Re: [Libguestfs] [PATCH] Report last-modified time of hive root and nodes
On Aug 10, 2011, at 11:19 , Richard W.M. Jones wrote:
On Wed, Aug 10, 2011 at 11:03:21AM -0700, Alex Nelson wrote:
> The reason for this change was to expose some of the handle's
> fields. I wasn't sure how to detect being at the root node.
From the public API you can use:
hive_node_h some_node = ...;
if (some_node == hivex_root (h)) {
// you're at the root node
}
Looks good, I'll use that. It looks like it'd be quicker to just query
h->rootoffs if within lib/hivex.c, but I'll stick with the API.
> It also looked like a good place to stash the last-modified time of
> the root node. With your ABI suggestions below, I think I have a
> better way that doesn't muck with the handle structure.
Stashing the last-modified time in the handle may be a good idea, but
the handle structure doesn't have to be public to do this. When
writing or changing the library (ie. in lib/hivex.c) you already have
access to the internal structure of struct hive_h.
> Thank you, I'll adjust my changes to use differently-named
> functions. Is it acceptable style to you to have these become
> Java-like wrapper functions, e.g.:
>
> static int
> node_start_with_time (hive_h *h, void *writer_v, hive_node_h node, const char *name,
const char *last_modified)
> {
> //Body: the node_start function as it is now, augmented with null-checking work on
last_modified
> }
>
> static int
> node_start (hive_h *h, void *writer_v, hive_node_h node, const char *name, const char
*last_modified)
> {
> return node_start_with_time (h, write_v, node, name, NULL);
> }
>
> This preserves the C ABI, and prevents code duplication.
I'm not entirely sure what you mean here. Functions like 'node_start'
are defined by the caller of the hivex API, and so have nothing to do
with the implementation. To make this clearer: xml/hivexml.c is a
caller of the public API, while lib/hivex.c is the internal
implementation of the API.
I apologize, I was unclear on where these functions
were. I meant the node_start within xml/hivexml.c. Fortunately, I've managed to make
the time changes without modifying the API, so the point here is moot. However, for the
changeset that adds data offsets, I've tried adding a few additional arguments to API
functions (hivex_value_*) so I could record data offsets and lengths, and then pass those
offsets and lengths to the visitor functions. This will probably be better explained with
a patch, I'll try to get that to you very soon.
--Alex
If you mean using node_start_with_time instead of node_start2, then
yes that's a better name.
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
libguestfs lets you edit virtual machines. Supports shell scripting,
bindings from many languages. http://libguestfs.org