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view src/core/ngx_syslog.h @ 9300:5be23505292b
SSI: fixed incorrect or duplicate stub output.
Following 3518:eb3aaf8bd2a9 (0.8.37), r->request_output is only set
if there are data in the first buffer sent in the subrequest. As a
result, following the change mentioned this flag cannot be used to
prevent duplicate ngx_http_ssi_stub_output() calls, since it is not
set if there was already some output, but the first buffer was empty.
Still, when there are multiple subrequests, even an empty subrequest
response might be delayed by the postpone filter, leading to a second
call of ngx_http_ssi_stub_output() during finalization from
ngx_http_writer() the subreqest buffers are released by the postpone
filter. Since r->request_output is not set after the first call, this
resulted in duplicate stub output.
Additionally, checking only the first buffer might be wrong in some
unusual cases. For example, the first buffer might be empty if
$r->flush() is called before printing any data in the embedded Perl
module.
Depending on the postpone_output value and corresponding sizes, this
issue can result in either duplicate or unexpected stub output, or
"zero size buf in writer" alerts.
Following 8124:f5515e727656 (1.23.4), it became slightly easier to
reproduce the issue, as empty static files and empty cache items now
result in a response with an empty buffer. Before the change, an empty
proxied response can be used to reproduce the issue.
Fix is check all buffers and set r->request_output if any non-empty
buffers are sent. This ensures that all unusual cases of non-empty
responses are covered, and also that r->request_output will be set
after the first stub output, preventing duplicate output.
Reported by Jan Gassen.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Thu, 04 Jul 2024 17:41:28 +0300 |
parents | 1c9264603adc |
children |
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/* * Copyright (C) Nginx, Inc. */ #ifndef _NGX_SYSLOG_H_INCLUDED_ #define _NGX_SYSLOG_H_INCLUDED_ typedef struct { ngx_uint_t facility; ngx_uint_t severity; ngx_str_t tag; ngx_str_t *hostname; ngx_addr_t server; ngx_connection_t conn; ngx_log_t log; ngx_log_t *logp; time_t error_log_time; time_t connect_error_time; unsigned busy:1; unsigned nohostname:1; } ngx_syslog_peer_t; char *ngx_syslog_process_conf(ngx_conf_t *cf, ngx_syslog_peer_t *peer); u_char *ngx_syslog_add_header(ngx_syslog_peer_t *peer, u_char *buf); void ngx_syslog_writer(ngx_log_t *log, ngx_uint_t level, u_char *buf, size_t len); ssize_t ngx_syslog_send(ngx_syslog_peer_t *peer, u_char *buf, size_t len); #endif /* _NGX_SYSLOG_H_INCLUDED_ */