From 3c53950d0ad8eb07d16d0f970fb753483ae47534 Mon Sep 17 00:00:00 2001
From: janis <code@kalofolias.de>
Date: Tue, 12 May 2026 12:51:17 +0200
Subject: [PATCH] Fixing TLS send as well

Adding missing check for graceously disconnected TLS transport, which
returns a zero write size. This solves a rare race condition, which
would arise if disconnect occurrs while in the writeit_tls loop; in that
case, the server would end in an infinite loop.
---
 nbd-server.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/nbd-server.c b/nbd-server.c
index 6a87d445..e9b00f96 100644
--- a/nbd-server.c
+++ b/nbd-server.c
@@ -315,6 +315,8 @@ static int writeit_tls(gnutls_session_t s, const void *buf, size_t len) {
 			m = g_strdup_printf("could not send data: %s", gnutls_strerror(res));
 			err_nonfatal(m);
 			return -1;
+		} else if(res == 0) {
+			nbd_err_code("Aborting write: TLS connection closed gracefully.", 0);
 		} else {
 			len -= res;
 			buf += res;
@@ -336,7 +338,7 @@ static int readit_tls(gnutls_session_t s, void *buf, size_t len) {
 			err_nonfatal(m);
 			return -1;
 		} else if(res == 0) {
-			nbd_err("TLS End of data: Remote connection closed.");
+			nbd_err_code("TLS connection closed gracefully.", 0);
 		} else {
 			len -= res;
 			buf += res;