diff --git a/src/chan.c b/src/chan.c
index eea119b..117041e 100644
--- a/src/chan.c
+++ b/src/chan.c
@@ -132,7 +132,7 @@ chan_disable(struct ovni_chan *chan)
 }
 
 int
-chan_is_enabled(struct ovni_chan *chan)
+chan_is_enabled(const struct ovni_chan *chan)
 {
 	return chan->enabled;
 }
@@ -287,7 +287,7 @@ chan_ev(struct ovni_chan *chan, int ev)
 }
 
 int
-chan_get_st(struct ovni_chan *chan)
+chan_get_st(const struct ovni_chan *chan)
 {
 	if (chan->enabled == 0)
 		return chan->badst;
@@ -301,6 +301,27 @@ chan_get_st(struct ovni_chan *chan)
 	return chan->stack[chan->n - 1];
 }
 
+void
+chan_copy(struct ovni_chan *dst, const struct ovni_chan *src)
+{
+	if (!chan_is_enabled(src)) {
+		chan_disable(dst);
+		return;
+	}
+
+	if (!chan_is_enabled(dst))
+		chan_enable(dst, 1);
+
+	if (src->ev != -1) {
+		chan_ev(dst, src->ev);
+	} else {
+		int src_st = chan_get_st(src);
+		int dst_st = chan_get_st(dst);
+		if (src_st != dst_st)
+			chan_set(dst, src_st);
+	}
+}
+
 static void
 emit(struct ovni_chan *chan, int64_t t, int state)
 {
diff --git a/src/chan.h b/src/chan.h
index 34c848a..0837b7e 100644
--- a/src/chan.h
+++ b/src/chan.h
@@ -37,7 +37,7 @@ void
 chan_disable(struct ovni_chan *chan);
 
 int
-chan_is_enabled(struct ovni_chan *chan);
+chan_is_enabled(const struct ovni_chan *chan);
 
 void
 chan_set(struct ovni_chan *chan, int st);
@@ -52,9 +52,12 @@ void
 chan_ev(struct ovni_chan *chan, int ev);
 
 int
-chan_get_st(struct ovni_chan *chan);
+chan_get_st(const struct ovni_chan *chan);
 
 void
 chan_emit(struct ovni_chan *chan);
 
+void
+chan_copy(struct ovni_chan *dst, const struct ovni_chan *src);
+
 #endif /* OVNI_CHAN_H */