build: Fall back to C11 for CMake <3.21

.github/workflows/build.yaml

@@ -11,22 +11,83 @@ jobs:
     strategy:
       matrix:
         os:
-          - ubuntu-latest
-          - ubuntu-22.04
-    runs-on: ${{ matrix.os }}
+          - ubuntu:latest
+          - ubuntu:22.04
+          - debian:latest
+          - debian:stable
+          - debian:oldstable
+          - almalinux:latest
+          - amazonlinux:latest
+          - fedora:latest
+          - oraclelinux:9
+          - archlinux:latest
+          - clearlinux:latest
+        config:
+          - cmake_args: "-DENABLE_API=ON -DCMAKE_C_COMPILER=gcc"
+          - cmake_args: "-DENABLE_API=ON -DCMAKE_C_COMPILER=clang"
+          - cmake_args: "-DENABLE_API=OFF"
+        exclude:
+          # Clang configured for C11 rejects our C23 usage
+          - os: debian:oldstable
+            config:
+              cmake_args: "-DENABLE_API=ON -DCMAKE_C_COMPILER=clang"
+
+    runs-on: ubuntu-latest
 
     steps:
       - name: Checkout code
         uses: actions/checkout@v2
 
-      - name: Create build directory
-        run: mkdir -p build
-
-      - name: Install dependencies
-        run: sudo apt-get update && sudo apt-get install -y libcurl4-openssl-dev libjansson-dev libmicrohttpd-dev libsodium-dev
-
-      - name: Build DATUM Gateway
+      - name: Build inside Docker
         run: |
-          cd build
-          cmake ..
-          make -j$(nproc)
+          PACKAGES_CLANG='clang'
+          PACKAGES_GCC='gcc'
+          case "${{ matrix.os }}" in
+            debian:*|ubuntu:*)
+              INSTALL_CMD="apt update && apt install -y"
+              PACKAGES="git libc6-dev cmake libcurl4-openssl-dev libjansson-dev libsodium-dev pkgconf"
+              PACKAGES_API="libmicrohttpd-dev"
+              ;;
+            almalinux:*|amazonlinux:*|fedora:*|oraclelinux:*)
+              INSTALL_CMD="dnf install -y"
+              [[ "${{ matrix.os }}" =~ ^almalinux: ]] && INSTALL_CMD="dnf install -y dnf-plugins-core && dnf config-manager --set-enabled crb && $INSTALL_CMD"
+              [[ "${{ matrix.os }}" =~ ^oraclelinux: ]] && INSTALL_CMD="dnf install -y dnf-plugins-core && dnf config-manager --set-enabled ol9_codeready_builder && $INSTALL_CMD"
+              [[ "${{ matrix.os }}" =~ ^(alma|oracle)linux: ]] && INSTALL_CMD="dnf install -y epel-release && $INSTALL_CMD"
+              PACKAGES="git cmake libcurl-devel jansson-devel libsodium-devel pkgconf"
+              PACKAGES_API="libmicrohttpd-devel"
+              [[ "${{ matrix.config.cmake_args }}" =~ clang|gcc ]] || PACKAGES="$PACKAGES gcc"
+              ;;
+            archlinux:*)
+              INSTALL_CMD="pacman -Syu --noconfirm"
+              PACKAGES="git base-devel cmake curl jansson libsodium"
+              PACKAGES_API="libmicrohttpd"
+              ;;
+            clearlinux:*)
+              INSTALL_CMD="swupd bundle-add"
+              PACKAGES="git c-basic devpkg-curl devpkg-jansson devpkg-libsodium"
+              PACKAGES_API="devpkg-libmicrohttpd"
+              PACKAGES_CLANG="llvm"
+              PACKAGES_GCC=''  # included in c-basic
+              ;;
+          esac
+          PACKAGES="$PACKAGES ${{ matrix.config.extra_deps }}"
+          if [[ "${{ matrix.config.cmake_args }}" =~ ENABLE_API=ON ]]; then
+              PACKAGES="$PACKAGES $PACKAGES_API"
+          fi
+          if [[ "${{ matrix.config.cmake_args }}" =~ CMAKE_C_COMPILER=gcc ]]; then
+              PACKAGES="$PACKAGES $PACKAGES_GCC"
+          elif [[ "${{ matrix.config.cmake_args }}" =~ CMAKE_C_COMPILER=clang ]]; then
+              PACKAGES="$PACKAGES $PACKAGES_CLANG"
+          fi
+          CMD="set -ex
+            ${INSTALL_CMD} ${PACKAGES}
+            git config --global --add safe.directory /workspace
+            mkdir -p build
+            cd build
+            cmake /workspace -DCMAKE_C_FLAGS='-Wall -Werror' ${{ matrix.config.cmake_args }}
+            make -j\$(nproc)
+          "
+          docker run \
+            -v "${{ github.workspace }}:/workspace":ro \
+            "${{ matrix.os }}" \
+            /bin/sh -c "${CMD}"

