/*

 * CDDL HEADER START

 *

 * The contents of this file are subject to the terms of the

 * Common Development and Distribution License (the "License").

 * You may not use this file except in compliance with the License.

 *

 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE

 * or http://www.opensolaris.org/os/licensing.

 * See the License for the specific language governing permissions

 * and limitations under the License.

 *

 * When distributing Covered Code, include this CDDL HEADER in each

 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.

 * If applicable, add the following below this CDDL HEADER, with the

 * fields enclosed by brackets "[]" replaced with your own identifying

 * information: Portions Copyright [yyyy] [name of copyright owner]

 *

 * CDDL HEADER END

 */

/*

 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.

 * Use is subject to license terms.

 */

/*	Copyright (c) 1988 AT&T	*/

/*	  All Rights Reserved  	*/

#pragma ident	"%Z%%M%	%I%	%E% SMI"

#pragma weak _getlogin = getlogin

#pragma weak _getlogin_r = getlogin_r

#include "lint.h"

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <string.h>

#include <stdlib.h>

#include <limits.h>

#include "utmpx.h"

#include <unistd.h>

#include <errno.h>

#include <thread.h>

#include <synch.h>

#include <mtlib.h>

#include "tsd.h"

/*

 * XXX - _POSIX_LOGIN_NAME_MAX limits the length of a login name.  The utmpx

 * interface provides for a 32 character login name, but for the sake of

 * compatibility, we are still using the old utmp-imposed limit.

 */

/*

 * POSIX.1c Draft-6 version of the function getlogin_r.

 * It was implemented by Solaris 2.3.

 */

char *

getlogin_r(char *answer, int namelen)

{

	int		uf;

	off64_t		me;

	struct futmpx	ubuf;

	if (namelen < _POSIX_LOGIN_NAME_MAX) {

		errno = ERANGE;

		return (NULL);

	}

	if ((me = (off64_t)ttyslot()) < 0)

		return (NULL);

	if ((uf = open64(UTMPX_FILE, 0)) < 0)

		return (NULL);

	(void) lseek64(uf, me * sizeof (ubuf), SEEK_SET);

	if (read(uf, &ubuf, sizeof (ubuf)) != sizeof (ubuf)) {

		(void) close(uf);

		return (NULL);

	}

	(void) close(uf);

	if (ubuf.ut_user[0] == '\0')

		return (NULL);

	(void) strncpy(&answer[0], &ubuf.ut_user[0],

	    _POSIX_LOGIN_NAME_MAX - 1);

	answer[_POSIX_LOGIN_NAME_MAX - 1] = '\0';

	return (&answer[0]);

}

/*

 * POSIX.1c standard version of the function getlogin_r.

 * User gets it via static getlogin_r from the header file.

 */

int

__posix_getlogin_r(char *name, int namelen)

{

	int nerrno = 0;

	int oerrno = errno;

	errno = 0;

	if (getlogin_r(name, namelen) == NULL) {

		if (errno == 0)

			nerrno = EINVAL;

		else

			nerrno = errno;

	}

	errno = oerrno;

	return (nerrno);

}

char *

getlogin(void)

{

	char *answer = tsdalloc(_T_LOGIN, _POSIX_LOGIN_NAME_MAX, NULL);

	if (answer == NULL)

		return (NULL);

	return (getlogin_r(answer, _POSIX_LOGIN_NAME_MAX));

}