Copied the implementation of netfs_S_file_get_translator_cntl from libdiskfs.

By default, libnetfs does not implement this callback, which,
BTW, makes impossible to trace the translator stack consisting
of libnetfs translators. nsmux not only needs an implementation
of this routine, but also requires customizations in order for
filters to trace translator stacks on real nodes.

2 files changed, 56 insertions, 1 deletions

diff --git a/nsmux.c b/nsmux.c
index 0269f09c7..4c8c50940 100644
--- a/nsmux.c
+++ b/nsmux.c
@@ -1708,7 +1708,52 @@ netfs_node_norefs
 	node_destroy(np);
 	}/*netfs_node_norefs*/
 /*----------------------------------------------------------------------------*/
-
+/*Implements file_get_translator_cntl as described in <hurd/fs.defs>
+	(according to diskfs_S_file_get_translator_cntl)*/
+kern_return_t
+netfs_S_file_get_translator_cntl
+	(
+	struct protid * user,
+	mach_port_t * cntl,
+	mach_msg_type_name_t * cntltype
+	)
+	{
+	/*If the information about the user is missing*/
+	if(!user)
+		return EOPNOTSUPP;
+		
+	error_t err = 0;
+	
+	/*Obtain the node for which we are called*/
+	node_t * np = user->po->np;
+	
+	/*Lock the node*/
+	mutex_lock(&np->lock);
+	
+	/*Check if the user is the owner of this node*/
+	err = fshelp_isowner(&np->nn_stat, user->user);
+	
+	/*If no errors have happened*/
+	if(!err)
+		/*try to fetch the control port*/
+		err = fshelp_fetch_control(&np->transbox, cntl);
+		
+	/*If no errors have occurred, but no port has been returned*/
+	if(!err && (cntl == MACH_PORT_NULL))
+		/*set the error accordingly*/
+		err = ENXIO;
+		
+	/*If no errors have occurred so far*/
+	if(!err)
+		/*set the control port type*/
+		*cntltype = MACH_MSG_TYPE_MOVE_SEND;
+		
+	/*Unlock the node*/
+	mutex_unlock(&np->lock);
+	
+	/*Return the result of operations*/
+	return err;
+	}/*netfs_S_file_get_translator_cntl*/
 /*----------------------------------------------------------------------------*/
 /*Entry point*/
 int
diff --git a/nsmux.h b/nsmux.h
index a38874d68..48b6a5b7b 100644
--- a/nsmux.h
+++ b/nsmux.h
@@ -377,4 +377,14 @@ netfs_node_norefs
 	struct node * np
 	);
 /*----------------------------------------------------------------------------*/
+/*Implements file_get_translator_cntl as described in <hurd/fs.defs>
+	(according to diskfs_S_file_get_translator_cntl)*/
+kern_return_t
+netfs_S_file_get_translator_cntl
+	(
+	struct protid * user,
+	mach_port_t * cntl,
+	mach_msg_type_name_t * cntltype
+	);
+/*----------------------------------------------------------------------------*/
 #endif /*__NSMUX_H__*/