Bundle libbpf/bpftool and systemtap-sdt

.github/workflows/ci.yml

@@ -2,14 +2,14 @@ name: CI
 
 on:
   push:
-    branches: [ main ]
+    branches: [main]
   pull_request:
-    branches: [ main ]
+    branches: [main]
   workflow_dispatch:
 
 jobs:
   fmt:
-    runs-on: [ self-hosted, silk-arm-small-cpu ]
+    runs-on: [self-hosted, silk-arm-small-cpu]
 
     steps:
       - uses: actions/checkout@v5
@@ -26,7 +26,7 @@ jobs:
         run: ./bb fmt --check
 
   test:
-    runs-on: [ self-hosted, "${{ matrix.arch.runner }}" ]
+    runs-on: [self-hosted, "${{ matrix.arch.runner }}"]
 
     strategy:
       fail-fast: false
@@ -68,7 +68,9 @@ jobs:
             contrib/librseq \
             contrib/liburing \
             contrib/googletest \
-            contrib/benchmark
+            contrib/benchmark \
+            contrib/libbpf \
+            contrib/bpftool
 
       - name: Init Poco submodule
         if: matrix.build.name == 'release' || matrix.build.name == 'tsan'
@@ -111,16 +113,15 @@ jobs:
             ccache \
             libboost-context-dev \
             libboost-program-options-dev \
-            libbpf-dev \
             libdouble-conversion-dev \
+            libelf-dev \
             zlib1g-dev
 
       - name: Cache ccache
         uses: actions/cache@v5
         with:
           path: ~/.cache/ccache
-          key: ${{ runner.os }}-ccache-${{ matrix.arch.name }}-${{ matrix.build.name
-            }}-${{ github.sha }}
+          key: ${{ runner.os }}-ccache-${{ matrix.arch.name }}-${{ matrix.build.name }}-${{ github.sha }}
           restore-keys: |
             ${{ runner.os }}-ccache-${{ matrix.arch.name }}-${{ matrix.build.name }}-
 
@@ -149,7 +150,7 @@ jobs:
   pages:
     needs: test
     if: github.ref == 'refs/heads/main'
-    runs-on: [ self-hosted, silk-amd-small-cpu ]
+    runs-on: [self-hosted, silk-amd-small-cpu]
 
     permissions:
       pages: write

.gitmodules

@@ -28,3 +28,9 @@
 [submodule "contrib/librseq"]
 	path = contrib/librseq
 	url = https://github.com/compudj/librseq.git
+[submodule "contrib/libbpf"]
+	path = contrib/libbpf
+	url = https://github.com/libbpf/libbpf.git
+[submodule "contrib/bpftool"]
+	path = contrib/bpftool
+	url = https://github.com/libbpf/bpftool.git

CMakeLists.txt

@@ -88,6 +88,9 @@ add_subdirectory(contrib/librseq-cmake)
 add_subdirectory(contrib/libbacktrace-cmake)
 add_subdirectory(contrib/googletest-cmake)
 add_subdirectory(contrib/benchmark-cmake)
+add_subdirectory(contrib/systemtap-sdt)
+add_subdirectory(contrib/libbpf-cmake)
+add_subdirectory(contrib/bpftool-cmake)
 
 option(BUILD_POCO "Build Poco library (required by http-perf)" OFF)
 if(BUILD_POCO)

contrib/bpftool-cmake/CMakeLists.txt

@@ -0,0 +1,47 @@
+if(NOT TARGET Libbpf::Libbpf)
+    return()
+endif()
+
+set(BPFTOOL_SRC ${CMAKE_CURRENT_SOURCE_DIR}/../bpftool)
+
+file(GLOB BPFTOOL_SOURCES ${BPFTOOL_SRC}/src/*.c)
+list(APPEND BPFTOOL_SOURCES ${BPFTOOL_SRC}/src/kernel/bpf/disasm.c)
+# jit_disasm.c needs libbfd or LLVM disassembler; without either the
+# inline stubs in main.h cover the API for everything else we use.
+list(REMOVE_ITEM BPFTOOL_SOURCES ${BPFTOOL_SRC}/src/jit_disasm.c)
+
+add_executable(bpftool ${BPFTOOL_SOURCES})
+
+target_compile_options(bpftool PRIVATE
+    -w
+    -Wno-unused-parameter
+    -Wno-missing-field-initializers
+    # struct list_head lives in <linux/types.h>; libbpf's <linux/list.h>
+    # uses it without including types.h directly.
+    -include linux/types.h
+    # bpftool is a build-time tool; don't pay the cost of sanitizers,
+    # and skip false positives like qsort_r(NULL, 0, ...) tripping
+    # UBSan's nonnull-attribute check.
+    -fno-sanitize=all
+)
+target_link_options(bpftool PRIVATE -fno-sanitize=all)
+
+# BPFTOOL_WITHOUT_SKELETONS turns the prog-profile / pid-iter paths (which
+# depend on bpftool's own bootstrap-built skel headers) into stubs. The
+# remaining commands -- including `btf dump` and `gen skeleton` that silk
+# uses -- compile without needing a bootstrap stage.
+target_compile_definitions(bpftool PRIVATE
+    BPFTOOL_WITHOUT_SKELETONS
+    BPFTOOL_VERSION="7.5.0"
+    PACKAGE="bpftool"
+    __EXPORTED_HEADERS__
+    _GNU_SOURCE
+)
+
+target_include_directories(bpftool PRIVATE
+    ${BPFTOOL_SRC}/include
+    ${BPFTOOL_SRC}/include/uapi
+    ${BPFTOOL_SRC}/src/kernel/bpf
+)
+
+target_link_libraries(bpftool PRIVATE Libbpf::Libbpf)

