update(build): use elftoolchain/libelf from fork instead of elfutils/…

…libelf

Signed-off-by: Luca Guerra <[email protected]>

CMakeLists.txt

@@ -121,6 +121,8 @@ if(BUILD_SHARED_LIBS)
 	message(STATUS "Shared library soversion: ${FALCOSECURITY_SHARED_LIBS_SOVERSION}")
 endif()
 
+include(libelf)
+
 include(libscap)
 include(libsinsp)
 

cmake/modules/libbpf.cmake

@@ -13,52 +13,51 @@
 # the License.
 #
 
-option(USE_BUNDLED_LIBBPF "Enable building of the bundled libbpf" ${USE_BUNDLED_DEPS})
-
 if(LIBBPF_INCLUDE)
 	# we already have libbpf
-elseif(NOT USE_BUNDLED_LIBBPF)
-	find_path(LIBBPF_INCLUDE bpf/libbpf.h)
-	find_library(LIBBPF_LIB NAMES bpf)
-	if(LIBBPF_INCLUDE AND LIBBPF_LIB)
-		message(STATUS "Found libbpf: include: ${LIBBPF_INCLUDE}, lib: ${LIBBPF_LIB}")
-	else()
-		message(FATAL_ERROR "Couldn't find system libbpf")
-	endif()
 else()
 	include(zlib)
-	include(libelf)
+	include(FetchContent)
+	FetchContent_MakeAvailable(libelf)
 	set(LIBBPF_SRC "${PROJECT_BINARY_DIR}/libbpf-prefix/src")
 	set(LIBBPF_BUILD_DIR "${LIBBPF_SRC}/libbpf-build")
 	set(LIBBPF_INCLUDE "${LIBBPF_BUILD_DIR}/root/usr/include")
 	set(LIBBPF_LIB "${LIBBPF_BUILD_DIR}/root/usr/lib64/libbpf.a")
+
+	get_target_property(LIBELF_INCLUDE_DIR elf INCLUDE_DIRECTORIES)
+
+	foreach(dir ${LIBELF_INCLUDE_DIR})
+		string(APPEND LIBELF_COMPILER_STRING "-I${dir} ")
+	endforeach()
+
 	ExternalProject_Add(
 		libbpf
 		PREFIX "${PROJECT_BINARY_DIR}/libbpf-prefix"
-		DEPENDS zlib libelf
+		DEPENDS zlib elf
 		URL "https://github.com/libbpf/libbpf/archive/refs/tags/v1.3.0.tar.gz"
 		URL_HASH "SHA256=11db86acd627e468bc48b7258c1130aba41a12c4d364f78e184fd2f5a913d861"
 		CONFIGURE_COMMAND mkdir -p build root
 		BUILD_COMMAND
 			make BUILD_STATIC_ONLY=y OBJDIR=${LIBBPF_BUILD_DIR}/build
 			DESTDIR=${LIBBPF_BUILD_DIR}/root NO_PKG_CONFIG=1
-			"EXTRA_CFLAGS=-fPIC -I${LIBELF_INCLUDE} -I${ZLIB_INCLUDE}" "LDFLAGS=-Wl,-Bstatic"
+			"EXTRA_CFLAGS=-fPIC ${LIBELF_COMPILER_STRING} -I${ZLIB_INCLUDE}" "LDFLAGS=-Wl,-Bstatic"
 			"EXTRA_LDFLAGS=-L${LIBELF_SRC}/libelf/libelf -L${ZLIB_SRC}" -C ${LIBBPF_SRC}/libbpf/src
 			install install_uapi_headers
 		INSTALL_COMMAND ""
 		UPDATE_COMMAND ""
 		BUILD_BYPRODUCTS ${LIBBPF_LIB}
 	)
+
+	add_library(lbpf STATIC IMPORTED)
+	set_target_properties(lbpf PROPERTIES IMPORTED_LOCATION ${LIBBPF_LIB})
+	file(MAKE_DIRECTORY ${LIBBPF_INCLUDE}) # necessary to make target_include_directories() work
+	target_include_directories(lbpf INTERFACE ${LIBBPF_INCLUDE})
+	target_link_libraries(lbpf INTERFACE elf ${ZLIB_LIB})
+
 	message(STATUS "Using bundled libbpf: include'${LIBBPF_INCLUDE}', lib: ${LIBBPF_LIB}")
 	install(
 		FILES "${LIBBPF_LIB}"
 		DESTINATION "${CMAKE_INSTALL_LIBDIR}/${LIBS_PACKAGE_NAME}"
 		COMPONENT "libs-deps"
 	)
 endif()
-
-if(NOT TARGET libbpf)
-	add_custom_target(libbpf)
-endif()
-
-include_directories(${LIBBPF_INCLUDE})

cmake/modules/libelf.cmake

@@ -13,86 +13,10 @@
 # the License.
 #
 
-option(USE_BUNDLED_LIBELF "Enable building of the bundled libelf" ${USE_BUNDLED_DEPS})
-option(USE_SHARED_LIBELF "When not using bundled libelf, link it dynamically" ON)
+include(FetchContent)
 
