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      1 /*	$NetBSD: utmp.c,v 1.10 2011/10/15 23:00:02 christos Exp $	 */
      2 
      3 /*-
      4  * Copyright (c) 2002 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Christos Zoulas.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 #include <sys/cdefs.h>
     32 
     33 #if defined(LIBC_SCCS) && !defined(lint)
     34 __RCSID("$NetBSD: utmp.c,v 1.10 2011/10/15 23:00:02 christos Exp $");
     35 #endif /* LIBC_SCCS and not lint */
     36 
     37 #include "namespace.h"
     38 #include <sys/types.h>
     39 #include <sys/param.h>
     40 #include <stdio.h>
     41 #include <string.h>
     42 #include <time.h>
     43 #include <utmp.h>
     44 #include <sys/stat.h>
     45 
     46 static struct utmp utmp;
     47 static FILE *ut;
     48 static char utfile[MAXPATHLEN] = _PATH_UTMP;
     49 
     50 void
     51 setutent(void)
     52 {
     53 	if (ut == NULL)
     54 		return;
     55 	(void)fseeko(ut, (off_t)0, SEEK_SET);
     56 }
     57 
     58 struct utmp *
     59 getutent(void)
     60 {
     61 	if (ut == NULL) {
     62 		struct stat st;
     63 		off_t numentries;
     64 		if ((ut = fopen(utfile, "re")) == NULL)
     65 			return NULL;
     66 		if (fstat(fileno(ut), &st) == -1)
     67 			goto out;
     68 		/*
     69 		 * If we have a an old version utmp file bail.
     70 		 */
     71 		numentries = st.st_size / sizeof(utmp);
     72 		if ((off_t)(numentries * sizeof(utmp)) != st.st_size)
     73 			goto out;
     74 	}
     75 	if (fread(&utmp, sizeof(utmp), 1, ut) == 1)
     76 		return &utmp;
     77 out:
     78 	(void)fclose(ut);
     79 	return NULL;
     80 }
     81 
     82 void
     83 endutent(void)
     84 {
     85 	if (ut != NULL) {
     86 		(void)fclose(ut);
     87 		ut = NULL;
     88 	}
     89 }
     90 
     91 int
     92 utmpname(const char *fname)
     93 {
     94 	size_t len = strlen(fname);
     95 
     96 	if (len >= sizeof(utfile))
     97 		return 0;
     98 
     99 	/* must not end in x! */
    100 	if (fname[len - 1] == 'x')
    101 		return 0;
    102 
    103 	(void)strlcpy(utfile, fname, sizeof(utfile));
    104 	endutent();
    105 	return 1;
    106 }
    107