1 files changed, 43 insertions, 0 deletions
diff --git a/ccan/list/list.c b/ccan/list/list.c
new file mode 100644
index 0000000..2717fa3
--- /dev/null
+++ b/ccan/list/list.c
@@ -0,0 +1,43 @@
+/* Licensed under BSD-MIT - see LICENSE file for details */
+#include <stdio.h>
+#include <stdlib.h>
+#include "list.h"
+
+static void *corrupt(const char *abortstr,
+                     const struct list_node *head,
+                     const struct list_node *node,
+                     unsigned int count)
+{
+        if (abortstr) {
+                fprintf(stderr,
+                        "%s: prev corrupt in node %p (%u) of %p\n",
+                        abortstr, node, count, head);
+                abort();
+        }
+        return NULL;
+}
+
+struct list_node *list_check_node(const struct list_node *node,
+                                  const char *abortstr)
+{
+        const struct list_node *p, *n;
+        int count = 0;
+
+        for (p = node, n = node->next; n != node; p = n, n = n->next) {
+                count++;
+                if (n->prev != p)
+                        return corrupt(abortstr, node, n, count);
+        }
+        /* Check prev on head node. */
+        if (node->prev != p)
+                return corrupt(abortstr, node, node, 0);
+
+        return (struct list_node *)node;
+}
+
+struct list_head *list_check(const struct list_head *h, const char *abortstr)
+{
+        if (!list_check_node(&h->n, abortstr))
+                return NULL;
+        return (struct list_head *)h;
+}