| Subject | Re: [PATCH 04/64] stddef: Introduce struct_group() helper macro | From | Rasmus Villemoes <> | Date | Wed, 28 Jul 2021 12:54:18 +0200 |
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On 27/07/2021 22.57, Kees Cook wrote:
> In order to have a regular programmatic way to describe a struct > region that can be used for references and sizing, can be examined for > bounds checking, avoids forcing the use of intermediate identifiers, > and avoids polluting the global namespace, introduce the struct_group() > macro. This macro wraps the member declarations to create an anonymous > union of an anonymous struct (no intermediate name) and a named struct > (for references and sizing): > > struct foo { > int one; > struct_group(thing, > int two, > int three, > ); > int four; > };
That example won't compile, the commas after two and three should be semicolons.
And your implementation relies on MEMBERS not containing any comma tokens, but as
int a, b, c, d;
is a valid way to declare multiple members, consider making MEMBERS variadic
#define struct_group(NAME, MEMBERS...)
to have it slurp up every subsequent argument and make that work.
> > Co-developed-by: Keith Packard <keithpac@amazon.com> > Signed-off-by: Keith Packard <keithpac@amazon.com> > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > include/linux/stddef.h | 34 ++++++++++++++++++++++++++++++++++
Bikeshedding a bit, but do we need to add 34 lines that need to be preprocessed to virtually each and every translation unit [as opposed to adding a struct_group.h header]? Oh well, you need it for struct skbuff.h, so it would be pulled in by a lot regardless :(
Rasmus
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