remove translatorslist-detect-passive-translators.patch

1 files changed, 0 insertions, 712 deletions

diff --git a/debian/patches/translatorslist-detect-passive-translators.patch b/debian/patches/translatorslist-detect-passive-translators.patch
deleted file mode 100644
index 25823bc7..00000000
--- a/debian/patches/translatorslist-detect-passive-translators.patch
+++ /dev/null
@@ -1,712 +0,0 @@
-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. */
-diff --git a/libdiskfs/file-set-trans.c b/libdiskfs/file-set-trans.c
-index 8de2e64..58f6255 100644
---- a/libdiskfs/file-set-trans.c
-+++ b/libdiskfs/file-set-trans.c
-@@ -1,5 +1,5 @@
- /* libdiskfs implementation of fs.defs: file_set_translator
--   Copyright (C) 1992,93,94,95,96,99,2001,02,13
-+   Copyright (C) 1992,93,94,95,96,99,2001,02,13,14
-      Free Software Foundation, Inc.
- 
-    This program is free software; you can redistribute it and/or
-@@ -208,20 +208,8 @@ diskfs_S_file_set_translator (struct protid *cred,
- 
-   pthread_mutex_unlock (&np->lock);
- 
--  if (! error && cred->po->path)
--    error = fshelp_set_active_translator (cred->po->path, active);
--
--  if (! error && active != MACH_PORT_NULL)
--    {
--      mach_port_t old;
--      error = mach_port_request_notification (mach_task_self (), active,
--					      MACH_NOTIFY_DEAD_NAME, 0,
--					      cred->pi.port_right,
--					      MACH_MSG_TYPE_MAKE_SEND_ONCE,
--					      &old);
--      if (old != MACH_PORT_NULL)
--	mach_port_deallocate (mach_task_self (), old);
--    }
-+  if (! error && cred->po->path && active_flags & FS_TRANS_SET)
-+    error = fshelp_set_active_translator (&cred->pi, cred->po->path, active);
- 
-   return error;
- }
-diff --git a/libfshelp/fshelp.h b/libfshelp/fshelp.h
-index a7702ca..5d3a0ce 100644
---- a/libfshelp/fshelp.h
-+++ b/libfshelp/fshelp.h
-@@ -1,5 +1,5 @@
- /* FS helper library definitions
--   Copyright (C) 1994,95,96,97,98,99,2000,01,02,13
-+   Copyright (C) 1994,95,96,97,98,99,2000,01,02,13,14
-      Free Software Foundation, Inc.
- 
-    This program is free software; you can redistribute it and/or
-@@ -34,14 +34,20 @@
- 
- 
- /* Keeping track of active translators */
--/* These routines keep a list of active translators.  They are
--   self-contained and do not require multi threading or the ports
--   library.  */
-+/* These routines keep a list of active translators.  They do not
-+   require multi threading but depend on the ports library.  */
-+
-+struct port_info;
- 
- /* Record an active translator being bound to the given file name
--   NAME.  ACTIVE is the control port of the translator.  */
-+   NAME.  ACTIVE is the control port of the translator.  PI references
-+   a receive port that is used to request dead name notifications,
-+   typically the port for the underlying node passed to the
-+   translator.  */
- error_t
--fshelp_set_active_translator (const char *name, mach_port_t active);
-+fshelp_set_active_translator (struct port_info *pi,
-+                              const char *name,
-+                              mach_port_t active);
- 
- /* Remove the active translator specified by its control port ACTIVE.
-    If there is no active translator with the given control port, this
-diff --git a/libfshelp/translator-list.c b/libfshelp/translator-list.c
-index 87dcb21..3ece711 100644
---- a/libfshelp/translator-list.c
-+++ b/libfshelp/translator-list.c
-@@ -1,6 +1,6 @@
- /* A list of active translators.
- 
--   Copyright (C) 2013 Free Software Foundation, Inc.
-+   Copyright (C) 2013,14 Free Software Foundation, Inc.
