source: MondoRescue/trunk/mindi-busybox/coreutils/who.c@ 904

/* vi: set sw=4 ts=4: */
/*----------------------------------------------------------------------
 * Mini who is used to display user name, login time,
 * idle time and host name.
 *
 * Author: Da Chen  <dchen@ayrnetworks.com>
 *
 * This is a free document; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation:
 *    http://www.gnu.org/copyleft/gpl.html
 *
 * Copyright (c) 2002 AYR Networks, Inc.
 *----------------------------------------------------------------------
 */

#include "busybox.h"
#include <utmp.h>
#include <time.h>

static const char * idle_string (time_t t)
{
    static char str[6];
    
    time_t s = time(NULL) - t;

    if (s < 60)
        return ".";
    if (s < (24 * 60 * 60)) {
        sprintf (str, "%02d:%02d",
                (int) (s / (60 * 60)),
                (int) ((s % (60 * 60)) / 60));
        return str;
    }
    return "old";
}

int who_main(int argc, char **argv)
{
    struct utmp *ut;
    struct stat st;
    char *name;
    
    if (argc > 1) {
        bb_show_usage();
    }
    
    setutent();
    printf("USER       TTY      IDLE      TIME           HOST\n");
    while ((ut = getutent()) != NULL) {
        if (ut->ut_user[0] && ut->ut_type == USER_PROCESS) {
            time_t thyme = ut->ut_tv.tv_sec;

            /* ut->ut_line is device name of tty - "/dev/" */
            name = concat_path_file("/dev", ut->ut_line);
            printf("%-10s %-8s %-8s  %-12.12s   %s\n", ut->ut_user, ut->ut_line,
                                    (stat(name, &st)) ?  "?" : idle_string(st.st_atime),
                                    ctime(&thyme) + 4, ut->ut_host);
            if (ENABLE_FEATURE_CLEAN_UP) free(name);
        }
    }
    if (ENABLE_FEATURE_CLEAN_UP) endutent();
    return 0;
}