100 lines
3.6 KiB
C
100 lines
3.6 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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#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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