CMakeLists.txt

cmake_minimum_required(VERSION 3.24)

set(CMAKE_C_STANDARD 17)
set(CMAKE_CXX_STANDARD 20)
set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
cmake_policy(SET CMP0068 NEW)
cmake_policy(SET CMP0135 NEW)

# This build configuration combines the following other build configurations:
# - `nginx-datadog.cmake`, the actual nginx module source in `src/`,
# - `nginx-module.cmake`, the nginx-specific boilerplate code generated by
#   nginx's `configure` script,
# - `dd-trace-cpp/CMakeLists.txt`, the Datadog tracing library.

project(ngx_http_datadog_module VERSION 1.2.1)

option(NGINX_DATADOG_ASM_ENABLED "Build with libddwaf" ON)
set(NGINX_SRC_DIR "" CACHE PATH "The path to a directory with nginx sources")
set(NGINX_VERSION "" CACHE STRING "The nginx version")
if (NGINX_SRC_DIR STREQUAL "" AND NGINX_VERSION STREQUAL "")
  message(FATAL_ERROR "Set NGINX_SRC_DIR or, alternatively NGINX_VERSION")
endif()
option(NGINX_PATCH_AWAY_LIBC "Patch away libc dependency" OFF)
option(NGINX_COVERAGE "Add coverage instrumentation" OFF)

# Make curl link against a static zlib (requires cmake 3.24)
set(ZLIB_USE_STATIC_LIBS ON)

# Prefer the build mode "release with debug info" if another mode wasn't
# specified.
if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
  set(CMAKE_BUILD_TYPE "RelWithDebInfo")
endif()

# Global compiler options
if(CMAKE_COMPILER_IS_GNUCXX)
  # This warning has a false positive. See
  # <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108088>.
  add_compile_options(-Wno-error=free-nonheap-object)

  # Looks like a false positive. Doesn't like a constructor taking
  # std::optional = nullopt and moving it to a null optional
  add_compile_options(-Wno-error=maybe-uninitialized)
endif()

# save frame pointers to make it more profiler friendly
add_compile_options(-fno-omit-frame-pointer)

# Nginx module boilerplate (code within the nginx repository)
include(./cmake/deps/nginx-module.cmake)

add_subdirectory(./dd-trace-cpp EXCLUDE_FROM_ALL)

set(RULES_VERSION "")
set(LIBDDWAF_VERSION "")
if(NGINX_DATADOG_ASM_ENABLED)
  include(./cmake/deps/rapidjson.cmake)
  # we need neither but libddwaf requires one enabled
  set(LIBDDWAF_BUILD_STATIC ON)
  set(LIBDDWAF_BUILD_SHARED OFF)
  set(LIBDDWAF_TESTING OFF)
  set(LIBDDWAF_ENABLE_LTO OFF)
  add_subdirectory(./libddwaf EXCLUDE_FROM_ALL)

  execute_process(
    COMMAND grep rules_version src/security/recommended.json
    COMMAND sed "s/.*\"\\([0-9.]\\+\\)\".*/\\1/"
    WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
    OUTPUT_VARIABLE RULES_VERSION
    OUTPUT_STRIP_TRAILING_WHITESPACE)
  file(READ ./libddwaf/version LIBDDWAF_VERSION)
endif()

configure_file(src/version.cpp.in ${CMAKE_BINARY_DIR}/version.cpp)

# The shared library (nginx module) that we are building.
add_library(ngx_http_datadog_module SHARED)

target_sources(ngx_http_datadog_module
  PRIVATE
    src/array_util.cpp
    src/datadog_conf.cpp
    src/datadog_conf_handler.cpp
    src/datadog_context.cpp
    src/datadog_directive.cpp
    src/datadog_handler.cpp
    src/datadog_variable.cpp
    src/dd.cpp
    src/defer.cpp
    src/glibc_compat.c
    src/global_tracer.cpp
    src/log_conf.cpp
    src/ngx_event_scheduler.cpp
    src/ngx_header_reader.cpp
    src/ngx_http_datadog_module.cpp
    src/ngx_logger.cpp
    src/ngx_script.cpp
    src/request_tracing.cpp
    src/string_util.cpp
    src/tracing_library.cpp
    ${CMAKE_BINARY_DIR}/version.cpp
)
if(NGINX_DATADOG_ASM_ENABLED)
  target_sources(ngx_http_datadog_module
    PRIVATE
    src/security/blocking.cpp
    src/security/client_ip.cpp
    src/security/collection.cpp
    src/security/context.cpp
    src/security/ddwaf_obj.cpp
    src/security/header_tags.cpp
    src/security/library.cpp)
  target_compile_definitions(ngx_http_datadog_module PRIVATE WITH_WAF)
endif()

if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
  target_compile_options(ngx_http_datadog_module PRIVATE -Wall -Werror)
endif()

if(NGINX_COVERAGE)
  if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
    target_compile_options(ngx_http_datadog_module PRIVATE
      -fprofile-instr-generate -fcoverage-mapping -mllvm -runtime-counter-relocation=true)
    target_link_options(ngx_http_datadog_module PRIVATE
      -fprofile-instr-generate -mllvm -runtime-counter-relocation=true)
    target_sources(ngx_http_datadog_module PRIVATE src/coverage_fixup.c)
  else()
    message(FATAL_ERROR "NGINX_COVERAGE is only supported with clang")
  endif()
endif()

target_include_directories(ngx_http_datadog_module
  PRIVATE
    src/
)

target_link_libraries(ngx_http_datadog_module dd_trace_cpp-objects nginx_module)
if(NGINX_DATADOG_ASM_ENABLED)
  target_link_libraries(ngx_http_datadog_module rapidjson libddwaf_objects)
endif()

# Remove the "lib" prefix to match NGINX convention
set_property(TARGET ngx_http_datadog_module PROPERTY PREFIX "")

if(CMAKE_COMPILER_IS_GNUCXX OR (CMAKE_CXX_COMPILER_ID MATCHES "Clang"))
  if(APPLE)
    set_property(TARGET ngx_http_datadog_module PROPERTY SUFFIX ".so")
    target_link_options(ngx_http_datadog_module PRIVATE -undefined dynamic_lookup)
  else()
    target_link_libraries(ngx_http_datadog_module -static-libstdc++ -static-libgcc)
  endif()
endif()

if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
  set(LINKER_SCRIPT ${CMAKE_SOURCE_DIR}/nginx_module.ld)
  set_target_properties(ngx_http_datadog_module PROPERTIES LINK_DEPENDS ${LINKER_SCRIPT})
  target_link_options(ngx_http_datadog_module PRIVATE "-Wl,--version-script=${LINKER_SCRIPT}")
elseif(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
  set(EXPORTED_SYMBOLS ${CMAKE_SOURCE_DIR}/nginx_module.ld)
  set_target_properties(ngx_http_datadog_module PROPERTIES LINK_DEPENDS ${EXPORTED_SYMBOLS})
  target_link_options(ngx_http_datadog_module PRIVATE "-Wl,-exported_symbols_list" "-Wl,${EXPORTED_SYMBOLS}")
endif()

if(NGINX_PATCH_AWAY_LIBC)
  include(./cmake/patchelf.cmake)
  patch_away_libc(ngx_http_datadog_module)
endif()

if(CMAKE_BUILD_TYPE STREQUAL "RelWithDebInfo" AND CMAKE_SYSTEM_NAME STREQUAL "Linux")
  include(./cmake/split_debug_info.cmake)
  split_debug_info(ngx_http_datadog_module)
endif()

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