path: root/source4/ntvfs/cifs/vfs_cifs.c

/* 
   Unix SMB/CIFS implementation.

   CIFS-on-CIFS NTVFS filesystem backend

   Copyright (C) Andrew Tridgell 2003
   Copyright (C) James J Myers 2003 <myersjj@samba.org>

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
  this implements a CIFS->CIFS NTVFS filesystem backend. 
  
*/

#include "includes.h"
#include "events.h"
#include "libcli/raw/libcliraw.h"
#include "smb_server/smb_server.h"

/* this is stored in ntvfs_private */
struct cvfs_private {
	struct smbcli_tree *tree;
	struct smbcli_transport *transport;
	struct smbsrv_tcon *tcon;
	BOOL map_generic;
};


/* a structure used to pass information to an async handler */
struct async_info {
	struct smbsrv_request *req;
	void *parms;
};

#define SETUP_PID private->tree->session->pid = SVAL(req->in.hdr, HDR_PID)

/*
  an idle function to cope with messages from the smbd client while 
  waiting for a reply from the server
  this function won't be needed once all of the cifs backend
  and the core of smbd is converted to use async calls
*/
static void idle_func(struct smbcli_transport *transport, void *p_private)
{
	struct cvfs_private *private = p_private;
	int fd = socket_get_fd(private->tcon->smb_conn->connection->socket);

	if (socket_pending(fd)) {
		smbd_process_async(private->tcon->smb_conn);
	}
}

/*
  a handler for oplock break events from the server - these need to be passed
  along to the client
 */
static BOOL oplock_handler(struct smbcli_transport *transport, uint16_t tid, uint16_t fnum, uint8_t level, void *p_private)
{
	struct cvfs_private *private = p_private;
	
	DEBUG(5,("vfs_cifs: sending oplock break level %d for fnum %d\n", level, fnum));
	return req_send_oplock_break(private->tcon, fnum, level);
}

 /*
  a handler for read events on a connection to a backend server
*/
static void cifs_socket_handler(struct event_context *ev, struct fd_event *fde, 
				struct timeval t, uint16_t flags)
{
	struct cvfs_private *private = fde->private;
	struct smbsrv_tcon *tcon = private->tcon;
	
	DEBUG(5,("cifs_socket_handler event on fd %d\n", fde->fd));
	
	if (!smbcli_transport_process(private->transport)) {
		/* the connection to our server is dead */
		talloc_free(tcon);
	}
}

/*
  connect to a share - used when a tree_connect operation comes in.
*/
static NTSTATUS cvfs_connect(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req, const char *sharename)
{
	struct smbsrv_tcon *tcon = req->tcon;
	NTSTATUS status;
	struct cvfs_private *private;
	const char *host, *user, *pass, *domain, *remote_share;

	/* Here we need to determine which server to connect to.
	 * For now we use parametric options, type cifs.
	 * Later we will use security=server and auth_server.c.
	 */
	host = lp_parm_string(req->tcon->service, "cifs", "server");
	user = lp_parm_string(req->tcon->service, "cifs", "user");
	pass = lp_parm_string(req->tcon->service, "cifs", "password");
	domain = lp_parm_string(req->tcon->service, "cifs", "domain");
	remote_share = lp_parm_string(req->tcon->service, "cifs", "share");
	if (!remote_share) {
		remote_share = sharename;
	}

	if (!host || !user || !pass || !domain) {
		DEBUG(1,("CIFS backend: You must supply server, user, password and domain\n"));
		return NT_STATUS_INVALID_PARAMETER;
	}
	
	private = talloc_p(req->tcon, struct cvfs_private);
	if (!private) {
		return NT_STATUS_NO_MEMORY;
	}
	ZERO_STRUCTP(private);

	ntvfs->private_data = private;

	status = smbcli_tree_full_connection(private,
					     &private->tree, 
					     "vfs_cifs",
					     host,
					     0,
					     remote_share, "?????",
					     user, domain,
					     pass);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}

	private->transport = private->tree->session->transport;
	SETUP_PID;
	private->tcon = req->tcon;

	tcon->fs_type = talloc_strdup(tcon, "NTFS");
	tcon->dev_type = talloc_strdup(tcon, "A:");
	
