coreutils/who.c

   1 /* vi: set sw=4 ts=4: */
   2 /*----------------------------------------------------------------------
   3  * Mini who is used to display user name, login time,
   4  * idle time and host name.
   5  *
   6  * Author: Da Chen  <dchen@ayrnetworks.com>
   7  *
   8  * This is a free document; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * as published by the Free Software Foundation:
  11  *    http://www.gnu.org/copyleft/gpl.html
  12  *
  13  * Copyright (c) 2002 AYR Networks, Inc.
  14  *
  15  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  16  *
  17  *----------------------------------------------------------------------
  18  */
  19 /* BB_AUDIT SUSv3 _NOT_ compliant -- missing options -b, -d, -l, -m, -p, -q, -r, -s, -t, -T, -u; Missing argument 'file'.  */
  20
  21 //usage:#define who_trivial_usage
  22 //usage:       "[-a]"
  23 //usage:#define who_full_usage "\n\n"
  24 //usage:       "Show who is logged on\n"
  25 //usage:     "\nOptions:"
  26 //usage:     "\n        -a      Show all"
  27
  28 #include "libbb.h"
  29
  30 static void idle_string(char *str6, time_t t)
  31 {
  32         t = time(NULL) - t;
  33
  34         /*if (t < 60) {
  35                 str6[0] = '.';
  36                 str6[1] = '\0';
  37                 return;
  38         }*/
  39         if (t >= 0 && t < (24 * 60 * 60)) {
  40                 sprintf(str6, "%02d:%02d",
  41                                 (int) (t / (60 * 60)),
  42                                 (int) ((t % (60 * 60)) / 60));
  43                 return;
  44         }
  45         strcpy(str6, "old");
  46 }
  47
  48 int who_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  49 int who_main(int argc UNUSED_PARAM, char **argv)
  50 {
  51         struct utmp *ut;
  52         unsigned opt;
  53
  54         opt_complementary = "=0";
  55         opt = getopt32(argv, "aH");
  56         if (opt & 2) // -H
  57                 printf("USER\t\tTTY\t\tIDLE\tTIME\t\t HOST\n");
  58
  59         setutent();
  60         while ((ut = getutent()) != NULL) {
  61                 if (ut->ut_user[0]
  62                  && ((opt & 1) || ut->ut_type == USER_PROCESS)
  63                 ) {
  64                         char str6[6];
  65                         char name[sizeof("/dev/") + sizeof(ut->ut_line) + 1];
  66                         struct stat st;
  67                         time_t seconds;
  68
  69                         str6[0] = '?';
  70                         str6[1] = '\0';
  71                         strcpy(name, "/dev/");
  72                         safe_strncpy(ut->ut_line[0] == '/' ? name : name + sizeof("/dev/")-1,
  73                                 ut->ut_line,
  74                                 sizeof(ut->ut_line)+1
  75                         );
  76                         if (stat(name, &st) == 0)
  77                                 idle_string(str6, st.st_atime);
  78                         /* manpages say ut_tv.tv_sec *is* time_t,
  79                          * but some systems have it wrong */
  80                         seconds = ut->ut_tv.tv_sec;
  81                         /* How wide time field can be?
  82                          * "Nov 10 19:33:20": 15 chars
  83                          * "2010-11-10 19:33": 16 chars
  84                          */
  85                         printf("%-15.*s %-15.*s %-7s %-16.16s %.*s\n",
  86                                         (int)sizeof(ut->ut_user), ut->ut_user,
  87                                         (int)sizeof(ut->ut_line), ut->ut_line,
  88                                         str6,
  89                                         ctime(&seconds) + 4,
  90                                         (int)sizeof(ut->ut_host), ut->ut_host
  91                         );
  92                 }
  93         }
  94         if (ENABLE_FEATURE_CLEAN_UP)
  95                 endutent();
  96         return EXIT_SUCCESS;
  97 }