[nginx] Added logging to PROXY protocol write buffer check.

[Sergey Kandaurov]

details:   https://hg.nginx.org/nginx/rev/251daa98cc87
branches:  
changeset: 8100:251daa98cc87
user:      Maxim Dounin <mdounin at mdounin.ru>
date:      Tue Nov 08 12:48:19 2022 +0300
description:
Added logging to PROXY protocol write buffer check.

The check is not expected to fail unless there is a bug in the calling
code.  But given the check is here, it should log an alert if it fails
instead of silently closing the connection.

diffstat:

 src/core/ngx_proxy_protocol.c |  2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diffs (12 lines):

diff -r 17d6a537fb1b -r 251daa98cc87 src/core/ngx_proxy_protocol.c
--- a/src/core/ngx_proxy_protocol.c	Wed Nov 02 13:46:16 2022 +0400
+++ b/src/core/ngx_proxy_protocol.c	Tue Nov 08 12:48:19 2022 +0300
@@ -282,6 +282,8 @@ ngx_proxy_protocol_write(ngx_connection_
     ngx_uint_t  port, lport;
 
     if (last - buf < NGX_PROXY_PROTOCOL_V1_MAX_HEADER) {
+        ngx_log_error(NGX_LOG_ALERT, c->log, 0,
+                      "too small buffer for PROXY protocol");
         return NULL;
     }