[PATCH 4/4] Supply the port to the real underlying node to the mountee.

[Sergiu Ivanov]

>From 973b0a6fd08d132306ddf40293062f3583f2980f Mon Sep 17 00:00:00 2001
From: Sergiu Ivanov <unlimitedscolobb@gmail.com>
Date: Thu, 16 Jul 2009 21:24:57 +0000
Subject: [PATCH 4/4] Supply the port to the real underlying node to the mountee.

* mount.c (unionmount_proxy): Remove variable.
(start_mountee): Remove parameter np.  Remove variable
underlying_port.  Create unauth_dir as a port to the root node
of unionfs.
(open_port): Return the port to the real underlying node.
* mount.h (unionmount_proxy): Remove variable.
(start_mountee): Remove parameter np.
---
 mount.c |   62 ++++++++++++++------------------------------------------------
 mount.h |   11 +++--------
 2 files changed, 17 insertions(+), 56 deletions(-)

diff --git a/mount.c b/mount.c
index 4d0a0d4..d0b9907 100644
--- a/mount.c
+++ b/mount.c
@@ -29,14 +29,12 @@
 #include "mount.h"
 #include "lib.h"
 #include "ulfs.h"
+#include "unionfs.h"
 
 /* The command line for starting the mountee.  */
 char * mountee_argz;
 size_t mountee_argz_len;
 
-/* The node the mountee is sitting on.  */
-node_t * unionmount_proxy;
-
 mach_port_t mountee_port;
 mach_port_t mountee_control = MACH_PORT_NULL;
 
@@ -53,15 +51,12 @@ int shutting_down = 0;
    mountee.  */
 mach_port_t mountee_listen_port;
 
-/* Starts the mountee (given by `argz` and `argz_len`), sets it on
-   node `np` and opens a port `port` to with `flags`.  `port` is not
-   modified when an error occurs.  */
+/* Starts the mountee (given by `argz` and `argz_len`) and opens a
+   port `port` to it with `flags`.  */
 error_t
-start_mountee (node_t * np, char * argz, size_t argz_len, int flags,
-              mach_port_t * port)
+start_mountee (char * argz, size_t argz_len, int flags, mach_port_t * port)
 {
   error_t err;
-  mach_port_t underlying_port;
 
   /* The intermediate container for the port to the root of the
      mountee.  */
@@ -113,37 +108,16 @@ start_mountee (node_t * np, char * argz, size_t argz_len, 
int flags,
   ngids = getgroups (ngids, gids);
   assert (ngids > 0);
 
-  /* Opens the port on which to set the mountee.  */
+  /* Provides the mountee with a port to the unionfs's underlying
+     node.  */
   error_t open_port (int flags, mach_port_t * underlying,
                     mach_msg_type_name_t * underlying_type, task_t task,
                     void *cookie)
   {
-    err = 0;
+    *underlying = underlying_node;
+    *underlying_type  = MACH_MSG_TYPE_COPY_SEND;
 
-    /* The user which has created this process.  */
-    struct iouser * user;
-
-    /* Create an iouser instance basing on the obtained authority
-       information.  */
-    err = iohelp_create_complex_iouser (&user, uids, nuids, gids, ngids);
-    if (err)
-      return err;
-
-    /* Create a port to `np`.  */
-    newpi = netfs_make_protid
-      (netfs_make_peropen (np, flags, NULL), user);
-    if (!newpi)
-      {
-       iohelp_free_iouser (user);
-       return errno;
-      }
-
-    *underlying = underlying_port = ports_get_send_right (newpi);
-    *underlying_type = MACH_MSG_TYPE_COPY_SEND;
-
-    ports_port_deref (newpi);
-
-    return err;
+    return 0;
   }                            /*open_port */
 
   /* Create a completely unprivileged user.  */
@@ -151,9 +125,10 @@ start_mountee (node_t * np, char * argz, size_t argz_len, 
int flags,
   if(err)
     return err;
 
-  /* Create a port to `np` for the unprivileged user.  */
+  /* Create a port to the root node of unionfs for the unprivileged
+     user.  */
   newpi = netfs_make_protid
-    (netfs_make_peropen (np, flags, NULL), nobody);
+    (netfs_make_peropen (netfs_root_node, flags, NULL), nobody);
   if (!newpi)
     {
       iohelp_free_iouser (nobody);
@@ -226,23 +201,14 @@ setup_unionmount (void)
 {
   error_t err = 0;
 
-  /* The proxy node on which the mountee will be sitting must be able
-     to forward some of the RPCs coming from the mountee to the
-     underlying filesystem.  That is why we create this proxy node as
-     a clone of the root node: the mountee will feel as if there is no
-     unionfs under itself.  */
-  unionmount_proxy = netfs_make_node (netfs_root_node->nn);
-  if (!unionmount_proxy)
-    return ENOMEM;
+  /* Start the mountee.
 
-  /* Set the mountee on the proxy node.
      Note that the O_READ flag does not actually limit access to the
      mountee's filesystem considerably.  Whenever a client looks up a
      node which is not a directory, unionfs will give off a port to
      the node itself, withouth proxying it.  Proxying happens only for
      directory nodes.  */
-  err = start_mountee (unionmount_proxy, mountee_argz,
-                      mountee_argz_len, O_READ, &mountee_port);
+  err = start_mountee (mountee_argz, mountee_argz_len, O_READ, &mountee_port);
   if (err)
     return err;
 
diff --git a/mount.h b/mount.h
index ebbfa93..94f13a6 100644
--- a/mount.h
+++ b/mount.h
@@ -33,9 +33,6 @@
 extern char * mountee_argz;
 extern size_t mountee_argz_len;
 
-/* The node the mountee is sitting on.  */
-extern node_t * unionmount_proxy;
-
 extern mach_port_t mountee_port;
 extern mach_port_t mountee_control;
 
@@ -48,12 +45,10 @@ extern int transparent_mount;
 /* Shows whether unionmount is shutting down.  */
 extern int shutting_down;
 
-/* Starts the mountee (given by `argz` and `argz_len`), sets it on
-   node `np` and opens a port `port` to with `flags`.  `port` is not
-   modified when an error occurs.  */
+/* Starts the mountee (given by `argz` and `argz_len`) and opens a
+   port `port` to it with `flags`.  */
 error_t
-start_mountee (node_t * np, char * argz, size_t argz_len, int flags,
-              mach_port_t * port);
+start_mountee (char * argz, size_t argz_len, int flags, mach_port_t * port);
 
 /* Sets up a proxy node, sets the translator on it, and registers the
    filesystem published by the translator in the list of merged
-- 
1.6.3.3