busybox/coreutils/who.c
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   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//config:config WHO
  18//config:       bool "who (3.9 kb)"
  19//config:       default y
  20//config:       depends on FEATURE_UTMP
  21//config:       help
  22//config:       Print users currently logged on.
  23//config:
  24// procps-ng has this variation of "who":
  25//config:config W
  26//config:       bool "w (3.8 kb)"
  27//config:       default y
  28//config:       depends on FEATURE_UTMP
  29//config:       help
  30//config:       Print users currently logged on.
  31//config:
  32//config:config USERS
  33//config:       bool "users (3.4 kb)"
  34//config:       default y
  35//config:       depends on FEATURE_UTMP
  36//config:       help
  37//config:       Print users currently logged on.
  38
  39//                APPLET_NOEXEC:name   main location        suid_type     help
  40//applet:IF_USERS(APPLET_NOEXEC(users, who, BB_DIR_USR_BIN, BB_SUID_DROP, users))
  41//applet:IF_W(    APPLET_NOEXEC(w,     who, BB_DIR_USR_BIN, BB_SUID_DROP, w))
  42//applet:IF_WHO(  APPLET_NOEXEC(who,   who, BB_DIR_USR_BIN, BB_SUID_DROP, who))
  43
  44//kbuild:lib-$(CONFIG_USERS) += who.o
  45//kbuild:lib-$(CONFIG_W)     += who.o
  46//kbuild:lib-$(CONFIG_WHO)   += who.o
  47
  48/* BB_AUDIT SUSv3 _NOT_ compliant -- missing options -b, -d, -l, -m, -p, -q, -r, -s, -t, -T, -u; Missing argument 'file'.  */
  49
  50//usage:#define users_trivial_usage
  51//usage:       ""
  52//usage:#define users_full_usage "\n\n"
  53//usage:       "Print the users currently logged on"
  54
  55//usage:#define w_trivial_usage
  56//usage:       ""
  57//usage:#define w_full_usage "\n\n"
  58//usage:       "Show who is logged on"
  59//
  60// procps-ng 3.3.10:
  61//           "\n        -h, --no-header"
  62//           "\n        -u, --no-current"
  63//      Ignores the username while figuring out the current process
  64//      and cpu times.  To demonstrate this, do a "su" and do a "w" and a "w -u".
  65//           "\n        -s, --short"
  66//      Short format.  Don't print the login time, JCPU or PCPU times.
  67//           "\n        -f, --from"
  68//      Toggle printing the from (remote hostname) field.
  69//      The default is for the from field to not be printed
  70//           "\n        -i, --ip-addr"
  71//      Display IP address instead of hostname for from field.
  72//           "\n        -o, --old-style"
  73//      Old style output. Prints blank space for idle times less than one minute.
  74// Example output:
  75//  17:28:00 up 4 days, 22:41,  4 users,  load average: 0.84, 0.97, 0.90
  76// USER     TTY        LOGIN@   IDLE   JCPU   PCPU WHAT
  77// root     tty1      Thu18    4days  4:33m  0.07s /bin/sh /etc/xdg/xfce4/xinitrc -- vt
  78// root     pts/1     Mon13    3:24m  1:01   0.01s w
  79
  80//usage:#define who_trivial_usage
  81//usage:       "[-aH]"
  82//usage:#define who_full_usage "\n\n"
  83//usage:       "Show who is logged on\n"
  84//usage:     "\n        -a      Show all"
  85//usage:     "\n        -H      Print column headers"
  86
  87#include "libbb.h"
  88
  89static void idle_string(char *str6, time_t t)
  90{
  91        t = time(NULL) - t;
  92
  93        /*if (t < 60) {
  94                str6[0] = '.';
  95                str6[1] = '\0';
  96                return;
  97        }*/
  98        if (t >= 0 && t < (24 * 60 * 60)) {
  99                sprintf(str6, "%02d:%02d",
 100                                (int) (t / (60 * 60)),
 101                                (int) ((t % (60 * 60)) / 60));
 102                return;
 103        }
 104        strcpy(str6, "old");
 105}
 106
 107int who_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 108int who_main(int argc UNUSED_PARAM, char **argv)
 109{
 110#define CNT_APPLET (ENABLE_USERS + ENABLE_W + ENABLE_WHO)
 111        int do_users = (ENABLE_USERS && (CNT_APPLET == 1 || applet_name[0] == 'u'));
 112        int do_w     = (ENABLE_W     && (CNT_APPLET == 1 || applet_name[1] == '\0'));
 113        int do_who   = (ENABLE_WHO   && (CNT_APPLET == 1 || applet_name[1] == 'h'));
 114        struct utmpx *ut;
 115        unsigned opt;
 116        const char *fmt = "%s";
 117
 118        opt = getopt32(argv, do_who ? "^" "aH" "\0" "=0": "^" "" "\0" "=0");
 119        if ((opt & 2) || do_w) /* -H or we are w */
 120                puts("USER\t\tTTY\t\tIDLE\tTIME\t\t HOST");
 121
 122        setutxent();
 123        while ((ut = getutxent()) != NULL) {
 124                if (ut->ut_user[0]
 125                 && ((opt & 1) || ut->ut_type == USER_PROCESS)
 126                ) {
 127                        if (!do_users) {
 128                                char str6[6];
 129                                char name[sizeof("/dev/") + sizeof(ut->ut_line) + 1];
 130                                struct stat st;
 131                                time_t seconds;
 132
 133                                str6[0] = '?';
 134                                str6[1] = '\0';
 135                                strcpy(name, "/dev/");
 136                                safe_strncpy(ut->ut_line[0] == '/' ? name : name + sizeof("/dev/")-1,
 137                                        ut->ut_line,
 138                                        sizeof(ut->ut_line)+1
 139                                );
 140                                if (stat(name, &st) == 0)
 141                                        idle_string(str6, st.st_atime);
 142                                /* manpages say ut_tv.tv_sec *is* time_t,
 143                                 * but some systems have it wrong */
 144                                seconds = ut->ut_tv.tv_sec;
 145                                /* How wide time field can be?
 146                                 * "Nov 10 19:33:20": 15 chars
 147                                 * "2010-11-10 19:33": 16 chars
 148                                 */
 149                                printf("%-15.*s %-15.*s %-7s %-16.16s %.*s\n",
 150                                                (int)sizeof(ut->ut_user), ut->ut_user,
 151                                                (int)sizeof(ut->ut_line), ut->ut_line,
 152                                                str6,
 153// TODO: with LANG=en_US.UTF-8, who from coreutils 8.25 shows
 154// TIME col as "2017-04-06 18:47" (the default format is "Apr  6 18:47").
 155// The former format looks saner to me. Switch to it unconditionally?
 156                                                ctime(&seconds) + 4,
 157                                                (int)sizeof(ut->ut_host), ut->ut_host
 158                                );
 159                        } else {
 160                                printf(fmt, ut->ut_user);
 161                                fmt = " %s";
 162                        }
 163                }
 164        }
 165        if (do_users)
 166                bb_putchar('\n');
 167        if (ENABLE_FEATURE_CLEAN_UP)
 168                endutxent();
 169        return EXIT_SUCCESS;
 170}
 171