vfs_streams_xattr: stream name prefix and type suffix

[Volker Lendecke]

On Wed, May 21, 2014 at 01:47:53PM +0200, Ralph Böhme wrote:
> With the patches applied, adding the following to smb.conf
> 
>       streams_xattr:prefix = user.
>       streams_xattr:store_stream_type = no
> 
> gives the desired behaviour.
> 
> Thoughts?

The idea sounds good.

> >From 066fcf3c5bb414b84a349a1a5fda07e3e0308593 Mon Sep 17 00:00:00 2001
> From: Ralph Boehme <rb at sernet.de>
> Date: Wed, 21 May 2014 11:52:27 +0200
> Subject: [PATCH 1/2] Convert samba_private_attr_name() to a public function
> 
> Signed-off-by: Ralph Boehme <rb at sernet.de>
> ---
>  source3/modules/vfs_streams_xattr.c | 3 +++
>  source3/smbd/proto.h                | 1 +
>  source3/smbd/trans2.c               | 2 +-
>  3 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/source3/modules/vfs_streams_xattr.c b/source3/modules/vfs_streams_xattr.c
> index 5e9bd3e..5ff4f82 100644
> --- a/source3/modules/vfs_streams_xattr.c
> +++ b/source3/modules/vfs_streams_xattr.c
> @@ -674,6 +674,9 @@ static NTSTATUS walk_xattr_streams(connection_struct *conn, files_struct *fsp,
>  			    prefix_len) != 0) {
>  			continue;
>  		}
> +		if (samba_private_attr_name(names[i])) {
> +			continue;
> +		}

This hunk is a bit more than is explained in the commit
message. Can you expand the message a bit with something
like ... in preparation of ... or split this into a separate
patch?

>  	if (stype == NULL) {
>  		/* Append an explicit stream type if one wasn't specified. */
> -		*xattr_name = talloc_asprintf(ctx, "%s:$DATA",
> -					       *xattr_name);
> +		*xattr_name = talloc_asprintf(ctx, "%s%s",
> +					      *xattr_name,
> +					      config->store_stream_type ? ":$DATA" : "");

Stylistic comment: Here I would do something like

	if ((stype == NULL) && (config->store_stream_type != NULL))

and just not do the talloc_asprintf in the NULL case.

> +static int streams_xattr_connect(vfs_handle_struct *handle, const char *service, const char *user)
> +{
> +	struct streams_xattr_config *config;
> +	const char *default_prefix = SAMBA_XATTR_DOSSTREAM_PREFIX;
> +	const char **prefix;
> +
> +	config = talloc_zero(handle->conn, struct streams_xattr_config);
> +	if (!config) {
> +		DEBUG(1, ("talloc_zero() failed\n"));
> +		errno = ENOMEM;
> +		return -1;
> +	}
> +
> +	prefix = lp_parm_string_list(SNUM(handle->conn),
> +				     "streams_xattr", "prefix",
> +				     &default_prefix);
> +	if (prefix) {
> +		config->prefix = *prefix;

Does this maintain the correct talloc hierarchy? Isn't
*prefix gone after the next tevent round with
talloc_free(frame)?

Volker

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