libstore: Fix dopen() with non-path which happens to be a path

For instance storeio on /dev/mem would try to open itself...

* libstore/device.c (dopen): Only file_name_lookup() name if it starts
with '/'.

1 files changed, 31 insertions, 27 deletions

diff --git a/libstore/device.c b/libstore/device.c
index 1a79c249..1d8f57fd 100644
--- a/libstore/device.c
+++ b/libstore/device.c
@@ -94,42 +94,46 @@ static error_t
 dopen (const char *name, device_t *device, int *mod_flags)
 {
   device_t dev_master;
-  error_t err;
-  if (*mod_flags & STORE_HARD_READONLY)
-    {
-      dev_master = file_name_lookup (name, O_READ, 0);
-      if (dev_master != MACH_PORT_NULL)
-	{
-	  err = device_open (dev_master, D_READ, "disk", device);
-	  if (err)
-	    err = ENODEV;
+  error_t err = ENODEV;
 
-	  mach_port_deallocate (mach_task_self (), dev_master);
-	}
-      else
-	err = ENODEV;
-    }
-  else
+  if (name[0] == '/')
     {
-      dev_master = file_name_lookup (name, O_READ | O_WRITE, 0);
-      if (dev_master != MACH_PORT_NULL)
+      if (*mod_flags & STORE_HARD_READONLY)
 	{
-	  err = device_open (dev_master, D_READ | D_WRITE, "disk", device);
-	  if (err == ED_READ_ONLY)
+	  dev_master = file_name_lookup (name, O_READ, 0);
+	  if (dev_master != MACH_PORT_NULL)
 	    {
 	      err = device_open (dev_master, D_READ, "disk", device);
-	      if (! err)
-		*mod_flags |= STORE_HARD_READONLY;
-	      else
+	      if (err)
 		err = ENODEV;
-	    }
-	  else if (! err)
-	    *mod_flags &= ~STORE_HARD_READONLY;
 
-	  mach_port_deallocate (mach_task_self (), dev_master);
+	      mach_port_deallocate (mach_task_self (), dev_master);
+	    }
+	  else
+	    err = ENODEV;
 	}
       else
-	err = ENODEV;
+	{
+	  dev_master = file_name_lookup (name, O_READ | O_WRITE, 0);
+	  if (dev_master != MACH_PORT_NULL)
+	    {
+	      err = device_open (dev_master, D_READ | D_WRITE, "disk", device);
+	      if (err == ED_READ_ONLY)
+		{
+		  err = device_open (dev_master, D_READ, "disk", device);
+		  if (! err)
+		    *mod_flags |= STORE_HARD_READONLY;
+		  else
+		    err = ENODEV;
+		}
+	      else if (! err)
+		*mod_flags &= ~STORE_HARD_READONLY;
+
+	      mach_port_deallocate (mach_task_self (), dev_master);
+	    }
+	  else
+	    err = ENODEV;
+	}
     }
 
   if (err)