-if(LIBELF_INCLUDE)
-	# we already have LIBELF
-elseif(NOT USE_BUNDLED_LIBELF)
-	find_path(LIBELF_INCLUDE elf.h PATH_SUFFIXES elf)
-	if(BUILD_SHARED_LIBS OR USE_SHARED_LIBELF)
-		set(LIBELF_LIB_SUFFIX ${CMAKE_SHARED_LIBRARY_SUFFIX})
-	else()
-		set(LIBELF_LIB_SUFFIX ${CMAKE_STATIC_LIBRARY_SUFFIX})
-	endif()
-	# Zig workaround: since it won't look up in /usr/lib/..., add an HINT
-	if(CMAKE_C_COMPILER MATCHES "zig")
-		find_library(
-			LIBELF_LIB
-			NAMES libelf${LIBELF_LIB_SUFFIX}
-			HINTS /usr/lib/${CMAKE_SYSTEM_PROCESSOR}-linux-gnu/
-		)
-	else()
-		find_library(LIBELF_LIB NAMES libelf${LIBELF_LIB_SUFFIX})
-	endif()
-	if(LIBELF_LIB)
-		# Zig workaround: avoid include whole /usr/include because it would include also system
-		# glibc headers breaking the build since we are targeting the build against our boostrapped
-		# zig.
-		if(CMAKE_C_COMPILER MATCHES "zig")
-			message(STATUS "Enabling zig workaround for libelf")
-			configure_file(${LIBELF_INCLUDE}/libelf.h libelf/libelf.h COPYONLY)
-			configure_file(${LIBELF_INCLUDE}/elf.h libelf/elf.h COPYONLY)
-			configure_file(${LIBELF_INCLUDE}/gelf.h libelf/gelf.h COPYONLY)
-			set(LIBELF_INCLUDE ${CMAKE_CURRENT_BINARY_DIR}/libelf)
-		endif()
-		message(STATUS "Found LIBELF: include: ${LIBELF_INCLUDE}, lib: ${LIBELF_LIB}")
-	else()
-		message(FATAL_ERROR "Couldn't find system libelf")
-	endif()
-else()
-	if(BUILD_SHARED_LIBS)
-		set(LIBELF_LIB_SUFFIX ${CMAKE_SHARED_LIBRARY_SUFFIX})
-	else()
-		set(LIBELF_LIB_SUFFIX ${CMAKE_STATIC_LIBRARY_SUFFIX})
-	endif()
-	set(LIBELF_CFLAGS "-I${ZLIB_INCLUDE}")
-	if(ENABLE_PIC)
-		set(LIBELF_CFLAGS "${LIBELF_CFLAGS} -fPIC")
-	endif()
-	get_filename_component(ZLIB_SRC ${ZLIB_LIB} DIRECTORY)
-	set(LIBELF_SRC "${PROJECT_BINARY_DIR}/libelf-prefix/src")
-	set(LIBELF_INCLUDE "${LIBELF_SRC}/libelf/libelf")
-	set(LIBELF_LIB "${LIBELF_SRC}/libelf/libelf/libelf${LIBELF_LIB_SUFFIX}")
-	ExternalProject_Add(
-		libelf
-		PREFIX "${PROJECT_BINARY_DIR}/libelf-prefix"
-		DEPENDS zlib
-		URL "https://sourceware.org/elfutils/ftp/0.189/elfutils-0.189.tar.bz2"
-		URL_HASH "SHA256=39bd8f1a338e2b7cd4abc3ff11a0eddc6e690f69578a57478d8179b4148708c8"
-		CONFIGURE_COMMAND
-			./configure LDFLAGS=-L${ZLIB_SRC} "CFLAGS=${LIBELF_CFLAGS}"
-			--enable-deterministic-archives --disable-debuginfod --disable-libdebuginfod
-			--without-zstd
-		BUILD_IN_SOURCE 1
-		BUILD_COMMAND make -C lib libeu.a
-		COMMAND make -C libelf libelf${LIBELF_LIB_SUFFIX}
-		INSTALL_COMMAND ""
-		UPDATE_COMMAND ""
-		BUILD_BYPRODUCTS ${LIBELF_LIB}
-	)
-	message(STATUS "Using bundled libelf: include'${LIBELF_INCLUDE}', lib: ${LIBELF_LIB}")
-	install(
-		FILES "${LIBELF_LIB}"
-		DESTINATION "${CMAKE_INSTALL_LIBDIR}/${LIBS_PACKAGE_NAME}"
-		COMPONENT "libs-deps"
-	)
-endif()
-
-# We add a custom target, in this way we can always depend on `libelf` without distinguishing
-# between "bundled" and "not-bundled" case
-if(NOT TARGET libelf)
-	add_custom_target(libelf)
-endif()
-
-include_directories(${LIBELF_INCLUDE})
+FetchContent_Declare(
+	libelf
+	URL https://github.com/LucaGuerra/elftoolchain/releases/download/libelf-r4053-0/libelf-r4053-0.tar.gz
+	URL_HASH SHA256=1861e6332d97f9cdc15a0c03b7b478b87abb47408ab41c50bebd9a384937e44e
+)

