1 files changed, 76 insertions, 0 deletions
diff --git a/devio/iostate.c b/devio/iostate.c
new file mode 100644
index 00000000..2f6863bc
--- /dev/null
+++ b/devio/iostate.c
@@ -0,0 +1,76 @@
+/* State for an I/O stream.
+
+   Copyright (C) 1995 Free Software Foundation, Inc.
+
+   Written by Miles Bader <miles@gnu.ai.mit.edu>
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   This program is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+
+#include <hurd.h>
+
+#include "iostate.h"
+#include "dev.h"
+
+/* ---------------------------------------------------------------- */
+
+/* Initialize the io_state structure IOS to be used with the device DEV.  If
+   a memory allocation error occurs, ENOMEM is returned, otherwise 0.  */
+error_t
+io_state_init(struct io_state *ios, struct dev *dev)
+{
+  error_t err =
+    vm_allocate(mach_task_self(),
+		(vm_address_t *)&ios->buffer, dev->block_size, 1);
+
+  ios->location = 0;
+  ios->buffer_size = dev->block_size;
+  ios->buffer_use = 0;
+  mutex_init(&ios->lock);
+
+  return err;
+}
+
+/* Frees all resources used by IOS.  */
+void
+io_state_finalize(struct io_state *ios)
+{
+  vm_deallocate(mach_task_self(), (vm_address_t)ios->buffer, ios->buffer_size);
+}
+
+/* If IOS's location isn't block aligned because writes have been buffered
+   there, then sync the whole buffer out to the device.  Any error that
+   occurs while writing is returned, otherwise 0.  */
+error_t
+io_state_sync(struct io_state *ios, struct dev *dev)
+{
+  error_t err = 0;
+
+  if (ios->buffer_use == IO_STATE_BUFFERED_WRITE)
+    {
+      vm_offset_t pos = ios->location;
+      int block_offs = pos % dev->block_size;
+
+      if (block_offs > 0)
+	{
+	  bzero((char *)ios->buffer + block_offs,
+		dev->block_size - block_offs);
+	  ios->location -= block_offs;
+	  err =
+	    dev_write(dev, ios->buffer, dev->block_size, &ios->location);
+	}
+    }
+
+  return err;
+}