Fix handling of vendored eBPF code in CMake. (#17556)

* Fix logic error in CMake code for kernel version detection.

* Force legacy libbpf for CentOS 7 and AL 2 package builds.

* Check target kernel version instead of host kernel version.

This should help when building in containers.

* Fix up handling for older versions of CMake.

* Use CMake C compiler for libbpf builds.

* Fix selection of legacy eBPF code in static builds.

* Explicitly pull in kernel headers on CentOS.

* Fix typo in FORCE_LEGACY_LIBBPF option.

* Only enable eBPF by default on x86.

* Fix detection of static builds.

* Fix libc detection logic.

* Fix handling of static builds.

* Fix musl libc detection.

* Fix check messages for libc detection.

CMakeLists.txt

@@ -171,7 +171,7 @@ mark_as_advanced(ENABLE_SENTRY)
 option(BUILD_FOR_PACKAGING "Include component files for native packages" False)
 mark_as_advanced(BUILD_FOR_PACKAGING)
 
-cmake_dependent_option(FORCE_LEGACY_LIBBPF "Force usage of libbpf 0.0.9 instead of the latest version." False "ENABLE_PLUGIN_LIBBPF" False)
+cmake_dependent_option(FORCE_LEGACY_LIBBPF "Force usage of libbpf 0.0.9 instead of the latest version." False "ENABLE_PLUGIN_EBPF" False)
 mark_as_advanced(FORCE_LEGACY_LIBBPF)
 
 if(ENABLE_ACLK OR ENABLE_EXPORTER_PROMETHEUS_REMOTE_WRITE)

netdata-installer.sh

@@ -246,7 +246,9 @@ HEREDOC
 }
 
 if [ "$(uname -s)" = "Linux" ]; then
-    ENABLE_EBPF=1
+  case "$(uname -m)" in
+    x86_64|i?86) ENABLE_EBPF=1 ;;
+  esac
 fi
 
 DONOTSTART=0

netdata.spec.in

@@ -332,6 +332,11 @@ happened, on your systems and applications.
 	%endif
 	%if %{_have_ebpf}
 	-DENABLE_PLUGIN_EBPF=On \
+	%if 0%{?centos_ver:1}
+	%if 0%{?centos_ver} < 8
+	-DFORCE_LEGACY_LIBBPF=On \
+	%endif
+	%endif
 	%else
 	-DENABLE_PLUGIN_EBPF=Off \
 	%endif

packaging/cmake/Modules/NetdataEBPFLegacy.cmake

@@ -13,7 +13,16 @@ set(ebpf-legacy_BUILD_DIR "${CMAKE_BINARY_DIR}/ebpf-legacy-build")
 function(netdata_fetch_legacy_ebpf_code)
     netdata_identify_libc(_libc)
 
-    if(_libc STREQUAL "glibc")
+    if(DEFINED BUILD_SHARED_LIBS)
+        if(NOT BUILD_SHARED_LIBS)
+            set(need_static TRUE)
+        endif()
+    endif()
+
+    if(need_static)
+        set(_hash 302714979470e300b81a64a4ebef9fac1f3488488482cf30c926fa98f73cabc1)
+        set(_libc "static")
+    elseif(_libc STREQUAL "glibc")
         set(_hash 7013753ef85c2d3681bdcfdd7544705cdaf5b640b70734ca223f43cc5adcdc53)
     elseif(_libc STREQUAL "musl")
         set(_hash b524d1fcbd67c82cdfc9f46d55f67c0c0c0412c3356c85b38c03ce03f6068747)

packaging/cmake/Modules/NetdataLibBPF.cmake

@@ -34,12 +34,20 @@ function(netdata_bundle_libbpf)
         set(_libbpf_tag b981a3a138e3a30024e4e143d62cff2dc307121e) # v1.4.0p_netdata
     endif()
 
-    netdata_identify_libc(_libc)
+    if(DEFINED BUILD_SHARED_LIBS)
+        if(NOT BUILD_SHARED_LIBS)
+            set(need_static TRUE)
+        endif()
+    endif()
 
-    string(REGEX MATCH "glibc|musl" _libc_supported "${_libc}")
+    if(NOT need_static)
+        netdata_identify_libc(_libc)
 
-    if(NOT _libc_supported)
+        string(REGEX MATCH "glibc|musl" _libc_supported "${_libc}")
-        message(FATAL_ERROR "This system’s libc (detected: ${_libc}) is not not supported by the eBPF plugin.")
+
+        if(NOT _libc_supported)
+            message(FATAL_ERROR "This system’s libc (detected: ${_libc}) is not not supported by the eBPF plugin.")
+        endif()
     endif()
 
     find_program(MAKE_COMMAND make)
@@ -65,7 +73,7 @@ function(netdata_bundle_libbpf)
         GIT_TAG ${_libbpf_tag}
         SOURCE_DIR "${libbpf_SOURCE_DIR}"
         CONFIGURE_COMMAND ""
-        BUILD_COMMAND ${MAKE_COMMAND} -C src BUILD_STATIC_ONLY=1 OBJDIR=build/ DESTDIR=../ install
+        BUILD_COMMAND ${MAKE_COMMAND} -C src CC=${CMAKE_C_COMPILER} BUILD_STATIC_ONLY=1 OBJDIR=build/ DESTDIR=../ install
         BUILD_IN_SOURCE 1
         BUILD_BYPRODUCTS "${_libbpf_library}"
         INSTALL_COMMAND ""

packaging/cmake/Modules/NetdataUtil.cmake

@@ -16,17 +16,55 @@ function(netdata_detect_host_kernel_version)
 
     message(CHECK_START "Determining host kernel version")
 
