From e51189ea43cac4d8d31f240a7d2b29f01324d4dd Mon Sep 17 00:00:00 2001
From: psychon <psychon@726aef4b-f618-498e-8847-2d620e286838>
Date: Wed, 18 Mar 2009 15:45:43 +0000
Subject: [PATCH] Get rid of znc.conf-backup

The old code created a copy of the config file before writing a new version.
This backup is now gone.

With this patch the config is written to a temporary file znc.conf~ and then
fsync()d to make sure the data safely is on the disk. Then the real config file
znc.conf is overwritten with this temporary file via a rename() call.

This should be safer than the old way, plus it gets rid of a unneeded file.


git-svn-id: https://znc.svn.sourceforge.net/svnroot/znc/trunk@1432 726aef4b-f618-498e-8847-2d620e286838
---
 znc.cpp | 28 +++++++---------------------
 znc.h   |  2 --
 2 files changed, 7 insertions(+), 23 deletions(-)

diff --git a/znc.cpp b/znc.cpp
index 338a9994..9b355f93 100644
--- a/znc.cpp
+++ b/znc.cpp
@@ -483,29 +483,11 @@ CString CZNC::ExpandConfigPath(const CString& sConfigFile) {
 	return sRetPath;
 }
 
-bool CZNC::BackupConfig() const {
-	CString sBackup = GetConfigFile() + "-backup";
-
-	// Create a new backup overwriting an old one we might have
-	if (CFile::Copy(m_sConfigFile, sBackup, true))
-		return true;
-
-	// Don't abort if no config file exists
-	if (!CFile::Exists(m_sConfigFile))
-		// No backup because we got nothing to backup
-		return true;
-
-	return false;
-}
-
 bool CZNC::WriteConfig() {
-	CFile File(GetConfigFile());
+	// We first write to a temporary file and then move it to the right place
+	CFile File(GetConfigFile() + "~");
 
-	if (!BackupConfig()) {
-		return false;
-	}
-
-	if (m_sConfigFile.empty() || !File.Open(O_WRONLY | O_CREAT | O_TRUNC, 0600)) {
+	if (GetConfigFile().empty() || !File.Open(O_WRONLY | O_CREAT | O_TRUNC, 0600)) {
 		return false;
 	}
 
@@ -576,8 +558,12 @@ bool CZNC::WriteConfig() {
 		}
 	}
 
+	File.Sync();
 	File.Close();
 
+	// We wrote to a temporary name, move it to the right place
+	File.Move(GetConfigFile(), true);
+
 	return true;
 }
 
diff --git a/znc.h b/znc.h
index d3c67620..553eacf5 100644
--- a/znc.h
+++ b/znc.h
@@ -185,8 +185,6 @@ private:
 	bool DoRehash(CString& sError);
 	// Returns true if something was done
 	bool HandleUserDeletion();
-	// Backup znc.conf
-	bool BackupConfig() const;
 
 protected:
 	time_t				m_TimeStarted;