view src/core/ngx_file.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 0c572ed91b36
children
line wrap: on
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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_ */