Mercurial > hg > nginx
view src/http/ngx_http_script.h @ 9203:0de20f43db25
Fixed request termination with AIO and subrequests (ticket #2555).
When a request was terminated due to an error via ngx_http_terminate_request()
while an AIO operation was running in a subrequest, various issues were
observed. This happened because ngx_http_request_finalizer() was only set
in the subrequest where ngx_http_terminate_request() was called, but not
in the subrequest where the AIO operation was running. After completion
of the AIO operation normal processing of the subrequest was resumed, leading
to issues.
In particular, in case of the upstream module, termination of the request
called upstream cleanup, which closed the upstream connection. Attempts to
further work with the upstream connection after AIO operation completion
resulted in segfaults in ngx_ssl_recv(), "readv() failed (9: Bad file
descriptor) while reading upstream" errors, or socket leaks.
In ticket #2555, issues were observed with the following configuration
with cache background update (with thread writing instrumented to
introduce a delay, when a client closes the connection during an update):
location = /background-and-aio-write {
proxy_pass ...
proxy_cache one;
proxy_cache_valid 200 1s;
proxy_cache_background_update on;
proxy_cache_use_stale updating;
aio threads;
aio_write on;
limit_rate 1000;
}
Similarly, the same issue can be seen with SSI, and can be caused by
errors in subrequests, such as in the following configuration
(where "/proxy" uses AIO, and "/sleep" returns 444 after some delay,
causing request termination):
location = /ssi-active-boom {
ssi on;
ssi_types *;
return 200 '
<!--#include virtual="/proxy" -->
<!--#include virtual="/sleep" -->
';
limit_rate 1000;
}
Or the same with both AIO operation and the error in non-active subrequests
(which needs slightly different handling, see below):
location = /ssi-non-active-boom {
ssi on;
ssi_types *;
return 200 '
<!--#include virtual="/static" -->
<!--#include virtual="/proxy" -->
<!--#include virtual="/sleep" -->
';
limit_rate 1000;
}
Similarly, issues can be observed with just static files. However,
with static files potential impact is limited due to timeout safeguards
in ngx_http_writer(), and the fact that c->error is set during request
termination.
In a simple configuration with an AIO operation in the active subrequest,
such as in the following configuration, the connection is closed right
after completion of the AIO operation anyway, since ngx_http_writer()
tries to write to the connection and fails due to c->error set:
location = /ssi-active-static-boom {
ssi on;
ssi_types *;
return 200 '
<!--#include virtual="/static-aio" -->
<!--#include virtual="/sleep" -->
';
limit_rate 1000;
}
In the following configuration, with an AIO operation in a non-active
subrequest, the connection is closed only after send_timeout expires:
location = /ssi-non-active-static-boom {
ssi on;
ssi_types *;
return 200 '
<!--#include virtual="/static" -->
<!--#include virtual="/static-aio" -->
<!--#include virtual="/sleep" -->
';
limit_rate 1000;
}
Fix is to introduce r->main->terminated flag, which is to be checked
by AIO event handlers when the r->main->blocked counter is decremented.
When the flag is set, handlers are expected to wake up the connection
instead of the subrequest (which might be already cleaned up).
Additionally, now ngx_http_request_finalizer() is always set in the
active subrequest, so waking up the connection properly finalizes the
request even if termination happened in a non-active subrequest.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Tue, 30 Jan 2024 03:20:05 +0300 |
parents | 3ab8e1e2f0f7 |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_HTTP_SCRIPT_H_INCLUDED_ #define _NGX_HTTP_SCRIPT_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> typedef struct { u_char *ip; u_char *pos; ngx_http_variable_value_t *sp; ngx_str_t buf; ngx_str_t line; /* the start of the rewritten arguments */ u_char *args; unsigned flushed:1; unsigned skip:1; unsigned quote:1; unsigned is_args:1; unsigned log:1; ngx_int_t status; ngx_http_request_t *request; } ngx_http_script_engine_t; typedef struct { ngx_conf_t *cf; ngx_str_t *source; ngx_array_t **flushes; ngx_array_t **lengths; ngx_array_t **values; ngx_uint_t variables; ngx_uint_t ncaptures; ngx_uint_t captures_mask; ngx_uint_t size; void *main; unsigned compile_args:1; unsigned complete_lengths:1; unsigned complete_values:1; unsigned zero:1; unsigned conf_prefix:1; unsigned root_prefix:1; unsigned dup_capture:1; unsigned args:1; } ngx_http_script_compile_t; typedef struct { ngx_str_t value; ngx_uint_t *flushes; void *lengths; void *values; union { size_t size; } u; } ngx_http_complex_value_t; typedef struct { ngx_conf_t *cf; ngx_str_t *value; ngx_http_complex_value_t *complex_value; unsigned zero:1; unsigned conf_prefix:1; unsigned root_prefix:1; } ngx_http_compile_complex_value_t; typedef void (*ngx_http_script_code_pt) (ngx_http_script_engine_t *e); typedef