Re: [PATCH bpf-next 2/4] security: Generate a header with the count of enabled LSMs

[Kees Cook <keescook@xxxxxxxxxxxx>]

On Fri, Jan 20, 2023 at 10:35:02AM -0800, Kui-Feng Lee wrote:
> The following idea should work with the use case here.
> 
> #define COUNT_8(x, y...) 8
> #define COUNT_7(x, y...) 7
> #define COUNT_6(x, y...) 6
> #define COUNT_5(x, y...) 5
> #define COUNT_4(x, y...) 4
> #define COUNT_3(x, y...) 3
> #define COUNT_2(x, y...) 2
> #define COUNT_1(x, y...) 1
> #define COUNT_0(x, y...) 0
> #define COUNT1_8(x, y...) COUNT ## x ## _9(y)
> #define COUNT1_7(x, y...) COUNT ## x ## _8(y)
> #define COUNT1_6(x, y...) COUNT ## x ## _7(y)
> #define COUNT1_5(x, y...) COUNT ## x ## _6(y)
> #define COUNT1_4(x, y...) COUNT ## x ## _5(y)
> #define COUNT1_3(x, y...) COUNT ## x ## _4(y)
> #define COUNT1_2(x, y...) COUNT ## x ## _3(y)
> #define COUNT1_1(x, y...) COUNT ## x ## _2(y)
> #define COUNT1_0(x, y...) COUNT ## x ## _1(y)
> #define COUNT(x, y...) COUNT ## x ## _0(y)
> 
> #define COUNT_EXPAND(x...) COUNT(x)
> 
> 
> #if IS_ENABLED(CONFIG_SECURITY_SELINUX)
> #define SELINUX_ENABLE 1,
> #else
> #define SELINUX_ENABLE
> #endif
> #if IS_ENABLED(CONFIG_SECURITY_XXXX)
> #define XXX_ENABLE 1,
> #else
> #define XXX_ENABLE
> #endif
> ....
> 
> #define MAX_LSM_COUNT COUNT_EXPAND(SELINUX_ENABLE XXX_ENABLE ......)

Oh, I love it! :) Yup, that should do it nicely.

-- 
Kees Cook