103 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			103 lines
		
	
	
		
			3.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* The system call implemented in this file:
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 *   m_type:	SYS_EXIT
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 *
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 * The parameters for this system call are:
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 *    m1_i1:	PR_PROC_NR		(slot number of exiting process)
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 *
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 * Changes:
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 *   Sep 09, 2004   updated to allow services to exit  (Jorrit N. Herder) 
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 */
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#include "../system.h"
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#if USE_EXIT
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FORWARD _PROTOTYPE( void clear_proc, (register struct proc *rc));
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/*===========================================================================*
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 *				do_exit					     *
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 *===========================================================================*/
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PUBLIC int do_exit(m_ptr)
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message *m_ptr;			/* pointer to request message */
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{
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/* Handle sys_exit. A user process has exited or a system process requests 
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 * to exit. Only the PM can request other process slots to be cleared.
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 * The routine to clean up a process table slot cancels outstanding timers, 
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 * possibly removes the process from the message queues, and resets certain 
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 * process table fields to the default values.
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 */
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  int exit_proc_nr;				
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  /* Determine what process exited. User processes are handled here. */
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  if (PM_PROC_NR == m_ptr->m_source) {
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      exit_proc_nr = m_ptr->PR_PROC_NR;		/* get exiting process */
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      if (exit_proc_nr != SELF) { 		/* PM tries to exit self */
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          if (! isokprocn(exit_proc_nr)) return(EINVAL);
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          clear_proc(proc_addr(exit_proc_nr));	/* exit a user process */
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          return(OK);				/* report back to PM */
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      }
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  } 
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  /* The PM or some other system process requested to be exited. */
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  clear_proc(proc_addr(m_ptr->m_source));
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  return(EDONTREPLY);
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}
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/*===========================================================================*
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 *			         clear_proc				     *
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 *===========================================================================*/
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PRIVATE void clear_proc(rc)
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register struct proc *rc;		/* slot of process to clean up */
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{
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  register struct proc *rp;		/* iterate over process table */
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  register struct proc **xpp;		/* iterate over caller queue */
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  int i;
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  /* Turn off any alarm timers at the clock. */   
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  reset_timer(&priv(rc)->s_alarm_timer);
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  /* Make sure that the exiting process is no longer scheduled. */
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  if (rc->p_rts_flags == 0) lock_unready(rc);
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  /* If the process being terminated happens to be queued trying to send a
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   * message (e.g., the process was killed by a signal, rather than it doing 
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   * a normal exit), then it must be removed from the message queues.
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   */
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  if (rc->p_rts_flags & SENDING) {
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      /* Check all proc slots to see if the exiting process is queued. */
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      for (rp = BEG_PROC_ADDR; rp < END_PROC_ADDR; rp++) {
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          if (rp->p_caller_q == NIL_PROC) continue;
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          /* Make sure that the exiting process is not on the queue. */
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          xpp = &rp->p_caller_q;
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          while (*xpp != NIL_PROC) {		/* check entire queue */
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              if (*xpp == rc) {			/* process is on the queue */
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                  *xpp = (*xpp)->p_q_link;	/* replace by next process */
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                  break;
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              }
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              xpp = &(*xpp)->p_q_link;		/* proceed to next queued */
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          }
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      }
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  }
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  /* Check the table with IRQ hooks to see if hooks should be released. */
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  for (i=0; i < NR_IRQ_HOOKS; i++) {
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      if (irq_hooks[i].proc_nr == proc_nr(rc)) {
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          rm_irq_handler(&irq_hooks[i]);	/* remove interrupt handler */
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          irq_hooks[i].proc_nr = NONE; 		/* mark hook as free */
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      }
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  }
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  /* Now it is safe to release the process table slot. If this is a system 
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   * process, also release its privilege structure.  Further cleanup is not
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   * needed at this point. All important fields are reinitialized when the 
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   * slots are assigned to another, new process. 
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   */
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  rc->p_rts_flags = SLOT_FREE;		
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  if (priv(rc)->s_flags & SYS_PROC) priv(rc)->s_proc_nr = NONE;
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}
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#endif /* USE_EXIT */
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