Programming

//int main code
 //ignore sighup signal, you can log out and server still runs.
    signal(SIGHUP,catcher);

 //stop user from using control c.
    signal(SIGINT, catcher);


    //not working
  //  signal(SIGTERM, catcher);
  //  signal(SIGKILL, catcher);

FUNCTIONS:---------------------------------------------------------------
//gracefully quit on sigterm and sigkill.
void catcher(int sig)
{

  printf ("Caught signal %d\n", sig);
  fflush(stdout);
  switch (sig)
        {
        case SIGINT:

          signal(SIGINT, catcher);
          printf("Control-C not Allowed\n");
          fflush(stdout);
          break;

        case SIGHUP:

          signal(SIGHUP,catcher); /* dont die on sighup */
          printf("SIGHUP Ignored\n");
          fflush(stdout);
          break;


          case SIGTERM:

          signal(SIGTERM, catcher);
          printf("exiting sigterm");
          exit(1);
          fflush(stdout);
          break;

        case SIGKILL:
          printf("sigkilla");
          fflush(stdout);
          signal(SIGKILL, catcher);
          printf("sigkilla");
          exit(1);
          fflush(stdout);
          break;
  }

//declare act to deal with action on signal set.
static struct sigaction act;

//setting to my function catcher

 act.sa_handler = catcher;       
 act.sa_flags    = 0;
 
 sigfillset(&(act.sa_mask));      /* create full set of signals */




    //ignore control c and dont hangup when loggedout.
    signal(SIGINT, SIG_IGN);
    signal(SIGHUP, SIG_IGN);


     //Terminate gracefully
     sigaction( SIGTERM, &act, NULL );
     sigaction( SIGKILL  , &act, NULL );


----------------------------------------------------------------
void catcher(int sig)
{

    switch (sig)
        {
          case SIGTERM:

                            signal(SIGTERM, catcher);
                            atexit();
           break;

        case SIGKILL:

                         signal(SIGKILL, catcher);
                         atexit();
          break;
       }
  }