From 26fd9321cffd808bb0d280e55fef3ee4e914b4f7 Mon Sep 17 00:00:00 2001 From: Azat Khuzhin Date: Tue, 7 Jun 2016 18:31:48 +0300 Subject: [PATCH] buffer: evbuffer_add_buffer(): clean empty chains from destination buffer @EMPanisset reported a problem (#358) with evbuffer_remove_buffer(), but actually I think that the problem is in evbuffer_add_buffer() which introduces this empty chain, all other callers (except evbuffer_prepend_buffer(), but it doesn't have this problem though) should be safe. And FWIW the only API that allows empty chains is evbuffer_add_reference(), and we can add check there to avoid such issues, but for now I leaved this without fixing, since I think that evbuffer_add_reference() with empty chains can be used as a barrier (but this can be tricky). Fixes: regress evbuffer/remove_buffer_with_empty2 v2: introduce/fixes evbuffer/add_buffer_with_empty --- buffer.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/buffer.c b/buffer.c index c5f1b8a5..6786f902 100644 --- a/buffer.c +++ b/buffer.c @@ -885,9 +885,13 @@ APPEND_CHAIN(struct evbuffer *dst, struct evbuffer *src) { ASSERT_EVBUFFER_LOCKED(dst); ASSERT_EVBUFFER_LOCKED(src); - dst->last->next = src->first; + + struct evbuffer_chain **chp; + chp = evbuffer_free_trailing_empty_chains(dst); + *chp = src->first; + if (src->last_with_datap == &src->first) - dst->last_with_datap = &dst->last->next; + dst->last_with_datap = chp; else dst->last_with_datap = src->last_with_datap; dst->last = src->last; -- 2.50.1