Initial version

code/threads/system.cc

@@ -0,0 +1,269 @@
+// system.cc 
+//      Nachos initialization and cleanup routines.
+//
+// Copyright (c) 1992-1993 The Regents of the University of California.
+// All rights reserved.  See copyright.h for copyright notice and limitation 
+// of liability and disclaimer of warranty provisions.
+
+#include "copyright.h"
+#include "system.h"
+#include <locale.h>
+#ifdef __GLIBC__
+#include <malloc.h>
+#endif
+
+// This defines *all* of the global data structures used by Nachos.
+// These are all initialized and de-allocated by this file.
+
+Thread *currentThread;		// the thread we are running now
+Thread *threadToBeDestroyed;	// the thread that just finished
+Scheduler *scheduler;		// the ready list
+Interrupt *interrupt;		// interrupt status
+Statistics *stats;		// performance metrics
+Timer *timer;			// the hardware timer device,
+					// for invoking context switches
+
+#ifdef FILESYS_NEEDED
+FileSystem *fileSystem;
+#endif
+
+#ifdef FILESYS
+SynchDisk *synchDisk;
+#endif
+
+#ifdef USER_PROGRAM		// requires either FILESYS or FILESYS_STUB
+Machine *machine;		// user program memory and registers
+#endif
+
+#ifdef NETWORK
+PostOffice *postOffice;
+#endif
+
+
+// External definition, to allow us to take a pointer to this function
+extern void Cleanup ();
+
+
+//----------------------------------------------------------------------
+// TimerInterruptHandler
+//      Interrupt handler for the timer device.  The timer device is
+//      set up to interrupt the CPU periodically (once every TimerTicks).
+//      This routine is called each time there is a timer interrupt,
+//      with interrupts disabled.
+//
+//      Note that instead of calling Yield() directly (which would
+//      suspend the interrupt handler, not the interrupted thread
+//      which is what we wanted to context switch), we set a flag
+//      so that once the interrupt handler is done, it will appear as 
+//      if the interrupted thread called Yield at the point it is 
+//      was interrupted.
+//
+//      "dummy" is because every interrupt handler takes one argument,
+//              whether it needs it or not.
+//----------------------------------------------------------------------
+static void
+TimerInterruptHandler (void *dummy)
+{
+    (void) dummy;
+    if (interrupt->getStatus () != IdleMode)
+	interrupt->YieldOnReturn ();
+}
+
+//----------------------------------------------------------------------
+// Initialize
+//      Initialize Nachos global data structures.  Interpret command
+//      line arguments in order to determine flags for the initialization.  
+// 
+//      "argc" is the number of command line arguments (including the name
+//              of the command) -- ex: "nachos -d +" -> argc = 3 
+//      "argv" is an array of strings, one for each command line argument
+//              ex: "nachos -d +" -> argv = {"nachos", "-d", "+"}
+//----------------------------------------------------------------------
+void
+Initialize (int argc, char **argv)
+{
+    int argCount;
+    const char *debugArgs = "";
+    bool randomYield = FALSE;
+
+#ifdef USER_PROGRAM
+    bool debugUserProg = FALSE;	// single step user program
+#endif
+#ifdef FILESYS_NEEDED
+    bool format = FALSE;	// format disk
+#endif
+#ifdef NETWORK
+    double rely = 1;		// network reliability
+    int netname = 0;		// UNIX socket name
+#endif
+
+    setlocale(LC_CTYPE,"");
+
+#ifdef __GLIBC__
+#if (__GLIBC__ > 2) || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 4)
+    /* Make free() fill freed memory, to trap bad code */
