usr.sbin/lastlogin/lastlogin.c

   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 1.5 2004/11/13 16:14:33 liamfoy 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  void    output(struct passwd *, struct lastlog *);
  48 static  void    usage(void);
  49
  50 int
  51 main(int argc, char **argv)
  52 {
  53         int     ch, i;
  54         FILE    *fp;
  55         struct passwd   *passwd;
  56         struct lastlog  last;
  57
  58         while ((ch = getopt(argc, argv, "")) != -1) {
  59                 usage();
  60         }
  61
  62         if ((fp = fopen(_PATH_LASTLOG, "r")) == NULL)
  63                 err(1, "%s", _PATH_LASTLOG);
  64
  65         setpassent(1);  /* Keep passwd file pointers open */
  66
  67         /* Process usernames given on the command line. */
  68         if (argc > 1) {
  69                 long offset;
  70                 for (i = 1; i < argc; ++i) {
  71                         if ((passwd = getpwnam(argv[i])) == NULL) {
  72                                 warnx("user '%s' not found", argv[i]);
  73                                 continue;
  74                         }
  75                         /* Calculate the offset into the lastlog file. */
  76                         offset = (long)(passwd->pw_uid * sizeof(last));
  77                         if (fseek(fp, offset, SEEK_SET)) {
  78                                 warn("fseek error");
  79                                 continue;
  80                         }
  81                         if (fread(&last, sizeof(last), 1, fp) != 1) {
  82                                 warnx("fread error on '%s'", passwd->pw_name);
  83                                 clearerr(fp);
  84                                 continue;
  85                         }
  86                         output(passwd, &last);
  87                 }
  88         }
  89         /* Read all lastlog entries, looking for active ones */
  90         else {
  91                 for (i = 0; fread(&last, sizeof(last), 1, fp) == 1; i++) {
  92                         if (last.ll_time == 0)
  93                                 continue;
  94                         if ((passwd = getpwuid((uid_t)i)) != NULL)
  95                                 output(passwd, &last);
  96                 }
  97                 if (ferror(fp))
  98                         warnx("fread error");
  99         }
 100
 101         setpassent(0);  /* Close passwd file pointers */
 102
 103         fclose(fp);
 104         exit(0);
 105 }
 106
 107 /* Duplicate the output of last(1) */
 108 static void
 109 output(struct passwd *p, struct lastlog *l)
 110 {
 111         printf("%-*.*s  %-*.*s %-*.*s   %s",
 112                 UT_NAMESIZE, UT_NAMESIZE, p->pw_name,
 113                 UT_LINESIZE, UT_LINESIZE, l->ll_line,
 114                 UT_HOSTSIZE, UT_HOSTSIZE, l->ll_host,
 115                 (l->ll_time) ? ctime(&(l->ll_time)) : "Never logged in\n");
 116 }
 117
 118 static void
 119 usage(void)
 120 {
 121         fprintf(stderr, "usage: lastlogin [user ...]\n");
 122         exit(1);
 123 }