source: trunk/minix/commands/simple/who.c@ 20

/*      who 1.5 - tell who is currently logged in       Author: Kees J. Bot
 *                                                              9 Jul 1989
 */
#define nil 0
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>
#include <utmp.h>
#include <time.h>
#include <string.h>
#include <minix/paths.h>

char PATH_UTMP[] = _PATH_UTMP;

char day[] = "SunMonTueWedThuFriSat";
char month[] = "JanFebMarAprMayJunJulAugSepOctNovDec";

int main(int argc, char **argv)
{
        char *tmp= PATH_UTMP;
        FILE *f;
        struct utmp ut;
        struct tm *tm;
        int slot, wtmp= 0, once= 0;

        if (argc > 3) {
                fprintf(stderr, "Usage: who <account-file>  |  who am i\n");
                exit(1);
        }
        if (argc == 2) {
                tmp= argv[1];
                wtmp= 1;
        }

        if ((f= fopen(tmp, "r")) == nil) {
                fprintf(stderr, "who: can't open %s\n", tmp);
                exit(1);
        }
        if (argc == 3) {
                if ((slot= ttyslot()) < 0) {
                        fprintf(stderr, "who: no access to terminal.\n");
                        exit(1);
                }
                fseek(f, (off_t) sizeof(ut) * slot, 0);
                once= 1;
        }

        while (fread((char *) &ut, sizeof(ut), 1, f) == 1) {
                if (!wtmp && ut.ut_name[0] == 0) continue;

                tm= localtime(&ut.ut_time);

                printf("%-9.8s %-9.8s %.3s %.3s %2d %02d:%02d",
                        ut.ut_name,
                        ut.ut_line,
                        day + (3 * tm->tm_wday),
                        month + (3 * tm->tm_mon),
                        tm->tm_mday,
                        tm->tm_hour,
                        tm->tm_min
                );

                if (ut.ut_host[0] != 0) printf("  (%.*s)",
                                (int) sizeof(ut.ut_host), ut.ut_host);

                printf("\n");
                if (once) break;
        }
        exit(0);
}