Initial revision

1 files changed, 57 insertions, 0 deletions

diff --git a/devio/mem.c b/devio/mem.c
new file mode 100644
index 00000000..65caa19f
--- /dev/null
+++ b/devio/mem.c
@@ -0,0 +1,57 @@
+/* Some random handy ops for dealing with rpcs that return memory.
+
+   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 <string.h>
+
+/* ---------------------------------------------------------------- */
+
+/* Makes sure that BUF, points to a buffer with AMOUNT bytes available.
+   *BUF_LEN should be the current length of *BUF, and if this isn't enough to
+   hold AMOUNT bytes, then more is allocated and the new buffer is returned
+   in *BUF and *BUF_LEN.  If a memory allocation error occurs, the error code
+   is returned, otherwise 0.  */
+error_t
+allocate(vm_address_t *buf, vm_size_t *buf_len, vm_size_t amount)
+{
+  if (*buf_len < amount)
+    {
+      error_t err = vm_allocate(mach_task_self(), buf, amount, 1);
+      if (err)
+	return err;
+    }
+
+  *buf_len = amount;
+  return 0;
+}
+
+/* Deallocates any pages entirely within the last EXCESS bytes of the BUF_LEN
+   long buffer, BUF.  */
+error_t
+deallocate_excess(vm_address_t buf, vm_size_t buf_len, vm_size_t excess)
+{
+  vm_size_t excess_pages = buf_len - round_page(buf_len - excess);
+  if (excess_pages > 0)
+    return 
+      vm_deallocate(mach_task_self(),
+		    round_page(buf + buf_len - excess), excess_pages);
+  else
+    return 0;
+}