Reorganized system call library; uses separate file per call now.

New configuration header file to include/ exclude functionality.
Extracted privileged features from struct proc and create new struct priv.
Renamed various system calls for readability.

kernel/system/do_exit.c

@@ -0,0 +1,42 @@
+/* The system call implemented in this file:
+ *   m_type:	SYS_EXIT
+ *
+ * The parameters for this system call are:
+ *    m1_i1:	PR_PROC_NR		(slot number of exiting process)
+ */
+
+#include "../system.h"
+
+#if USE_EXIT
+
+/*===========================================================================*
+ *				do_exit					     *
+ *===========================================================================*/
+PUBLIC int do_exit(m_ptr)
+message *m_ptr;			/* pointer to request message */
+{
+/* Handle sys_exit. A user process has exited or a system process requests 
+ * to exit. Only the PM can request other process slots to be cleared.
+ * The routine to clean up a process table slot cancels outstanding timers, 
+ * possibly removes the process from the message queues, and resets certain 
+ * process table fields to the default values.
+ */
+  int exit_proc_nr;				
+
+  /* Determine what process exited. User processes are handled here. */
+  if (PM_PROC_NR == m_ptr->m_source) {
+      exit_proc_nr = m_ptr->PR_PROC_NR;		/* get exiting process */
+      if (exit_proc_nr != SELF) { 		/* PM tries to exit self */
+          if (! isokprocn(exit_proc_nr)) return(EINVAL);
+          clear_proc(exit_proc_nr);		/* exit a user process */
+          return(OK);				/* report back to PM */
+      }
+  } 
+
+  /* The PM or some other system process requested to be exited. */
+  clear_proc(m_ptr->m_source);
+  return(EDONTREPLY);
+}
+#endif /* USE_EXIT */
+
+