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

[Sergiu Ivanov]

* 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.
---

Hello,

In this patch I tried to take into consideration the corrections to
the original version suggested by Zheng and, probably, other people
whom I don't remember :-(

Regards,
Sergiu

---
 eth-multiplexer/device_impl.c |   49 +++++++++++++++++++++++++++++-----------
 eth-multiplexer/multiplexer.c |    6 ++++-
 eth-multiplexer/netfs_impl.c  |   15 +++++++++++-
 eth-multiplexer/netfs_impl.h  |    8 ++++++
 4 files changed, 62 insertions(+), 16 deletions(-)

diff --git a/eth-multiplexer/device_impl.c b/eth-multiplexer/device_impl.c
index 8c82606..8830093 100644
--- a/eth-multiplexer/device_impl.c
+++ b/eth-multiplexer/device_impl.c
@@ -92,31 +92,52 @@ ds_device_open (mach_port_t master_port, mach_port_t 
reply_port,
   if (pi == NULL)
     return D_NO_SUCH_DEVICE;
 
-  /* If the virtual device hasn't been created yet,
-   * create it now. */
-  if (pi->po->np->nn->ln == NULL)
+  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 light node (virtual device). */
-      struct lnode *ln = (struct lnode *) add_vdev (pi->po->np->nn->name,
-                                                   sizeof (*ln),
-                                                   vdev_portclass,
-                                                   port_bucket);
-      if (ln == NULL)
+
+      /* 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
+    {
+      /* If the virtual device hasn't been created yet,
+       * create it now. */
+      if (pi->po->np->nn->ln == NULL)
+       {
+         extern struct port_bucket *port_bucket;
+         extern struct port_class *vdev_portclass;
+         /* Create a new light node (virtual device). */
+         struct lnode *ln = (struct lnode *) add_vdev (pi->po->np->nn->name,
+                                                       sizeof (*ln),
+                                                       vdev_portclass,
+                                                       port_bucket);
+         if (ln == NULL)
+           {
+             ports_port_deref (pi);
+             return D_NO_MEMORY;
+           }
+
+         /* Connect the libnetfs node and the light node together.  */
+         ln->n = pi->po->np;
+         ln->n->nn->ln = ln;
 
-      /* Connect the libnetfs node and the light node together.  */
-      ln->n = pi->po->np;
-      ln->n->nn->ln = ln;
+         ln->st = ln->n->nn_stat;
+       }
 
-      ln->st = ln->n->nn_stat;
+      dev = (struct vether_device *) pi->po->np->nn->ln;
     }
 
-  dev = (struct vether_device *) pi->po->np->nn->ln;
   /* check the mode */
   openstat = pi->po->openstat;
   if (mode & D_READ && !(openstat & O_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..257cf9d 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 +89,12 @@ new_node (struct lnode *ln, struct node **np)
 struct node *
 lookup (char *name)
 {
+  if (strcmp(name, MASTER_NODE_NAME) == 0)
+    {
+      netfs_nref (master_node);
+      return master_node;
+    }
+
   struct lnode *ln = (struct lnode *) lookup_dev_by_name (name);
 
   char *copied_name = malloc (strlen (name) + 1);
@@ -276,10 +286,13 @@ 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
-- 
1.6.6