Initial revision

2 files changed, 94 insertions, 0 deletions

diff --git a/libiohelp/iohelp.h b/libiohelp/iohelp.h
new file mode 100644
index 00000000..35cb11d2
--- /dev/null
+++ b/libiohelp/iohelp.h
@@ -0,0 +1,61 @@
+/* 
+   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. */
+
+#include <mach.h>
+#include <hurd/hurd_types.h>
+#include <cthreads.h>
+#include <hurd/shared.h>
+
+/* Conch manipulation.  */
+struct conch
+{
+  struct mutex *lock;
+  struct condition wait;
+  void *holder;
+  struct shared_io *holder_shared_page;
+};
+
+/* Initialize a conch box */
+void initialize_conch (struct conch *, struct mutex *);
+
+/* These routines are not reentrant.  The server is responsible
+   for ensuring that all calls to these routines are serialized
+   by locking the lock passed to initialize_conch. */
+
+/* Handle a user request to obtain the conch (io_get_conch) */
+error_t handle_io_get_conch (struct conch *, void *, struct shared_io *);
+
+/* Obtain the conch for the server */
+error_t get_conch (struct conch *);
+
+/* Handle a user request to release the conch (io_release_conch). */
+error_t handle_io_release_conch (struct conch *, void *);
+
+/* Check if the user is allowed to make a shared-data notification
+   message. */
+error_t verify_user_conch (struct conch *, void *);
+
+/* This function must by defined by the server.  It should transfer
+   information from the current conch holder's shared page to the server's
+   data (the arg is the conch owner). */
+error_t fetch_shared_data (void *);
+
+/* This function must be defined by the server.  It should transfer
+   information from the server's data to the current conch holder's
+   shared page (the arg is the conch owner). */
+error_t put_shared_data (void *);
+
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);
+}