Programming

#include <string.h>
#include <stdlib.h>
#include <pwd.h>
#include <unistd.h>
#include <utmp.h>
#include <stdio.h>
#include <time.h>

int main(int argc, char *argv[])
{
  struct utmp entry;
  char *fd;
  system("echo before adding entry:;who");

  entry.ut_type=USER_PROCESS;
  entry.ut_pid=getpid();
  fd = ttyname(0);
  printf("The current tty is: %s\n",fd);
  strcpy(entry.ut_line,ttyname(0)+strlen("/dev/"));
  /* only correct for ptys named /dev/tty[pqr][0-9a-z] */
  strcpy(entry.ut_id,ttyname(0)+strlen("/dev/tty"));
  time(&entry.ut_time);
  strcpy(entry.ut_user,getpwuid(getuid())->pw_name);
  memset(entry.ut_host,0,UT_HOSTSIZE);
  entry.ut_addr=0;
  setutent();
  pututline(&entry);

  system("echo after adding entry:;who");

  entry.ut_type=DEAD_PROCESS;
  memset(entry.ut_line,0,UT_LINESIZE);
  entry.ut_time=0;
  memset(entry.ut_user,0,UT_NAMESIZE);
  setutent();
  pututline(&entry);

  system("echo after removing entry:;who");

  endutent();
  return 0;