lib: hashtable: Prevent recursive calling of callback functions
In case there are two variables which each implement env callback
that performs env_set() on the other variable, the callbacks will
call each other recursively until the stack runs out. Prevent such
a recursion from happening.
Example which triggers this behavior:
static int on_foo(...) { env_set("bar", 0); ... }
static int on_bar(...) { env_set("foo", 0); ... }
U_BOOT_ENV_CALLBACK(foo, on_foo);
U_BOOT_ENV_CALLBACK(bar, on_bar);
Signed-off-by: Christoph Niedermaier <cniedermaier@dh-electronics.com>
Suggested-by: Marek Vasut <marex@denx.de>
diff --git a/lib/hashtable.c b/lib/hashtable.c
index e8a59e2..75c263b 100644
--- a/lib/hashtable.c
+++ b/lib/hashtable.c
@@ -221,11 +221,32 @@
do_callback(const struct env_entry *e, const char *name, const char *value,
enum env_op op, int flags)
{
+ int ret = 0;
+
#ifndef CONFIG_XPL_BUILD
- if (e->callback)
- return e->callback(name, value, op, flags);
+ static bool in_callback;
+
+ if (!e->callback || in_callback)
+ return 0;
+
+ /*
+ * In case there are two variables which each implement env callback
+ * that performs env_set() on the other variable, the callbacks will
+ * call each other recursively until the stack runs out. Prevent such
+ * a recursion from happening.
+ *
+ * Example which triggers this behavior:
+ * static int on_foo(...) { env_set("bar", 0); ... }
+ * static int on_bar(...) { env_set("foo", 0); ... }
+ * U_BOOT_ENV_CALLBACK(foo, on_foo);
+ * U_BOOT_ENV_CALLBACK(bar, on_bar);
+ */
+ in_callback = true;
+ ret = e->callback(name, value, op, flags);
+ in_callback = false;
#endif
- return 0;
+
+ return ret;
}
/*