1 files changed, 63 insertions, 0 deletions
diff --git a/libfshelp/set-active.c b/libfshelp/set-active.c
new file mode 100644
index 00000000..4f25a50e
--- /dev/null
+++ b/libfshelp/set-active.c
@@ -0,0 +1,63 @@
+/* 
+   Copyright (C) 1995, 1996 Free Software Foundation, Inc.
+   Written by Michael I. Bushnell.
+
+   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., 675 Mass Ave, Cambridge, MA 02139, USA. */
+
+#include "fshelp.h"
+#include <hurd/fsys.h>
+
+error_t
+fshelp_set_active (struct transbox *box,
+		   mach_port_t active,
+		   int excl)
+{
+  int cancel;
+  
+  if (excl)
+    {
+      if (box->flags & TRANSBOX_STARTING)
+	return EBUSY;
+      if (box->active != MACH_PORT_NULL)
+	/* It looks like there's an existing translator, but make sure.  */
+	{
+	  mach_port_urefs_t dead_refs;
+	  error_t err =
+	    mach_port_get_refs (mach_task_self (),
+				box->active, MACH_PORT_RIGHT_DEAD_NAME,
+				&dead_refs);
+	  if (!err && dead_refs == 0)
+	    /* Still active, we lose.  */
+	    return EBUSY;
+	}
+    }
+  
+  while (box->flags & TRANSBOX_STARTING)
+    {
+      box->flags |= TRANSBOX_WANTED;
+      cancel = hurd_condition_wait (&box->wakeup, box->lock);
+      if (cancel)
+	return EINTR;
+    }
+
+  if (box->active != MACH_PORT_NULL)
+    mach_port_deallocate (mach_task_self (), box->active);
+
+  box->active = active;
+  return 0;
+}
+