Make seek information part of the xfer metadata, rather than an entirely

separate xfer method.

Add missing .alloc_iob entries to several xfer_interface_operations
structures.

src/core/downloader.c

@@ -96,6 +96,9 @@ static int downloader_ensure_size ( struct downloader *downloader,
 	if ( len <= downloader->image->len )
 		return 0;
 
+	DBGC ( downloader, "Downloader %p extending to %zd bytes\n",
+	       downloader, len );
+
 	/* Extend buffer */
 	new_buffer = urealloc ( downloader->image->data, len );
 	if ( ! new_buffer ) {
@@ -141,68 +144,44 @@ static struct job_interface_operations downloader_job_operations = {
  *
  */
 
-/**
- * Handle seek() event received via data transfer interface
- *
- * @v xfer		Downloader data transfer interface
- * @v pos		New position
- * @ret rc		Return status code
- */
-static int downloader_xfer_seek ( struct xfer_interface *xfer, off_t offset,
-				  int whence ) {
-	struct downloader *downloader =
-		container_of ( xfer, struct downloader, xfer );
-	off_t new_pos;
-	int rc;
-
-	/* Calculate new buffer position */
-	switch ( whence ) {
-	case SEEK_SET:
-		new_pos = offset;
-		break;
-	case SEEK_CUR:
-		new_pos = ( downloader->pos + offset );
-		break;
-	default:
-		assert ( 0 );
-		return -EINVAL;
-	}
-
-	/* Ensure that we have enough buffer space for this buffer position */
-	if ( ( rc = downloader_ensure_size ( downloader, new_pos ) ) != 0 )
-		return rc;
-	downloader->pos = new_pos;
-
-	return 0;
-}
-
 /**
  * Handle deliver_raw() event received via data transfer interface
  *
  * @v xfer		Downloader data transfer interface
- * @v data		Data buffer
- * @v len		Length of data buffer
+ * @v iobuf		Datagram I/O buffer
+ * @v meta		Data transfer metadata
  * @ret rc		Return status code
  */
-static int downloader_xfer_deliver_raw ( struct xfer_interface *xfer,
-					 const void *data, size_t len ) {
+static int downloader_xfer_deliver_iob ( struct xfer_interface *xfer,
+					 struct io_buffer *iobuf,
+					 struct xfer_metadata *meta ) {
 	struct downloader *downloader =
 		container_of ( xfer, struct downloader, xfer );
+	size_t len;
 	size_t max;
 	int rc;
 
+	/* Calculate new buffer position */
+	if ( meta->whence != SEEK_CUR )
+		downloader->pos = 0;
+	downloader->pos += meta->offset;
+
 	/* Ensure that we have enough buffer space for this data */
+	len = iob_len ( iobuf );
 	max = ( downloader->pos + len );
 	if ( ( rc = downloader_ensure_size ( downloader, max ) ) != 0 )
-		return rc;
+		goto done;
 
 	/* Copy data to buffer */
-	copy_to_user ( downloader->image->data, downloader->pos, data, len );
+	copy_to_user ( downloader->image->data, downloader->pos,
+		       iobuf->data, len );
 
 	/* Update current buffer position */
 	downloader->pos += len;
 
-	return 0;
+ done:
+	free_iob ( iobuf );
+	return rc;
 }
 
 /**
@@ -227,10 +206,10 @@ static void downloader_xfer_close ( struct xfer_interface *xfer, int rc ) {
 static struct xfer_interface_operations downloader_xfer_operations = {
 	.close		= downloader_xfer_close,
 	.vredirect	= xfer_vopen,
-	.seek		= downloader_xfer_seek,
 	.window		= unlimited_xfer_window,
-	.deliver_iob	= xfer_deliver_as_raw,
-	.deliver_raw	= downloader_xfer_deliver_raw,
+	.alloc_iob	= default_xfer_alloc_iob,
+	.deliver_iob	= downloader_xfer_deliver_iob,
+	.deliver_raw	= xfer_deliver_as_iob,
 };
 
