cleanup(build): self-contained BPF probe build

The BPF build now no longer touches the source directory and does not depend on any files outside the (generated) source directory. Signed-off-by: Grzegorz Nosek <[email protected]>
falcosecurity · Jul 5, 2023 · 8a4c3d2 · 8a4c3d2
1 parent a483002
commit 8a4c3d2
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Showing 5 changed files with 41 additions and 28 deletions.
diff --git a/driver/bpf/CMakeLists.txt b/driver/bpf/CMakeLists.txt
@@ -9,6 +9,32 @@ configure_file(../driver_config.h.in ${CMAKE_CURRENT_SOURCE_DIR}/../driver_confi
 
 option(BUILD_BPF "Build the BPF driver on Linux" OFF)
 
+# Note: probe.c *must* be the first entry to generate a proper Makefile
+set(BPF_SOURCES
+ probe.c
+ bpf_helpers.h
+ builtins.h
+ filler_helpers.h
+ fillers.h
+ maps.h
+ missing_definitions.h
+ plumbing_helpers.h
+ quirks.h
+ ring_helpers.h
+ types.h
+ ${CMAKE_CURRENT_SOURCE_DIR}/../driver_config.h
+ ../ppm_api_version.h
+ ../ppm_events_public.h
+ ../feature_gates.h
+ ../ppm_version.h
+ ../ppm_fillers.h
+ ../ppm_flag_helpers.h
+ ../ppm.h
+ ../ppm_consumer.h
+ ../capture_macro.h
+ ../systype_compat.h
+ )
+
 if(BUILD_BPF)
  # Check minimum kernel version
  set(bpf_min_kver_map_x86_64 4.14)
@@ -18,25 +44,21 @@ if(BUILD_BPF)
  message(WARNING "[BPF] To run this driver you need a Linux kernel version >= ${bpf_min_kver_map_${TARGET_ARCH}} but actual kernel version is: ${UNAME_RESULT}")
  endif()
 
+ foreach(FILENAME IN LISTS BPF_SOURCES)
+ get_filename_component(BASENAME ${FILENAME} NAME)
+ configure_file(${FILENAME} src/${BASENAME} COPYONLY)
+ string(APPEND BPF_DEPENDENCIES "$(src)/${BASENAME} ")
+ endforeach()
+
  add_custom_target(bpf ALL
  COMMAND make
  COMMAND "${CMAKE_COMMAND}" -E copy_if_different probe.o "${CMAKE_CURRENT_BINARY_DIR}"
- WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
+ WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/src"
  VERBATIM)
 endif()
 
 install(FILES
- bpf_helpers.h
- builtins.h
- filler_helpers.h
- fillers.h
+ ${BPF_SOURCES}
  Makefile
- maps.h
- plumbing_helpers.h
- probe.c
- quirks.h
- ring_helpers.h
- missing_definitions.h
- types.h
  DESTINATION "src/${DRIVER_PACKAGE_NAME}-${DRIVER_VERSION}/bpf"
  COMPONENT ${DRIVER_COMPONENT_NAME})
diff --git a/driver/bpf/Makefile → driver/bpf/Makefile.in b/driver/bpf/Makefile → driver/bpf/Makefile.in
@@ -41,16 +41,7 @@ clean:
  $(MAKE) -C $(KERNELDIR) M=$$PWD clean
  @rm -f *~
 
-$(obj)/probe.o: $(src)/probe.c \
- $(src)/bpf_helpers.h \
- $(src)/filler_helpers.h \
- $(src)/fillers.h \
- $(src)/maps.h \
- $(src)/plumbing_helpers.h \
- $(src)/quirks.h \
- $(src)/ring_helpers.h \
- $(src)/missing_definitions.h \
- $(src)/types.h
+$(obj)/probe.o: @BPF_DEPENDENCIES@
  $(CLANG) $(LINUXINCLUDE) \
  $(KBUILD_CPPFLAGS) \
  $(KBUILD_EXTRA_CPPFLAGS) \

diff --git a/driver/bpf/filler_helpers.h b/driver/bpf/filler_helpers.h
@@ -18,7 +18,7 @@ or GPL2.txt for full copies of the license.
 #include <linux/fdtable.h>
 #include <linux/net.h>
 
-#include "../ppm_flag_helpers.h"
+#include "ppm_flag_helpers.h"
 #include "builtins.h"
 
 // Old kernels (like 4.14) have too strict limits on the bpf program length to support 32 path components. For the moment we decrease the limit to 16.

diff --git a/driver/bpf/fillers.h b/driver/bpf/fillers.h
@@ -9,9 +9,9 @@ or GPL2.txt for full copies of the license.
 #ifndef __FILLERS_H
 #define __FILLERS_H
 
-#include "../systype_compat.h"
-#include "../ppm_flag_helpers.h"
-#include "../ppm_version.h"
+#include "systype_compat.h"
+#include "ppm_flag_helpers.h"
+#include "ppm_version.h"
 #include "bpf_helpers.h"
 #include "missing_definitions.h"
 

diff --git a/driver/bpf/probe.c b/driver/bpf/probe.c
@@ -15,8 +15,8 @@ or GPL2.txt for full copies of the license.
 #endif
 #include <linux/sched.h>
 
-#include "../driver_config.h"
-#include "../ppm_events_public.h"
+#include "driver_config.h"
+#include "ppm_events_public.h"
 #include "bpf_helpers.h"
 #include "types.h"
 #include "maps.h"