CMakeLists.txt

@@ -1,12 +1,23 @@
-cmake_minimum_required(VERSION 3.21)
+cmake_minimum_required(VERSION 3.13)
 
 project(DATUM VERSION 0.2.3 LANGUAGES C)
-set(CMAKE_C_STANDARD 23)
+
+# Enable C23 if supported, else fall back to C11 for compatibility
+if(CMAKE_VERSION VERSION_LESS "3.21")
+    # Older CMake: C23 not recognized; use C11
+    set(CMAKE_C_STANDARD 11)
+    set(CMAKE_C_STANDARD_REQUIRED ON)
+else()
+    # CMake 3.21+: C23 is available
+    set(CMAKE_C_STANDARD 23)
+    set(CMAKE_C_STANDARD_REQUIRED OFF)
+endif()
+
+option(ENABLE_API "Build API support." ON)
 
 include(GNUInstallDirs)
 
 add_executable(datum_gateway
-	src/datum_api.c
 	src/datum_blocktemplates.c
 	src/datum_coinbaser.c
 	src/datum_conf.c
@@ -42,17 +53,25 @@ set(WEB_RESOURCES
 find_package(PkgConfig REQUIRED)
 pkg_check_modules(CURL REQUIRED libcurl)
 pkg_check_modules(JANSSON REQUIRED jansson)
+if(ENABLE_API)
 pkg_check_modules(MICROHTTPD REQUIRED libmicrohttpd)
+endif()
 pkg_check_modules(SODIUM REQUIRED libsodium)
 find_package(Threads REQUIRED)
 
-set(POW_LIBS "")
 include(CheckLibraryExists)
+include(CMakePushCheckState)
+cmake_push_check_state(RESET)
+string(APPEND CMAKE_REQUIRED_FLAGS -Wno-error)
+
+set(POW_LIBS "")
 check_library_exists(m pow "" LIBM)
 if(LIBM)
 	list(APPEND POW_LIBS "m")
 endif()
 