	/* we need to receive oplock break requests from the server */
	smbcli_oplock_handler(private->transport, oplock_handler, private);
	smbcli_transport_idle_handler(private->transport, idle_func, 50000, private);

	private->transport->socket->event.fde->handler = cifs_socket_handler;
	private->transport->socket->event.fde->private = private;

	private->transport->socket->event.ctx = event_context_merge(tcon->smb_conn->connection->event.ctx,
								    private->transport->socket->event.ctx);
	talloc_reference(private, private->transport->socket->event.ctx);
	private->map_generic = lp_parm_bool(req->tcon->service, 
					    "cifs", "mapgeneric", False);

	return NT_STATUS_OK;
}

/*
  disconnect from a share
*/
static NTSTATUS cvfs_disconnect(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_tcon *tcon)
{
	struct cvfs_private *private = ntvfs->private_data;

	talloc_free(private);

	return NT_STATUS_OK;
}

/*
  a handler for simple async replies
  this handler can only be used for functions that don't return any
  parameters (those that just return a status code)
 */
static void async_simple(struct smbcli_request *c_req)
{
	struct async_info *async = c_req->async.private;
	struct smbsrv_request *req = async->req;
	req->async_states->status = smbcli_request_simple_recv(c_req);
	req->async_states->send_fn(req);
}


/* save some typing for the simple functions */
#define ASYNC_RECV_TAIL(io, async_fn) do { \
	if (!c_req) return NT_STATUS_UNSUCCESSFUL; \
	{ \
		struct async_info *async; \
		async = talloc_p(req, struct async_info); \
		if (!async) return NT_STATUS_NO_MEMORY; \
		async->parms = io; \
		async->req = req; \
		c_req->async.private = async; \
	} \
	c_req->async.fn = async_fn; \
	req->async_states->state |= NTVFS_ASYNC_STATE_ASYNC; \
	return NT_STATUS_OK; \
} while (0)

#define SIMPLE_ASYNC_TAIL ASYNC_RECV_TAIL(NULL, async_simple)

/*
  delete a file - the dirtype specifies the file types to include in the search. 
  The name can contain CIFS wildcards, but rarely does (except with OS/2 clients)
*/
static NTSTATUS cvfs_unlink(struct ntvfs_module_context *ntvfs, 
			    struct smbsrv_request *req, struct smb_unlink *unl)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	/* see if the front end will allow us to perform this
	   function asynchronously.  */
	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_unlink(private->tree, unl);
	}

	c_req = smb_raw_unlink_send(private->tree, unl);

	SIMPLE_ASYNC_TAIL;
}

/*
  a handler for async ioctl replies
 */
static void async_ioctl(struct smbcli_request *c_req)
{
	struct async_info *async = c_req->async.private;
	struct smbsrv_request *req = async->req;
	req->async_states->status = smb_raw_ioctl_recv(c_req, req, async->parms);
	req->async_states->send_fn(req);
}

/*
  ioctl interface
*/
static NTSTATUS cvfs_ioctl(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req, union smb_ioctl *io)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	/* see if the front end will allow us to perform this
	   function asynchronously.  */
	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_ioctl(private->tree, req, io);
	}

	c_req = smb_raw_ioctl_send(private->tree, io);

	ASYNC_RECV_TAIL(io, async_ioctl);
}

/*
  check if a directory exists
*/
static NTSTATUS cvfs_chkpath(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req, struct smb_chkpath *cp)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_chkpath(private->tree, cp);
	}

	c_req = smb_raw_chkpath_send(private->tree, cp);

	SIMPLE_ASYNC_TAIL;
}

/*
  a handler for async qpathinfo replies
 */
static void async_qpathinfo(struct smbcli_request *c_req)
{
	struct async_info *async = c_req->async.private;
	struct smbsrv_request *req = async->req;
	req->async_states->status = smb_raw_pathinfo_recv(c_req, req, async->parms);
	req->async_states->send_fn(req);
}

/*
  return info on a pathname
*/
static NTSTATUS cvfs_qpathinfo(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req, union smb_fileinfo *info)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_pathinfo(private->tree, req, info);
	}

	c_req = smb_raw_pathinfo_send(private->tree, info);

