1 files changed, 70 insertions, 1 deletions

diff --git a/src/include/ipxe/xferbuf.h b/src/include/ipxe/xferbuf.h
index 22d8e8e8e..f2f336252 100644
--- a/src/include/ipxe/xferbuf.h
+++ b/src/include/ipxe/xferbuf.h
@@ -11,6 +11,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 
 #include <stdint.h>
 #include <ipxe/iobuf.h>
+#include <ipxe/uaccess.h>
 #include <ipxe/xfer.h>
 
 /** A data transfer buffer */
@@ -21,9 +22,77 @@ struct xfer_buffer {
 	size_t len;
 	/** Current offset within data */
 	size_t pos;
+	/** Data transfer buffer operations */
+	struct xfer_buffer_operations *op;
 };
 
-extern void xferbuf_done ( struct xfer_buffer *xferbuf );
+/** Data transfer buffer operations */
+struct xfer_buffer_operations {
+	/** Reallocate data buffer
+	 *
+	 * @v xferbuf		Data transfer buffer
+	 * @v len		New length (or zero to free buffer)
+	 * @ret rc		Return status code
+	 */
+	int ( * realloc ) ( struct xfer_buffer *xferbuf, size_t len );
+	/** Write data to buffer
+	 *
+	 * @v xferbuf		Data transfer buffer
+	 * @v offset		Starting offset
+	 * @v data		Data to write
+	 * @v len		Length of data
+	 *
+	 * This call is simply a wrapper for the appropriate
+	 * memcpy()-like operation: the caller is responsible for
+	 * ensuring that the write does not exceed the buffer length.
+	 */
+	void ( * write ) ( struct xfer_buffer *xferbuf, size_t offset,
+			   const void *data, size_t len );
+	/** Read data from buffer
+	 *
+	 * @v xferbuf		Data transfer buffer
+	 * @v offset		Starting offset
+	 * @v data		Data to read
+	 * @v len		Length of data
+	 *
+	 * This call is simply a wrapper for the appropriate
+	 * memcpy()-like operation: the caller is responsible for
+	 * ensuring that the read does not exceed the buffer length.
+	 */
+	void ( * read ) ( struct xfer_buffer *xferbuf, size_t offset,
+			  void *data, size_t len );
+};
+
+extern struct xfer_buffer_operations xferbuf_malloc_operations;
+extern struct xfer_buffer_operations xferbuf_umalloc_operations;
+
+/**
+ * Initialise malloc()-based data transfer buffer
+ *
+ * @v xferbuf		Data transfer buffer
+ */
+static inline __attribute__ (( always_inline )) void
+xferbuf_malloc_init ( struct xfer_buffer *xferbuf ) {
+	xferbuf->op = &xferbuf_malloc_operations;
+}
+
+/**
+ * Initialise umalloc()-based data transfer buffer
+ *
+ * @v xferbuf		Data transfer buffer
+ * @v data		User pointer
+ */
+static inline __attribute__ (( always_inline )) void
+xferbuf_umalloc_init ( struct xfer_buffer *xferbuf, userptr_t *data ) {
+	xferbuf->data = data;
+	xferbuf->op = &xferbuf_umalloc_operations;
+}
+
+extern void xferbuf_free ( struct xfer_buffer *xferbuf );
+extern int xferbuf_write ( struct xfer_buffer *xferbuf, size_t offset,
+			   const void *data, size_t len );
+extern int xferbuf_read ( struct xfer_buffer *xferbuf, size_t offset,
+			  void *data, size_t len );
 extern int xferbuf_deliver ( struct xfer_buffer *xferbuf,
 			     struct io_buffer *iobuf,
 			     struct xfer_metadata *meta );