[PATCH 2/4] tests: Fix mock chaining on macOS

[Michal Privoznik]

On 11/8/20 10:24 PM, Roman Bolshakov wrote:
> Some tests in qemuxml2argvtest need opendir() from virpcimock, others
> need opendir() from virfilewrapper.
> 
> But as of now, only opendir() from virpcimock has an effect.
> real_opendir in virpcimock has a pointer to opendir$INODE64 in
> libsystem_kernel.dylib instead of pointing to opendir$INODE64 in
> qemuxml2argvtest (from virfilewrapper). And because the second one is
> never used, tests that rely on prefixes added by virFileWrapperAddPrefix
> fail.
> 
> That can be fixed if dlsym(3) is asked explicitly to search symbols in
> main executable with RTLD_MAIN_ONLY before going to other dylibs.
> Existing RTLD_NEXT handle results into libsystem_kernel.dylib being
> searched before main executable.
> 
> Signed-off-by: Roman Bolshakov <r.bolshakov at yadro.com>
> ---
>   tests/virmock.h    | 37 +++++++++++++++++++++++++++++++++++--
>   tests/virpcimock.c |  1 +
>   2 files changed, 36 insertions(+), 2 deletions(-)
> 
> diff --git a/tests/virmock.h b/tests/virmock.h
> index dea5feb80f..db051f3636 100644
> --- a/tests/virmock.h
> +++ b/tests/virmock.h
> @@ -284,8 +284,19 @@
>       static void (*real_##name)(void); \
>       void wrap_##name(void)
>   
> +#ifdef __APPLE__
> +# define VIR_MOCK_REAL_INIT_MAIN(name, alias) \
> +    do { \
> +        if (real_##name == NULL) { \
> +            real_##name = dlsym(RTLD_MAIN_ONLY, alias); \
> +        } \
> +    } while (0)
> +#else
> +# define VIR_MOCK_REAL_INIT_MAIN(name, alias) \
> +    do {} while (0)
> +#endif
>   
> -#define VIR_MOCK_REAL_INIT(name) \
> +#define VIR_MOCK_REAL_INIT_NEXT(name) \
>       do { \
>           if (real_##name == NULL && \
>               !(real_##name = dlsym(RTLD_NEXT, \
> @@ -295,7 +306,7 @@
>           } \
>       } while (0)
>   
> -#define VIR_MOCK_REAL_INIT_ALIASED(name, alias) \
> +#define VIR_MOCK_REAL_INIT_ALIASED_NEXT(name, alias) \
>       do { \
>           if (real_##name == NULL && \
>               !(real_##name = dlsym(RTLD_NEXT, \
> @@ -304,3 +315,25 @@
>               abort(); \
>           } \
>       } while (0)
> +
> +#ifdef VIR_MOCK_LOOKUP_MAIN

I think we can do this even without this macro. If the 
VIR_MOCK_LOOKUP_MAIN macro is not defined then we are still guarded by 
VIR_MOCK_REAL_INIT_MAIN() being a NOP on !__APPLE__. Also ..

> +# define VIR_MOCK_REAL_INIT(name) \
> +    do { \
> +        VIR_MOCK_REAL_INIT_MAIN(name, #name); \
> +        VIR_MOCK_REAL_INIT_NEXT(name); \
> +    } while (0)
> +# define VIR_MOCK_REAL_INIT_ALIASED(name, alias) \
> +    do { \
> +        VIR_MOCK_REAL_INIT_MAIN(name, alias); \
> +        VIR_MOCK_REAL_INIT_ALIASED_NEXT(name, alias); \
> +    } while (0)
> +#else
> +# define VIR_MOCK_REAL_INIT(name) \
> +    do { \
> +        VIR_MOCK_REAL_INIT_NEXT(name); \
> +    } while (0)
> +# define VIR_MOCK_REAL_INIT_ALIASED(name, alias) \
> +    do { \
> +        VIR_MOCK_REAL_INIT_ALIASED_NEXT(name, alias); \
> +    } while (0)
> +#endif
> diff --git a/tests/virpcimock.c b/tests/virpcimock.c
> index 686f894e99..4aa96cae08 100644
> --- a/tests/virpcimock.c
> +++ b/tests/virpcimock.c
> @@ -19,6 +19,7 @@
>   #include <config.h>
>   
>   #if defined(__linux__) || defined(__FreeBSD__) || defined(__APPLE__)
> +# define VIR_MOCK_LOOKUP_MAIN

.. it feels a bit odd that this is defined for virpcimock only.

Michal