	ASYNC_RECV_TAIL(info, async_qpathinfo);
}

/*
  a handler for async qfileinfo replies
 */
static void async_qfileinfo(struct smbcli_request *c_req)
{
	struct async_info *async = c_req->async.private;
	struct smbsrv_request *req = async->req;
	req->async_states->status = smb_raw_fileinfo_recv(c_req, req, async->parms);
	req->async_states->send_fn(req);
}

/*
  query info on a open file
*/
static NTSTATUS cvfs_qfileinfo(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req, union smb_fileinfo *info)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_fileinfo(private->tree, req, info);
	}

	c_req = smb_raw_fileinfo_send(private->tree, info);

	ASYNC_RECV_TAIL(info, async_qfileinfo);
}


/*
  set info on a pathname
*/
static NTSTATUS cvfs_setpathinfo(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req, union smb_setfileinfo *st)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_setpathinfo(private->tree, st);
	}

	c_req = smb_raw_setpathinfo_send(private->tree, st);

	SIMPLE_ASYNC_TAIL;
}


/*
  a handler for async open replies
 */
static void async_open(struct smbcli_request *c_req)
{
	struct async_info *async = c_req->async.private;
	struct smbsrv_request *req = async->req;
	req->async_states->status = smb_raw_open_recv(c_req, req, async->parms);
	req->async_states->send_fn(req);
}

/*
  open a file
*/
static NTSTATUS cvfs_open(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req, union smb_open *io)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	if (io->generic.level != RAW_OPEN_GENERIC &&
	    private->map_generic) {
		return ntvfs_map_open(req, io, ntvfs);
	}

	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_open(private->tree, req, io);
	}

	c_req = smb_raw_open_send(private->tree, io);

	ASYNC_RECV_TAIL(io, async_open);
}

/*
  create a directory
*/
static NTSTATUS cvfs_mkdir(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req, union smb_mkdir *md)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_mkdir(private->tree, md);
	}

	c_req = smb_raw_mkdir_send(private->tree, md);

	SIMPLE_ASYNC_TAIL;
}

/*
  remove a directory
*/
static NTSTATUS cvfs_rmdir(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req, struct smb_rmdir *rd)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_rmdir(private->tree, rd);
	}
	c_req = smb_raw_rmdir_send(private->tree, rd);

	SIMPLE_ASYNC_TAIL;
}

/*
  rename a set of files
*/
static NTSTATUS cvfs_rename(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req, union smb_rename *ren)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_rename(private->tree, ren);
	}

	c_req = smb_raw_rename_send(private->tree, ren);

	SIMPLE_ASYNC_TAIL;
}

/*
  copy a set of files
*/
static NTSTATUS cvfs_copy(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req, struct smb_copy *cp)
{
	return NT_STATUS_NOT_SUPPORTED;
}

/*
  a handler for async read replies
 */
static void async_read(struct smbcli_request *c_req)
{
	struct async_info *async = c_req->async.private;
	struct smbsrv_request *req = async->req;
	req->async_states->status = smb_raw_read_recv(c_req, async->parms);
	req->async_states->send_fn(req);
}

/*
  read from a file
*/
static NTSTATUS cvfs_read(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req, union smb_read *rd)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	if (rd->generic.level != RAW_READ_GENERIC &&
	    private->map_generic) {
		return ntvfs_map_read(req, rd, ntvfs);
	}

	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_read(private->tree, rd);
	}

	c_req = smb_raw_read_send(private->tree, rd);

	ASYNC_RECV_TAIL(rd, async_read);
}

/*
  a handler for async write replies
 */
static void async_write(struct smbcli_request *c_req)
{
	struct async_info *async = c_req->async.private;
	struct smbsrv_request *req = async->req;
	req->async_states->status = smb_raw_write_recv(c_req, async->parms);
	req->async_states->send_fn(req);
}

/*
  write to a file
*/
static NTSTATUS cvfs_write(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req, union smb_write *wr)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	if (wr->generic.level != RAW_WRITE_GENERIC &&
	    private->map_generic) {
		return ntvfs_map_write(req, wr, ntvfs);
	}