- 
-    Written by Justus Winter <4winter@informatik.uni-hamburg.de>
- 
-@@ -22,6 +22,7 @@
- #include <argz.h>
- #include <hurd/fsys.h>
- #include <hurd/ihash.h>
-+#include <hurd/ports.h>
- #include <mach.h>
- #include <mach/notify.h>
- #include <pthread.h>
-@@ -33,6 +34,7 @@
- 
- struct translator
- {
-+  struct port_info *pi;
-   char *name;
-   mach_port_t active;
- };
-@@ -49,8 +51,10 @@ translator_ihash_cleanup (void *element, void *arg)
- {
-   struct translator *translator = element;
- 
--  /* No need to deallocate port, we only keep the name of the
--     port, not a reference.  */
-+  if (translator->pi)
-+    ports_port_deref (translator->pi);
-+  /* No need to deallocate translator->active, we only keep the name of
-+     the port, not a reference.  */
-   free (translator->name);
-   free (translator);
- }
-@@ -58,7 +62,9 @@ translator_ihash_cleanup (void *element, void *arg)
- /* Record an active translator being bound to the given file name
-    NAME.  ACTIVE is the control port of the translator.  */
- error_t
--fshelp_set_active_translator (const char *name, mach_port_t active)
-+fshelp_set_active_translator (struct port_info *pi,
-+			      const char *name,
-+			      mach_port_t active)
- {
-   error_t err = 0;
-   pthread_mutex_lock (&translator_ihash_lock);
-@@ -79,6 +85,7 @@ fshelp_set_active_translator (const char *name, mach_port_t active)
-     return ENOMEM;
- 
-   t->active = MACH_PORT_NULL;
-+  t->pi = NULL;
-   t->name = strdup (name);
-   if (! t->name)
-     {
-@@ -93,9 +100,31 @@ fshelp_set_active_translator (const char *name, mach_port_t active)
- 
-  update:
-   if (active)
--    /* No need to increment the reference count, we only keep the
--       name, not a reference.  */
--    t->active = active;
-+    {
-+      if (t->pi != pi)
-+	{
-+	  mach_port_t old;
-+	  err = mach_port_request_notification (mach_task_self (), active,
-+						MACH_NOTIFY_DEAD_NAME, 0,
-+						pi->port_right,
-+						MACH_MSG_TYPE_MAKE_SEND_ONCE,
-+						&old);
-+	  if (err)
-+	    return err;
-+	  if (old != MACH_PORT_NULL)
-+	    mach_port_deallocate (mach_task_self (), old);
-+
-+	  if (t->pi)
-+	    ports_port_deref (t->pi);
-+
-+	  ports_port_ref (pi);
-+	  t->pi = pi;
-+	}
-+
-+      /* No need to increment the reference count, we only keep the
-+	 name, not a reference.  */
-+      t->active = active;
-+    }
-   else
-     hurd_ihash_remove (&translator_ihash, (hurd_ihash_key_t) t);
- 
-diff --git a/libnetfs/dir-lookup.c b/libnetfs/dir-lookup.c
-index 74351fa..99a8746 100644
---- a/libnetfs/dir-lookup.c
-+++ b/libnetfs/dir-lookup.c
-@@ -1,5 +1,5 @@
- /*
--   Copyright (C) 1995,96,97,98,99,2000,01,02,13
-+   Copyright (C) 1995,96,97,98,99,2000,01,02,13,14
-      Free Software Foundation, Inc.
-    Written by Michael I. Bushnell, p/BSG.
- 
-@@ -67,6 +67,10 @@ netfs_S_dir_lookup (struct protid *diruser,
-   if (! relpath)
-     return ENOMEM;
- 
-+  /* Keep a pointer to the start of the filename for length
-+     calculations.  */
-+  char *filename_start = filename;
-+
-   *retry_port_type = MACH_MSG_TYPE_MAKE_SEND;
-   *do_retry = FS_RETRY_NORMAL;
-   *retry_name = '\0';
-@@ -256,10 +260,16 @@ netfs_S_dir_lookup (struct protid *diruser,
- 		}
- 	    }
- 
-+	  boolean_t register_translator;
- 	  if (! error)
- 	    {
- 	      dirport = ports_get_send_right (newpi);
--	      ports_port_deref (newpi);
-+
-+	      /* 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.  */
-+	      register_translator = np->transbox.active == MACH_PORT_NULL;
- 
- 	      error = fshelp_fetch_root (&np->transbox, diruser->po,
- 					 dirport,
-@@ -283,9 +293,38 @@ netfs_S_dir_lookup (struct protid *diruser,
- 		  strcat (retry_name, "/");
- 		  strcat (retry_name, 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 - filename_start] = '\0';
-+		    }
-+
-+		  error = fshelp_set_active_translator (&newpi->pi,
-+							translator_path,
-+							np->transbox.active);
-+		  if (error)
-+		    {
-+		      ports_port_deref (newpi);
-+		      goto out;
-+		    }
-+		}
-+
-+	      ports_port_deref (newpi);
- 	      goto out;
- 	    }
- 
-+	  ports_port_deref (newpi);
-+
- 	  /* ENOENT means there was a hiccup, and the translator vanished
- 	     while NP was unlocked inside fshelp_fetch_root; continue as normal. */
- 	  error = 0;
-diff --git a/libnetfs/file-set-translator.c b/libnetfs/file-set-translator.c
-index a9883a3..b46eb02 100644
---- a/libnetfs/file-set-translator.c
-+++ b/libnetfs/file-set-translator.c
-@@ -1,5 +1,6 @@
- /*
--   Copyright (C) 1996, 1997, 1999, 2001, 2013 Free Software Foundation, Inc.
