This is a  patch file for  "treesize" 0.54.1.  It makes  the following
changes:

      a. If the user selects the root directory,  a warning message is
         displayed.  The message advises  the user that the  specified
         operation may take a long time.

      b. Traversal of  "/proc" and "/sys" is  blocked.  This  prevents
         some lockups and/or crashes.

--- treesize-0.54.1.old/src/FAfolderAnalyzer.c
+++ treesize-0.54.1/src/FAfolderAnalyzer.c
@@ -90,7 +90,7 @@
 
 	int numSubFiles=0;
 	int numSubFolders=0;
-	DIR *dirFD;
+	DIR *dirFD = 0;
 	struct dirent *dirEnt;
 
 	bool accessible=true;
@@ -98,6 +98,14 @@
 	char *dirPath;
 
 	if( ! TSrunning ) return false;
+    dirPath = makeDirPath (dirName, father);
+
+                                // Handle two special cases
+    if (!strcmp (dirPath, "/proc") ||
+        !strcmp (dirPath, "/sys" ))
+    {
+        return false;
+    }
 
 	/* let's go to the directory! */
 	if( chdir( dirName ) == -1 ) {
@@ -110,8 +118,6 @@
 		perror( dirName );
 	}
 
-	dirPath= makeDirPath( dirName, father );
-
 	/*   printf("dirName [%s] , dirPath [%s]\n" , dirName , dirPath ); */
 
 	*newFolderInfo=thisFolderInfo=FInew( dirPath , dirStat , accessible , father );
@@ -155,7 +161,8 @@
 				sizeof( thisFolderInfo ) , folderSorter );
 
 	}
-	closedir( dirFD );
+
+    if (dirFD) closedir (dirFD);
 	if( father ) chdir( FIgetPath( father ));
 	return accessible;
 }
@@ -212,8 +219,14 @@
 	char absoluteDirName[MAX_DIR_NAME];
 	FAgetFolderAbsoluteName(dirName, absoluteDirName, &dirStat, GO_TO_FOLDER);
 	/*   printf("%s %s\n" , __FUNCTION__ , dirName ); */
-
 	/*   puts( absoluteDirName ); */
+                                // Handle two special cases
+    if (!strcmp (absoluteDirName, "/proc") ||
+        !strcmp (absoluteDirName, "/sys" ))
+    {
+        return 0;
+    }
+
 	ok = FAanalyzeRec(absoluteDirName, &dirStat, 0, &rootFolder,
 			onlyOneFileSystem);
 	/*   FIprint( rootFolder ); */
--- treesize-0.54.1.old/src/TStreeSizeGui.c
+++ treesize-0.54.1/src/TStreeSizeGui.c
@@ -158,10 +158,11 @@
 
   FolderInfo     theFolder = FAanalyze( folder , onlyOneFileSystem );
 
-  if( !TSrunning ){
-    FIfree( theFolder );
-    return 0;
-  }
+    if (!TSrunning || !theFolder)
+    {
+        FIfree (theFolder);
+        return 0;
+    }
   
   treeStore = gtk_tree_store_new(NUM_COLS,
 				 G_TYPE_INT   ,	   /* COL_PORCENT */
@@ -245,11 +246,12 @@
 
   }
 
-  if( !TSrunning ){		/* were we aborted ? */
-    gtk_widget_set_sensitive (btnCancel, FALSE);
-    pthread_mutex_unlock(&mutexCalcSize);
-    return;
-  }
+    if (!TSrunning || !treeStoreModel)
+    {                           // Operation aborted
+        gtk_widget_set_sensitive (btnCancel, FALSE);
+        pthread_mutex_unlock (&mutexCalcSize);
+        return;
+    }
   
   gtk_tree_view_set_model(GTK_TREE_VIEW( treeView ), treeStoreModel);
 
@@ -263,6 +265,52 @@
 
 void TScalculateSize( GtkWidget *treeView , char *folderName ){
 
+//--------------------------------------------------------------------
+
+    if (!strcmp (folderName, "/"))
+    {
+        gint response;
+
+        GtkWindow *mainWindow =
+            (GtkWindow *) lookup_widget (treeView, "mainWindow");
+
+        GtkWidget *dialog = gtk_message_dialog_new
+        (
+            mainWindow, GTK_DIALOG_DESTROY_WITH_PARENT,
+            GTK_MESSAGE_WARNING, GTK_BUTTONS_OK_CANCEL,
+            "Entire system is selected - This may take 15 minutes or longer in some cases!"
+        );
+
+        gtk_window_set_title (GTK_WINDOW(dialog), "Warning");
+        response = gtk_dialog_run (GTK_DIALOG (dialog));
+        gtk_widget_destroy (dialog);
+        if (response == GTK_RESPONSE_CANCEL) return;
+    }
+
+//--------------------------------------------------------------------
+
+    if (!strcmp (folderName, "/proc") ||
+        !strcmp (folderName, "/sys"))
+    {
+        GtkWindow *mainWindow =
+            (GtkWindow *) lookup_widget (treeView, "mainWindow");
+
+        GtkWidget *dialog = gtk_message_dialog_new
+        (
+            mainWindow, GTK_DIALOG_DESTROY_WITH_PARENT,
+            GTK_MESSAGE_ERROR, GTK_BUTTONS_CLOSE,
+            "%s is a special case - Inadvisable to start there",
+            folderName
+        );
+
+        gtk_window_set_title (GTK_WINDOW(dialog), "Error");
+        gtk_dialog_run (GTK_DIALOG (dialog));
+        gtk_widget_destroy (dialog);
+        return;
+    }
+
+//--------------------------------------------------------------------
+
   if( !FAgetFolderAbsoluteName( folderName , p.absoluteDirName , 0  , 1 ) ){
     GtkWindow           *mainWindow = (GtkWindow *) lookup_widget( treeView , "mainWindow" );
     GtkWidget *dialog = gtk_message_dialog_new ( mainWindow ,