size_t (*ngx_http_script_len_code_pt) (ngx_http_script_engine_t *e); typedef struct { ngx_http_script_code_pt code; uintptr_t len; } ngx_http_script_copy_code_t; typedef struct { ngx_http_script_code_pt code; uintptr_t index; } ngx_http_script_var_code_t; typedef struct { ngx_http_script_code_pt code; ngx_http_set_variable_pt handler; uintptr_t data; } ngx_http_script_var_handler_code_t; typedef struct { ngx_http_script_code_pt code; uintptr_t n; } ngx_http_script_copy_capture_code_t; #if (NGX_PCRE) typedef struct { ngx_http_script_code_pt code; ngx_http_regex_t *regex; ngx_array_t *lengths; uintptr_t size; uintptr_t status; uintptr_t next; unsigned test:1; unsigned negative_test:1; unsigned uri:1; unsigned args:1; /* add the r->args to the new arguments */ unsigned add_args:1; unsigned redirect:1; unsigned break_cycle:1; ngx_str_t name; } ngx_http_script_regex_code_t; typedef struct { ngx_http_script_code_pt code; unsigned uri:1; unsigned args:1; /* add the r->args to the new arguments */ unsigned add_args:1; unsigned redirect:1; } ngx_http_script_regex_end_code_t; #endif typedef struct { ngx_http_script_code_pt code; uintptr_t conf_prefix; } ngx_http_script_full_name_code_t; typedef struct { ngx_http_script_code_pt code; uintptr_t status; ngx_http_complex_value_t text; } ngx_http_script_return_code_t; typedef enum { ngx_http_script_file_plain = 0, ngx_http_script_file_not_plain, ngx_http_script_file_dir, ngx_http_script_file_not_dir, ngx_http_script_file_exists, ngx_http_script_file_not_exists, ngx_http_script_file_exec, ngx_http_script_file_not_exec } ngx_http_script_file_op_e; typedef struct { ngx_http_script_code_pt code; uintptr_t op; } ngx_http_script_file_code_t; typedef struct { ngx_http_script_code_pt code; uintptr_t next; void **loc_conf; } ngx_http_script_if_code_t; typedef struct { ngx_http_script_code_pt code; ngx_array_t *lengths; } ngx_http_script_complex_value_code_t; typedef struct { ngx_http_script_code_pt code; uintptr_t value; uintptr_t text_len; uintptr_t text_data; } ngx_http_script_value_code_t; void ngx_http_script_flush_complex_value(ngx_http_request_t *r, ngx_http_complex_value_t *val); ngx_int_t ngx_http_complex_value(ngx_http_request_t *r, ngx_http_complex_value_t *val, ngx_str_t *value); size_t ngx_http_complex_value_size(ngx_http_request_t *r, ngx_http_complex_value_t *val, size_t default_value); ngx_int_t ngx_http_compile_complex_value(ngx_http_compile_complex_value_t *ccv); char *ngx_http_set_complex_value_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); char *ngx_http_set_complex_value_zero_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); char *ngx_http_set_complex_value_size_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); ngx_int_t ngx_http_test_predicates(ngx_http_request_t *r, ngx_array_t *predicates); ngx_int_t ngx_http_test_required_predicates(ngx_http_request_t *r, ngx_array_t *predicates); char *ngx_http_set_predicate_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); ngx_uint_t ngx_http_script_variables_count(ngx_str_t *value); ngx_int_t ngx_http_script_compile(ngx_http_script_compile_t *sc); u_char *ngx_http_script_run(ngx_http_request_t *r, ngx_str_t *value, void *code_lengths, size_t reserved, void *code_values); void ngx_http_script_flush_no_cacheable_variables(ngx_http_request_t *r, ngx_array_t *indices); void *ngx_http_script_start_code(ngx_pool_t *pool, ngx_array_t **codes, size_t size); void *ngx_http_script_add_code(ngx_array_t *codes, size_t size, void *code); size_t ngx_http_script_copy_len_code(ngx_http_script_engine_t *e); void ngx_http_script_copy_code(ngx_http_script_engine_t *e); size_t ngx_http_script_copy_var_len_code(ngx_http_script_engine_t *e); void ngx_http_script_copy_var_code(ngx_http_script_engine_t *e); size_t ngx_http_script_copy_capture_len_code(ngx_http_script_engine_t *e); void ngx_http_script_copy_capture_code(ngx_http_script_engine_t *e); size_t ngx_http_script_mark_args_code(ngx_http_script_engine_t *e); void ngx_http_script_start_args_code(ngx_http_script_engine_t *e); #if (NGX_PCRE) void ngx_http_script_regex_start_code(ngx_http_script_engine_t *e); void ngx_http_script_regex_end_code(ngx_http_script_engine_t *e); #endif void ngx_http_script_return_code(ngx_http_script_engine_t *e); void ngx_http_script_break_code(ngx_http_script_engine_t *e); void ngx_http_script_if_code(ngx_http_script_engine_t *e); void ngx_http_script_equal_code(ngx_http_script_engine_t *e); void ngx_http_script_not_equal_code(ngx_http_script_engine_t *e); void ngx_http_script_file_code(ngx_http_script_engine_t *e); void ngx_http_script_complex_value_code(ngx_http_script_engine_t *e); void ngx_http_script_value_code(ngx_http_script_engine_t *e); void ngx_http_script_set_var_code(ngx_http_script_engine_t *e); void ngx_http_script_var_set_handler_code(ngx_http_script_engine_t *e); void ngx_http_script_var_code(ngx_http_script_engine_t *e); void ngx_http_script_nop_code(ngx_http_script_engine_t *e); #endif /* _NGX_HTTP_SCRIPT_H_INCLUDED_ */