/*      $NetBSD: utmp.c,v 1.10 2011/10/15 23:00:02 christos Exp $        */

/*-
* Copyright (c) 2002 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Christos Zoulas.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
*/
#include <sys/cdefs.h>

#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: utmp.c,v 1.10 2011/10/15 23:00:02 christos Exp $");
#endif /* LIBC_SCCS and not lint */

#include "namespace.h"
#include <sys/types.h>
#include <sys/param.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <utmp.h>
#include <sys/stat.h>

static struct utmp utmp;
static FILE *ut;
static char utfile[MAXPATHLEN] = _PATH_UTMP;

void
setutent(void)
{
       if (ut == NULL)
               return;
       (void)fseeko(ut, (off_t)0, SEEK_SET);
}

struct utmp *
getutent(void)
{
       if (ut == NULL) {
               struct stat st;
               off_t numentries;
               if ((ut = fopen(utfile, "re")) == NULL)
                       return NULL;
               if (fstat(fileno(ut), &st) == -1)
                       goto out;
               /*
                * If we have a an old version utmp file bail.
                */
               numentries = st.st_size / sizeof(utmp);
               if ((off_t)(numentries * sizeof(utmp)) != st.st_size)
                       goto out;
       }
       if (fread(&utmp, sizeof(utmp), 1, ut) == 1)
               return &utmp;
out:
       (void)fclose(ut);
       return NULL;
}

void
endutent(void)
{
       if (ut != NULL) {
               (void)fclose(ut);
               ut = NULL;
       }
}

int
utmpname(const char *fname)
{
       size_t len = strlen(fname);

       if (len >= sizeof(utfile))
               return 0;

       /* must not end in x! */
       if (fname[len - 1] == 'x')
               return 0;

       (void)strlcpy(utfile, fname, sizeof(utfile));
       endutent();
       return 1;
}