Mercurial > hg > nginx
view src/http/ngx_http.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 | 8d0753760546 |
| children | f3df785649ae |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_HTTP_H_INCLUDED_ #define _NGX_HTTP_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> typedef struct ngx_http_request_s ngx_http_request_t; typedef struct ngx_http_upstream_s ngx_http_upstream_t; typedef struct ngx_http_cache_s ngx_http_cache_t; typedef struct ngx_http_file_cache_s ngx_http_file_cache_t; typedef struct ngx_http_log_ctx_s ngx_http_log_ctx_t; typedef struct ngx_http_chunked_s ngx_http_chunked_t; typedef struct ngx_http_v2_stream_s ngx_http_v2_stream_t; typedef struct ngx_http_v3_parse_s ngx_http_v3_parse_t; typedef struct ngx_http_v3_session_s ngx_http_v3_session_t; typedef ngx_int_t (*ngx_http_header_handler_pt)(ngx_http_request_t *r, ngx_table_elt_t *h, ngx_uint_t offset); typedef u_char *(*ngx_http_log_handler_pt)(ngx_http_request_t *r, ngx_http_request_t *sr, u_char *buf, size_t len); #include <ngx_http_variables.h> #include <ngx_http_config.h> #include <ngx_http_request.h> #include <ngx_http_script.h> #include <ngx_http_upstream.h> #include <ngx_http_upstream_round_robin.h> #include <ngx_http_core_module.h> #if (NGX_HTTP_V2) #include <ngx_http_v2.h> #endif #if (NGX_HTTP_V3) #include <ngx_http_v3.h> #endif #if (NGX_HTTP_CACHE) #include <ngx_http_cache.h> #endif #if (NGX_HTTP_SSI) #include <ngx_http_ssi_filter_module.h> #endif #if (NGX_HTTP_SSL) #include <ngx_http_ssl_module.h> #endif struct ngx_http_log_ctx_s { ngx_connection_t *connection; ngx_http_request_t *request; ngx_http_request_t *current_request; }; struct ngx_http_chunked_s { ngx_uint_t state; off_t size; off_t length; }; typedef struct { ngx_uint_t http_version; ngx_uint_t code; ngx_uint_t count; u_char *start; u_char *end; } ngx_http_status_t; #define ngx_http_get_module_ctx(r, module) (r)->ctx[module.ctx_index] #define ngx_http_set_ctx(r, c, module) r->ctx[module.ctx_index] = c; ngx_int_t ngx_http_add_location(ngx_conf_t *cf, ngx_queue_t **locations, ngx_http_core_loc_conf_t *clcf); ngx_int_t ngx_http_add_listen(ngx_conf_t *cf, ngx_http_core_srv_conf_t *cscf, ngx_http_listen_opt_t *lsopt); void ngx_http_init_connection(ngx_connection_t *c); void ngx_http_close_connection(ngx_connection_t *c); #if (NGX_HTTP_SSL && defined SSL_CTRL_SET_TLSEXT_HOSTNAME) int ngx_http_ssl_servername(ngx_ssl_conn_t *ssl_conn, int *ad, void *arg); #endif #if (NGX_HTTP_SSL && defined SSL_R_CERT_CB_ERROR) int ngx_http_ssl_certificate(ngx_ssl_conn_t *ssl_conn, void *arg); #endif ngx_int_t ngx_http_parse_request_line(ngx_http_request_t *r, ngx_buf_t *b); ngx_int_t ngx_http_parse_uri(ngx_http_request_t *r); ngx_int_t ngx_http_parse_complex_uri(ngx_http_request_t *r, ngx_uint_t merge_slashes); ngx_int_t ngx_http_parse_status_line(ngx_http_request_t *r, ngx_buf_t *b, ngx_http_status_t *status); ngx_int_t ngx_http_parse_unsafe_uri(ngx_http_request_t *r, ngx_str_t *uri, ngx_str_t *args, ngx_uint_t *flags); ngx_int_t ngx_http_parse_header_line(ngx_http_request_t *r, ngx_buf_t *b, ngx_uint_t allow_underscores); ngx_table_elt_t *ngx_http_parse_multi_header_lines(ngx_http_request_t *r, ngx_table_elt_t *headers, ngx_str_t *name, ngx_str_t *value); ngx_table_elt_t *ngx_http_parse_set_cookie_lines(ngx_http_request_t *r, ngx_table_elt_t *headers, ngx_str_t *name, ngx_str_t *value); ngx_int_t ngx_http_arg(ngx_http_request_t *r, u_char *name, size_t len, ngx_str_t *value); void ngx_http_split_args(ngx_http_request_t *r, ngx_str_t *uri, ngx_str_t *args); ngx_int_t ngx_http_parse_chunked(ngx_http_request_t *r, ngx_buf_t *b, ngx_http_chunked_t *ctx); ngx_http_request_t *ngx_http_create_request(ngx_connection_t *c); ngx_int_t ngx_http_process_request_uri(ngx_http_request_t *r); ngx_int_t ngx_http_process_request_header(ngx_http_request_t *r); void ngx_http_process_request(ngx_http_request_t *r); void ngx_http_update_location_config(ngx_http_request_t *r); void ngx_http_handler(ngx_http_request_t *r); void ngx_http_run_posted_requests(ngx_connection_t *c); ngx_int_t ngx_http_post_request(ngx_http_request_t *r, ngx_http_posted_request_t *pr); ngx_int_t ngx_http_set_virtual_server(ngx_http_request_t *r, ngx_str_t *host); ngx_int_t ngx_http_validate_host(ngx_str_t *host, ngx_pool_t *pool, ngx_uint_t alloc); void ngx_http_close_request(ngx_http_request_t *r, ngx_int_t rc); void ngx_http_finalize_request(ngx_http_request_t *r, ngx_int_t rc); void ngx_http_free_request(ngx_http_request_t *r, ngx_int_t rc); void ngx_http_empty_handler(ngx_event_t *wev); void ngx_http_request_empty_handler(ngx_http_request_t *r); #define NGX_HTTP_LAST 1 #define NGX_HTTP_FLUSH 2 ngx_int_t ngx_http_send_special(ngx_http_request_t *r, ngx_uint_t flags); ngx_int_t ngx_http_read_client_request_body(ngx_http_request_t *r, ngx_http_client_body_handler_pt post_handler); ngx_int_t ngx_http_read_unbuffered_request_body(ngx_http_request_t *r); ngx_int_t ngx_http_send_header(ngx_http_request_t *r); ngx_int_t ngx_http_special_response_handler(ngx_http_request_t *r, ngx_int_t error); ngx_int_t ngx_http_filter_finalize_request(ngx_http_request_t *r, ngx_module_t *m, ngx_int_t error); void ngx_http_clean_header(ngx_http_request_t *r); ngx_int_t ngx_http_discard_request_body(ngx_http_request_t *r); void ngx_http_discarded_request_body_handler(ngx_http_request_t *r); void ngx_http_block_reading(ngx_http_request_t *r); void ngx_http_test_reading(ngx_http_request_t *r); char *ngx_http_types_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); char *ngx_http_merge_types(ngx_conf_t *cf, ngx_array_t **keys, ngx_hash_t *types_hash, ngx_array_t **prev_keys, ngx_hash_t *prev_types_hash, ngx_str_t *default_types); ngx_int_t ngx_http_set_default_types(ngx_conf_t *cf, ngx_array_t **types, ngx_str_t *default_type); #if (NGX_HTTP_DEGRADATION) ngx_uint_t ngx_http_degraded(ngx_http_request_t *); #endif #if (NGX_HTTP_V2 || NGX_HTTP_V3) ngx_int_t ngx_http_huff_decode(u_char *state, u_char *src, size_t len, u_char **dst, ngx_uint_t last, ngx_log_t *log); size_t ngx_http_huff_encode(u_char *src, size_t len, u_char *dst, ngx_uint_t lower); #endif extern ngx_module_t ngx_http_module; extern ngx_str_t ngx_http_html_default_types[]; extern ngx_http_output_header_filter_pt ngx_http_top_header_filter; extern ngx_http_output_body_filter_pt ngx_http_top_body_filter; extern ngx_http_request_body_filter_pt ngx_http_top_request_body_filter; #endif /* _NGX_HTTP_H_INCLUDED_ */