view src/core/ngx_file.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 0c572ed91b36
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_FILE_H_INCLUDED_
#define _NGX_FILE_H_INCLUDED_


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


struct ngx_file_s {
    ngx_fd_t                   fd;
    ngx_str_t                  name;
    ngx_file_info_t            info;

    off_t                      offset;
    off_t                      sys_offset;

    ngx_log_t                 *log;

#if (NGX_THREADS || NGX_COMPAT)
    ngx_int_t                (*thread_handler)(ngx_thread_task_t *task,
                                               ngx_file_t *file);
    void                      *thread_ctx;
    ngx_thread_task_t         *thread_task;
#endif

#if (NGX_HAVE_FILE_AIO || NGX_COMPAT)
    ngx_event_aio_t           *aio;
#endif

    unsigned                   valid_info:1;
    unsigned                   directio:1;
};


#define NGX_MAX_PATH_LEVEL  3


typedef ngx_msec_t (*ngx_path_manager_pt) (void *data);
typedef ngx_msec_t (*ngx_path_purger_pt) (void *data);
typedef void (*ngx_path_loader_pt) (void *data);


typedef struct {
    ngx_str_t                  name;
    size_t                     len;
    size_t                     level[NGX_MAX_PATH_LEVEL];

    ngx_path_manager_pt        manager;
    ngx_path_purger_pt         purger;
    ngx_path_loader_pt         loader;
    void                      *data;

    u_char                    *conf_file;
    ngx_uint_t                 line;
} ngx_path_t;


typedef struct {
    ngx_str_t                  name;
    size_t                     level[NGX_MAX_PATH_LEVEL];
} ngx_path_init_t;


typedef struct {
    ngx_file_t                 file;
    off_t                      offset;
    ngx_path_t                *path;
    ngx_pool_t                *pool;
    char                      *warn;

    ngx_uint_t                 access;

    unsigned                   log_level:8;
    unsigned                   persistent:1;
    unsigned                   clean:1;
    unsigned                   thread_write:1;
} ngx_temp_file_t;


typedef struct {
    ngx_uint_t                 access;
    ngx_uint_t                 path_access;
    time_t                     time;
    ngx_fd_t                   fd;

    unsigned                   create_path:1;
    unsigned                   delete_file:1;

    ngx_log_t                 *log;
} ngx_ext_rename_file_t;


typedef struct {
    off_t                      size;
    size_t                     buf_size;

    ngx_uint_t                 access;
    time_t                     time;

    ngx_log_t                 *log;
} ngx_copy_file_t;


typedef struct ngx_tree_ctx_s  ngx_tree_ctx_t;

typedef ngx_int_t (*ngx_tree_init_handler_pt) (void *ctx, void *prev);
typedef ngx_int_t (*ngx_tree_handler_pt) (ngx_tree_ctx_t *ctx, ngx_str_t *name);

struct ngx_tree_ctx_s {
    off_t                      size;
    off_t                      fs_size;
    ngx_uint_t                 access;
    time_t                     mtime;

    ngx_tree_init_handler_pt   init_handler;
    ngx_tree_handler_pt        file_handler;
    ngx_tree_handler_pt        pre_tree_handler;
    ngx_tree_handler_pt        post_tree_handler;
    ngx_tree_handler_pt        spec_handler;

    void                      *data;
    size_t                     alloc;

    ngx_log_t                 *log;
};


ngx_int_t ngx_get_full_name(ngx_pool_t *pool, ngx_str_t *prefix,
    ngx_str_t *name);

ssize_t ngx_write_chain_to_temp_file(ngx_temp_file_t *tf, ngx_chain_t *chain);
ngx_int_t ngx_create_temp_file(ngx_file_t *file, ngx_path_t *path,
    ngx_pool_t *pool, ngx_uint_t persistent, ngx_uint_t clean,
    ngx_uint_t access);
void ngx_create_hashed_filename(ngx_path_t *path, u_char *file, size_t len);
ngx_int_t ngx_create_path(ngx_file_t *file, ngx_path_t *path);
ngx_err_t ngx_create_full_path(u_char *dir, ngx_uint_t access);
ngx_int_t ngx_add_path(ngx_conf_t *cf, ngx_path_t **slot);
ngx_int_t ngx_create_paths(ngx_cycle_t *cycle, ngx_uid_t user);
ngx_int_t ngx_ext_rename_file(ngx_str_t *src, ngx_str_t *to,
    ngx_ext_rename_file_t *ext);
ngx_int_t ngx_copy_file(u_char *from, u_char *to, ngx_copy_file_t *cf);
ngx_int_t ngx_walk_tree(ngx_tree_ctx_t *ctx, ngx_str_t *tree);

ngx_atomic_uint_t ngx_next_temp_number(ngx_uint_t collision);

char *ngx_conf_set_path_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
char *ngx_conf_merge_path_value(ngx_conf_t *cf, ngx_path_t **path,
    ngx_path_t *prev, ngx_path_init_t *init);
char *ngx_conf_set_access_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);


extern ngx_atomic_t      *ngx_temp_number;
extern ngx_atomic_int_t   ngx_random_number;


#endif /* _NGX_FILE_H_INCLUDED_ */