From 444963e2690d0a2a05df62429379e633e1dfb1d4 Mon Sep 17 00:00:00 2001 From: Arseny Kapoulkine Date: Fri, 7 Oct 2022 22:13:04 -0700 Subject: Fix error handling in xml_document::save_file There were two conditions under which xml_document::save_file could previously return true even though the saving failed: - The last write to the file was buffered in stdio buffer, and it's that last write that would fail due to lack of disk space - The data has been written correctly but fclose failed to update file metadata, which can result in truncated size / missing inode updates. This change fixes both by adjusting save_file to fflush before the check, and also checking fclose results. Note that while fflush here is technically redundant, because it's implied by fclose, we must check ferror explicitly anyway, and so it feels a little cleaner to do most of the error handling in save_file_impl, so that the changes of fclose() failing are very slim. Of course, neither change guarantees that the contents of the file are going to be safe on disk following a power failure. --- src/pugixml.cpp | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/src/pugixml.cpp b/src/pugixml.cpp index 6b16dbb..7c84038 100644 --- a/src/pugixml.cpp +++ b/src/pugixml.cpp @@ -5070,7 +5070,7 @@ PUGI__NS_BEGIN xml_writer_file writer(file); doc.save(writer, indent, flags, encoding); - return ferror(file) == 0; + return fflush(file) == 0 && ferror(file) == 0; } struct name_null_sentry @@ -7423,7 +7423,7 @@ namespace pugi using impl::auto_deleter; // MSVC7 workaround auto_deleter file(impl::open_file(path_, (flags & format_save_file_text) ? "w" : "wb"), impl::close_file); - return impl::save_file_impl(*this, file.data, indent, flags, encoding); + return impl::save_file_impl(*this, file.data, indent, flags, encoding) && fclose(file.release()) == 0; } PUGI__FN bool xml_document::save_file(const wchar_t* path_, const char_t* indent, unsigned int flags, xml_encoding encoding) const @@ -7431,7 +7431,7 @@ namespace pugi using impl::auto_deleter; // MSVC7 workaround auto_deleter file(impl::open_file_wide(path_, (flags & format_save_file_text) ? L"w" : L"wb"), impl::close_file); - return impl::save_file_impl(*this, file.data, indent, flags, encoding); + return impl::save_file_impl(*this, file.data, indent, flags, encoding) && fclose(file.release()) == 0; } PUGI__FN xml_node xml_document::document_element() const -- cgit v1.1