Re: [PATCH] kbuild: avoid scripts/kallsyms parsing /dev/null

[Daniel Gomez]

On Thu, Aug 08, 2024 at 03:03:00AM GMT, Masahiro Yamada wrote:
> On macOS, getline() sets ENOTTY to errno if it is requested to read
> from /dev/null.
> 
> If this is worth fixing, I would rather pass an empty file to
> scripts/kallsyms instead of adding the ugly #ifdef __APPLE__.
> 
> Fixes: c442db3f49f2 ("kbuild: remove PROVIDE() for kallsyms symbols")
> Reported-by: Daniel Gomez <da.gomez@xxxxxxxxxxx>
> Closes: https://lore.kernel.org/all/20240807-macos-build-support-v1-12-4cd1ded85694@xxxxxxxxxxx/
> Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
> ---
> 
>  scripts/link-vmlinux.sh | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
> index f7b2503cdba9..41c68ae3415d 100755
> --- a/scripts/link-vmlinux.sh
> +++ b/scripts/link-vmlinux.sh
> @@ -219,7 +219,8 @@ kallsymso=
>  strip_debug=
>  
>  if is_enabled CONFIG_KALLSYMS; then
> -	kallsyms /dev/null .tmp_vmlinux0.kallsyms
> +	truncate -s0 .tmp_vmlinux.kallsyms0.syms

This looks nicer. Thanks for a quick alternative!

I prefer self explained commands and use the larger argument if available:
	truncate --size=0 .tmp_vmlinux.kallsyms0.syms

But other than that, LGTM.

Reviewed-by: Daniel Gomez <da.gomez@xxxxxxxxxxx>

> +	kallsyms .tmp_vmlinux.kallsyms0.syms .tmp_vmlinux0.kallsyms
>  fi
>  
>  if is_enabled CONFIG_KALLSYMS || is_enabled CONFIG_DEBUG_INFO_BTF; then
> -- 
> 2.43.0
>