[PATCH] Add the .MASTER node to the eth-multiplexer.

[Sergiu Ivanov]

>From 82f635e6ecafe74c70269babfb0e0bb0e7db99db Mon Sep 17 00:00:00 2001
From: Sergiu Ivanov <unlimitedscolobb@gmail.com>
Date: Mon, 10 Aug 2009 20:13:26 +0300
Subject: [PATCH] Add the .MASTER node to the eth-multiplexer.

* eth-multiplexer/device_impl.c (ds_device_open): Handle
the .MASTER node specially.
* eth-multiplexer/multiplexer.c (main): Create the .MASTER
node.
* eth-multiplexer/netfs_impl.c (master_node): New variable.
(lookup): Handle the lookups for .MASTER specially.
(netfs_add_dirents): Add the .MASTER node.
* eth-multiplexer/netfs_impl.h (MASTER_NODE_NAME): New
definition.
(master_node): New variable.
---
 eth-multiplexer/device_impl.c |   21 ++++++++++++++++++++-
 eth-multiplexer/multiplexer.c |    6 +++++-
 eth-multiplexer/netfs_impl.c  |   21 ++++++++++++++++++++-
 eth-multiplexer/netfs_impl.h  |    8 ++++++++
 4 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/eth-multiplexer/device_impl.c b/eth-multiplexer/device_impl.c
index abbd146..6aa27dd 100644
--- a/eth-multiplexer/device_impl.c
+++ b/eth-multiplexer/device_impl.c
@@ -116,7 +116,26 @@ ds_device_open (mach_port_t master_port, mach_port_t 
reply_port,
       ln->st = ln->n->nn_stat;
     }
 
-  dev = (struct vether_device *) pi->po->np->nn->ln;
+  if (pi->po->np == master_node)
+    {
+      /* This device_open RPC was invoked on a port the .MASTER node,
+        so we don't care about light nodes (because the .MASTER node
+        does not have one).  */
+      extern struct port_bucket *port_bucket;
+      extern struct port_class *vdev_portclass;
+
+      /* Create a new virtual device. */
+      dev = (struct lnode *) add_vdev (name, sizeof (*dev), vdev_portclass,
+                                      port_bucket);
+      if (dev == NULL)
+       {
+         ports_port_deref (pi);
+         return D_NO_MEMORY;
+       }
+    }
+  else
+    dev = (struct vether_device *) pi->po->np->nn->ln;
+
   /* check the mode */
   openstat = pi->po->openstat;
   if ((openstat & O_READ) && !(mode & D_READ))
diff --git a/eth-multiplexer/multiplexer.c b/eth-multiplexer/multiplexer.c
index 173a8f9..a87c9c4 100644
--- a/eth-multiplexer/multiplexer.c
+++ b/eth-multiplexer/multiplexer.c
@@ -162,9 +162,13 @@ main (int argc, char *argv[])
   if (err)
     error (5, err, "Cannot create root node");
 
+  err = new_node (NULL, &master_node);
+  if (err)
+    error (6, err, "Cannot create the .MASTER node");
+
   err = io_stat (root_file, &underlying_node_stat);
   if (err) 
-    error (6, err, "Cannot stat underlying node");
+    error (7, err, "Cannot stat underlying node");
 
   struct stat stat = underlying_node_stat;
   /* If the underlying node is not a directory, increase its permissions */
diff --git a/eth-multiplexer/netfs_impl.c b/eth-multiplexer/netfs_impl.c
index c70701b..875ff48 100644
--- a/eth-multiplexer/netfs_impl.c
+++ b/eth-multiplexer/netfs_impl.c
@@ -31,6 +31,10 @@
 #include "vdev.h"
 #include "util.h"
 
+/* The .MASTER node which will be used by static instances of
+   devnode.  */
+struct node * master_node;
+
 #define DIRENTS_CHUNK_SIZE      (8*1024)
 /* Returned directory entries are aligned to blocks this many bytes long.
  * Must be a power of two.  */
@@ -85,6 +89,18 @@ new_node (struct lnode *ln, struct node **np)
 struct node *
 lookup (char *name)
 {
+  if (strcmp(name, MASTER_NODE_NAME) == 0)
+    {
+      netfs_nref (master_node);
+
+      /* netfs_attempt_lookup expects the returned node not to be
+        locked, while `master_node` might have been locked in the
+        previous lookups.  */
+      mutex_unlock (&master_node->lock);
+
+      return master_node;
+    }
+
   struct lnode *ln = (struct lnode *) lookup_dev_by_name (name);
 
   char *copied_name = malloc (strlen (name) + 1);
@@ -276,10 +292,13 @@ netfs_get_dirents (struct iouser *cred, struct node *dir,
   if (!err)
     {
       data_p = *data;
-      if (first_entry < 2 + get_dev_num ())
+      /* Count the .MASTER node, too.  */
+      if (first_entry < 2 + get_dev_num () + 1)
        {
          add_dirent (".", 2, DT_DIR);
          add_dirent ("..", 2, DT_DIR);
+         add_dirent (MASTER_NODE_NAME, 2, DT_CHR);
+
          foreach_dev_do (add_each_dev);
        }
 
diff --git a/eth-multiplexer/netfs_impl.h b/eth-multiplexer/netfs_impl.h
index ec3b389..1c9662a 100644
--- a/eth-multiplexer/netfs_impl.h
+++ b/eth-multiplexer/netfs_impl.h
@@ -29,6 +29,10 @@
 /* Shows the stat information in the node is invalid.  */
 #define NODE_STAT_INVALID 0x0001
 
+/* The name of the node which provides the pseudo master device port
+   functionality for static instances of devnode.  */
+#define MASTER_NODE_NAME ".MASTER"
+
 struct netnode
 {
   struct lnode *ln;
@@ -47,6 +51,10 @@ struct lnode
 extern file_t root_file;
 volatile struct mapped_time_value *multiplexer_maptime;
 
+/* The .MASTER node which will be used by static instances of
+   devnode.  */
+extern struct node * master_node;
+
 error_t new_node (struct lnode *ln, struct node **np);
 
 #endif
-- 
1.5.2.4