Re: [PATCH v3 11/11] selftests: error out if kernel header files are not yet built

[Muhammad Usama Anjum <usama.anjum@collabora.com>]

On 6/6/23 12:16 PM, John Hubbard wrote:
> As per a discussion with Muhammad Usama Anjum [1], the following is how
> one is supposed to build selftests:
> 
>     make headers && make -C tools/testing/selftests/mm
> 
> Change the selftest build system's lib.mk to fail out with a helpful
> message if that prerequisite "make headers" has not been done yet.
> 
> [1] https://lore.kernel.org/all/bf910fa5-0c96-3707-cce4-5bcc656b6274@collabora.com/
> 
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Peter Xu <peterx@redhat.com>
> Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
> Cc: Jonathan Corbet <corbet@lwn.net>
> Cc: linux-doc@vger.kernel.org
> Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>

> ---
>  tools/testing/selftests/lib.mk | 36 +++++++++++++++++++++++++++++++---
>  1 file changed, 33 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/testing/selftests/lib.mk b/tools/testing/selftests/lib.mk
> index 05400462c779..b8ea03b9a015 100644
> --- a/tools/testing/selftests/lib.mk
> +++ b/tools/testing/selftests/lib.mk
> @@ -44,10 +44,22 @@ endif
>  selfdir = $(realpath $(dir $(filter %/lib.mk,$(MAKEFILE_LIST))))
>  top_srcdir = $(selfdir)/../../..
>  
> -ifeq ($(KHDR_INCLUDES),)
> -KHDR_INCLUDES := -isystem $(top_srcdir)/usr/include
> +ifneq ($(KBUILD_OUTPUT),)
> +  # Make's built-in functions such as $(abspath ...), $(realpath ...) cannot
> +  # expand a shell special character '~'. We use a somewhat tedious way here.
> +  abs_objtree := $(shell cd $(top_srcdir) && mkdir -p $(KBUILD_OUTPUT) && cd $(KBUILD_OUTPUT) && pwd)
> +  $(if $(abs_objtree),, \
> +    $(error failed to create output directory "$(KBUILD_OUTPUT)"))
> +  # $(realpath ...) resolves symlinks
> +  abs_objtree := $(realpath $(abs_objtree))
> +  KHDR_DIR := ${abs_objtree}/usr/include
> +else
> +  abs_srctree := $(shell cd $(top_srcdir) && pwd)
> +  KHDR_DIR := ${abs_srctree}/usr/include
>  endif
>  
> +KHDR_INCLUDES := -isystem $(KHDR_DIR)
> +
>  # The following are built by lib.mk common compile rules.
>  # TEST_CUSTOM_PROGS should be used by tests that require
>  # custom build rule and prevent common build rule use.
> @@ -58,7 +70,25 @@ TEST_GEN_PROGS := $(patsubst %,$(OUTPUT)/%,$(TEST_GEN_PROGS))
>  TEST_GEN_PROGS_EXTENDED := $(patsubst %,$(OUTPUT)/%,$(TEST_GEN_PROGS_EXTENDED))
>  TEST_GEN_FILES := $(patsubst %,$(OUTPUT)/%,$(TEST_GEN_FILES))
>  
> -all: $(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED) $(TEST_GEN_FILES)
> +all: kernel_header_files $(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED) \
> +     $(TEST_GEN_FILES)
> +
> +kernel_header_files:
> +	@ls $(KHDR_DIR)/linux/*.h >/dev/null 2>/dev/null;                      \
> +	if [ $$? -ne 0 ]; then                                                 \
> +            RED='\033[1;31m';                                                  \
> +            NOCOLOR='\033[0m';                                                 \
> +            echo;                                                              \
> +            echo -e "$${RED}error$${NOCOLOR}: missing kernel header files.";   \
> +            echo "Please run this and try again:";                             \
> +            echo;                                                              \
> +            echo "    cd $(top_srcdir)";                                       \
> +            echo "    make headers";                                           \
> +            echo;                                                              \
> +	    exit 1; \
> +	fi
> +
> +.PHONY: kernel_header_files
>  
>  define RUN_TESTS
>  	BASE_DIR="$(selfdir)";			\

-- 
BR,
Muhammad Usama Anjum