystems, Inc. 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 COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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.
 */

/*
 * netname utility routines
 * convert from unix names to network names and vice-versa
 * This module is operating system dependent!
 * What we define here will work with any unix system that has adopted
 * the sun NIS domain architecture.
 */

#include "namespace.h"
#include <sys/param.h>
#include <rpc/rpc.h>
#include <rpc/rpc_com.h>
#ifdef YP
#include <rpcsvc/yp_prot.h>
#include <rpcsvc/ypclnt.h>
#endif
#include <ctype.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "un-namespace.h"

#ifndef MAXHOSTNAMELEN
#define MAXHOSTNAMELEN 256
#endif

#define TYPE_BIT(type)  (sizeof (type) * CHAR_BIT)

#define TYPE_SIGNED(type) (((type) -1) < 0)

/*
** 302 / 1000 is log10(2.0) rounded up.
** Subtract one for the sign bit if the type is signed;
** add one for integer division truncation;
** add one more for a minus sign if the type is signed.
*/
#define INT_STRLEN_MAXIMUM(type) \
    ((TYPE_BIT(type) - TYPE_SIGNED(type)) * 302 / 1000 + 1 + TYPE_SIGNED(type))

static char *OPSYS = "unix";

/*
 * Figure out my fully qualified network name
 */
int
getnetname(char name[MAXNETNAMELEN+1])
{
	uid_t uid;

	uid = geteuid();
	if (uid == 0) {
		return (host2netname(name, (char *) NULL, (char *) NULL));
	} else {
		return (user2netname(name, uid, (char *) NULL));
	}
}


/*
 * Convert unix cred to network-name
 */
int
user2netname(char netname[MAXNETNAMELEN + 1], const uid_t uid, const char *domain)
{
	char *dfltdom;

	if (domain == NULL) {
		if (__rpc_get_default_domain(&dfltdom) != 0) {
			return (0);
		}
		domain = dfltdom;
	}
	if (strlen(domain) + 1 + INT_STRLEN_MAXIMUM(u_long) + 1 + strlen(OPSYS) > MAXNETNAMELEN) {
		return (0);
	}
	(void) sprintf(netname, "%s.%ld@%s", OPSYS, (u_long)uid, domain);	
	return (1);
}


/*
 * Convert host to network-name
 */
int
host2netname(char netname[MAXNETNAMELEN + 1], const char *host, const char *domain)
{
	char *dfltdom;
	char hostname[MAXHOSTNAMELEN+1];

	if (domain == NULL) {
		if (__rpc_get_default_domain(&dfltdom) != 0) {
			return (0);
		}
		domain = dfltdom;
	}
	if (host == NULL) {
		(void) gethostname(hostname, sizeof(hostname));
		host = hostname;
	}
	if (strlen(domain) + 1 + strlen(host) + 1 + strlen(OPSYS) > MAXNETNAMELEN) {
		return (0);
	} 
	(void) sprintf(netname, "%s.%s@%s", OPSYS, host, domain);
	return (1);
}