-+   Copyright (C) 1996, 1997, 1999, 2001, 2013, 2014
-+     Free Software Foundation, Inc.
-    Written by Michael I. Bushnell, p/BSG.
- 
-    This file is part of the GNU Hurd.
-@@ -175,20 +176,8 @@ netfs_S_file_set_translator (struct protid *user,
- 	}
-     }
- 
--  if (! err && user->po->path)
--    err = fshelp_set_active_translator (user->po->path, active);
--
--  if (! err && active != MACH_PORT_NULL)
--    {
--      mach_port_t old;
--      err = mach_port_request_notification (mach_task_self (), active,
--					    MACH_NOTIFY_DEAD_NAME, 0,
--					    user->pi.port_right,
--					    MACH_MSG_TYPE_MAKE_SEND_ONCE,
--					    &old);
--      if (old != MACH_PORT_NULL)
--	mach_port_deallocate (mach_task_self (), old);
--    }
-+  if (! err && user->po->path && active_flags & FS_TRANS_SET)
-+    err = fshelp_set_active_translator (&user->pi, user->po->path, active);
- 
-  out:
-   pthread_mutex_unlock (&np->lock);
-diff --git a/trans/mtab.c b/trans/mtab.c
-index 250de7d..75ef1d3 100644
---- a/trans/mtab.c
-+++ b/trans/mtab.c
-@@ -1,6 +1,6 @@
- /* This is an mtab translator.
- 
--   Copyright (C) 2013 Free Software Foundation, Inc.
-+   Copyright (C) 2013,14 Free Software Foundation, Inc.
- 
-    Written by Justus Winter <4winter@informatik.uni-hamburg.de>
- 
-@@ -27,6 +27,7 @@
- #include <hurd/trivfs.h>
- #include <inttypes.h>
- #include <mntent.h>
-+#include <pthread.h>
- #include <stdlib.h>
- #include <stdio.h>
- #include <string.h>
-@@ -39,6 +40,7 @@
- 
- static char *target_path = NULL;
- static int insecure = 0;
-+static int all_translators = 0;
- 
- /* Our control port.  */
- struct trivfs_control *control;
-@@ -47,6 +49,7 @@ struct trivfs_control *control;
-    They keep track of the content and file position of the client.  */
- struct mtab
- {
-+  pthread_mutex_t lock;
-   char *contents;
-   size_t contents_len;
-   off_t offs;
-@@ -58,6 +61,9 @@ static const struct argp_option options[] =
- {
-   {"insecure", 'I', 0, 0,
-    "Follow translators not bound to nodes owned by you or root"},
-+  {"all-translators", 'A', 0, 0,
-+   "List all translators, even those that are probably not "
-+   "filesystem translators"},
-   {}
- };
- 
-@@ -70,6 +76,10 @@ error_t parse_opt (int key, char *arg, struct argp_state *state)
-       insecure = 1;
-       break;
- 
-+    case 'A':
-+      all_translators = 1;
-+      break;
-+
-     case ARGP_KEY_ARG:
-       target_path = realpath (arg, NULL);
-       if (! target_path)
-@@ -233,9 +243,13 @@ main (int argc, char *argv[])
- 	error (4, err, "trivfs_startup");
- 
-       /* Launch.  */
--      ports_manage_port_operations_one_thread (control->pi.bucket,
--					       trivfs_demuxer,
--					       0);
-+      ports_manage_port_operations_multithread (control->pi.bucket,
-+                                                trivfs_demuxer,
-+                                                /* idle thread timeout */
-+                                                30 * 1000,
-+                                                /* idle server timeout */
-+                                                0,
-+                                                NULL);
-     }
-   else
-     {
-@@ -271,6 +285,32 @@ mtab_add_entry (struct mtab *mtab, const char *entry, size_t length)
-   return 0;
- }
- 
-+/* Check whether the given NODE is a directory on a filesystem
-+   translator.  */
-+static boolean_t
-+is_filesystem_translator (file_t node)
-+{
-+  error_t err;
-+  char *data = NULL;
-+  size_t datacnt = 0;
-+  int amount;
-+  err = dir_readdir (node, &data, &datacnt, 0, 1, 0, &amount);
-+  if (data != NULL && datacnt > 0)
-+    vm_deallocate (mach_task_self (), (vm_address_t) data, datacnt);
-+
-+  /* Filesystem translators return either no error, or, if NODE has
-+     not been looked up with O_READ, EBADF to dir_readdir
-+     requests.  */
-+  switch (err)
-+    {
-+    case 0:
-+    case EBADF:
-+      return TRUE;
-+    default:
-+      return FALSE;
-+    }
-+}
-+
- /* Populates the given MTAB object with the information for PATH.  If
