From d800f6cf4f11962f0db05178d716b4eda494e1fa Mon Sep 17 00:00:00 2001
From: Michael Zanetti <michael_zanetti@gmx.net>
Date: Wed, 13 Sep 2017 18:26:28 +0200
Subject: [PATCH] try to fix broken databases (by rotating the old file and
 starting a new one)

---
 server/logging/logengine.cpp | 36 +++++++++++++++++++++++++++++++-----
 server/logging/logengine.h   |  4 +++-
 2 files changed, 34 insertions(+), 6 deletions(-)

diff --git a/server/logging/logengine.cpp b/server/logging/logengine.cpp
index 61757f43..ac86b922 100644
--- a/server/logging/logengine.cpp
+++ b/server/logging/logengine.cpp
@@ -123,6 +123,7 @@
 #include <QSqlError>
 #include <QMetaEnum>
 #include <QDateTime>
+#include <QFileInfo>
 
 #define DB_SCHEMA_VERSION 2
 
@@ -145,14 +146,20 @@ LogEngine::LogEngine(QObject *parent):
 
     if (!m_db.isValid()) {
         qCWarning(dcLogEngine) << "Database not valid:" << m_db.lastError().driverText() << m_db.lastError().databaseText();
-        return;
+        rotate(m_db.databaseName());
     }
     if (!m_db.open()) {
         qCWarning(dcLogEngine) << "Error opening log database:" << m_db.lastError().driverText() << m_db.lastError().databaseText();
-        return;
+        rotate(m_db.databaseName());
     }
 
-    initDB();
+    if (!initDB()) {
+        qCWarning(dcLogEngine()) << "Error initializing database. Trying to correct it.";
+        rotate(m_db.databaseName());
+        if (!initDB()) {
+            qCWarning(dcLogEngine()) << "Error fixing log database. Giving up. Logs can't be stored.";
+        }
+    }
 }
 
 /*! Destructs the \l{LogEngine}. */
@@ -376,7 +383,22 @@ void LogEngine::checkDBSize()
     }
 }
 
-void LogEngine::initDB()
+void LogEngine::rotate(const QString &dbName)
+{
+    int index = 1;
+    while (QFileInfo(QString("%1.%2").arg(dbName).arg(index)).exists()) {
+        index++;
+    }
+    qCDebug(dcLogEngine()) << "Backing up old database file to" << QString("%1.%2").arg(dbName).arg(index);
+    QFile f(dbName);
+    if (!f.rename(QString("%1.%2").arg(dbName).arg(index))) {
+        qCWarning(dcLogEngine()) << "Error backing up old database.";
+    } else {
+        qCDebug(dcLogEngine()) << "Successfully moved old databse";
+    }
+}
+
+bool LogEngine::initDB()
 {
     m_db.close();
     m_db.open();
@@ -397,6 +419,7 @@ void LogEngine::initDB()
         }
     } else {
         qCWarning(dcLogEngine) << "Broken log database. Version not found in metadata table.";
+        return false;
     }
 
     if (!m_db.tables().contains("sourceTypes")) {
@@ -435,13 +458,16 @@ void LogEngine::initDB()
                    "FOREIGN KEY(loggingEventType) REFERENCES loggingEventTypes(id)"
                    ");");
 
-        if (m_db.lastError().isValid())
+        if (m_db.lastError().isValid()) {
             qCWarning(dcLogEngine) << "Error creating log table in database. Driver error:" << m_db.lastError().driverText() << "Database error:" << m_db.lastError().databaseText();
+            return false;
+        }
 
 
     }
 
     qCDebug(dcLogEngine) << "Initialized logging DB successfully. (maximum DB size:" << m_dbMaxSize << ")";
+    return true;
 }
 
 }
diff --git a/server/logging/logengine.h b/server/logging/logengine.h
index 8dcd9aa0..a9184f0b 100644
--- a/server/logging/logengine.h
+++ b/server/logging/logengine.h
@@ -52,10 +52,12 @@ private:
     QSqlDatabase m_db;
     int m_dbMaxSize;
 
-    void initDB();
+    bool initDB();
     void appendLogEntry(const LogEntry &entry);
     void checkDBSize();
 
+    void rotate(const QString &dbName);
+
 private:
     // Only GuhCore and ruleEngine are allowed to log events.
     friend class GuhCore;