Added IMAGE_LOADED flag and find_image()

src/core/image.c

@@ -72,6 +72,23 @@ void unregister_image ( struct image *image ) {
 	DBGC ( image, "IMAGE %p unregistered\n", image );
 }
 
+/**
+ * Find image by name
+ *
+ * @v name		Image name
+ * @ret image		Executable/loadable image, or NULL
+ */
+struct image * find_image ( const char *name ) {
+	struct image *image;
+
+	list_for_each_entry ( image, &images, list ) {
+		if ( strcmp ( image->name, name ) == 0 )
+			return image;
+	}
+
+	return NULL;
+}
+
 /**
  * Load executable/loadable image into memory
  *
@@ -89,6 +106,7 @@ int image_load ( struct image *image ) {
 		return rc;
 	}
 
+	image->flags |= IMAGE_LOADED;
 	return 0;
 }
 
@@ -111,6 +129,7 @@ int image_autoload ( struct image *image ) {
 			       image, image->type->name, strerror ( rc ) );
 			return rc;
 		}
+		image->flags |= IMAGE_LOADED;
 		return 0;
 	}
 
@@ -127,8 +146,16 @@ int image_autoload ( struct image *image ) {
 int image_exec ( struct image *image ) {
 	int rc;
 
+	/* Image must be loaded first */
+	if ( ! ( image->flags & IMAGE_LOADED ) ) {
+		DBGC ( image, "IMAGE %p could not execute: not loaded\n",
+		       image );
+		return -ENOTTY;
+	}
+
 	assert ( image->type != NULL );
 
+	/* Try executing the image */
 	if ( ( rc = image->type->exec ( image ) ) != 0 ) {
 		DBGC ( image, "IMAGE %p could not execute: %s\n",
 		       image, strerror ( rc ) );

src/include/gpxe/image.h

@@ -45,8 +45,14 @@ struct image {
 
 	/** Image type, if known */
 	struct image_type *type;
+
+	/** Flags */
+	unsigned int flags;
 };
 
+/** Image is loaded */
+#define IMAGE_LOADED 0x0001
+
 /** An executable or loadable image type */
 struct image_type {
 	/** Name of this image type */
@@ -102,6 +108,7 @@ extern struct list_head images;
 
 extern int register_image ( struct image *image );
 extern void unregister_image ( struct image *image );
+struct image * find_image ( const char *name );
 extern int image_load ( struct image *image );
 extern int image_autoload ( struct image *image );
 extern int image_exec ( struct image *image );