/*
 * 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 (c) 2013 Gary Mills
 *
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1988 AT&T */
/*        All Rights Reserved   */

#pragma weak _getlogin = getloginx
#pragma weak _getlogin_r = getloginx_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"

/* Revert the renames done in unistd.h */
#ifdef  __PRAGMA_REDEFINE_EXTNAME
#pragma redefine_extname        getlogint       getlogin
#pragma redefine_extname        getlogint_r     getlogin_r
#pragma redefine_extname        __posix_getlogint_r     __posix_getlogin_r
#else   /* __PRAGMA_REDEFINE_EXTNAME */
#ifdef  getlogin
#undef  getlogin
#endif  /* getlogin */
#ifdef  getlogin_r
#undef  getlogin_r
#endif  /* getlogin_r */
#ifdef  __posix_getlogin_r
#undef  __posix_getlogin_r
#endif  /* __posix_getlogin_r */
#define getlogint       getlogin
#define getlogint_r     getlogin_r
#define __posix_getlogint_r     __posix_getlogin_r
#endif  /* __PRAGMA_REDEFINE_EXTNAME */
extern char *getlogint(void);
extern char *getlogint_r(char *, int);
extern int __posix_getlogint_r(char *, int);

/*
 * Use the full length of a login name.
 * The utmpx interface provides for a 32 character login name.
 */
#define NMAX    (sizeof (((struct utmpx *)0)->ut_user))

/*
 * Common function
 */
static char *
getl_r_common(char *answer, size_t namelen, size_t maxlen)
{
        int             uf;
        off64_t         me;
        struct futmpx   ubuf;
        size_t          ulen;

        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);

        /* Insufficient buffer size */
        ulen = strnlen(ubuf.ut_user, maxlen);
        if (namelen <= ulen) {
                errno = ERANGE;
                return (NULL);
        }

        /*
         * While the interface to getlogin_r says that a user should supply a
         * buffer with at least LOGIN_NAME_MAX bytes, we shouldn't assume they
         * have, especially since we've been supplied with its actual size.
         * Doing otherwise is just asking us to corrupt memory (and has in the
         * past).
         */
        (void) strncpy(answer, ubuf.ut_user, ulen);
        answer[ulen] = '\0';
        return (answer);
}

/*
 * POSIX.1c Draft-6 version of the function getlogin_r.
 * It was implemented by Solaris 2.3.
 */
char *
getlogint_r(char *answer, int namelen)
{
        return (getl_r_common(answer, (size_t)namelen, LOGNAME_MAX_TRAD));
}

/*
 * POSIX.1c standard version of the function getlogin_r.
 * User gets it via static getlogin_r from the header file.
 */
int
__posix_getlogint_r(char *name, int namelen)
{
        int nerrno = 0;
        int oerrno = errno;

        errno = 0;
        if (getl_r_common(name, (size_t)namelen, LOGNAME_MAX_TRAD) == NULL) {
                if (errno == 0)
                        nerrno = EINVAL;
                else
                        nerrno = errno;
        }
        errno = oerrno;
        return (nerrno);
}

char *
getlogint(void)
{
        char *answer = tsdalloc(_T_LOGIN, LOGIN_NAME_MAX_TRAD, NULL);

        if (answer == NULL)
                return (NULL);
        return (getl_r_common(answer, LOGIN_NAME_MAX_TRAD, LOGNAME_MAX_TRAD));
}

/*
 * POSIX.1c Draft-6 version of the function getlogin_r.
 * It was implemented by Solaris 2.3.
 * For extended login names, selected by redefine_extname in unistd.h.
 */
char *
getloginx_r(char *answer, int namelen)
{
        return (getl_r_common(answer, (size_t)namelen, NMAX));
}

/*
 * POSIX.1c standard version of the function getlogin_r.
 * User gets it via static getlogin_r from the header file.
 * For extended login names, selected by redefine_extname in unistd.h.
 */
int
__posix_getloginx_r(char *name, int namelen)
{
        int nerrno = 0;
        int oerrno = errno;

        errno = 0;
        if (getl_r_common(name, (size_t)namelen, NMAX) == NULL) {
                if (errno == 0)
                        nerrno = EINVAL;
                else
                        nerrno = errno;
        }
        errno = oerrno;
        return (nerrno);
}

/*
 * For extended login names, selected by redefine_extname in unistd.h.
 */
char *
getloginx(void)
{
        char *answer = tsdalloc(_T_LOGIN, LOGIN_NAME_MAX, NULL);

        if (answer == NULL)
                return (NULL);
        return (getl_r_common(answer, LOGIN_NAME_MAX, NMAX));
}