	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_write(private->tree, wr);
	}

	c_req = smb_raw_write_send(private->tree, wr);

	ASYNC_RECV_TAIL(wr, async_write);
}

/*
  seek in a file
*/
static NTSTATUS cvfs_seek(struct ntvfs_module_context *ntvfs, 
			  struct smbsrv_request *req, struct smb_seek *io)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_seek(private->tree, io);
	}

	c_req = smb_raw_seek_send(private->tree, io);

	SIMPLE_ASYNC_TAIL;
}

/*
  flush a file
*/
static NTSTATUS cvfs_flush(struct ntvfs_module_context *ntvfs, 
			   struct smbsrv_request *req, struct smb_flush *io)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_flush(private->tree, io);
	}

	c_req = smb_raw_flush_send(private->tree, io);

	SIMPLE_ASYNC_TAIL;
}

/*
  close a file
*/
static NTSTATUS cvfs_close(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req, union smb_close *io)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	if (io->generic.level != RAW_CLOSE_GENERIC &&
	    private->map_generic) {
		return ntvfs_map_close(req, io, ntvfs);
	}

	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_close(private->tree, io);
	}

	c_req = smb_raw_close_send(private->tree, io);

	SIMPLE_ASYNC_TAIL;
}

/*
  exit - closing files open by the pid
*/
static NTSTATUS cvfs_exit(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_exit(private->tree->session);
	}

	c_req = smb_raw_exit_send(private->tree->session);

	SIMPLE_ASYNC_TAIL;
}

/*
  logoff - closing files open by the user
*/
static NTSTATUS cvfs_logoff(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req)
{
	/* we can't do this right in the cifs backend .... */
	return NT_STATUS_OK;
}

/*
  setup for an async call - nothing to do yet
*/
static NTSTATUS cvfs_async_setup(struct ntvfs_module_context *ntvfs, 
				 struct smbsrv_request *req, 
				 void *private)
{
	return NT_STATUS_OK;
}

/*
  cancel an async call
*/
static NTSTATUS cvfs_cancel(struct ntvfs_module_context *ntvfs, 
			    struct smbsrv_request *req)
{
	return NT_STATUS_NOT_IMPLEMENTED;
}

/*
  lock a byte range
*/
static NTSTATUS cvfs_lock(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req, union smb_lock *lck)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	if (lck->generic.level != RAW_LOCK_GENERIC &&
	    private->map_generic) {
		return ntvfs_map_lock(req, lck, ntvfs);
	}

	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_lock(private->tree, lck);
	}

	c_req = smb_raw_lock_send(private->tree, lck);
	SIMPLE_ASYNC_TAIL;
}

/*
  set info on a open file
*/
static NTSTATUS cvfs_setfileinfo(struct ntvfs_module_context *ntvfs, 
				 struct smbsrv_request *req, 
				 union smb_setfileinfo *info)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_setfileinfo(private->tree, info);
	}
	c_req = smb_raw_setfileinfo_send(private->tree, info);

	SIMPLE_ASYNC_TAIL;
}


/*
  a handler for async fsinfo replies
 */
static void async_fsinfo(struct smbcli_request *c_req)
{
	struct async_info *async = c_req->async.private;
	struct smbsrv_request *req = async->req;
	req->async_states->status = smb_raw_fsinfo_recv(c_req, req, async->parms);
	req->async_states->send_fn(req);
}

/*
  return filesystem space info
*/
static NTSTATUS cvfs_fsinfo(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req, union smb_fsinfo *fs)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_fsinfo(private->tree, req, fs);
	}

	c_req = smb_raw_fsinfo_send(private->tree, req, fs);

	ASYNC_RECV_TAIL(fs, async_fsinfo);
}

/*
  return print queue info
*/
static NTSTATUS cvfs_lpq(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req, union smb_lpq *lpq)
{
	return NT_STATUS_NOT_SUPPORTED;
}

/* 
   list files in a directory matching a wildcard pattern
*/
static NTSTATUS cvfs_search_first(struct ntvfs_module_context *ntvfs, 
				  struct smbsrv_request *req, union smb_search_first *io, 
				  void *search_private, 
				  BOOL (*callback)(void *, union smb_search_data *))
{
	struct cvfs_private *private = ntvfs->private_data;

