FS:

. unmap device drivers from dmap when PM signals they are dead
	. new null-io function (no_dev_io) to fill in for io functions
	  of unmapped drivers
	. driver (process number) of unmapped drivers is NONE instead of
	  0 (a valid process number)

IS:
	. print mutable flag of dmap table too

FS changes require sync() to be done 'manually' (currently by
reboot/shutdown) at shutdown time; could be caught by SIGTERM in
the future.

servers/fs/device.c

@@ -9,6 +9,7 @@
  *   gen_opcl:   generic call to a task to perform an open/close
  *   gen_io:     generic call to a task to perform an I/O operation
  *   no_dev:     open/close processing for devices that don't exist
+ *   no_dev_io:  i/o processing for devices that don't exist
  *   tty_opcl:   perform tty-specific processing for open/close
  *   ctty_opcl:  perform controlling-tty-specific processing for open/close
  *   ctty_io:    perform controlling-tty-specific processing for I/O
@@ -49,6 +50,8 @@ int flags;			/* mode bits and flags */
   dp = &dmap[major];
   r = (*dp->dmap_opcl)(DEV_OPEN, dev, proc, flags);
   if (r == SUSPEND) panic(__FILE__,"suspend on open from", dp->dmap_driver);
+  if (r == OK && dp->dmap_driver == NONE)
+	panic(__FILE__, "no driver for dev %d", dev);
   return(r);
 }
 
@@ -120,6 +123,10 @@ int flags;			/* special flags, like O_NONBLOCK */
   /* Determine task dmap. */
   dp = &dmap[(dev >> MAJOR) & BYTE];
 
+  /* See if driver is roughly valid. */
+  if (dp->dmap_driver == NONE)
+	panic(__FILE__, "no driver for i/o on dev %d", dev);
+
   /* Set up the message passed to task. */
   dev_mess.m_type   = op;
   dev_mess.DEVICE   = (dev >> MINOR) & BYTE;
@@ -347,7 +354,7 @@ message *mess_ptr;		/* pointer to message for task */
    */
   for (;;) {
 	if (r != OK) {
-		if (r == EDEADDST) return;	/* give up */
+		if (r == EDEADSRCDST) return;	/* give up */
 		else panic(__FILE__,"call_task: can't send/receive", r);
 	}
 
@@ -404,10 +411,19 @@ int proc;			/* process to open/close for */
 int flags;			/* mode bits and flags */
 {
 /* Called when opening a nonexistent device. */
-
   return(ENODEV);
 }
 
+/*===========================================================================*
+ *				no_dev_io				     *
+ *===========================================================================*/
+PUBLIC void no_dev_io(int proc, message *m)
+{
+/* Called when doing i/o on a nonexistent device. */
+  printf("FS: I/O on unmapped device number\n");
+  return;
+}
+
 /*===========================================================================*
  *				clone_opcl				     *
  *===========================================================================*/

servers/fs/dmap.c

@@ -98,18 +98,22 @@ int style;			/* style of the device */
   if (major < 0 || major >= NR_DEVICES) return(ENODEV);
   dp = &dmap[major];		
 
+  /* Check if we're supposed to unmap it. If so, do it even
+   * if busy or unmutable, as unmap is called when driver has
+   * exited.
+   */
+ if(proc_nr == NONE) {
+	dp->dmap_opcl = no_dev;
+	dp->dmap_io = no_dev_io;
+	dp->dmap_driver = NONE;
+	dp->dmap_flags = DMAP_MUTABLE;	/* When gone, not busy or reserved. */
+	return(OK);
+  }
+	
   /* See if updating the entry is allowed. */
   if (! (dp->dmap_flags & DMAP_MUTABLE))  return(EPERM);
   if (dp->dmap_flags & DMAP_BUSY)  return(EBUSY);
 
-  /* Check if we're supposed to unmap it. */
- if(proc_nr == NONE) {
-	dp->dmap_opcl = no_dev;
-	dp->dmap_io = 0;
-	dp->dmap_driver = 0;
-	return(OK);
-  }
-
   /* Check process number of new driver. */
   if (! isokprocnr(proc_nr))  return(EINVAL);
 
