4 files changed, 56 insertions, 0 deletions
diff --git a/src/client.cpp b/src/client.cpp
index 483b260ee..d27896a14 100644
--- a/src/client.cpp
+++ b/src/client.cpp
@@ -110,6 +110,7 @@
 #include "utils/files.h"
 #include "utils/fuzzer.h"
 #include "utils/gettext.h"
+#include "utils/files.h"
 #include "utils/mkdir.h"
 #include "utils/paths.h"
 #include "utils/physfstools.h"
@@ -297,6 +298,7 @@ void Client::gameInit()
 #ifdef USE_FUZZER
     Fuzzer::init();
 #endif
+    backupConfig();
     initConfiguration();
     paths.setDefaultValues(getPathsDefaults());
     initFeatures();
@@ -2142,6 +2144,22 @@ void Client::initConfiguration() const
     }
 }
 
+void Client::backupConfig() const
+{
+    const std::string confName = mConfigDir + "/config.xml.bak";
+    const int maxFileIndex = 5;
+    ::remove((confName + toString(maxFileIndex)).c_str());
+    for (int f = maxFileIndex; f > 1; f --)
+    {
+        const std::string fileName1 = confName + toString(f - 1);
+        const std::string fileName2 = confName + toString(f);
+        Files::renameFile(fileName1, fileName2);
+    }
+    const std::string fileName3 = mConfigDir + "/config.xml";
+    const std::string fileName4 = confName + toString(1);
+    Files::copyFile(fileName3, fileName4);
+}
+
 /**
  * Parse the update host and determine the updates directory
  * Then verify that the directory exists (creating if needed).
diff --git a/src/client.h b/src/client.h
index dcf761847..dce388439 100644
--- a/src/client.h
+++ b/src/client.h
@@ -366,6 +366,8 @@ private:
 
     void storeSafeParameters() const;
 
+    void backupConfig() const;
+
     void gameClear();
 
     void testsClear();
diff --git a/src/utils/files.cpp b/src/utils/files.cpp
index 216a83991..40a4da757 100644
--- a/src/utils/files.cpp
+++ b/src/utils/files.cpp
@@ -163,3 +163,36 @@ int Files::renameFile(const std::string &restrict srcName,
     return ::rename(srcName.c_str(), dstName.c_str());
 #endif
 }
+
+int Files::copyFile(const std::string &restrict srcName,
+                    const std::string &restrict dstName)
+{
+    FILE *srcFile = fopen(srcName.c_str(), "rb");
+    if (srcFile == nullptr)
+        return -1;
+    FILE *dstFile = fopen(dstName.c_str(), "w+b");
+    if (dstFile == nullptr)
+    {
+        fclose(srcFile);
+        return -1;
+    }
+
+    const int chunkSize = 500000;
+    char *buf = new char[chunkSize];
+    size_t sz = 0;
+    while ((sz = fread(buf, 1, chunkSize, srcFile)))
+    {
+        if (fwrite(buf, 1, sz, dstFile) != sz)
+        {
+            delete [] buf;
+            fclose(srcFile);
+            fclose(dstFile);
+            return -1;
+        }
+    }
+
+    delete [] buf;
+    fclose(srcFile);
+    fclose(dstFile);
+    return 0;
+}
diff --git a/src/utils/files.h b/src/utils/files.h
index 5eb29031e..e7106c111 100644
--- a/src/utils/files.h
+++ b/src/utils/files.h
@@ -49,6 +49,9 @@ namespace Files
 
     int renameFile(const std::string &restrict pFrom,
                    const std::string &restrict pTo);
+
+    int copyFile(const std::string &restrict pFrom,
+                 const std::string &restrict pTo);
 }  // namespace Files
 
 #endif  // UTILS_FILES_H