 /****************************************************************************

src/core/filter.c

@@ -44,12 +44,6 @@ int filter_vredirect ( struct xfer_interface *xfer, int type,
 	return xfer_vredirect ( other, type, args );
 }
 
-int filter_seek ( struct xfer_interface *xfer, off_t offset, int whence ) {
-	struct xfer_interface *other = filter_other_half ( xfer );
-
-	return xfer_seek ( other, offset, whence );
-}
-
 size_t filter_window ( struct xfer_interface *xfer ) {
 	struct xfer_interface *other = filter_other_half ( xfer );
 

src/core/hw.c

@@ -36,8 +36,8 @@ static void hw_xfer_close ( struct xfer_interface *xfer, int rc ) {
 static struct xfer_interface_operations hw_xfer_operations = {
 	.close		= hw_xfer_close,
 	.vredirect	= ignore_xfer_vredirect,
-	.seek		= ignore_xfer_seek,
 	.window		= unlimited_xfer_window,
+	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= xfer_deliver_as_raw,
 	.deliver_raw	= ignore_xfer_deliver_raw,
 };

src/core/posix_io.c

@@ -103,39 +103,12 @@ static void posix_file_xfer_close ( struct xfer_interface *xfer, int rc ) {
 	posix_file_finished ( file, rc );
 }
 
-/**
- * Handle seek() event
- *
- * @v xfer		POSIX file data transfer interface
- * @v pos		New position
- * @ret rc		Return status code
- */
-static int posix_file_xfer_seek ( struct xfer_interface *xfer, off_t offset,
-				  int whence ) {
-	struct posix_file *file =
-		container_of ( xfer, struct posix_file, xfer );
-
-	switch ( whence ) {
-	case SEEK_SET:
-		file->pos = offset;
-		break;
-	case SEEK_CUR:
-		file->pos += offset;
-		break;
-	}
-
-	if ( file->filesize < file->pos )
-		file->filesize = file->pos;
-
-	return 0;
-}
-
 /**
  * Handle deliver_iob() event
  *
  * @v xfer		POSIX file data transfer interface
  * @v iobuf		I/O buffer
- * @v meta		Data transfer metadata, or NULL
+ * @v meta		Data transfer metadata
  * @ret rc		Return status code
  */
 static int
@@ -145,6 +118,13 @@ posix_file_xfer_deliver_iob ( struct xfer_interface *xfer,
 	struct posix_file *file =
 		container_of ( xfer, struct posix_file, xfer );
 
+	/* Keep track of file position solely for the filesize */
+	if ( meta->whence != SEEK_CUR )
+		file->pos = 0;
+	file->pos += meta->offset;
+	if ( file->filesize < file->pos )
+		file->filesize = file->pos;
+
 	list_add_tail ( &iobuf->list, &file->data );
 	return 0;
 }
@@ -153,7 +133,6 @@ posix_file_xfer_deliver_iob ( struct xfer_interface *xfer,
 static struct xfer_interface_operations posix_file_xfer_operations = {
 	.close		= posix_file_xfer_close,
 	.vredirect	= xfer_vopen,
-	.seek		= posix_file_xfer_seek,
 	.window		= unlimited_xfer_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= posix_file_xfer_deliver_iob,

src/core/resolv.c

@@ -312,7 +312,6 @@ struct named_socket {
 static struct xfer_interface_operations named_xfer_ops = {
 	.close		= ignore_xfer_close,
 	.vredirect	= ignore_xfer_vredirect,
-	.seek		= ignore_xfer_seek,
 	.window		= no_xfer_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= xfer_deliver_as_raw,

src/core/xfer.c

@@ -85,31 +85,6 @@ int xfer_redirect ( struct xfer_interface *xfer, int type, ... ) {
 	return rc;
 }
 
