view src/stream/ngx_stream_variables.h @ 7969:84c60a3cd12a stable-1.20

Changed ngx_chain_update_chains() to test tag first (ticket #2248). Without this change, aio used with HTTP/2 can result in connection hang, as observed with "aio threads; aio_write on;" and proxying (ticket #2248). The problem is that HTTP/2 updates buffers outside of the output filters (notably, marks them as sent), and then posts a write event to call output filters. If a filter does not call the next one for some reason (for example, because of an AIO operation in progress), this might result in a state when the owner of a buffer already called ngx_chain_update_chains() and can reuse the buffer, while the same buffer is still sitting in the busy chain of some other filter. In the particular case a buffer was sitting in output chain's ctx->busy, and was reused by event pipe. Output chain's ctx->busy was permanently blocked by it, and this resulted in connection hang. Fix is to change ngx_chain_update_chains() to skip buffers from other modules unconditionally, without trying to wait for these buffers to become empty.
author Maxim Dounin <mdounin@mdounin.ru>
date Sat, 30 Oct 2021 02:39:19 +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_ */