1 files changed, 87 insertions, 0 deletions
diff --git a/libfshelp/rlock.h b/libfshelp/rlock.h
new file mode 100644
index 00000000..5c620279
--- /dev/null
+++ b/libfshelp/rlock.h
@@ -0,0 +1,87 @@
+/*
+   Copyright (C) 2001, 2014-2019 Free Software Foundation
+
+   Written by Neal H Walfield <neal@cs.uml.edu>
+
+   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 the GNU Hurd.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef FSHELP_RLOCK_H
+#define FSHELP_RLOCK_H
+
+#include <pthread.h>
+#include <string.h>
+
+struct rlock_linked_list
+{
+  struct rlock_list *next;
+  struct rlock_list **prevp;
+};
+
+struct rlock_list
+{
+  loff_t start;
+  loff_t len;
+  int type;
+
+  struct rlock_linked_list node;
+  struct rlock_linked_list po;
+
+  pthread_cond_t wait;
+  int waiting;
+
+  void *po_id;
+};
+
+extern inline error_t
+rlock_list_init (struct rlock_peropen *po, struct rlock_list *l)
+{
+  memset (l, 0, sizeof (struct rlock_list));
+  pthread_cond_init (&l->wait, NULL);
+  l->po_id = po->locks;
+  return 0;
+}
+
+/* void list_list (X ={po,node}, struct rlock_list **head,
+		   struct rlock_list *node)
+
+   Insert a node in the given list, X, in sorted order.  */
+#define list_link(X, head, node)				\
+	do							\
+	  {							\
+	    struct rlock_list **e;				\
+	    for (e = head;					\
+		 *e && ((*e)->start < node->start);		\
+		 e = &(*e)->X.next)				\
+	      ;							\
+	    node->X.next = *e;					\
+	    if (node->X.next)					\
+	      node->X.next->X.prevp = &node->X.next;		\
+	    node->X.prevp = e;					\
+	    *e = node;						\
+	  }							\
+	while (0)
+
+/* void list_unlock (X = {po,node}, struct rlock_list *node)  */
+#define list_unlink(X, node)					\
+	do							\
+	  {							\
+	    *node->X.prevp = node->X.next;			\
+	    if (node->X.next)					\
+	      node->X.next->X.prevp = node->X.prevp;		\
+	  }							\
+	while (0)
+
+#endif /* FSHELP_RLOCK_H */