xref: /dragonfly/usr.sbin/lastlogin/lastlogin.c (revision 2d8a3be7)
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  * $NetBSD: lastlogin.c,v 1.4 1998/02/03 04:45:35 perry Exp $
33  * $FreeBSD: src/usr.sbin/lastlogin/lastlogin.c,v 1.2.2.2 2001/07/19 05:02:46 kris Exp $
34  * $DragonFly: src/usr.sbin/lastlogin/lastlogin.c,v 1.3 2003/11/03 19:31:38 eirikn Exp $
35  */
36 
37 #include <sys/cdefs.h>
38 
39 #include <err.h>
40 #include <pwd.h>
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include <time.h>
44 #include <utmp.h>
45 #include <unistd.h>
46 
47 static	const char *logfile = _PATH_LASTLOG;
48 
49 	int	main(int, char **);
50 static	void	output(struct passwd *, struct lastlog *);
51 static	void	usage(void);
52 
53 int
54 main(argc, argv)
55 	int argc;
56 	char *argv[];
57 {
58 	int	ch, i;
59 	FILE	*fp;
60 	struct passwd	*passwd;
61 	struct lastlog	last;
62 
63 	while ((ch = getopt(argc, argv, "")) != -1) {
64 		usage();
65 	}
66 
67 	fp = fopen(logfile, "r");
68 	if (fp == NULL)
69 		err(1, "%s", logfile);
70 
71 	setpassent(1);	/* Keep passwd file pointers open */
72 
73 	/* Process usernames given on the command line. */
74 	if (argc > 1) {
75 		long offset;
76 		for (i = 1; i < argc; ++i) {
77 			if ((passwd = getpwnam(argv[i])) == NULL) {
78 				warnx("user '%s' not found", argv[i]);
79 				continue;
80 			}
81 			/* Calculate the offset into the lastlog file. */
82 			offset = (long)(passwd->pw_uid * sizeof(last));
83 			if (fseek(fp, offset, SEEK_SET)) {
84 				warn("fseek error");
85 				continue;
86 			}
87 			if (fread(&last, sizeof(last), 1, fp) != 1) {
88 				warnx("fread error on '%s'", passwd->pw_name);
89 				clearerr(fp);
90 				continue;
91 			}
92 			output(passwd, &last);
93 		}
94 	}
95 	/* Read all lastlog entries, looking for active ones */
96 	else {
97 		for (i = 0; fread(&last, sizeof(last), 1, fp) == 1; i++) {
98 			if (last.ll_time == 0)
99 				continue;
100 			if ((passwd = getpwuid((uid_t)i)) != NULL)
101 				output(passwd, &last);
102 		}
103 		if (ferror(fp))
104 			warnx("fread error");
105 	}
106 
107 	setpassent(0);	/* Close passwd file pointers */
108 
109 	fclose(fp);
110 	exit(0);
111 }
112 
113 /* Duplicate the output of last(1) */
114 static void
115 output(p, l)
116 	struct passwd *p;
117 	struct lastlog *l;
118 {
119 	printf("%-*.*s  %-*.*s %-*.*s   %s",
120 		UT_NAMESIZE, UT_NAMESIZE, p->pw_name,
121 		UT_LINESIZE, UT_LINESIZE, l->ll_line,
122 		UT_HOSTSIZE, UT_HOSTSIZE, l->ll_host,
123 		(l->ll_time) ? ctime(&(l->ll_time)) : "Never logged in\n");
124 }
125 
126 static void
127 usage()
128 {
129 	fprintf(stderr, "usage: lastlogin [user ...]\n");
130 	exit(1);
131 }
132