Backup znc.conf once when updating to networks

This copies znc.conf to znc.conf.backup, if that file doesn't exist yet.

Signed-off-by: Uli Schlachter <psychon@znc.in>

User.cpp

@@ -338,6 +338,7 @@ bool CUser::ParseConfig(CConfig* pConfig, CString& sError) {
 		}
 
 		if (pNetwork) {
+			CZNC::Get().BackupConfigOnce();
 			CUtils::PrintMessage("NOTICE: Found deprecated config, upgrading to a network");
 
 			if (!pNetwork->ParseConfig(pConfig, sError, true)) {

znc.cpp

@@ -984,6 +984,22 @@ size_t CZNC::FilterUncommonModules(set<CModInfo>& ssModules) {
 	return uNrRemoved;
 }
 
+void CZNC::BackupConfigOnce()
+{
+	static bool didBackup = false;
+	if (didBackup)
+		return;
+	didBackup = true;
+
+	CUtils::PrintAction("Creating a config backup");
+
+	CString sBackup = CDir::ChangeDir(m_sConfigFile, "../znc.conf.backup");
+	if (CFile::Copy(m_sConfigFile, sBackup))
+		CUtils::PrintStatus(true, sBackup);
+	else
+		CUtils::PrintStatus(false, strerror(errno));
+}
+
 bool CZNC::ParseConfig(const CString& sConfig)
 {
 	CString s;

znc.h

@@ -51,6 +51,7 @@ public:
 	bool WriteConfig();
 	bool ParseConfig(const CString& sConfig);
 	bool RehashConfig(CString& sError);
+	void BackupConfigOnce();
 	static CString GetVersion();
 	static CString GetTag(bool bIncludeVersion = true);
 	CString GetUptime() const;