-    execute_process(COMMAND uname -r
+    if(NOT CMAKE_CROSSCOMPILING)
-                    RESULT_VARIABLE _uname_result
+        include(CheckIncludeFile)
-                    OUTPUT_VARIABLE _uname_output)
 
-    if(NOT _uname_result)
+        check_include_file("linux/version.h" CAN_USE_VERSION_H)
-        message(CHECK_FAIL "unknown")
+
-        set(HOST_KERNEL_VERSION "0.0.0" CACHE STRING "Detected host kernel version")
+        if(CAN_USE_VERSION_H)
-        return()
+            message(CHECK_START "Checking version using linux/version.h")
+            file(WRITE "${CMAKE_BINARY_DIR}/kversion-test.c" "
+            #include <stdio.h>
+            #include <linux/version.h>
+
+            int main() {
+                printf(\"%i.%i.%i\", LINUX_VERSION_MAJOR, LINUX_VERSION_PATCHLEVEL, LINUX_VERSION_SUBLEVEL);
+            }
+            ")
+
+            try_run(_run_success _compile_success
+                    ${CMAKE_BINARY_DIR}
+                    SOURCES ${CMAKE_BINARY_DIR}/kversion-test.c
+                    RUN_OUTPUT_VARIABLE _kversion_output)
+
+            if(_compile_success AND _run_success EQUAL 0)
+                message(CHECK_PASS "success")
+                set(_kversion_value "${_kversion_output}")
+            else()
+                message(CHECK_FAIL "failed")
+            endif()
+        endif()
     endif()
 
-    string(REGEX REPLACE "-.+$" "" _kversion "${_uname_output}")
+    if(NOT DEFINED _kversion_value)
+        message(CHECK_START "Checking version using uname")
+        execute_process(COMMAND uname -r
+                        RESULT_VARIABLE _uname_result
+                        OUTPUT_VARIABLE _uname_output)
+
+        if(NOT _uname_result EQUAL 0)
+            message(CHECK_FAIL "failed")
+            message(CHECK_FAIL "unknown")
+            set(HOST_KERNEL_VERSION "0.0.0" CACHE STRING "Detected host kernel version")
+            return()
+        else()
+            message(CHECK_PASS "success")
+        endif()
+
+        set(_kversion_value "${_uname_output}")
+    endif()
+
+    string(REGEX REPLACE "-.+$" "" _kversion "${_kversion_value}")
     message(CHECK_PASS "${_kversion}")
     set(HOST_KERNEL_VERSION "${_kversion}" CACHE STRING "Detected host kernel version")
 endfunction()
@@ -36,34 +74,36 @@ endfunction()
 # Sets the specified variable to the name of the libc or "unknown"
 function(netdata_identify_libc _libc_name)
     if(NOT DEFINED _ND_DETECTED_LIBC)
-        message(INFO "Detecting libc implementation")
+        message(CHECK_START "Detecting libc implementation")
 
         execute_process(COMMAND ldd --version
                         COMMAND grep -q -i -E "glibc|gnu libc"
-                        RESULT_VARIABLE LDD_IS_GLIBC
+                        RESULT_VARIABLE LDD_RESULT
                         OUTPUT_VARIABLE LDD_OUTPUT
                         ERROR_VARIABLE LDD_OUTPUT)
 
-        if(LDD_IS_GLIBC)
+        if(NOT LDD_RESULT)
             set(${_libc_name} glibc PARENT_SCOPE)
             set(_ND_DETECTED_LIBC glibc CACHE INTERNAL "")
+            message(CHECK_PASS "glibc")
             return()
         endif()
 
-        execute_process(COMMAND ldd --version
+        execute_process(COMMAND sh -c "ldd --version 2>&1 | grep -q -i 'musl'"
-                        COMMAND grep -q -i -E "musl"
+                        RESULT_VARIABLE LDD_RESULT
-                        RESULT_VARIABLE LDD_IS_MUSL
                         OUTPUT_VARIABLE LDD_OUTPUT
                         ERROR_VARIABLE LDD_OUTPUT)
 
-        if(LDD_IS_MUSL)
+        if(NOT LDD_RESULT)
             set(${_libc_name} musl PARENT_SCOPE)
             set(_ND_DETECTED_LIBC musl CACHE INTERNAL "")
+            message(CHECK_PASS "musl")
             return()
         endif()
 
         set(${_libc_name} unknown PARENT_SCOPE)
         set(_ND_DETECTED_LIBC unknown CACHE INTERNAL "")
+        message(CHECK_FAIL "unknown")
     else()
         set(${_libc_name} ${_ND_DETECTED_LIBC} PARENT_SCOPE)
     endif()

packaging/installer/install-required-packages.sh

@@ -623,6 +623,7 @@ declare -A pkg_find=(
 
 declare -A pkg_distro_sdk=(
   ['alpine']="alpine-sdk"
+  ['centos']="kernel-headers"
   ['default']="NOTREQUIRED"
 )