Keep our driver installed on switch back from P8.

driver.c

@@ -258,7 +258,9 @@ static Word DoMountURL(struct GSOSDP *dp) {
     err = CheckTwoImg(sess);
     if (err != OPERATION_SUCCESSFUL) {
         EndNetDiskSession(sess);
-        // TODO error
+        // TODO better error
+        dp->transferCount = 0;
+        return drvrIOError;
     }
     
     dp->dibPointer->extendedDIBPtr = sess;
@@ -328,8 +330,18 @@ static Word DoEject(struct GSOSDP *dp) {
 }
 
 static Word DoShutdown(struct GSOSDP *dp) {
-    EndNetDiskSession(dp->dibPointer->extendedDIBPtr);
+    /*
-    dp->dibPointer->extendedDIBPtr = NULL;
+     * We don't actually end the session here, because this may just be
-    //TODO should return error unless all of our other DIBs are already shut down?
+     * a switch to P8.  If so, this driver won't work within P8, but if we
-    return 0;
+     * leave things in place it should work again once we're back in GS/OS.
+     * Do end the current TCP connection, since it would probably time out.
+     */
+    EndTCPConnection(dp->dibPointer->extendedDIBPtr);
+    
+    /*
+     * Return error to indicate we shouldn't be purged.
+     * (I don't think we would be anyhow, since this isn't an
+     * actual device driver file, but let's do this to be safe.)
+     */
+    return drvrIOError;
 }

netdiskinit.c

@@ -5,25 +5,41 @@
 #include <misctool.h>
 #include <tcpip.h>
 #include <memory.h>
+#include <gsos.h>
 #include <orca.h>
 #include "driver.h"
 #include "installdriver.h"
+#include "asmglue.h"
 #include "version.h"
 
 const char bootInfoString[] = "NetDisk               " BOOT_INFO_VERSION;
 
 Word *unloadFlagPtr;
 
+static struct NotificationProcRec {
+    Long reserved1;
+    Word reserved2;
+    Word Signature;
+    Long Event_flags;
+    Long Event_code;
+    Byte jml;
+    void (*proc)(void);
+} notificationProcRec;
+
+#define NOTIFY_SHUTDOWN    0x20
+#define NOTIFY_GSOS_SWITCH 0x04
+
+static void notificationProc(void);
+
+#define JML 0x5C
+
+
 static void setUnloadFlag(void) {
     if (unloadFlagPtr != NULL && *unloadFlagPtr == 0)
         *unloadFlagPtr = 1;
 }
 
 int main(void) {
-    for (int i = 1; i < 256; i++) {
-        UnloadOneTool(i); // event mgr
-    }
-
     /*
      * Load Marinetti.
      * We may get an error if the TCPIP init isn't loaded yet, but we ignore it.
@@ -45,6 +61,14 @@ int main(void) {
     /* We're not going to error out, so show boot info. */
     ShowBootInfo(bootInfoString, NULL);
 
+    /* Add notification proc to be called on shutdown and switches to GS/OS */
+    notificationProcRec.Signature = 0xA55A;
+    notificationProcRec.Event_flags = NOTIFY_SHUTDOWN | NOTIFY_GSOS_SWITCH;
+    notificationProcRec.jml = JML;
+    notificationProcRec.proc = notificationProc;
+    NotifyProcRecGS addNotifyProcRec = {1, (ProcPtr)&notificationProcRec};
+    AddNotifyProcGS(&addNotifyProcRec);
+
     /*
      * Put Marinetti in the default TPT so its tool stub won't be unloaded,
      * even if UnloadOneTool is called on it.  Programs may still call
@@ -61,3 +85,22 @@ error:
     setUnloadFlag();
     return;
 }
+
+/*
+ * Notification procedure called at shutdown time or when switching to GS/OS.
+ */
+#pragma databank 1
+static void notificationProc(void) {
+    Word stateReg = ForceRomIn();
+
+    if (notificationProcRec.Event_code & NOTIFY_GSOS_SWITCH) {
+        /* Reinstall our driver on switch back to GS/OS from P8 */
+        InstallDriver();
+    } else if (notificationProcRec.Event_code & NOTIFY_SHUTDOWN) {
+        //TODO eject disks
+    }
+
+    RestoreStateReg(stateReg);
+}
+#pragma databank 0
+