Initial revision

1 files changed, 33 insertions, 0 deletions

diff --git a/libiohelp/verify_user_conch.c b/libiohelp/verify_user_conch.c
new file mode 100644
index 00000000..180d132f
--- /dev/null
+++ b/libiohelp/verify_user_conch.c
@@ -0,0 +1,33 @@
+/* 
+   Copyright (C) 1993 Free Software Foundation
+
+   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. */
+
+error_t
+verify_user_conch (struct conch *c, void *user)
+{
+  struct shared_io *user_sh;
+  
+  if (user != c->holder)
+    return EPERM;
+  user_sh = c->holder_shared_page;
+  spin_lock (&user_sh->lock);
+  if (user_sh != USER_HAS_CONCH && user_sh != USER_RELEASE_CONCH)
+    {
+      spin_unlock (&user_sh->lock);
+      return EPERM;
+    }
+  spin_unlock (&user_sh->lock);
+}