userspace/libpman/CMakeLists.txt

@@ -15,6 +15,7 @@
 
 add_compile_options(${FALCOSECURITY_LIBS_USERSPACE_COMPILE_FLAGS})
 add_link_options(${FALCOSECURITY_LIBS_USERSPACE_LINK_FLAGS})
+include(libbpf)
 
 add_library(
 	pman
@@ -35,23 +36,15 @@ target_include_directories(
 			$<BUILD_INTERFACE:${LIBS_DIR}> # ppm_enum and tables
 			$<BUILD_INTERFACE:${LIBS_DIR}/userspace> # scap-stats struct
 			${ZLIB_INCLUDE}
-			${LIBBPF_INCLUDE}
 			${MODERN_BPF_SKEL_DIR}
-			${LIBELF_INCLUDE}
 )
 
-target_link_libraries(
-	pman PUBLIC scap_event_schema scap_platform ${LIBBPF_LIB} ${LIBELF_LIB} ${ZLIB_LIB}
-)
+target_link_libraries(pman PUBLIC scap_event_schema scap_platform lbpf ${ZLIB_LIB})
 
 if(TARGET ProbeSkeleton)
 	add_dependencies(pman ProbeSkeleton)
 endif()
 
-if(USE_BUNDLED_LIBBPF)
-	add_dependencies(pman libbpf)
-endif()
-
 install(
 	TARGETS pman
 	ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}"

userspace/libscap/CMakeLists.txt

@@ -171,14 +171,12 @@ if(HAS_ENGINE_KMOD)
 endif()
 
 if(HAS_ENGINE_BPF)
-	include(libelf)
 	add_subdirectory(engine/bpf)
 	target_link_libraries(scap PUBLIC scap_engine_bpf)
 	target_include_directories(scap_engine_bpf PRIVATE ${PROJECT_BINARY_DIR}/driver/src)
 endif()
 
 if(HAS_ENGINE_MODERN_BPF)
-	include(libelf)
 	add_subdirectory(engine/modern_bpf)
 	target_link_libraries(scap PUBLIC scap_engine_modern_bpf)
 	target_include_directories(scap_engine_modern_bpf PRIVATE ${PROJECT_BINARY_DIR}/driver/src)

userspace/libscap/engine/bpf/CMakeLists.txt

@@ -13,11 +13,12 @@
 # the License.
 #
 add_library(scap_engine_bpf scap_bpf.c attached_prog.c)
-add_dependencies(scap_engine_bpf libelf zlib)
+add_dependencies(scap_engine_bpf zlib)
+include(FetchContent)
+FetchContent_MakeAvailable(libelf)
 target_link_libraries(
-	scap_engine_bpf PRIVATE scap_event_schema scap_platform scap_engine_util scap_error
-							${LIBELF_LIB} ${ZLIB_LIB}
+	scap_engine_bpf PRIVATE scap_event_schema scap_platform scap_engine_util scap_error elf
+							${ZLIB_LIB}
 )
-target_include_directories(scap_engine_bpf PRIVATE ${LIBELF_INCLUDE})
 
 set_scap_target_properties(scap_engine_bpf)

userspace/libscap/engine/bpf/scap_bpf.c

@@ -706,7 +706,7 @@ static int32_t load_bpf_file(struct bpf_engine *handle) {
 			                      handle->m_filepath);
 		}
 
-		handle->elf = elf_begin(handle->program_fd, ELF_C_READ_MMAP_PRIVATE, NULL);
+		handle->elf = elf_begin(handle->program_fd, ELF_C_READ, NULL);
 		if(!handle->elf) {
 			scap_errprintf(handle->m_lasterr, 0, "can't read ELF format");
 			goto end;