puzzles: fix a minor bug in the configuration screen

- when an invalid string setting was entered, the string value would
  continue to be used after being freed

Change-Id: I3a9da016f6f32eac8636b9f55e4e09006bc6059e

1 files changed, 16 insertions, 4 deletions

diff --git a/apps/plugins/puzzles/rockbox.c b/apps/plugins/puzzles/rockbox.c
index f1c3d45e76..86dc9cffd4 100644
--- a/apps/plugins/puzzles/rockbox.c
+++ b/apps/plugins/puzzles/rockbox.c
@@ -682,7 +682,8 @@ static int list_choose(const char *list_str, const char *title)
     }
 }
 
-static void do_configure_item(config_item *cfg)
+/* return value is only meaningful when type == C_STRING */
+static bool do_configure_item(config_item *cfg)
 {
     switch(cfg->type)
     {
@@ -696,11 +697,11 @@ static void do_configure_item(config_item *cfg)
         if(rb->kbd_input(newstr, MAX_STRLEN) < 0)
         {
             sfree(newstr);
-            break;
+            return false;
         }
         sfree(cfg->sval);
         cfg->sval = newstr;
-        break;
+        return true;
     }
     case C_BOOLEAN:
     {
@@ -724,6 +725,7 @@ static void do_configure_item(config_item *cfg)
         fatal("bad type");
         break;
     }
+    return false;
 }
 
 const char *config_formatter(int sel, void *data, char *buf, size_t len)
@@ -779,12 +781,22 @@ static void config_menu(void)
             config_item old;
             int pos = rb->gui_synclist_get_sel_pos(&list);
             memcpy(&old, config + pos, sizeof(old));
-            do_configure_item(config + pos);
+            char *old_str;
+            if(old.type == C_STRING)
+                old_str = dupstr(old.sval);
+            bool freed_str = do_configure_item(config + pos);
             char *err = midend_set_config(me, CFG_SETTINGS, config);
             if(err)
             {
                 rb->splash(HZ, err);
                 memcpy(config + pos, &old, sizeof(old));
+                if(freed_str)
+                    config[pos].sval = old_str;
+            }
+            else if(old.type == C_STRING)
+            {
+                /* success, and we duplicated the old string, so free it */
+                sfree(old_str);
             }
             break;
         }