Re: [Libguestfs] [PATCH] Report last-modified time of hive root and nodes
On Aug 10, 2011, at 02:44 , Richard W.M. Jones wrote:
On Tue, Aug 09, 2011 at 09:54:40PM -0700, Alex Nelson wrote:
> The infrastructure for modified-time reporting has been essentially
> unused. These changes report the registry time by treating the
> time fields as Windows filetime fields stored in little-Endian
> (which means they can be treated as a single 64-bit little-Endian
> integer). Some of the code changes necessary include:
>
> * Exposing the hive_h structure in the hivex header file (via
> generator.ml)
You can't make the hive_h internal structure visible in the header
file. I don't understand why you'd want callers to be delving into
the internals of the handle anyway. What's the reason for this
change?
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. 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.
> * Adding an additional argument to the node_start function, which
> should cause no complications since the change is specific to the
> C API.
This is a change to the C ABI, which is not allowed. Instead:
Add a new node_start field to the hivex_visitor struct. (Obviously
call it something different, like node_start2 or whatever, and it has
to be added to the end of the current struct).
In the code you can differentiate between whether the caller supplied
the old function or the new function:
if (vtor->node_start2) {
// call new vtor->node_start2 with extra argument
} else if (vtor->node_start) {
// call old vtor->node_start
}
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.
The last_modified changes in themselves seem quite reasonable to me,
but this patch cannot be applied as-is.
I should have patch version 2 out soon. Thanks!
--Alex
Rich.