#include <stdio.h>
#include <utmp.h>

void show_info(struct utmp * current_record) {
  if (current_record->ut_type==USER_PROCESS) {
    char * s=ctime(&current_record->ut_time)+4; /*start at month*/
    s[12]='\0'; /*end at minutes*/
    printf("%s\t%s\t%s\t", current_record->ut_name, current_record->ut_line, s);
    if (strlen(current_record->ut_host)!=0) 
      printf("(%s)", current_record->ut_host);
    printf("\n");
  }
}

int main() {
  struct utmp current_record;
  FILE * utmpfile=fopen(UTMP_FILE, "r");  
  while(1) {
    fread(&current_record, sizeof(current_record), 1, utmpfile);
    show_info(&current_record);
    if (feof(utmpfile)) {
      break;
    }
  }
  fclose(utmpfile);
}