Add alternative logging backends

This commit allows for btop to log to either syslog(3) or systemd's
journal

CMakeLists.txt

@@ -35,6 +35,8 @@ set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 option(BTOP_STATIC "Link btop statically" OFF)
 option(BTOP_LTO "Enable LTO" ON)
 option(BTOP_USE_MOLD "Use mold to link btop" OFF)
+option(BTOP_SYSLOG "Log with syslog instead of log file" OFF)
+option(BTOP_JOURNALD "Directly log to journald instead of log file" OFF)
 option(BTOP_PEDANTIC "Enable a bunch of additional warnings" OFF)
 option(BTOP_WERROR "Compile with warnings as errors" OFF)
 
@@ -52,13 +54,15 @@ if(CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")
 endif()
 
 include(CheckCXXCompilerFlag)
+include(CheckIncludeFileCXX)
 include(CheckIPOSupported)
 
 add_executable(btop
   src/btop.cpp
   src/btop_config.cpp
   src/btop_draw.cpp
   src/btop_input.cpp
+  src/btop_log.cpp
   src/btop_menu.cpp
   src/btop_shared.cpp
   src/btop_theme.cpp
@@ -150,6 +154,22 @@ set(THREADS_PREFER_PTHREAD_FLAG ON)
 find_package(Threads REQUIRED)
 target_link_libraries(btop PRIVATE Threads::Threads)
 
+# Logging
+if(BTOP_JOURNALD)
+  find_package(Systemd REQUIRED)
+  target_compile_definitions(btop PRIVATE HAVE_JOURNALD)
+  target_link_libraries(btop PRIVATE Systemd::Journald)
+  message(STATUS "Using journald as logging backend")
+elseif(BTOP_SYSLOG)
+  check_include_file_cxx("syslog.h" HAVE_SYSLOG)
+  if(HAVE_SYSLOG)
+    target_compile_definitions(btop PRIVATE HAVE_SYSLOG)
+    message(STATUS "Using syslog as logging backend")
+  endif()
+else()
+  message(STATUS "Using plain log file")
+endif()
+
 if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
   target_link_libraries(btop PRIVATE $<LINK_LIBRARY:FRAMEWORK,CoreFoundation)
   target_link_libraries(btop PRIVATE $<LINK_LIBRARY:FRAMEWORK,IOKit)

Makefile

@@ -156,9 +156,16 @@ else
 	LTO := $(THREADS)
 endif
 
+#? Enable journald direct logging
+ifeq ($(ENABLE_JOURNALD),true)
+	override ADDFLAGS += $(shell echo "int main() {}" | $(CXX) -include "systemd/sd-journal.h" -lsystemd -o /dev/null -x c++ - >/dev/null 2>&1 && echo "-DHAVE_JOURNALD -lsystemd")
+else ifeq ($(ENABLE_SYSLOG),true)
+	override ADDFLAGS += $(strip $(shell echo "int main() {}" | $(CXX) -include "syslog.h" -o /dev/null -x c++ - >/dev/null 2>&1 && echo "-DHAVE_SYSLOG"))
+endif
+
 #? The Directories, Source, Includes, Objects and Binary
 SRCDIR		:= src
-INCDIRS		:= include $(wildcard lib/**/include)
+INCDIRS		:= include
 BUILDDIR	:= obj
 TARGETDIR	:= bin
 SRCEXT		:= cpp
@@ -172,7 +179,7 @@ override GOODFLAGS := $(foreach flag,$(TESTFLAGS),$(strip $(shell echo "int main
 override REQFLAGS   := -std=c++20
 WARNFLAGS			:= -Wall -Wextra -pedantic
 OPTFLAGS			:= -O2 -ftree-vectorize -flto=$(LTO)
-LDCXXFLAGS			:= -pthread -DFMT_HEADER_ONLY -D_FORTIFY_SOURCE=2 -D_GLIBCXX_ASSERTIONS -D_FILE_OFFSET_BITS=64 $(GOODFLAGS) $(ADDFLAGS)
+LDCXXFLAGS			:= -pthread -DFMT_HEADER_ONLY -D_FORTIFY_SOURCE=2 -D_GLIBCXX_ASSERTIONS _LIBCPP_ENABLE_ASSERTIONS=1 -D_FILE_OFFSET_BITS=64 $(GOODFLAGS) $(ADDFLAGS)
 override CXXFLAGS	+= $(REQFLAGS) $(LDCXXFLAGS) $(OPTFLAGS) $(WARNFLAGS)
 override LDFLAGS	+= $(LDCXXFLAGS) $(OPTFLAGS) $(WARNFLAGS)
 INC					:= $(foreach incdir,$(INCDIRS),-isystem $(incdir)) -I$(SRCDIR)

README.md

@@ -344,6 +344,10 @@ Also needs a UTF8 locale and a font that covers:
 
    Append `STRIP=true` to force stripping of debug symbols (adds `-s` linker flag).
 
