slightly more robust error handling

src/EventLoop.cpp

@@ -8,12 +8,15 @@ namespace nanosm {
 		epollFd = epoll_create1(EPOLL_CLOEXEC);
 
 		if(epollFd == -1) {
-			perror("You Banned From Epoll, Rules");
+			throw std::system_error(std::make_error_code(static_cast<std::errc>(errno)));
+			return;
 		}
 	}
 
 	EventLoop::~EventLoop() {
-		close(epollFd);
+		if(epollFd == -1) {
+			close(epollFd);
+		}
 	}
 
 	void EventLoop::Post(PostFn func) {
@@ -56,25 +59,27 @@ namespace nanosm {
 		UniqueArray<epoll_event> events { 16 };
 
 		while(!shouldStop) {
-			auto nevents = epoll_wait(epollFd, events.Get(), events.Size(), 10);
+			// The timeout here is larger than it probably would be if e.g: this was dealing with sockets,
-			if(nevents == -1) {
+			// mostly because nanosm is designed to only really use CPU if it has to (i.e: a process died, timer elapsed, etc)
-				perror("epoll_wait");
+			auto nrEvents = epoll_wait(epollFd, events.Get(), events.Size(), 50);
-				break;
+			if(nrEvents == -1) {
+				throw std::system_error(std::make_error_code(static_cast<std::errc>(errno)));
 			}
 
-			// All OK, let's check for events now
+			if(nrEvents != 0) {
-
+				for(int i = 0; i < nrEvents; ++i) {
-			for(int i = 0; i < nevents; ++i) {
+					for(auto pollable : ioObjects) {
-				for(auto pollable : ioObjects) {
+						if(auto fd = pollable->GetFD(); fd != -1) {
-					if(auto fd = pollable->GetFD(); fd != -1) {
+							// Signal any events that occur for this
-						// Signal any events that occur for this
+							if(events[i].data.fd == fd)
-						if(events[i].data.fd == fd)
+								pollable->OnReady(events[i].events);
-							pollable->OnReady(events[i].events);
+						}
 					}
 				}
 			}
 
-			// Run the topmost callback once every event loop iteration.
+			// Run the topmost callback once every event loop iteration,
+			// even if epoll never signaled readiness.
 			if(!postCallbacks.empty()) {
 				auto& frontCallback = postCallbacks.front();
 				frontCallback();

src/Timer.cpp

@@ -7,8 +7,9 @@ namespace nanosm {
 	Timer::Timer(nanosm::EventLoop& ev)
 		: nanosm::EventLoop::IoObject(ev) {
 		timerFd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK | TFD_CLOEXEC);
-		if(timerFd < 0)
+		if(timerFd < 0) {
-			perror("timerfd_create");
+			throw std::system_error(std::make_error_code(static_cast<std::errc>(errno)));
+		}
 	}
 
 	Timer::~Timer() {

src/main.cpp

@@ -2,6 +2,7 @@
 #include <format>
 #include <map>
 #include <memory>
+#include <system_error>
 #include <toml++/toml.hpp>
 
 #include "EventLoop.hpp"
@@ -82,7 +83,12 @@ struct NanoSm {
 			this->SpawnAllApps();
 		});
 
-		ev.Run();
+		try {
+			ev.Run();
+		} catch(std::exception& ec) {
+			nanosm::log::Error("NanoSm", "Unhandled exception in event loop: {}", ec.what());
+			return 1;
+		}
 		return 0;
 	}
 
@@ -105,51 +111,55 @@ fs::path GetConfigPath() {
 }
 
 int main(int argc, char** argv) {
-	NanoSm nanosm;
-
-	auto configPath = GetConfigPath();
-
 	try {
-		auto tomlTable = toml::parse_file(configPath.string());
+		NanoSm nanosm;
 
-		if(tomlTable["nanosm"].is_table() && tomlTable["nanosm"]["apps"].is_table()) {
+		auto configPath = GetConfigPath();
-			auto restartptr = tomlTable["nanosm"]["restart-time"].as_integer();
 
-			if(!restartptr) {
+		try {
-				nanosm::log::Warn("NanoSm", "No restart time provided in nanosm.toml. Defaulting to 1 second.");
+			auto tomlTable = toml::parse_file(configPath.string());
-				nanosm.SetRestartTime(1);
+
+			if(tomlTable["nanosm"].is_table() && tomlTable["nanosm"]["apps"].is_table()) {
+				auto restartptr = tomlTable["nanosm"]["restart-time"].as_integer();
+
+				if(!restartptr) {
+					nanosm::log::Warn("NanoSm", "No restart time provided in nanosm.toml. Defaulting to 1 second.");
+					nanosm.SetRestartTime(1);
+				} else {
+					nanosm.SetRestartTime(static_cast<u32>(restartptr->get()));
+				}
+
+				for(auto [key, value] : *tomlTable["nanosm"]["apps"].as_table()) {
+					if(!value.is_table()) {
+						nanosm::log::Warn("NanoSm", "Ignoring invalid app \"{}\" in configuration file", key.str());
+						continue;
+					}
+
+					auto& appTable = *value.as_table();
+
+					if(!appTable.get("command")->is_string()) {
+						nanosm::log::Warn("NanoSm", "Ignoring invalid app \"{}\" in configuration file", key.str());
+						continue;
+					}
+
+					auto cmd = appTable.get("command")->as_string()->get();
+
+					nanosm::log::Info("NanoSm", "Adding app \"{}\" with command \"{}\"", key.str(), cmd);
+
+					nanosm.AddApp(std::string(key.data(), key.length()), std::string(cmd.data(), cmd.length()));
+				}
 			} else {
-				nanosm.SetRestartTime(static_cast<u32>(restartptr->get()));
+				nanosm::log::Error("NanoSm", "Configuration file {} doesn't have required values. Exiting with failure.", configPath.string());
+				return 1;
 			}
 
-			for(auto [key, value] : *tomlTable["nanosm"]["apps"].as_table()) {
+			return nanosm.Run();
-				if(!value.is_table()) {
+		} catch(toml::parse_error& pe) {
-					nanosm::log::Warn("NanoSm", "Ignoring invalid app \"{}\" in configuration file", key.str());
+			std::fprintf(stderr, "Error parsing config file \"%s\": %s\n", configPath.c_str(), pe.description().data());
-					continue;
-				}
-
-				auto& appTable = *value.as_table();
-
-				if(!appTable.get("command")->is_string()) {
-					nanosm::log::Warn("NanoSm", "Ignoring invalid app \"{}\" in configuration file", key.str());
-					continue;
-				}
-
-				auto cmd = appTable.get("command")->as_string()->get();
-
-				nanosm::log::Info("NanoSm", "Adding app \"{}\" with command \"{}\"", key.str(), cmd);
-
-				nanosm.AddApp(std::string(key.data(), key.length()), std::string(cmd.data(), cmd.length()));
-			}
-		} else {
-			nanosm::log::Error("NanoSm", "Configuration file {} doesn't have required values. Exiting with failure.", configPath.string());
 			return 1;
 		}
-
+	} catch(std::exception& ec) {
-	} catch(toml::parse_error& pe) {
+		nanosm::log::Error("NanoSm", "Error initalizing NanoSm: {}", ec.what());
-		std::fprintf(stderr, "Error parsing config file \"%s\": %s\n", configPath.c_str(), pe.description().data());
 		return 1;
 	}
-
-	return nanosm.Run();
 }