1 files changed, 94 insertions, 0 deletions
diff --git a/libports/transfer-right.c b/libports/transfer-right.c
new file mode 100644
index 00000000..d5844ea2
--- /dev/null
+++ b/libports/transfer-right.c
@@ -0,0 +1,94 @@
+/* Transfer the receive right from one port structure to another
+   Copyright (C) 1996 Free Software Foundation, Inc.
+   Written by Michael I. Bushnell, p/BSG.
+
+   This file is part of the GNU Hurd.
+
+   The GNU Hurd 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.
+
+   The GNU Hurd 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., 59 Temple Place - Suite 330, Boston, MA  02111, USA. */
+
+
+#include "ports.h"
+#include <hurd/ihash.h>
+
+error_t
+ports_transfer_right (void *tostruct, 
+		      void *fromstruct)
+{
+  struct port_info *topi = tostruct;
+  struct port_info *frompi = fromstruct;
+  mach_port_t port;
+  int dereffrompi = 0;
+  int dereftopi = 0;
+  int hassendrights = 0;
+  error_t err;
+
+  mutex_lock (&_ports_lock);
+
+  /* Fetch the port in FROMPI and clear its use */
+  port = frompi->port_right;
+  if (port != MACH_PORT_NULL)
+    {
+      ihash_locp_remove (frompi->bucket->htable, frompi->hentry);
+      frompi->port_right = MACH_PORT_NULL;
+      if (frompi->flags & PORT_HAS_SENDRIGHTS)
+	{
+	  frompi->flags &= ~PORT_HAS_SENDRIGHTS;
+	  hassendrights = 1;
+	  dereffrompi = 1;
+	}
+    }
+  
+  /* Destroy the existing right in TOPI. */
+  if (topi->port_right != MACH_PORT_NULL)
+    {
+      ihash_locp_remove (topi->bucket->htable, topi->hentry);
+      err = mach_port_mod_refs (mach_task_self (), topi->port_right,
+				MACH_PORT_RIGHT_RECEIVE, -1);
+      if ((topi->flags & PORT_HAS_SENDRIGHTS) && !hassendrights)
+	{
+	  dereftopi = 1;
+	  topi->flags &= ~PORT_HAS_SENDRIGHTS;
+	}
+      else if (((topi->flags & PORT_HAS_SENDRIGHTS) == 0) && hassendrights)
+	{
+	  topi->flags |= PORT_HAS_SENDRIGHTS;
+	  topi->refcnt++;
+	}
+    }
+  
+  /* Install the new right in TOPI. */
+  topi->port_right = port;
+  topi->cancel_threshold = frompi->cancel_threshold;
+  topi->mscount = frompi->mscount;
+  
+  if (port)
+    {
+      ihash_add (topi->bucket->htable, port, topi, &topi->hentry);
+      if (topi->bucket != frompi->bucket)
+	mach_port_move_member (mach_task_self (), port, topi->bucket->portset);
+    }
+  
+  mutex_unlock (&_ports_lock);
+  
+  /* Take care of any lowered reference counts. */
+  if (dereffrompi)
+    ports_port_deref (frompi);
+  if (dereftopi)
+    ports_port_deref (topi);
+  return 0;
+}
+
+
+