+   Append `ENABLE_SYSLOG=true` to log to syslog instead of a log file.
+
+   Append `ENABLE_JOURNALD=true` to log to journald instead of a log file.
+
    Append `ARCH=<architecture>` to manually set the target architecture.
    If omitted the makefile uses the machine triple (output of `-dumpmachine` compiler parameter) to detect the target system.
 
@@ -447,6 +451,8 @@ Also needs a UTF8 locale and a font that covers:
    | `-DBTOP_STATIC=<ON\|OFF>`       | Enables static linking (OFF by default)                                 |
    | `-DBTOP_LTO=<ON\|OFF>`          | Enables link time optimization (ON by default)                          |
    | `-DBTOP_USE_MOLD=<ON\|OFF>`     | Use mold to link btop (OFF by default)                                  |
+   | `-DBTOP_SYSLOG=<ON\|OFF>`       | Log to syslog instead of a log file (OFF by default)                    |
+   | `-DBTOP_JOURNALD=<ON\|OFF>`     | Log to journald instead of a log file (OFF by default)                  |
    | `-DBTOP_PEDANTIC=<ON\|OFF>`     | Compile with additional warnings (OFF by default)                       |
    | `-DBTOP_WERROR=<ON\|OFF>`       | Compile with warnings as errors (OFF by default)                        |
    | `-DCMAKE_INSTALL_PREFIX=<path>` | The installation prefix ('/usr/local' by default)                       |
@@ -509,6 +515,8 @@ Also needs a UTF8 locale and a font that covers:
 
    Append `STRIP=true` to force stripping of debug symbols (adds `-s` linker flag).
 
+   Append `ENABLE_SYSLOG=true` to log to syslog instead of a log file.
+
    Append `ARCH=<architecture>` to manually set the target architecture.
    If omitted the makefile uses the machine triple (output of `-dumpmachine` compiler parameter) to detect the target system.
 
@@ -603,6 +611,8 @@ Also needs a UTF8 locale and a font that covers:
 
    Append `STRIP=true` to force stripping of debug symbols (adds `-s` linker flag).
 
+   Append `ENABLE_SYSLOG=true` to log to syslog instead of a log file.
+
    Append `ARCH=<architecture>` to manually set the target architecture.
    If omitted the makefile uses the machine triple (output of `-dumpmachine` compiler parameter) to detect the target system.
 
@@ -719,6 +729,7 @@ Also needs a UTF8 locale and a font that covers:
    | `-DBTOP_STATIC=<ON\|OFF>`       | Enables static linking (OFF by default)                                 |
    | `-DBTOP_LTO=<ON\|OFF>`          | Enables link time optimization (ON by default)                          |
    | `-DBTOP_USE_MOLD=<ON\|OFF>`     | Use mold to link btop (OFF by default)                                  |
+   | `-DBTOP_SYSLOG=<ON\|OFF>`       | Log to syslog instead of a log file (OFF by default)                    |
    | `-DBTOP_PEDANTIC=<ON\|OFF>`     | Compile with additional warnings (OFF by default)                       |
    | `-DBTOP_WERROR=<ON\|OFF>`       | Compile with warnings as errors (OFF by default)                        |
    | `-DCMAKE_INSTALL_PREFIX=<path>` | The installation prefix ('/usr/local' by default)                       |

cmake/Modules/FindSystemd.cmake

@@ -0,0 +1,26 @@
+# SPDX-License-Identifier: Apache-2.0
+#
+# Find libSystemd, the Kernel Data Access Library
+#
+
+if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
+  find_path(Systemd_INCLUDE_DIR NAMES systemd/sd-journal.h)
+  find_library(Systemd_LIBRARY NAMES systemd)
+
+  include(FindPackageHandleStandardArgs)
+  find_package_handle_standard_args(Systemd REQUIRED_VARS Systemd_LIBRARY Systemd_INCLUDE_DIR)
+
+  if(Systemd_FOUND AND NOT TARGET Systemd::Systemd)
+    add_library(Systemd::Systemd UNKNOWN IMPORTED)
+    set_target_properties(Systemd::Systemd PROPERTIES
+      IMPORTED_LOCATION "${Systemd_LIBRARY}"
+    )
+  endif()
+
+  if(Systemd_FOUND AND NOT TARGET Systemd::Journald)
+    add_library(Systemd::Journald ALIAS Systemd::Systemd)
+  endif()
+
+  mark_as_advanced(Systemd_INCLUDE_DIR Systemd_LIBRARY)
+endif()
+

src/btop_log.cpp

@@ -5,9 +5,16 @@
 #include <filesystem>
 #include <iostream>
 #include <mutex>
+#include <source_location>
 #include <string>
 #include <string_view>
 
+#if defined(HAVE_JOURNALD)
+	#include <systemd/sd-journal.h>
+#elif defined(HAVE_SYSLOG)
+	#include <syslog.h>
+#endif
+
 #include <fmt/core.h>
 #include <fmt/ostream.h>
 
@@ -18,7 +25,7 @@ namespace fs = std::filesystem;
 
 namespace Logger {
 	using namespace Tools;
-	std::mutex log_mtx {};
+	std::mutex log_mtx{};
 	bool first = true;
 	const string tdf = "%Y/%m/%d (%T) | ";
 
