view src/stream/ngx_stream_variables.h @ 9300:5be23505292b default tip

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 2a288909abc6
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_STREAM_VARIABLES_H_INCLUDED_
#define _NGX_STREAM_VARIABLES_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_stream.h>


typedef ngx_variable_value_t  ngx_stream_variable_value_t;

#define ngx_stream_variable(v)     { sizeof(v) - 1, 1, 0, 0, 0, (u_char *) v }

typedef struct ngx_stream_variable_s  ngx_stream_variable_t;

typedef void (*ngx_stream_set_variable_pt) (ngx_stream_session_t *s,
    ngx_stream_variable_value_t *v, uintptr_t data);
typedef ngx_int_t (*ngx_stream_get_variable_pt) (ngx_stream_session_t *s,
    ngx_stream_variable_value_t *v, uintptr_t data);


#define NGX_STREAM_VAR_CHANGEABLE   1
#define NGX_STREAM_VAR_NOCACHEABLE  2
#define NGX_STREAM_VAR_INDEXED      4
#define NGX_STREAM_VAR_NOHASH       8
#define NGX_STREAM_VAR_WEAK         16
#define NGX_STREAM_VAR_PREFIX       32


struct ngx_stream_variable_s {
    ngx_str_t                     name;   /* must be first to build the hash */
    ngx_stream_set_variable_pt    set_handler;
    ngx_stream_get_variable_pt    get_handler;
    uintptr_t                     data;
    ngx_uint_t                    flags;
    ngx_uint_t                    index;
};

#define ngx_stream_null_variable  { ngx_null_string, NULL, NULL, 0, 0, 0 }


ngx_stream_variable_t *ngx_stream_add_variable(ngx_conf_t *cf, ngx_str_t *name,
    ngx_uint_t flags);
ngx_int_t ngx_stream_get_variable_index(ngx_conf_t *cf, ngx_str_t *name);
ngx_stream_variable_value_t *ngx_stream_get_indexed_variable(
    ngx_stream_session_t *s, ngx_uint_t index);
ngx_stream_variable_value_t *ngx_stream_get_flushed_variable(
    ngx_stream_session_t *s, ngx_uint_t index);

ngx_stream_variable_value_t *ngx_stream_get_variable(ngx_stream_session_t *s,
    ngx_str_t *name, ngx_uint_t key);


#if (NGX_PCRE)

typedef struct {
    ngx_uint_t                    capture;
    ngx_int_t                     index;
} ngx_stream_regex_variable_t;


typedef struct {
    ngx_regex_t                  *regex;
    ngx_uint_t                    ncaptures;
    ngx_stream_regex_variable_t  *variables;
    ngx_uint_t                    nvariables;
    ngx_str_t                     name;
} ngx_stream_regex_t;


typedef struct {
    ngx_stream_regex_t           *regex;
    void                         *value;
} ngx_stream_map_regex_t;


ngx_stream_regex_t *ngx_stream_regex_compile(ngx_conf_t *cf,
    ngx_regex_compile_t *rc);
ngx_int_t ngx_stream_regex_exec(ngx_stream_session_t *s, ngx_stream_regex_t *re,
    ngx_str_t *str);

#endif


typedef struct {
    ngx_hash_combined_t           hash;
#if (NGX_PCRE)
    ngx_stream_map_regex_t       *regex;
    ngx_uint_t                    nregex;
#endif
} ngx_stream_map_t;


void *ngx_stream_map_find(ngx_stream_session_t *s, ngx_stream_map_t *map,
    ngx_str_t *match);


ngx_int_t ngx_stream_variables_add_core_vars(ngx_conf_t *cf);
ngx_int_t ngx_stream_variables_init_vars(ngx_conf_t *cf);


extern ngx_stream_variable_value_t  ngx_stream_variable_null_value;
extern ngx_stream_variable_value_t  ngx_stream_variable_true_value;


#endif /* _NGX_STREAM_VARIABLES_H_INCLUDED_ */