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lastlogin.c revision 1.6 
      1 /*	$NetBSD: lastlogin.c,v 1.6 2001/02/19 23:22:44 cgd 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 1.6 2001/02/19 23:22:44 cgd 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 static	char *logfile = _PATH_LASTLOG;
     50 
     51 	int	main __P((int, char **));
     52 static	void	output __P((struct passwd *, struct lastlog *));
     53 static	void	usage __P((void));
     54 
     55 int
     56 main(argc, argv)
     57 	int argc;
     58 	char *argv[];
     59 {
     60 	int	ch, i;
     61 	FILE	*fp;
     62 	struct passwd	*passwd;
     63 	struct lastlog	last;
     64 
     65 	while ((ch = getopt(argc, argv, "")) != -1) {
     66 		usage();
     67 	}
     68 
     69 	fp = fopen(logfile, "r");
     70 	if (fp == NULL)
     71 		err(1, "%s", logfile);
     72 
     73 	setpassent(1);	/* Keep passwd file pointers open */
     74 
     75 	/* Process usernames given on the command line. */
     76 	if (argc > 1) {
     77 		long offset;
     78 		for (i = 1; i < argc; ++i) {
     79 			if ((passwd = getpwnam(argv[i])) == NULL) {
     80 				warnx("user '%s' not found", argv[i]);
     81 				continue;
     82 			}
     83 			/* Calculate the offset into the lastlog file. */
     84 			offset = (long)(passwd->pw_uid * sizeof(last));
     85 			if (fseek(fp, offset, SEEK_SET)) {
     86 				warn("fseek error");
     87 				continue;
     88 			}
     89 			if (fread(&last, sizeof(last), 1, fp) != 1) {
     90 				warnx("fread error on '%s'", passwd->pw_name);
     91 				clearerr(fp);
     92 				continue;
     93 			}
     94 			output(passwd, &last);
     95 		}
     96 	}
     97 	/* Read all lastlog entries, looking for active ones */
     98 	else {
     99 		for (i = 0; fread(&last, sizeof(last), 1, fp) == 1; i++) {
    100 			if (last.ll_time == 0)
    101 				continue;
    102 			if ((passwd = getpwuid(i)) != NULL)
    103 				output(passwd, &last);
    104 		}
    105 		if (ferror(fp))
    106 			warnx("fread error");
    107 	}
    108 
    109 	setpassent(0);	/* Close passwd file pointers */
    110 
    111 	fclose(fp);
    112 	exit(0);
    113 }
    114 
    115 /* Duplicate the output of last(1) */
    116 static void
    117 output(p, l)
    118 	struct passwd *p;
    119 	struct lastlog *l;
    120 {
    121 	printf("%-*.*s  %-*.*s %-*.*s   %s",
    122 		UT_NAMESIZE, UT_NAMESIZE, p->pw_name,
    123 		UT_LINESIZE, UT_LINESIZE, l->ll_line,
    124 		UT_HOSTSIZE, UT_HOSTSIZE, l->ll_host,
    125 		(l->ll_time) ? ctime(&(l->ll_time)) : "Never logged in\n");
    126 }
    127 
    128 static void
    129 usage()
    130 {
    131 	fprintf(stderr, "usage: %s [user ...]\n", getprogname());
    132 	exit(1);
    133 }
    134