+cmake_pop_check_state()
+
 add_custom_target(generate_git_version
 	BYPRODUCTS ${PROJECT_BINARY_DIR}/git_version.h
 	COMMAND ${CMAKE_COMMAND} -DBUILD_INFO_HEADER_PATH=${PROJECT_BINARY_DIR}/git_version.h -DSOURCE_DIR=${PROJECT_SOURCE_DIR} -P ${PROJECT_SOURCE_DIR}/cmake/script/GenerateBuildInfo.cmake
@@ -73,14 +92,12 @@ target_include_directories(datum_gateway
 	PRIVATE
 	$<BUILD_INTERFACE:${PROJECT_BINARY_DIR}>
 	${CURL_INCLUDE_DIRS}
-	${MICROHTTPD_INCLUDE_DIRS}
 	${JANSSON_INCLUDE_DIRS}
 	${SODIUM_INCLUDE_DIRS}
 )
 target_link_directories(datum_gateway
 	PUBLIC
 	${CURL_LIBRARY_DIRS}
-	${MICROHTTPD_LIBRARY_DIRS}
 	${JANSSON_LIBRARY_DIRS}
 	${SODIUM_LIBRARY_DIRS}
 )
@@ -89,17 +106,26 @@ target_link_libraries(datum_gateway
 	${POW_LIBS}
 	Threads::Threads
 	${CURL_LIBRARIES} ${CURL_LDFLAGS} ${CURL_LDFLAGS_OTHER}
-	${MICROHTTPD_LIBRARIES} ${MICROHTTPD_LDFLAGS} ${MICROHTTPD_LDFLAGS_OTHER}
 	${JANSSON_LIBRARIES} ${JANSSON_LDFLAGS} ${JANSSON_LDFLAGS_OTHER}
 	${SODIUM_LIBRARIES} ${SODIUM_LDFLAGS} ${SODIUM_LDFLAGS_OTHER}
 )
 target_compile_options(datum_gateway
 	PUBLIC
 	${CURL_CFLAGS} ${CURL_CFLAGS_OTHER}
-	${MICROHTTPD_CFLAGS} ${MICROHTTPD_CFLAGS_OTHER}
 	${JANSSON_CFLAGS} ${JANSSON_CFLAGS_OTHER}
 	${SODIUM_CFLAGS} ${SODIUM_CFLAGS_OTHER}
 )
 
+if(ENABLE_API)
+	target_sources(datum_gateway PRIVATE src/datum_api.c)
+	target_include_directories(datum_gateway PRIVATE ${MICROHTTPD_INCLUDE_DIRS})
+	target_link_directories(datum_gateway PUBLIC ${MICROHTTPD_LIBRARY_DIRS})
+	target_link_libraries(datum_gateway PUBLIC ${MICROHTTPD_LIBRARIES} ${MICROHTTPD_LDFLAGS} ${MICROHTTPD_LDFLAGS_OTHER})
+	target_compile_options(datum_gateway PUBLIC
+		-DENABLE_API
+		${MICROHTTPD_CFLAGS} ${MICROHTTPD_CFLAGS_OTHER}
+	)
+endif()
+
 install(FILES README.md DESTINATION ${CMAKE_INSTALL_DOCDIR})
 install(FILES doc/DATUM_recommended_setup-network_diagram.svg DESTINATION ${CMAKE_INSTALL_DOCDIR}/doc)

src/datum_conf.c

@@ -313,6 +313,11 @@ int datum_read_config(const char *conffile) {
 		datum_config.bitcoind_work_update_seconds = 120;
 	}
 
+#ifndef ENABLE_API
+	if (datum_config.api_listen_port) {
+		DLOG_WARN("API is enabled in configuration, but this build was compiled without API support");
+	}
+#else
 	datum_config.api_admin_password_len = strlen(datum_config.api_admin_password);
 	if (datum_config.api_admin_password_len) {
 		static const char hash_tag[] = "DATUM Anti-CSRF Token";
@@ -326,6 +331,7 @@ int datum_read_config(const char *conffile) {
 		my_sha256(hash, data, data_sz);
 		hash2hex(hash, datum_config.api_csrf_token);
 	}
+#endif
 
 	if (datum_config.stratum_v1_max_threads > MAX_THREADS) {
 		DLOG_FATAL("Maximum threads must be less than %d.", MAX_THREADS);

src/datum_gateway.c

@@ -161,11 +161,13 @@ int main(int argc, char **argv) {
 	}
 	last_datum_protocol_connect_tsms = current_time_millis();
 
+#ifdef ENABLE_API
 	if (datum_api_init()) {
 		DLOG_FATAL("Error initializing API interface");
 		usleep(100000);
 		exit(1);
 	}
+#endif
 
 	if (datum_coinbaser_init()) {
 		DLOG_FATAL("Error initializing coinbaser thread");