From 64c060e1f2d94d8277246d8cdd8a886010564770 Mon Sep 17 00:00:00 2001 From: Perttu Ahola Date: Fri, 1 Jan 2016 18:14:30 +0200 Subject: [PATCH] filesys: safeWriteToFile(): Remove the target file before rename only on Windows Removing the target file on other platforms was enabled likely unintentionally by commit 5f1f1151d3a9c113902630adc16cc3f4845da7ba. This may be the reason why there has been corruption of files on Linux on hard shutdowns. Previously I described the problem and this fix in issue #3084. --- src/filesys.cpp | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/src/filesys.cpp b/src/filesys.cpp index 5fdc97634..501f9ad6c 100644 --- a/src/filesys.cpp +++ b/src/filesys.cpp @@ -693,13 +693,22 @@ bool safeWriteToFile(const std::string &path, const std::string &content) os.flush(); os.close(); if (os.fail()) { + // Remove the temporary file because writing it failed and it's useless. remove(tmp_file.c_str()); return false; } - // Copy file + // Move the finished temporary file over the real file +#ifdef _WIN32 + // On POSIX compliant systems rename() is specified to be able to swap the + // file in place of the destination file, making this a truly error-proof + // transaction. + // However, on Windows, the target file has to be removed first. remove(path.c_str()); +#endif if(rename(tmp_file.c_str(), path.c_str())) { + // Remove the temporary file because moving it over the target file + // failed. remove(tmp_file.c_str()); return false; } else { -- 2.25.1