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lastlogin.c revision 1.5 
      1 /*	$NetBSD: lastlogin.c,v 1.5 2000/07/04 20:27:37 matt Exp $	*/
      2 /*
      3  * Copyright (c) 1996 John M. Vinopal
      4  * All rights reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  * 3. All advertising materials mentioning features or use of this software
     15  *    must display the following acknowledgement:
     16  *	This product includes software developed for the NetBSD Project
     17  *	by John M. Vinopal.
     18  * 4. The name of the author may not be used to endorse or promote products
     19  *    derived from this software without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     26  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     27  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     28  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #include <sys/cdefs.h>
     35 #ifndef lint
     36 __RCSID("$NetBSD: lastlogin.c,v 1.5 2000/07/04 20:27:37 matt Exp $");
     37 #endif
     38 
     39 #include <sys/types.h>
     40 #include <err.h>
     41 #include <errno.h>
     42 #include <pwd.h>
     43 #include <stdio.h>
     44 #include <stdlib.h>
     45 #include <time.h>
     46 #include <utmp.h>
     47 #include <unistd.h>
     48 
     49 extern	char *__progname;
     50 static	char *logfile = _PATH_LASTLOG;
     51 
     52 	int	main __P((int, char **));
     53 static	void	output __P((struct passwd *, struct lastlog *));
     54 static	void	usage __P((void));
     55 
     56 int
     57 main(argc, argv)
     58 	int argc;
     59 	char *argv[];
     60 {
     61 	int	ch, i;
     62 	FILE	*fp;
     63 	struct passwd	*passwd;
     64 	struct lastlog	last;
     65 
     66 	while ((ch = getopt(argc, argv, "")) != -1) {
     67 		usage();
     68 	}
     69 
     70 	fp = fopen(logfile, "r");
     71 	if (fp == NULL)
     72 		err(1, "%s", logfile);
     73 
     74 	setpassent(1);	/* Keep passwd file pointers open */
     75 
     76 	/* Process usernames given on the command line. */
     77 	if (argc > 1) {
     78 		long offset;
     79 		for (i = 1; i < argc; ++i) {
     80 			if ((passwd = getpwnam(argv[i])) == NULL) {
     81 				warnx("user '%s' not found", argv[i]);
     82 				continue;
     83 			}
     84 			/* Calculate the offset into the lastlog file. */
     85 			offset = (long)(passwd->pw_uid * sizeof(last));
     86 			if (fseek(fp, offset, SEEK_SET)) {
     87 				warn("fseek error");
     88 				continue;
     89 			}
     90 			if (fread(&last, sizeof(last), 1, fp) != 1) {
     91 				warnx("fread error on '%s'", passwd->pw_name);
     92 				clearerr(fp);
     93 				continue;
     94 			}
     95 			output(passwd, &last);
     96 		}
     97 	}
     98 	/* Read all lastlog entries, looking for active ones */
     99 	else {
    100 		for (i = 0; fread(&last, sizeof(last), 1, fp) == 1; i++) {
    101 			if (last.ll_time == 0)
    102 				continue;
    103 			if ((passwd = getpwuid(i)) != NULL)
    104 				output(passwd, &last);
    105 		}
    106 		if (ferror(fp))
    107 			warnx("fread error");
    108 	}
    109 
    110 	setpassent(0);	/* Close passwd file pointers */
    111 
    112 	fclose(fp);
    113 	exit(0);
    114 }
    115 
    116 /* Duplicate the output of last(1) */
    117 static void
    118 output(p, l)
    119 	struct passwd *p;
    120 	struct lastlog *l;
    121 {
    122 	printf("%-*.*s  %-*.*s %-*.*s   %s",
    123 		UT_NAMESIZE, UT_NAMESIZE, p->pw_name,
    124 		UT_LINESIZE, UT_LINESIZE, l->ll_line,
    125 		UT_HOSTSIZE, UT_HOSTSIZE, l->ll_host,
    126 		(l->ll_time) ? ctime(&(l->ll_time)) : "Never logged in\n");
    127 }
    128 
    129 static void
    130 usage()
    131 {
    132 	fprintf(stderr, "usage: %s [user ...]\n", __progname);
    133 	exit(1);
    134 }
    135