Backup application files before patches

source/ApplicationState.cpp

@@ -129,6 +129,8 @@ void ApplicationState::render() {
         }
     } else if (this->state == STATE_INSTALL_STARTED) {
         WiiUScreen::drawLine("Installing...");
+    } else if (this->state == STATE_INSTALL_BACKUP) {
+        WiiUScreen::drawLine("... backing up files");
     } else if (this->state == STATE_INSTALL_FST) {
         WiiUScreen::drawLine("... patching title.fst");
     } else if (this->state == STATE_INSTALL_COS) {
@@ -233,7 +235,15 @@ void ApplicationState::update(Input *input) {
             return;
         }
     } else if (this->state == STATE_INSTALL_STARTED) {
+        this->state = STATE_INSTALL_BACKUP;
+    } else if (this->state == STATE_INSTALL_BACKUP) {
+        auto result = InstallerService::backupAppFiles(this->appInfo->path);
+        if (result != InstallerService::SUCCESS) {
+            setError(ERROR_INSTALLER_ERROR);
+            this->installerError = result;
+        } else {
             this->state = STATE_INSTALL_FST;
+        }
     } else if (this->state == STATE_INSTALL_FST) {
         auto result = InstallerService::patchFST(this->appInfo->path, this->appInfo->fstHash);
         if (result != InstallerService::SUCCESS) {

source/ApplicationState.h

@@ -26,6 +26,7 @@ public:
         STATE_INSTALL_NO_COLDBOOT_ALLOWED,
         STATE_INSTALL_CONFIRM_DIALOG,
         STATE_INSTALL_STARTED,
+        STATE_INSTALL_BACKUP,
         STATE_INSTALL_FST,
         STATE_INSTALL_COS,
         STATE_INSTALL_RPX,

source/InstallerService.cpp

@@ -317,6 +317,41 @@ std::string InstallerService::ErrorMessage(InstallerService::eResults error) {
 
 }
 
+InstallerService::eResults InstallerService::backupAppFiles(const std::string &path) {
+    std::string backupList[][2] = {
+        {"/code/title.fst", "/content/title.fst.bak"},
+        {"/code/cos.xml",   "/content/cos.xml.bak"  },
+        {"/code/safe.rpx",  "/content/safe.rpx.bak" },
+    };
+
+    for (auto &backupOp : backupList) {
+        std::string backupSrc = path + backupOp[0];
+        std::string backupDst = path + backupOp[1];
+
+        if (FSUtils::CheckFile(backupDst.c_str())) {
+            DEBUG_FUNCTION_LINE("Already backed up: %s", backupSrc.c_str());
+            continue;
+        }
+
+        if (!FSUtils::copyFile(backupSrc, backupDst)) {
+            DEBUG_FUNCTION_LINE("Failed to copy files");
+            return FAILED_TO_COPY_FILES;
+        }
+
+        std::string srcHash = Utils::hashFile(backupSrc);
+        std::string dstHash = Utils::hashFile(backupDst);
+
+        if (srcHash != dstHash) {
+            ::remove(backupDst.c_str());
+            DEBUG_FUNCTION_LINE("Hashes do not match. %s %s", srcHash.c_str(), dstHash.c_str());
+            return FAILED_TO_CHECK_HASH_COPIED_FILES;
+        }
+    }
+
+    DEBUG_FUNCTION_LINE("Successfully backed up app files");
+    return SUCCESS;
+}
+
 InstallerService::eResults InstallerService::patchFST(const std::string &path, const char *fstHash) {
     std::string fstFilePath = path + "/code/title.fst";
     std::string fstBackupFilePath = path + "/code/backup.fst";

source/InstallerService.h

@@ -43,6 +43,8 @@ public:
         return false;
     }
 
+    static eResults backupAppFiles(const std::string &path);
+
     static eResults patchCOS(const std::string &path, char *hash);
 
     static eResults checkCOS(const std::string &path, char *hash);