-    INSECURE is given, also follow translators bound to nodes not owned
-    by root or the current user.  */
-@@ -282,7 +322,6 @@ mtab_populate (struct mtab *mtab, const char *path, int insecure)
- 
-   /* These resources are freed in the epilogue.	 */
-   file_t node = MACH_PORT_NULL;
--  fsys_t fsys = MACH_PORT_NULL;
-   char *argz = NULL;
-   size_t argz_len = 0;
-   char **argv = NULL;
-@@ -295,16 +334,16 @@ mtab_populate (struct mtab *mtab, const char *path, int insecure)
-   char *children = NULL;
-   size_t children_len = 0;
- 
--  /* Get the underlying node.  */
--  node = file_name_lookup (path, O_NOTRANS, 0666);
--  if (node == MACH_PORT_NULL)
--    {
--      err = errno;
--      goto errout;
--    }
--
-   if (! insecure)
-     {
-+      /* Get the underlying node.  */
-+      node = file_name_lookup (path, O_NOTRANS, 0666);
-+      if (node == MACH_PORT_NULL)
-+        {
-+          err = errno;
-+          goto errout;
-+        }
-+
-       /* Check who owns the node the translator is bound to.  */
-       io_statbuf_t st;
-       err = io_stat (node, &st);
-@@ -316,28 +355,11 @@ mtab_populate (struct mtab *mtab, const char *path, int insecure)
- 	  err = EPERM;
- 	  goto errout;
- 	}
--    }
--
--  err = file_get_translator_cntl (node, &fsys);
--  if (err == EPERM)
--    /* If we do not have permission to do that, it cannot be a node
--       bound to our control port, so ignore this error.	 */
--    err = 0;
--
--  if (err == ENXIO && strcmp (path, "/") == 0)
--    /* The root translator fails differently, but this can't be bound
--       to our control port either, so ignore this error.  */
--    err = 0;
- 
--  if (err)
--    return err;
--
--  if (control && control->pi.port_right == fsys)
--    /* This node is bound to our control port, ignore it.  */
--    goto errout;
-+      mach_port_deallocate (mach_task_self (), node);
-+    }
- 
--  /* Re-do the lookup without O_NOTRANS to get the root node.  */
--  mach_port_deallocate (mach_task_self (), node);
-+  /* (Re-)do the lookup without O_NOTRANS to get the root node.  */
-   node = file_name_lookup (path, 0, 0666);
-   if (node == MACH_PORT_NULL)
-     {
-@@ -345,6 +367,12 @@ mtab_populate (struct mtab *mtab, const char *path, int insecure)
-       goto errout;
-     }
- 
-+  if (! (all_translators || is_filesystem_translator (node)))
-+    {
-+      err = 0;
-+      goto errout;
-+    }
-+
-   /* Query its options.	 */
-   err = file_get_fs_options (node, &argz, &argz_len);
-   if (err)
-@@ -461,9 +489,6 @@ mtab_populate (struct mtab *mtab, const char *path, int insecure)
-   if (node != MACH_PORT_NULL)
-     mach_port_deallocate (mach_task_self (), node);
- 
--  if (fsys != MACH_PORT_NULL)
--    mach_port_deallocate (mach_task_self (), fsys);
--
-   if (argz)
-     vm_deallocate (mach_task_self (), (vm_address_t) argz, argz_len);
- 
-@@ -590,18 +615,44 @@ open_hook (struct trivfs_peropen *peropen)
-   peropen->hook = mtab;
- 
-   /* Initialize the fields.  */
-+  pthread_mutex_init (&mtab->lock, NULL);
-   mtab->offs = 0;
-   mtab->contents = NULL;
-   mtab->contents_len = 0;
- 
--  return mtab_populate (mtab, target_path, insecure);
-+  /* The mtab object is initialized, but not yet populated.  We delay
-+     that until that data is really needed.  This avoids the following
-+     problems:
-+
-+     Suppose you have
-+
-+     settrans -ac /foo /hurd/mtab /
-+
-+     If you now access /foo, the mtab translator will walk the tree of
-+     all active translators starting from /.  If it visits /foo, it
-+     will talk to itself.  Previously the translator migitated this by
-+     comparing the control port of the translator with its own.  This
-+     does not work if you got two mtab translators like this:
-+
-+     settrans -ac /foo /hurd/mtab /
-+     settrans -ac /bar /hurd/mtab /
-+
-+     With a single-threaded mtab server this results in a dead-lock,
-+     with a multi-threaded server this will create more and more
-+     threads.
