Re: [PATCH v5 02/11] tools: mkeficapsule: add firmwware image signing

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

Hi Mark,

On Thu, Nov 04, 2021 at 03:31:40PM +0100, Mark Kettenis wrote:
> > From: Simon Glass <sjg@chromium.org>
> > Date: Wed, 3 Nov 2021 20:51:25 -0600
> > 
> > Hi Mark,
> > 
> > On Tue, 2 Nov 2021 at 09:13, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
> > >
> > > > From: Simon Glass <sjg@chromium.org>
> > > > Date: Tue, 2 Nov 2021 08:56:50 -0600
> > > >
> > > > Hi Takahiro,
> > > >
> > > > > > - can we just build the tool always?
> > > > >
> > > > > This is one of my questions.
> > > > > Why do you want to do so while there are bunch of tools that are
> > > > > not always built.
> > > >
> > > > Because I think all tools should be built always. It is fine if that
> > > > happens due to CONFIG options but we should try to avoid making it
> > > > complicated.
> > >
> > > Well, unless this patchset fixes things, we can't, because
> > > mkeficapsule doesn't build on OpenBSD.  I tried looking into it, but I
> > > can't figure out how this is even supposed to compile as a host tool:
> > >
> > >
> > > In file included from tools/mkeficapsule.c:8:
> > > In file included from include/malloc.h:369:
> > > include/linux/string.h:15:24: error: conflicting types for 'strspn'
> > > extern __kernel_size_t strspn(const char *,const char *);
> > >                        ^
> > > /usr/include/string.h:88:9: note: previous declaration is here
> > > size_t   strspn(const char *, const char *);
> > 
> > My guess is that linux/string.h should not be included, or perhaps
> > __kernel_size_t should be defined to size_t.
> > 
> > I doubt it would take an age to figure out, with a bit of fiddling.
> 
> Well, I think the problem is quite fundamental.  Indeed I agree that
> linux/string.h shouldn't be included.  It gets pulled in because the
> tools include <malloc.h>.  Modern software really shouldn't include
> that header anymore, and we removed it in OpenBSD some time ago.  But
> even with that fixed, things break since the same header gets pulled
> in from <efi.h>.
> 
> Redefining __kernel_size_t doesn't provide a way out:
> 
> tools/mkeficapsule.c:23:16: error: typedef redefinition with different types ('size_t' (aka 'unsigned long') vs 'unsigned int')
> typedef size_t __kernel_size_t;
>                ^
> ./arch/arm/include/asm/posix_types.h:37:23: note: previous definition is here
> typedef unsigned int            __kernel_size_t;
> 	                                       ^
> 					       
> This is on an amd64 host, so "unsigned int" clearly is the wrong type
> for size_t.
> 
> The fundamental problem seems to be that <efi.h> isn't safe to include
> in a "host" tool because it includes "target" headers that
> accidentally resolve to "system" headers on Linux systems.
> 
> Maybe Takahiro or Heinrich have an idea how to fix that?  But in the
> meantime it would be good if building this tool would remain optional.

Please let me confirm one thing; you can't build this tool even
without my patch applied. Right?
If so, we may want to discuss and figure out a solution after the patch is
merged as long as the tool won't be built neither by Kconfig default nor
by tools-only_defconfig.

-Takahiro Akashi