lastlogin.c revision 98069 
1/*
2 * Copyright (c) 1996 John M. Vinopal
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed for the NetBSD Project
16 *	by John M. Vinopal.
17 * 4. The name of the author may not be used to endorse or promote products
18 *    derived from this software without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
24 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
25 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
26 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
27 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
28 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#include <sys/cdefs.h>
34#ifndef lint
35__RCSID("$FreeBSD: head/usr.sbin/lastlogin/lastlogin.c 98069 2002-06-09 19:29:55Z mike $");
36__RCSID("$NetBSD: lastlogin.c,v 1.4 1998/02/03 04:45:35 perry Exp $");
37#endif
38
39#include <sys/types.h>
40#include <err.h>
41#include <pwd.h>
42#include <stdio.h>
43#include <stdlib.h>
44#include <time.h>
45#include <utmp.h>
46#include <unistd.h>
47
48static	const char *logfile = _PATH_LASTLOG;
49
50	int	main __P((int, char **));
51static	void	output __P((struct passwd *, struct lastlog *));
52static	void	usage __P((void));
53
54int
55main(argc, argv)
56	int argc;
57	char *argv[];
58{
59	int	ch, i;
60	FILE	*fp;
61	struct passwd	*passwd;
62	struct lastlog	last;
63
64	while ((ch = getopt(argc, argv, "")) != -1) {
65		usage();
66	}
67
68	fp = fopen(logfile, "r");
69	if (fp == NULL)
70		err(1, "%s", logfile);
71
72	setpassent(1);	/* Keep passwd file pointers open */
73
74	/* Process usernames given on the command line. */
75	if (argc > 1) {
76		long offset;
77		for (i = 1; i < argc; ++i) {
78			if ((passwd = getpwnam(argv[i])) == NULL) {
79				warnx("user '%s' not found", argv[i]);
80				continue;
81			}
82			/* Calculate the offset into the lastlog file. */
83			offset = (long)(passwd->pw_uid * sizeof(last));
84			if (fseek(fp, offset, SEEK_SET)) {
85				warn("fseek error");
86				continue;
87			}
88			if (fread(&last, sizeof(last), 1, fp) != 1) {
89				warnx("fread error on '%s'", passwd->pw_name);
90				clearerr(fp);
91				continue;
92			}
93			output(passwd, &last);
94		}
95	}
96	/* Read all lastlog entries, looking for active ones */
97	else {
98		for (i = 0; fread(&last, sizeof(last), 1, fp) == 1; i++) {
99			if (last.ll_time == 0)
100				continue;
101			if ((passwd = getpwuid((uid_t)i)) != NULL)
102				output(passwd, &last);
103		}
104		if (ferror(fp))
105			warnx("fread error");
106	}
107
108	setpassent(0);	/* Close passwd file pointers */
109
110	fclose(fp);
111	exit(0);
112}
113
114/* Duplicate the output of last(1) */
115static void
116output(p, l)
117	struct passwd *p;
118	struct lastlog *l;
119{
120	time_t t = _int_to_time(l->ll_time);
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(&t) : "Never logged in\n");
126}
127
128static void
129usage()
130{
131	fprintf(stderr, "usage: lastlogin [user ...]\n");
132	exit(1);
133}
134