	SETUP_PID;

	return smb_raw_search_first(private->tree, req, io, search_private, callback);
}

/* continue a search */
static NTSTATUS cvfs_search_next(struct ntvfs_module_context *ntvfs, 
				 struct smbsrv_request *req, union smb_search_next *io, 
				 void *search_private, 
				 BOOL (*callback)(void *, union smb_search_data *))
{
	struct cvfs_private *private = ntvfs->private_data;

	SETUP_PID;

	return smb_raw_search_next(private->tree, req, io, search_private, callback);
}

/* close a search */
static NTSTATUS cvfs_search_close(struct ntvfs_module_context *ntvfs, 
				  struct smbsrv_request *req, union smb_search_close *io)
{
	struct cvfs_private *private = ntvfs->private_data;

	SETUP_PID;

	return smb_raw_search_close(private->tree, io);
}

/*
  a handler for async trans2 replies
 */
static void async_trans2(struct smbcli_request *c_req)
{
	struct async_info *async = c_req->async.private;
	struct smbsrv_request *req = async->req;
	req->async_states->status = smb_raw_trans2_recv(c_req, req, async->parms);
	req->async_states->send_fn(req);
}

/* raw trans2 */
static NTSTATUS cvfs_trans2(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req, struct smb_trans2 *trans2)
{
	struct cvfs_private *private = ntvfs->private_data;
	struct smbcli_request *c_req;

	SETUP_PID;

	if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
		return smb_raw_trans2(private->tree, req, trans2);
	}

	c_req = smb_raw_trans2_send(private->tree, trans2);

	ASYNC_RECV_TAIL(trans2, async_trans2);
}


/* SMBtrans - not used on file shares */
static NTSTATUS cvfs_trans(struct ntvfs_module_context *ntvfs, 
				struct smbsrv_request *req, struct smb_trans2 *trans2)
{
	return NT_STATUS_ACCESS_DENIED;
}

/*
  initialise the CIFS->CIFS backend, registering ourselves with the ntvfs subsystem
 */
NTSTATUS ntvfs_cifs_init(void)
{
	NTSTATUS ret;
	struct ntvfs_ops ops;

	ZERO_STRUCT(ops);

	/* fill in the name and type */
	ops.name = "cifs";
	ops.type = NTVFS_DISK;
	
	/* fill in all the operations */
	ops.connect = cvfs_connect;
	ops.disconnect = cvfs_disconnect;
	ops.unlink = cvfs_unlink;
	ops.chkpath = cvfs_chkpath;
	ops.qpathinfo = cvfs_qpathinfo;
	ops.setpathinfo = cvfs_setpathinfo;
	ops.openfile = cvfs_open;
	ops.mkdir = cvfs_mkdir;
	ops.rmdir = cvfs_rmdir;
	ops.rename = cvfs_rename;
	ops.copy = cvfs_copy;
	ops.ioctl = cvfs_ioctl;
	ops.read = cvfs_read;
	ops.write = cvfs_write;
	ops.seek = cvfs_seek;
	ops.flush = cvfs_flush;	
	ops.close = cvfs_close;
	ops.exit = cvfs_exit;
	ops.lock = cvfs_lock;
	ops.setfileinfo = cvfs_setfileinfo;
	ops.qfileinfo = cvfs_qfileinfo;
	ops.fsinfo = cvfs_fsinfo;
	ops.lpq = cvfs_lpq;
	ops.search_first = cvfs_search_first;
	ops.search_next = cvfs_search_next;
	ops.search_close = cvfs_search_close;
	ops.trans = cvfs_trans;
	ops.logoff = cvfs_logoff;
	ops.async_setup = cvfs_async_setup;
	ops.cancel = cvfs_cancel;

	if (lp_parm_bool(-1, "cifs", "maptrans2", False)) {
		ops.trans2 = cvfs_trans2;
	}

	/* register ourselves with the NTVFS subsystem. We register
	   under the name 'cifs'. */
	ret = ntvfs_register(&ops);

	if (!NT_STATUS_IS_OK(ret)) {
		DEBUG(0,("Failed to register CIFS backend!\n"));
	}
	
	return ret;
}