diff --git a/buffer.c b/buffer.c
index a042a1ed..d048a622 100644
--- a/buffer.c
+++ b/buffer.c
@@ -2582,14 +2582,21 @@ evbuffer_peek(struct evbuffer *buffer, ev_ssize_t len,
 		chain = buffer->first;
 	}
 
+	if (n_vec == 0 && len < 0) {
+		/* If no vectors are provided and they asked for "everything",
+		 * pretend they asked for the actual available amount. */
+		len = buffer->total_len - len_so_far;
+	}
+
 	while (chain) {
 		if (len >= 0 && len_so_far >= len)
 			break;
 		if (idx<n_vec) {
 			vec[idx].iov_base = chain->buffer + chain->misalign;
 			vec[idx].iov_len = chain->off;
-		} else if (len<0)
+		} else if (len<0) {
 			break;
+		}
 		++idx;
 		len_so_far += chain->off;
 		chain = chain->next;
diff --git a/test/regress_buffer.c b/test/regress_buffer.c
index e51770df..addd5f9a 100644
--- a/test/regress_buffer.c
+++ b/test/regress_buffer.c
@@ -1441,6 +1441,10 @@ test_evbuffer_peek(void *info)
 		evbuffer_add_buffer(buf, tmp_buf);
 	}
 
+	/* How many chunks do we need for everything? */
+	i = evbuffer_peek(buf, -1, NULL, NULL, 0);
+	tt_int_op(i, ==, 16);
+
 	/* Simple peek: get everything. */
 	i = evbuffer_peek(buf, -1, NULL, v, 20);
 	tt_int_op(i, ==, 16); /* we used only 16 chunks. */