Fix crash if exception thrown during daemon startup

include/multipass/logging/multiplexing_logger.h

@@ -31,11 +31,13 @@ namespace logging
 class MultiplexingLogger : public Logger
 {
 public:
+    explicit MultiplexingLogger(UPtr system_logger);
     void log(Level level, CString category, CString message) const override;
     void add_logger(const Logger* logger);
     void remove_logger(const Logger* logger);
 
 private:
+    UPtr system_logger;
     mutable std::shared_timed_mutex mutex;
     std::vector<const Logger*> loggers;
 };

src/daemon/daemon_config.cpp

@@ -64,8 +64,7 @@ std::unique_ptr<const mp::DaemonConfig> mp::DaemonConfigBuilder::build()
     if (logger == nullptr)
         logger = std::make_unique<mpl::StandardLogger>(verbosity_level);
 
-    auto multiplexing_logger = std::make_shared<mpl::MultiplexingLogger>();
-    multiplexing_logger->add_logger(logger.get());
+    auto multiplexing_logger = std::make_shared<mpl::MultiplexingLogger>(std::move(logger));
     mpl::set_logger(multiplexing_logger);
 
     if (cache_directory.isEmpty())
@@ -113,6 +112,6 @@ std::unique_ptr<const mp::DaemonConfig> mp::DaemonConfigBuilder::build()
     return std::unique_ptr<const DaemonConfig>(
         new DaemonConfig{std::move(url_downloader), std::move(factory), std::move(image_hosts), std::move(vault),
                          std::move(name_generator), std::move(ssh_key_provider), std::move(cert_provider),
-                         std::move(client_cert_store), std::move(logger), multiplexing_logger, cache_directory,
+                         std::move(client_cert_store), multiplexing_logger, cache_directory,
                          data_directory, server_address, ssh_username, connection_type, image_refresh_timer});
 }

src/daemon/daemon_config.h

@@ -49,7 +49,6 @@ struct DaemonConfig
     const std::unique_ptr<SSHKeyProvider> ssh_key_provider;
     const std::unique_ptr<CertProvider> cert_provider;
     const std::unique_ptr<CertStore> client_cert_store;
-    const std::unique_ptr<logging::Logger> system_logger;
     const std::shared_ptr<logging::MultiplexingLogger> logger;
     const multipass::Path cache_directory;
     const multipass::Path data_directory;

src/logging/multiplexing_logger.cpp

@@ -21,9 +21,15 @@
 
 namespace mpl = multipass::logging;
 
+multipass::logging::MultiplexingLogger::MultiplexingLogger(UPtr system_logger)
+    : system_logger{std::move(system_logger)}
+{
+}
+
 void mpl::MultiplexingLogger::log(mpl::Level level, CString category, CString message) const
 {
     std::shared_lock<decltype(mutex)> lock{mutex};
+    system_logger->log(level, category, message);
     for (auto logger : loggers)
         logger->log(level, category, message);
 }
@@ -38,4 +44,4 @@ void mpl::MultiplexingLogger::remove_logger(const Logger* logger)
 {
     std::lock_guard<decltype(mutex)> lock{mutex};
     loggers.erase(std::remove(loggers.begin(), loggers.end(), logger), loggers.end());
-}
+}