+    mallopt(M_PERTURB, 0xfefefefe);
+#endif
+#endif
+    ThrashStack();
+
+    for (argc--, argv++; argc > 0; argc -= argCount, argv += argCount)
+      {
+	  argCount = 1;
+	  if (!strcmp (*argv, "-d"))
+	    {
+		if (argc == 1)
+		    debugArgs = "+";	// turn on all debug flags
+		else
+		  {
+		      debugArgs = *(argv + 1);
+		      argCount = 2;
+		  }
+	    }
+	  else if (!strcmp (*argv, "-rs"))
+	    {
+		int seed;
+		ASSERT (argc > 1);
+		seed = atoi (*(argv + 1));
+		if (seed == 0)
+		  {
+		    fprintf(stderr,"-rs option needs a seed value\n");
+		    exit(EXIT_FAILURE);
+		  }
+		RandomInit (seed);	// initialize pseudo-random
+		// number generator
+		randomYield = TRUE;
+		argCount = 2;
+	    }
+#ifdef USER_PROGRAM
+	  if (!strcmp (*argv, "-s"))
+	      debugUserProg = TRUE;
+#endif
+#ifdef FILESYS_NEEDED
+	  if (!strcmp (*argv, "-f"))
+	      format = TRUE;
+#endif
+#ifdef NETWORK
+	  if (!strcmp (*argv, "-l"))
+	    {
+		ASSERT (argc > 1);
+		rely = atof (*(argv + 1));
+		argCount = 2;
+	    }
+	  else if (!strcmp (*argv, "-m"))
+	    {
+		ASSERT (argc > 1);
+		netname = atoi (*(argv + 1));
+		argCount = 2;
+	    }
+#endif
+      }
+
+    DebugInit (debugArgs);	// initialize DEBUG messages
+    stats = new Statistics ();	// collect statistics
+    interrupt = new Interrupt;	// start up interrupt handling
+    scheduler = new Scheduler ();	// initialize the ready queue
+    if (randomYield)		// start the timer (if needed)
+	timer = new Timer (TimerInterruptHandler, 0, randomYield);
+
+    threadToBeDestroyed = NULL;
+
+    // We didn't explicitly allocate the current thread we are running in.
+    // But if it ever tries to give up the CPU, we better have a Thread
+    // object to save its state. 
+    currentThread = new Thread ("main");
+    currentThread->SetMain ();
+
+    interrupt->Enable ();
+    CallOnUserAbort (Cleanup);	// if user hits ctl-C
+
+#ifdef USER_PROGRAM
+    machine = new Machine (debugUserProg);	// this must come first
+#endif
+
+#ifdef FILESYS
+    synchDisk = new SynchDisk ("DISK");
+#endif
+
+#ifdef FILESYS_NEEDED
+    fileSystem = new FileSystem (format);
+#endif
+
+#ifdef NETWORK
+    postOffice = new PostOffice (netname, rely, 10);
+#endif
+}
+
+//----------------------------------------------------------------------
+// Cleanup
+//      Nachos is halting.  De-allocate global data structures.
+//----------------------------------------------------------------------
+void
+Cleanup ()
+{
+    static int cleaning;
+
+    if (cleaning) {
+	printf ("\nCtrl-C while cleaning, stopping here hard.\n");
+	Exit (0);
+    }
+    cleaning = 1;
+
+    printf ("\nCleaning up...\n");
+
+    /* Allow more interrupts but prevent other threads from continuing to use
+     * the system while we are waiting for the last interrupts */
+    if (scheduler)
+	scheduler->Stop();
+    if (interrupt)
+	interrupt->Enable();
+
+#ifdef NETWORK
+    if (postOffice) {
+	delete postOffice;
+	postOffice = NULL;
+    }
+#endif
+
+#ifdef USER_PROGRAM
+    if (machine) {
+	delete machine;
+	machine = NULL;
+    }
+#endif
+
+#ifdef FILESYS_NEEDED
+    if (fileSystem) {
+	delete fileSystem;
+	fileSystem = NULL;
+    }
+#endif
+
+#ifdef FILESYS
+    if (synchDisk) {
+	delete synchDisk;
+	synchDisk = NULL;
+    }
+#endif
+
+    if (timer) {
+	delete timer;
+	timer = NULL;
+    }
+    if (scheduler) {
+	delete scheduler;
+	scheduler = NULL;
+    }
+    if (interrupt) {
+	delete interrupt;
+	interrupt = NULL;
+    }
+    if (stats) {
+	delete stats;
+	stats = NULL;
+    }
+
+    ThreadList.Remove(currentThread);
+
+    Exit (0);
+}