Make URI structures reference-counted.

src/core/download.c

  err:
 	async_uninit ( &download->async );
 	ufree ( download->buffer.addr );
-	free_uri ( download->uri );
+	uri_put ( download->uri );
 	free ( download );
 	return rc;
 }
 		/* Discard the buffer */
 		ufree ( download->buffer.addr );
 	}
-	free_uri ( download->uri );
+	uri_put ( download->uri );
 	download->uri = NULL;
 
 	/* Terminate ourselves */

src/core/open.c

 int xfer_open_uri ( struct xfer_interface *xfer, const char *uri_string ) {
 	struct uri *uri;
 	struct uri_opener *opener;
+	int rc = -ENOTSUP;
 
 	DBGC ( xfer, "XFER %p opening URI %s\n", xfer, uri_string );
 
 
 	for ( opener = uri_openers ; opener < uri_openers_end ; opener++ ) {
 		if ( strcmp ( uri->scheme, opener->scheme ) == 0 ) {
-			return opener->open ( xfer, uri );
+			rc = opener->open ( xfer, uri );
+			goto done;
 		}
 	}
 
 	DBGC ( xfer, "XFER %p attempted to open unsupported URI scheme "
 	       "\"%s\"\n", xfer, uri->scheme );
-	free_uri ( uri );
-	return -ENOTSUP;
+ done:
+	uri_put ( uri );
+	return rc;
 }
 
 /**

src/core/uri.c

  *
  * Splits a URI into its component parts.  The return URI structure is
  * dynamically allocated and must eventually be freed by calling
- * free_uri().
+ * uri_put().
  */
 struct uri * parse_uri ( const char *uri_string ) {
 	struct uri *uri;

src/include/gpxe/open.h

 	 * @v xfer		Data transfer interface
 	 * @v uri		URI
 	 * @ret rc		Return status code
-	 *
-	 * This method takes ownership of the URI structure, and is
-	 * responsible for eventually calling free_uri().
 	 */
 	int ( * open ) ( struct xfer_interface *xfer, struct uri *uri );
 };

src/include/gpxe/uri.h

  */
 
 #include <stdlib.h>
+#include <gpxe/refcnt.h>
 
 /** A Uniform Resource Identifier
  *
  *   query = "what=is", fragment = "this"
  */
 struct uri {
+	/** Reference count */
+	struct refcnt refcnt;
 	/** Scheme */
 	const char *scheme;
 	/** Opaque part */
 }
 
 /**
- * Free URI structure
+ * Increment URI reference count
  *
  * @v uri		URI
+ * @ret uri		URI
+ */
+static inline __attribute__ (( always_inline )) struct uri *
+uri_get ( struct uri *uri ) {
+	ref_get ( &uri->refcnt );
+	return uri;
+}
+
+/**
+ * Decrement URI reference count
  *
- * Frees all the dynamically-allocated storage used by the URI
- * structure.
+ * @v uri		URI
  */
-static inline void free_uri ( struct uri *uri ) {
-	free ( uri );
+static inline __attribute__ (( always_inline )) void
+uri_put ( struct uri *uri ) {
+	ref_put ( &uri->refcnt );
 }
 
 extern struct uri * parse_uri ( const char *uri_string );