contrib/libbpf-cmake/CMakeLists.txt

@@ -0,0 +1,48 @@
+find_library(LIBELF_LIBRARY NAMES elf)
+find_path(LIBELF_INCLUDE_DIR libelf.h)
+if(NOT LIBELF_LIBRARY OR NOT LIBELF_INCLUDE_DIR)
+    message(STATUS "Skipping libbpf: libelf not found (install libelf-dev)")
+    return()
+endif()
+find_package(ZLIB REQUIRED)
+
+set(LIBBPF_SRC ${CMAKE_CURRENT_SOURCE_DIR}/../libbpf)
+set(LIBBPF_BIN ${CMAKE_BINARY_DIR}/libbpf-generated)
+
+# Stage src/*.h under a bpf/ subdir so consumers can use <bpf/X.h>.
+# The headers live directly in src/ in the repo but ship under bpf/ in
+# the install layout that <bpf/...> includes assume.
+file(MAKE_DIRECTORY ${LIBBPF_BIN}/include/bpf)
+file(GLOB _libbpf_public_headers ${LIBBPF_SRC}/src/*.h)
+foreach(_hdr IN LISTS _libbpf_public_headers)
+    get_filename_component(_name ${_hdr} NAME)
+    configure_file(${_hdr} ${LIBBPF_BIN}/include/bpf/${_name} COPYONLY)
+endforeach()
+
+file(GLOB LIBBPF_SOURCES ${LIBBPF_SRC}/src/*.c)
+
+add_library(_libbpf STATIC ${LIBBPF_SOURCES})
+
+target_compile_options(_libbpf PRIVATE
+    -w
+    -std=gnu89
+    # Don't sanitize third-party libbpf source; lets bpftool (which we
+    # also build with -fno-sanitize=all) link it without pulling in the
+    # sanitizer runtime, and keeps silk's profiler binary slimmer.
+    -fno-sanitize=all
+)
+
+target_compile_definitions(_libbpf PRIVATE
+    _LARGEFILE64_SOURCE
+    _FILE_OFFSET_BITS=64
+)
+
+target_include_directories(_libbpf
+    PRIVATE ${LIBBPF_SRC}/src
+    PUBLIC ${LIBBPF_BIN}/include ${LIBBPF_SRC}/include ${LIBBPF_SRC}/include/uapi
+)
+
+target_link_libraries(_libbpf PUBLIC ZLIB::ZLIB ${LIBELF_LIBRARY})
+target_include_directories(_libbpf SYSTEM PUBLIC ${LIBELF_INCLUDE_DIR})
+
+add_library(Libbpf::Libbpf ALIAS _libbpf)

contrib/systemtap-sdt/CMakeLists.txt

@@ -0,0 +1,12 @@
+# Vendored copy of systemtap's <sys/sdt.h> + <sys/sdt-config.h>, the two
+# header files needed to emit USDT (Statically Defined Tracepoint) probes.
+# Both files are dedicated to the public domain (CC0) by upstream specifically
+# so user programs incorporating them are not GPL-tainted; no further attribution
+# or LICENSE artifact is required.
+#
+# We vendor instead of relying on the systemtap-sdt-dev distro package so that
+# the silk build has zero extra apt dependencies for USDT.
+
+add_library(systemtap-sdt INTERFACE)
+target_include_directories(systemtap-sdt INTERFACE ${CMAKE_CURRENT_SOURCE_DIR})
+add_library(SystemTap::Sdt ALIAS systemtap-sdt)

contrib/systemtap-sdt/sys/sdt-config.h

@@ -0,0 +1,6 @@
+/* includes/sys/sdt-config.h.  Generated from sdt-config.h.in by configure.
+
+   This file just defines _SDT_ASM_SECTION_AUTOGROUP_SUPPORT to 0 or 1 to
+   indicate whether the assembler supports "?" in .pushsection directives.  */
+
+#define _SDT_ASM_SECTION_AUTOGROUP_SUPPORT 1