minix/kernel/system/do_clear.c

   1 /* The kernel call implemented in this file:
   2  *   m_type:    SYS_CLEAR
   3  *
   4  * The parameters for this kernel call are:
   5  *   m_lsys_krn_sys_clear.endpt         (endpoint of process to clean up)
   6  */
   7
   8 #include "kernel/system.h"
   9
  10 #include <minix/endpoint.h>
  11
  12 #if USE_CLEAR
  13
  14 /*===========================================================================*
  15  *                              do_clear                                     *
  16  *===========================================================================*/
  17 int do_clear(struct proc * caller, message * m_ptr)
  18 {
  19 /* Handle sys_clear. Only the PM can request other process slots to be cleared
  20  * when a process has exited.
  21  * The routine to clean up a process table slot cancels outstanding timers,
  22  * possibly removes the process from the message queues, and resets certain
  23  * process table fields to the default values.
  24  */
  25   struct proc *rc;
  26   int exit_p;
  27   int i;
  28
  29   if(!isokendpt(m_ptr->m_lsys_krn_sys_clear.endpt, &exit_p)) {
  30       /* get exiting process */
  31       return EINVAL;
  32   }
  33   rc = proc_addr(exit_p);       /* clean up */
  34
  35   release_address_space(rc);
  36
  37   /* Don't clear if already cleared. */
  38   if(isemptyp(rc)) return OK;
  39
  40   /* Check the table with IRQ hooks to see if hooks should be released. */
  41   for (i=0; i < NR_IRQ_HOOKS; i++) {
  42       if (rc->p_endpoint == irq_hooks[i].proc_nr_e) {
  43         rm_irq_handler(&irq_hooks[i]);  /* remove interrupt handler */
  44         irq_hooks[i].proc_nr_e = NONE;  /* mark hook as free */
  45       }
  46   }
  47
  48   /* Remove the process' ability to send and receive messages */
  49   clear_endpoint(rc);
  50
  51   /* Turn off any alarm timers at the clock. */
  52   reset_kernel_timer(&priv(rc)->s_alarm_timer);
  53
  54   /* Make sure that the exiting process is no longer scheduled,
  55    * and mark slot as FREE. Also mark saved fpu contents as not significant.
  56    */
  57   RTS_SETFLAGS(rc, RTS_SLOT_FREE);
  58
  59   /* release FPU */
  60   release_fpu(rc);
  61   rc->p_misc_flags &= ~MF_FPU_INITIALIZED;
  62
  63   /* Release the process table slot. If this is a system process, also
  64    * release its privilege structure.  Further cleanup is not needed at
  65    * this point. All important fields are reinitialized when the
  66    * slots are assigned to another, new process.
  67    */
  68   if (priv(rc)->s_flags & SYS_PROC) priv(rc)->s_proc_nr = NONE;
  69
  70 #if 0
  71   /* Clean up virtual memory */
  72   if (rc->p_misc_flags & MF_VM) {
  73         vm_map_default(rc);
  74   }
  75 #endif
  76
  77   return OK;
  78 }
  79
  80 #endif /* USE_CLEAR */