@@ -125,6 +129,21 @@ int style;			/* style of the device */
   return(OK); 
 }
 
+/*===========================================================================*
+ *				dmap_unmap_by_proc	 		     *
+ *===========================================================================*/
+PUBLIC void dmap_unmap_by_proc(int proc_nr)
+{
+	int i, r;
+	for (i=0; i<NR_DEVICES; i++)
+	  if(dmap[i].dmap_driver && dmap[i].dmap_driver == proc_nr)
+	    if((r=map_driver(i, NONE, 0)) != OK)
+		printf("FS: unmap of p %d / d %d failed: %d\n", proc_nr, i, r);
+
+	return;
+
+}
+
 /*===========================================================================*
  *				build_dmap		 		     *
  *===========================================================================*/
@@ -152,8 +171,8 @@ PUBLIC void build_dmap()
           dp->dmap_flags = init_dmap[i].dmap_flags;
       } else {						/* no default */
           dp->dmap_opcl = no_dev;
-          dp->dmap_io = 0;
-          dp->dmap_driver = 0;
+          dp->dmap_io = no_dev_io;
+          dp->dmap_driver = NONE;
           dp->dmap_flags = DMAP_MUTABLE;
       }
   }

servers/fs/misc.c

@@ -339,6 +339,9 @@ PUBLIC int do_exit()
   fp->fp_rootdir = NIL_INODE;
   fp->fp_workdir = NIL_INODE;
 
+  /* If a driver exits, unmap its entries in the dmap table. */
+  dmap_unmap_by_proc(exitee);
+
   /* If a session leader exits then revoke access to its controlling tty from
    * all other processes using it.
    */
@@ -369,6 +372,7 @@ PUBLIC int do_exit()
 
   /* Mark slot as free. */
   fp->fp_pid = PID_FREE;
+
   return(OK);
 }
 

servers/fs/proto.h

@@ -35,6 +35,7 @@ _PROTOTYPE( int dev_io, (int op, Dev_t dev, int proc, void *buf,
 _PROTOTYPE( int gen_opcl, (int op, Dev_t dev, int proc, int flags)	);
 _PROTOTYPE( void gen_io, (int task_nr, message *mess_ptr)		);
 _PROTOTYPE( int no_dev, (int op, Dev_t dev, int proc, int flags)	);
+_PROTOTYPE( void no_dev_io, (int, message *)				);
 _PROTOTYPE( int tty_opcl, (int op, Dev_t dev, int proc, int flags)	);
 _PROTOTYPE( int ctty_opcl, (int op, Dev_t dev, int proc, int flags)	);
 _PROTOTYPE( int clone_opcl, (int op, Dev_t dev, int proc, int flags)	);
@@ -50,6 +51,7 @@ _PROTOTYPE( int do_fkey_pressed, (void)					);
 _PROTOTYPE( int do_devctl, (void)					);
 _PROTOTYPE( void build_dmap, (void)					);
 _PROTOTYPE( int map_driver, (int major, int proc_nr, int dev_style)	);
+_PROTOTYPE( void dmap_unmap_by_proc, (int proc_nr)			);
 
 /* filedes.c */
 _PROTOTYPE( struct filp *find_filp, (struct inode *rip, mode_t bits)	);

servers/is/dmp_fs.c

@@ -48,6 +48,18 @@ PUBLIC void fproc_dmp()
   prev_i = i;
 }
 
+/*===========================================================================*
+ *				dmap_flags				     *
+ *===========================================================================*/
+PRIVATE char * dmap_flags(int flags)
+{
+	static char fl[10];
+	fl[0] = '-';
+	if(flags & DMAP_MUTABLE) fl[0] = 'M';
+	fl[1] = '\0';
+	return fl;
+}
+
 /*===========================================================================*
  *				dtab_dmp				     *
  *===========================================================================*/
@@ -58,12 +70,12 @@ PUBLIC void dtab_dmp()
     getsysinfo(FS_PROC_NR, SI_DMAP_TAB, dmap);
     
     printf("File System (FS) device <-> driver mappings\n");
-    printf("Major  Proc\n");
-    printf("-----  ----\n");
+    printf("Major  Proc  Flags\n");
+    printf("-----  ----  -----\n");
     for (i=0; i<NR_DEVICES; i++) {
         if (dmap[i].dmap_driver == 0) continue;
-        printf("%5d  ", i);
-        printf("%4d\n", dmap[i].dmap_driver);
+        printf("%5d  %4d  %s\n",
+		i, dmap[i].dmap_driver, dmap_flags(dmap[i].dmap_flags));
     }
 }