view src/stream/ngx_stream_script.h @ 9300:5be23505292b default tip

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 3ab8e1e2f0f7
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_STREAM_SCRIPT_H_INCLUDED_
#define _NGX_STREAM_SCRIPT_H_INCLUDED_


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


typedef struct {
    u_char                       *ip;
    u_char                       *pos;
    ngx_stream_variable_value_t  *sp;

    ngx_str_t                     buf;
    ngx_str_t                     line;

    unsigned                      flushed:1;
    unsigned                      skip:1;

    ngx_stream_session_t         *session;
} ngx_stream_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                    size;

    void                         *main;

    unsigned                      complete_lengths:1;
    unsigned                      complete_values:1;
    unsigned                      zero:1;
    unsigned                      conf_prefix:1;
    unsigned                      root_prefix:1;
} ngx_stream_script_compile_t;


typedef struct {
    ngx_str_t                     value;
    ngx_uint_t                   *flushes;
    void                         *lengths;
    void                         *values;

    union {
        size_t                    size;
    } u;
} ngx_stream_complex_value_t;


typedef struct {
    ngx_conf_t                   *cf;
    ngx_str_t                    *value;
    ngx_stream_complex_value_t   *complex_value;

    unsigned                      zero:1;
    unsigned                      conf_prefix:1;
    unsigned                      root_prefix:1;
} ngx_stream_compile_complex_value_t;


typedef void (*ngx_stream_script_code_pt) (ngx_stream_script_engine_t *e);
typedef size_t (*ngx_stream_script_len_code_pt) (ngx_stream_script_engine_t *e);


typedef struct {
    ngx_stream_script_code_pt     code;
    uintptr_t                     len;
} ngx_stream_script_copy_code_t;


typedef struct {
    ngx_stream_script_code_pt     code;
    uintptr_t                     index;
} ngx_stream_script_var_code_t;


typedef struct {
    ngx_stream_script_code_pt     code;
    uintptr_t                     n;
} ngx_stream_script_copy_capture_code_t;


typedef struct {
    ngx_stream_script_code_pt     code;
    uintptr_t                     conf_prefix;
} ngx_stream_script_full_name_code_t;


void ngx_stream_script_flush_complex_value(ngx_stream_session_t *s,
    ngx_stream_complex_value_t *val);
ngx_int_t ngx_stream_complex_value(ngx_stream_session_t *s,
    ngx_stream_complex_value_t *val, ngx_str_t *value);
size_t ngx_stream_complex_value_size(ngx_stream_session_t *s,
    ngx_stream_complex_value_t *val, size_t default_value);
ngx_int_t ngx_stream_compile_complex_value(
    ngx_stream_compile_complex_value_t *ccv);
char *ngx_stream_set_complex_value_slot(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
char *ngx_stream_set_complex_value_zero_slot(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
char *ngx_stream_set_complex_value_size_slot(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);


ngx_uint_t ngx_stream_script_variables_count(ngx_str_t *value);
ngx_int_t ngx_stream_script_compile(ngx_stream_script_compile_t *sc);
u_char *ngx_stream_script_run(ngx_stream_session_t *s, ngx_str_t *value,
    void *code_lengths, size_t reserved, void *code_values);
void ngx_stream_script_flush_no_cacheable_variables(ngx_stream_session_t *s,
    ngx_array_t *indices);

void *ngx_stream_script_add_code(ngx_array_t *codes, size_t size, void *code);

size_t ngx_stream_script_copy_len_code(ngx_stream_script_engine_t *e);
void ngx_stream_script_copy_code(ngx_stream_script_engine_t *e);
size_t ngx_stream_script_copy_var_len_code(ngx_stream_script_engine_t *e);
void ngx_stream_script_copy_var_code(ngx_stream_script_engine_t *e);
size_t ngx_stream_script_copy_capture_len_code(ngx_stream_script_engine_t *e);
void ngx_stream_script_copy_capture_code(ngx_stream_script_engine_t *e);

#endif /* _NGX_STREAM_SCRIPT_H_INCLUDED_ */