Mercurial > hg > nginx
view src/http/ngx_http_variables.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 | 08b3ea81ff5f |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_HTTP_VARIABLES_H_INCLUDED_ #define _NGX_HTTP_VARIABLES_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> typedef ngx_variable_value_t ngx_http_variable_value_t; #define ngx_http_variable(v) { sizeof(v) - 1, 1, 0, 0, 0, (u_char *) v } typedef struct ngx_http_variable_s ngx_http_variable_t; typedef void (*ngx_http_set_variable_pt) (ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data); typedef ngx_int_t (*ngx_http_get_variable_pt) (ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data); #define NGX_HTTP_VAR_CHANGEABLE 1 #define NGX_HTTP_VAR_NOCACHEABLE 2 #define NGX_HTTP_VAR_INDEXED 4 #define NGX_HTTP_VAR_NOHASH 8 #define NGX_HTTP_VAR_WEAK 16 #define NGX_HTTP_VAR_PREFIX 32 struct ngx_http_variable_s { ngx_str_t name; /* must be first to build the hash */ ngx_http_set_variable_pt set_handler; ngx_http_get_variable_pt get_handler; uintptr_t data; ngx_uint_t flags; ngx_uint_t index; }; #define ngx_http_null_variable { ngx_null_string, NULL, NULL, 0, 0, 0 } ngx_http_variable_t *ngx_http_add_variable(ngx_conf_t *cf, ngx_str_t *name, ngx_uint_t flags); ngx_int_t ngx_http_get_variable_index(ngx_conf_t *cf, ngx_str_t *name); ngx_http_variable_value_t *ngx_http_get_indexed_variable(ngx_http_request_t *r, ngx_uint_t index); ngx_http_variable_value_t *ngx_http_get_flushed_variable(ngx_http_request_t *r, ngx_uint_t index); ngx_http_variable_value_t *ngx_http_get_variable(ngx_http_request_t *r, ngx_str_t *name, ngx_uint_t key); ngx_int_t ngx_http_variable_unknown_header(ngx_http_request_t *r, ngx_http_variable_value_t *v, ngx_str_t *var, ngx_list_part_t *part, size_t prefix); #if (NGX_PCRE) typedef struct { ngx_uint_t capture; ngx_int_t index; } ngx_http_regex_variable_t; typedef struct { ngx_regex_t *regex; ngx_uint_t ncaptures; ngx_http_regex_variable_t *variables; ngx_uint_t nvariables; ngx_str_t name; } ngx_http_regex_t; typedef struct { ngx_http_regex_t *regex; void *value; } ngx_http_map_regex_t; ngx_http_regex_t *ngx_http_regex_compile(ngx_conf_t *cf, ngx_regex_compile_t *rc); ngx_int_t ngx_http_regex_exec(ngx_http_request_t *r, ngx_http_regex_t *re, ngx_str_t *s); #endif typedef struct { ngx_hash_combined_t hash; #if (NGX_PCRE) ngx_http_map_regex_t *regex; ngx_uint_t nregex; #endif } ngx_http_map_t; void *ngx_http_map_find(ngx_http_request_t *r, ngx_http_map_t *map, ngx_str_t *match); ngx_int_t ngx_http_variables_add_core_vars(ngx_conf_t *cf); ngx_int_t ngx_http_variables_init_vars(ngx_conf_t *cf); extern ngx_http_variable_value_t ngx_http_variable_null_value; extern ngx_http_variable_value_t ngx_http_variable_true_value; #endif /* _NGX_HTTP_VARIABLES_H_INCLUDED_ */