-/**
- * Seek to position
- *
- * @v xfer		Data transfer interface
- * @v offset		Offset to new position
- * @v whence		Basis for new position
- * @ret rc		Return status code
- */
-int xfer_seek ( struct xfer_interface *xfer, off_t offset, int whence ) {
-	struct xfer_interface *dest = xfer_get_dest ( xfer );
-	int rc;
-
-	DBGC ( xfer, "XFER %p->%p seek %s+%ld\n", xfer, dest,
-	       whence_text ( whence ), offset );
-
-	rc = dest->op->seek ( dest, offset, whence );
-
-	if ( rc != 0 ) {
-		DBGC ( xfer, "XFER %p<-%p seek: %s\n", xfer, dest,
-		       strerror ( rc ) );
-	}
-	xfer_put ( dest );
-	return rc;
-}
-
 /**
  * Check flow control window
  *
@@ -153,7 +128,7 @@ struct io_buffer * xfer_alloc_iob ( struct xfer_interface *xfer, size_t len ) {
  *
  * @v xfer		Data transfer interface
  * @v iobuf		Datagram I/O buffer
- * @v meta		Data transfer metadata, or NULL
+ * @v meta		Data transfer metadata
  * @ret rc		Return status code
  */
 int xfer_deliver_iob_meta ( struct xfer_interface *xfer,
@@ -184,7 +159,8 @@ int xfer_deliver_iob_meta ( struct xfer_interface *xfer,
  */
 int xfer_deliver_iob ( struct xfer_interface *xfer,
 		       struct io_buffer *iobuf ) {
-	return xfer_deliver_iob_meta ( xfer, iobuf, NULL );
+	static struct xfer_metadata dummy_metadata;
+	return xfer_deliver_iob_meta ( xfer, iobuf, &dummy_metadata );
 }
 
 /**
@@ -253,6 +229,31 @@ int xfer_printf ( struct xfer_interface *xfer, const char *format, ... ) {
 	return rc;
 }
 
+/**
+ * Seek to position
+ *
+ * @v xfer		Data transfer interface
+ * @v offset		Offset to new position
+ * @v whence		Basis for new position
+ * @ret rc		Return status code
+ */
+int xfer_seek ( struct xfer_interface *xfer, off_t offset, int whence ) {
+	struct io_buffer *iobuf;
+	struct xfer_metadata meta = {
+		.offset = offset,
+		.whence = whence,
+	};
+
+	DBGC ( xfer, "XFER %p seek %s+%ld\n", xfer,
+	       whence_text ( whence ), offset );
+
+	/* Allocate and send a zero-length data buffer */
+	iobuf = xfer_alloc_iob ( xfer, 0 );
+	if ( ! iobuf )
+		return -ENOMEM;
+	return xfer_deliver_iob_meta ( xfer, iobuf, &meta );
+}
+
 /****************************************************************************
  *
  * Helper methods
@@ -286,19 +287,6 @@ int ignore_xfer_vredirect ( struct xfer_interface *xfer __unused,
 	return 0;
 }
 
-/**
- * Ignore seek() event
- *
- * @v xfer		Data transfer interface
- * @v offset		Offset to new position
- * @v whence		Basis for new position
- * @ret rc		Return status code
- */
-int ignore_xfer_seek ( struct xfer_interface *xfer __unused,
-		       off_t offset __unused, int whence __unused ) {
-	return 0;
-}
-
 /**
  * Unlimited flow control window
  *
@@ -401,7 +389,6 @@ int ignore_xfer_deliver_raw ( struct xfer_interface *xfer,
 struct xfer_interface_operations null_xfer_ops = {
 	.close		= ignore_xfer_close,
 	.vredirect	= ignore_xfer_vredirect,
-	.seek		= ignore_xfer_seek,
 	.window		= unlimited_xfer_window,
 	.alloc_iob	= default_xfer_alloc_iob,
 	.deliver_iob	= xfer_deliver_as_raw,