@@ -44,12 +51,39 @@ namespace Logger {
 
 	void set(const string& level) { loglevel = v_index(log_levels, level); }
 
-	void log_write(const size_t level, const std::string_view msg) {
-		if (loglevel < level or logfile.empty()) {
+	void log(const size_t level, const std::string_view msg, const std::source_location location) {
+		if (loglevel < level) {
 			return;
 		}
-		std::lock_guard lock {log_mtx};
+
+		std::lock_guard lock{log_mtx};
 		lose_priv neutered{};
+
+#if defined(HAVE_JOURNALD) || defined(HAVE_SYSLOG)
+		int status = LOG_DEBUG;
+		switch (level) {
+			case 1: status = LOG_ERR; break;
+			case 2: status = LOG_WARNING; break;
+			case 3: status = LOG_INFO; break;
+			case 4: status = LOG_DEBUG; break;
+		}
+#endif
+
+#if defined(HAVE_JOURNALD)
+		sd_journal_print_with_location( // NOLINT(cppcoreguidelines-pro-type-vararg)
+			status,
+			("CODE_FILE="s + location.file_name()).data(),
+			("CODE_LINE="s + std::to_string(location.line())).data(),
+			location.function_name(),
+			"%s",
+			msg.data()
+		);
+#elif defined(HAVE_SYSLOG)
+		syslog(status, "%s", msg.data()); // NOLINT(cppcoreguidelines-pro-type-vararg)
+#else
+		if (logfile.empty()) {
+			return;
+		}
 		std::error_code ec;
 		try {
 			if (fs::exists(logfile) and fs::file_size(logfile, ec) > 1024 << 10 and not ec) {
@@ -80,5 +114,6 @@ namespace Logger {
 			logfile.clear();
 			throw std::runtime_error(fmt::format("Exception in Logger::log_write() : {}", e.what()));
 		}
+#endif
 	}
 } // namespace Logger

src/btop_log.hpp

@@ -3,6 +3,7 @@
 #pragma once
 
 #include <filesystem>
+#include <source_location>
 #include <string_view>
 #include <vector>
 
@@ -16,30 +17,64 @@ namespace Logger {
 		"INFO",
 		"DEBUG",
 	};
+
 	extern std::filesystem::path logfile;
 
 	//* Set log level, valid arguments: "DISABLED", "ERROR", "WARNING", "INFO" and "DEBUG"
 	void set(const std::string& level);
 
-	void log_write(const size_t level, const std::string_view msg);
+	void log(const size_t level, const std::string_view msg, const std::source_location location);
+
+	template<typename... Args>
+	struct error {
+		error(
+			const fmt::format_string<Args...> fmt, Args&&... args,
+			const std::source_location location = std::source_location::current()
+		) {
+			log(1, fmt::format(fmt, std::forward<Args>(args)...), location);
+		}
+	};
+
+	template<typename... Args>
+	struct warning {
+		warning(
+			const fmt::format_string<Args...> fmt, Args&&... args,
+			const std::source_location location = std::source_location::current()
+		) {
+			log(2, fmt::format(fmt, std::forward<Args>(args)...), location);
+		}
+	};
+
+	template<typename... Args>
+	struct info {
+		info(
+			const fmt::format_string<Args...> fmt, Args&&... args,
+			const std::source_location location = std::source_location::current()
+		) {
+			log(3, fmt::format(fmt, std::forward<Args>(args)...), location);
+		}
+	};
+
+	template<typename... Args>
+	struct debug {
+		debug(
+			const fmt::format_string<Args...> fmt, Args&&... args,
+			const std::source_location location = std::source_location::current()
+		) {
+			log(4, fmt::format(fmt, std::forward<Args>(args)...), location);
+		}
+	};
 
-	template <typename... T>
-	inline void error(const fmt::format_string<T...> fmt, T&&... args) {
-		log_write(1, fmt::format(fmt, std::forward<T>(args)...));
-	}
+	// Deduction guide to allow default arguement after variadic template
+	template<typename... Args>
+	error(const std::string_view, Args&&...) -> error<Args...>;
 
-	template <typename... T>
-	inline void warning(const fmt::format_string<T...> fmt, T&&... args) {
-		log_write(2, fmt::format(fmt, std::forward<T>(args)...));
-	}
+	template<typename... Args>
+	warning(const std::string_view, Args&&...) -> warning<Args...>;
 
-	template <typename... T>
-	inline void info(const fmt::format_string<T...> fmt, T&&... args) {
-		log_write(3, fmt::format(fmt, std::forward<T>(args)...));
-	}
+	template<typename... Args>
+	info(const std::string_view, Args&&...) -> info<Args...>;
 
-	template <typename... T>
-	inline void debug(const fmt::format_string<T...> fmt, T&&... args) {
-		log_write(4, fmt::format(fmt, std::forward<T>(args)...));
-	}
+	template<typename... Args>
+	debug(const std::string_view, Args&&...) -> debug<Args...>;
 } // namespace Logger