Implement CLI set (resize, change readonly status) command

src/cli_create.cpp

@@ -427,6 +427,7 @@ resume_3:
                 exit(1);
             }
             this->result = res;
+            parent->ringloop->wakeup();
         });
     }
 };
@@ -478,6 +479,11 @@ std::function<bool(void)> cli_tool_t::start_create(json11::Json cfg)
             fprintf(stderr, "Invalid syntax for size: %s\n", cfg["size"].string_value().c_str());
             exit(1);
         }
+        if (size % 4096)
+        {
+            fprintf(stderr, "Image size should be a multiple of 4096\n");
+            exit(1);
+        }
         image_creator->size = size;
         if (image_creator->new_snap != "")
         {