[PATCH 7/8] libdiskfs: register passive translator startups

[Justus Winter]

Detect passive translator startup and add the resulting active
translator to the list of active translators.

Note that newpi is properly deallocated in the function epilogue.

* libdiskfs/dir-lookup.c (diskfs_S_dir_lookup): Detect and register
  passive translator startup.
---
 libdiskfs/dir-lookup.c | 41 ++++++++++++++++++++++++++++++++++++++---
 1 file changed, 38 insertions(+), 3 deletions(-)

diff --git a/libdiskfs/dir-lookup.c b/libdiskfs/dir-lookup.c
index 86116e3..3950bf9 100644
--- a/libdiskfs/dir-lookup.c
+++ b/libdiskfs/dir-lookup.c
@@ -1,6 +1,6 @@
 /* libdiskfs implementation of fs.defs:dir_lookup
    Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
-     2002, 2008, 2013 Free Software Foundation, Inc.
+     2002, 2008, 2013, 2014 Free Software Foundation, Inc.
 
    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
@@ -74,6 +74,10 @@ diskfs_S_dir_lookup (struct protid *dircred,
   if (! relpath)
     return ENOMEM;
 
+  /* Keep a pointer to the start of the path for length
+     calculations.  */
+  char *path_start = path;
+
   *returned_port_poly = MACH_MSG_TYPE_MAKE_SEND;
   *retry = FS_RETRY_NORMAL;
   retryname[0] = '\0';
@@ -274,11 +278,16 @@ diskfs_S_dir_lookup (struct protid *dircred,
            goto out;
 
          dirport = ports_get_send_right (newpi);
-         ports_port_deref (newpi);
-         newpi = 0;
          if (np != dnp)
            pthread_mutex_unlock (&dnp->lock);
 
+         /* Check if an active translator is currently running.  If
+            not, fshelp_fetch_root will start one.  In that case, we
+            need to register it in the list of active
+            translators.  */
+         boolean_t register_translator =
+           np->transbox.active == MACH_PORT_NULL;
+
          error = fshelp_fetch_root (&np->transbox, dircred->po,
                                     dirport, dircred->user,
                                     lastcomp ? flags : 0,
@@ -301,9 +310,35 @@ diskfs_S_dir_lookup (struct protid *dircred,
                  *end++ = '/';
                  strcpy (end, nextname);
                }
+
+             if (register_translator)
+               {
+                 char *translator_path = strdupa (relpath);
+                 if (nextname != NULL)
+                   {
+                     /* This was not the last path component.
+                        NEXTNAME points to the next component, locate
+                        the end of the current component and use it
+                        to trim TRANSLATOR_PATH.  */
+                     char *end = nextname;
+                     while (*end != 0)
+                       end--;
+                     translator_path[end - path_start] = '\0';
+                   }
+
+                 error = fshelp_set_active_translator (&newpi->pi,
+                                                       translator_path,
+                                                       np->transbox.active);
+                 if (error)
+                   goto out;
+               }
+
              goto out;
            }
 
+         ports_port_deref (newpi);
+         newpi = NULL;
+
          /* ENOENT means there was a hiccup, and the translator
             vanished while NP was unlocked inside fshelp_fetch_root.
             Reacquire the locks, and continue as normal. */
-- 
1.8.5.2