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-rw-r--r--lib/base/atomic-file.cpp116
1 files changed, 116 insertions, 0 deletions
diff --git a/lib/base/atomic-file.cpp b/lib/base/atomic-file.cpp
new file mode 100644
index 0000000..361a3d2
--- /dev/null
+++ b/lib/base/atomic-file.cpp
@@ -0,0 +1,116 @@
+/* Icinga 2 | (c) 2022 Icinga GmbH | GPLv2+ */
+
+#include "base/atomic-file.hpp"
+#include "base/exception.hpp"
+#include "base/utility.hpp"
+#include <utility>
+
+#ifdef _WIN32
+# include <io.h>
+# include <windows.h>
+#else /* _WIN32 */
+# include <errno.h>
+# include <unistd.h>
+#endif /* _WIN32 */
+
+using namespace icinga;
+
+AtomicFile::AtomicFile(String path, int mode) : m_Path(std::move(path))
+{
+ m_TempFilename = m_Path + ".tmp.XXXXXX";
+
+#ifdef _WIN32
+ m_Fd = Utility::MksTemp(&m_TempFilename[0]);
+#else /* _WIN32 */
+ m_Fd = mkstemp(&m_TempFilename[0]);
+#endif /* _WIN32 */
+
+ if (m_Fd < 0) {
+ auto error (errno);
+
+ BOOST_THROW_EXCEPTION(posix_error()
+ << boost::errinfo_api_function("mkstemp")
+ << boost::errinfo_errno(error)
+ << boost::errinfo_file_name(m_TempFilename));
+ }
+
+ try {
+ exceptions(failbit | badbit);
+
+ open(boost::iostreams::file_descriptor(
+ m_Fd,
+ // Rationale: https://github.com/boostorg/iostreams/issues/152
+ boost::iostreams::never_close_handle
+ ));
+
+ if (chmod(m_TempFilename.CStr(), mode) < 0) {
+ auto error (errno);
+
+ BOOST_THROW_EXCEPTION(posix_error()
+ << boost::errinfo_api_function("chmod")
+ << boost::errinfo_errno(error)
+ << boost::errinfo_file_name(m_TempFilename));
+ }
+ } catch (...) {
+ if (is_open()) {
+ close();
+ }
+
+ (void)::close(m_Fd);
+ (void)unlink(m_TempFilename.CStr());
+ throw;
+ }
+}
+
+AtomicFile::~AtomicFile()
+{
+ if (is_open()) {
+ try {
+ close();
+ } catch (...) {
+ // Destructor must not throw
+ }
+ }
+
+ if (m_Fd >= 0) {
+ (void)::close(m_Fd);
+ }
+
+ if (!m_TempFilename.IsEmpty()) {
+ (void)unlink(m_TempFilename.CStr());
+ }
+}
+
+void AtomicFile::Commit()
+{
+ flush();
+
+ auto h ((*this)->handle());
+
+#ifdef _WIN32
+ if (!FlushFileBuffers(h)) {
+ auto err (GetLastError());
+
+ BOOST_THROW_EXCEPTION(win32_error()
+ << boost::errinfo_api_function("FlushFileBuffers")
+ << errinfo_win32_error(err)
+ << boost::errinfo_file_name(m_TempFilename));
+ }
+#else /* _WIN32 */
+ if (fsync(h)) {
+ auto err (errno);
+
+ BOOST_THROW_EXCEPTION(posix_error()
+ << boost::errinfo_api_function("fsync")
+ << boost::errinfo_errno(err)
+ << boost::errinfo_file_name(m_TempFilename));
+ }
+#endif /* _WIN32 */
+
+ close();
+ (void)::close(m_Fd);
+ m_Fd = -1;
+
+ Utility::RenameFile(m_TempFilename, m_Path);
+ m_TempFilename = "";
+}