-+
-+     Delaying the data generation until it is really needed cleanly
-+     avoids these kind of problems.  */
-+  return 0;
- }
- 
- static void
- close_hook (struct trivfs_peropen *peropen)
- {
--  free (((struct mtab *) peropen->hook)->contents);
--  free (peropen->hook);
-+  struct mtab *op = peropen->hook;
-+  pthread_mutex_destroy (&op->lock);
-+  free (op->contents);
-+  free (op);
- }
- 
- /* Read data from an IO object.	 If offset is -1, read from the object
-@@ -613,6 +664,7 @@ trivfs_S_io_read (struct trivfs_protid *cred,
- 		  char **data, mach_msg_type_number_t *data_len,
- 		  loff_t offs, mach_msg_type_number_t amount)
- {
-+  error_t err = 0;
-   struct mtab *op;
- 
-   /* Deny access if they have bad credentials.	*/
-@@ -624,6 +676,15 @@ trivfs_S_io_read (struct trivfs_protid *cred,
- 
-   /* Get the offset.  */
-   op = cred->po->hook;
-+  pthread_mutex_lock (&op->lock);
-+
-+  if (op->contents == NULL)
-+    {
-+      err = mtab_populate (op, target_path, insecure);
-+      if (err)
-+	goto out;
-+    }
-+
-   if (offs == -1)
-     offs = op->offs;
- 
-@@ -640,7 +701,10 @@ trivfs_S_io_read (struct trivfs_protid *cred,
- 	{
- 	  *data = mmap (0, amount, PROT_READ|PROT_WRITE, MAP_ANON, 0, 0);
- 	  if (*data == MAP_FAILED)
--	    return ENOMEM;
-+	    {
-+	      err = ENOMEM;
-+	      goto out;
-+	    }
- 	}
- 
-       /* Copy the constant data into the buffer.  */
-@@ -651,7 +715,9 @@ trivfs_S_io_read (struct trivfs_protid *cred,
-     }
- 
-   *data_len = amount;
--  return 0;
-+ out:
-+  pthread_mutex_unlock (&op->lock);
-+  return err;
- }
- 
- 
-@@ -661,10 +727,19 @@ trivfs_S_io_seek (struct trivfs_protid *cred,
- 		  mach_port_t reply, mach_msg_type_name_t reply_type,
- 		  off_t offs, int whence, off_t *new_offs)
- {
-+  error_t err = 0;
-   if (! cred)
-     return EOPNOTSUPP;
- 
-   struct mtab *op = cred->po->hook;
-+  pthread_mutex_lock (&op->lock);
-+
-+  if (op->contents == NULL)
-+    {
-+      err = mtab_populate (op, target_path, insecure);
-+      if (err)
-+	goto out;
-+    }
- 
-   switch (whence)
-     {
-@@ -681,10 +756,12 @@ trivfs_S_io_seek (struct trivfs_protid *cred,
- 	  break;
- 	}
-     default:
--      return EINVAL;
-+      err = EINVAL;
-     }
- 
--  return 0;
-+ out:
-+  pthread_mutex_unlock (&op->lock);
-+  return err;
- }
- 
- /* If this variable is set, it is called every time a new peropen
-@@ -703,6 +780,7 @@ trivfs_S_io_readable (struct trivfs_protid *cred,
- 		      mach_port_t reply, mach_msg_type_name_t replytype,
- 		      mach_msg_type_number_t *amount)
- {
-+  error_t err = 0;
-   if (!cred)
-     return EOPNOTSUPP;
- 
-@@ -710,9 +788,19 @@ trivfs_S_io_readable (struct trivfs_protid *cred,
-     return EINVAL;
- 
-   struct mtab *op = cred->po->hook;
-+  pthread_mutex_lock (&op->lock);
-+
-+  if (op->contents == NULL)
-+    {
-+      error_t err = mtab_populate (op, target_path, insecure);
-+      if (err)
-+	goto out;
-+    }
- 
-   *amount = op->contents_len - op->offs;
--  return 0;
-+ out:
-+  pthread_mutex_unlock (&op->lock);
-+  return err;
- }
- 
- /* SELECT_TYPE is the bitwise OR of SELECT_READ, SELECT_WRITE, and SELECT_URG.