Developing a VFS module [english checked and now better]

Julien Thomas omnikron at
Wed May 4 11:39:31 GMT 2005

Jeremy Allison wrote:

>>From conn->snum call lp_servicename(conn->snum).


With the help of Marek Grác, I succeed to store data using handle->data. 
I store it in the CONNECT VFS operation and so, I am able to get it in 
the DISCONNECT VFS operation.

Here the next message I post him, you could give your opinion. In 
particular, I have a question about the build of the module.

Marek Grác wrote:

> Salut,
> Ok, so you have to write your own pc_data (my own struct 
> firefs_per_connection) and then use
> SMB_VFS_HANDLE_GET_DATA(handle, pc_data, firefs_per_connection, return);
> SMB_VFS_HANDLE_SET_DATA(handle, pc_data, NULL, firefs_per_connection, 
> return -1);
> Using this method you can pass values to every operation. I used it to 
> pass database handlers and configuration options.
> PS: Be patient next time :) There is hockey championship so I'm not 
> online everyday

Thanks a lot !!
That was the good way !

Here is what I done. Tell me if I should use SMB_VFS_HANDLE_GET/SET_DATA 
macros instead of :

static int inra_connect(vfs_handle_struct *handle,
            connection_struct *conn,
            const char *service,
            const char *user)
  int result;
  result = SMB_VFS_NEXT_CONNECT(handle, conn, service, user);
  handle->data = (void *) malloc(sizeof(fstring));
  fstr_sprintf(handle->data, "%s", service);
  return result;

And so I can get back "service" on disconnection events :

static void inra_disconnect(vfs_handle_struct *handle,
               connection_struct *conn)
  char *service;
  SMB_VFS_NEXT_DISCONNECT(handle, conn);
  service = (char *)handle->data

It is dangerous to store data like this ? Should I use the macros 
functions ?

I have another question... I can't build my module himself. I have to 
use Samba's sources Makefile and update it to deal with my module. So I 
put it (the module) in sources/vfs and it is built as an .so in 

I tryed the example provided with a configure/autogen and co in 
example/VFS... The module build fine but is not usable. Samba's log 
report that it is not found (same if I put the complete path in 
smb.conf). I think it should be better for my use to buil it 
staticaly... but I don't know well how to build (static or shared).

Thanks a lot Marek,

Julien Thomas

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