From 997d84bfa0b8c53144590547bcffdb6d30695e9b Mon Sep 17 00:00:00 2001
From: "Alexander A. Klimov" <alexander.klimov@icinga.com>
Date: Wed, 17 Apr 2019 14:31:49 +0200
Subject: [PATCH] ApiListener#RotateLogFile(): don't overwrite previous log

---
 lib/remote/apilistener.cpp | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/lib/remote/apilistener.cpp b/lib/remote/apilistener.cpp
index 8aea09159..a5bbb8079 100644
--- a/lib/remote/apilistener.cpp
+++ b/lib/remote/apilistener.cpp
@@ -1148,13 +1148,11 @@ void ApiListener::RotateLogFile()
 	String oldpath = GetApiDir() + "log/current";
 	String newpath = GetApiDir() + "log/" + Convert::ToString(static_cast<int>(ts)+1);
 
-
-#ifdef _WIN32
-	_unlink(newpath.CStr());
-#endif /* _WIN32 */
-
-
-	(void) rename(oldpath.CStr(), newpath.CStr());
+	// If the log is being rotated more than once per second,
+	// don't overwrite the previous one, but silently deny rotation.
+	if (!Utility::PathExists(newpath)) {
+		(void) rename(oldpath.CStr(), newpath.CStr());
+	}
 }
 
 void ApiListener::LogGlobHandler(std::vector<int>& files, const String& file)