From e6facbfe7abc50de374300ecd83873ead65b4b04 Mon Sep 17 00:00:00 2001
From: Nick Mathewson <nickm@torproject.org>
Date: Fri, 2 Dec 2016 12:15:07 -0500
Subject: [PATCH] Add accessor for inspecting timer callbacks.

---
 src/common/timers.c | 14 ++++++++++++++
 src/common/timers.h |  2 ++
 2 files changed, 16 insertions(+)

diff --git a/src/common/timers.c b/src/common/timers.c
index 41b2008ac4..e1ad47b15b 100644
--- a/src/common/timers.c
+++ b/src/common/timers.c
@@ -254,6 +254,20 @@ timer_set_cb(tor_timer_t *t, timer_cb_fn_t cb, void *arg)
   t->callback.arg = arg;
 }
 
+/**
+ * Set *<b>cb_out</b> (if provided) to this timer's callback function,
+ * and *<b>arg_out</b> (if provided) to this timer's callback argument.
+ */
+void
+timer_get_cb(const tor_timer_t *t,
+             timer_cb_fn_t *cb_out, void **arg_out)
+{
+  if (cb_out)
+    *cb_out = t->callback.cb;
+  if (arg_out)
+    *arg_out = t->callback.arg;
+}
+
 /**
  * Schedule the timer t to fire at the current time plus a delay of
  * <b>delay</b> microseconds.  All times are relative to monotime_get().
diff --git a/src/common/timers.h b/src/common/timers.h
index 5f918f8e15..c5246a3335 100644
--- a/src/common/timers.h
+++ b/src/common/timers.h
@@ -13,6 +13,8 @@ typedef void (*timer_cb_fn_t)(tor_timer_t *, void *,
                               const struct monotime_t *);
 tor_timer_t *timer_new(timer_cb_fn_t cb, void *arg);
 void timer_set_cb(tor_timer_t *t, timer_cb_fn_t cb, void *arg);
+void timer_get_cb(const tor_timer_t *t,
+                  timer_cb_fn_t *cb_out, void **arg_out);
 void timer_schedule(tor_timer_t *t, const struct timeval *delay);
 void timer_disable(tor_timer_t *t);
 void timer_free(tor_timer_t *t);