From bbd65d9c1adcb9d8c76ba6fcb2b76a8064935648 Mon Sep 17 00:00:00 2001
From: Jelmer de Hen <18084450+jelmerdehen@users.noreply.github.com>
Date: Sun, 26 Apr 2026 04:04:42 +0200
Subject: [PATCH] fix(config): write config atomically via tmp + rename

writeFile overwrote the existing config in place. A crash, power loss,
or out-of-disk during the write would leave a truncated or corrupt
config behind. Write to <path>.tmp and rename, so the destination
either holds the previous contents or the full new contents. Clean up
the tmp file on error.
---
 src/logid/Configuration.cpp | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/logid/Configuration.cpp b/src/logid/Configuration.cpp
index e49b5eaf..2b90a73e 100644
--- a/src/logid/Configuration.cpp
+++ b/src/logid/Configuration.cpp
@@ -56,13 +56,19 @@ Configuration::Configuration() {
 
 void Configuration::save() {
     config::set(_config.getRoot(), *this);
+    const std::string tmp_path = _config_file + ".tmp";
     try {
-        _config.writeFile(_config_file.c_str());
+        _config.writeFile(tmp_path.c_str());
+        std::filesystem::rename(tmp_path, _config_file);
     } catch (const FileIOException& e) {
+        std::error_code ec;
+        std::filesystem::remove(tmp_path, ec);
         logPrintf(ERROR, "I/O Error while writing %s: %s",
                   _config_file.c_str(), e.what());
         throw;
     } catch (const std::exception& e) {
+        std::error_code ec;
+        std::filesystem::remove(tmp_path, ec);
         logPrintf(ERROR, "Error while writing %s: %s",
                   _config_file.c_str(), e.what());
         throw;