Mercurial > hg > nginx
view src/os/unix/ngx_process.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 | 8b84d60ef13d |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_PROCESS_H_INCLUDED_ #define _NGX_PROCESS_H_INCLUDED_ #include <ngx_setaffinity.h> #include <ngx_setproctitle.h> typedef pid_t ngx_pid_t; #define NGX_INVALID_PID -1 typedef void (*ngx_spawn_proc_pt) (ngx_cycle_t *cycle, void *data); typedef struct { ngx_pid_t pid; int status; ngx_socket_t channel[2]; ngx_spawn_proc_pt proc; void *data; char *name; unsigned respawn:1; unsigned just_spawn:1; unsigned detached:1; unsigned exiting:1; unsigned exited:1; } ngx_process_t; typedef struct { char *path; char *name; char *const *argv; char *const *envp; } ngx_exec_ctx_t; #define NGX_MAX_PROCESSES 1024 #define NGX_PROCESS_NORESPAWN -1 #define NGX_PROCESS_JUST_SPAWN -2 #define NGX_PROCESS_RESPAWN -3 #define NGX_PROCESS_JUST_RESPAWN -4 #define NGX_PROCESS_DETACHED -5 #define ngx_getpid getpid #define ngx_getppid getppid #ifndef ngx_log_pid #define ngx_log_pid ngx_pid #endif ngx_pid_t ngx_spawn_process(ngx_cycle_t *cycle, ngx_spawn_proc_pt proc, void *data, char *name, ngx_int_t respawn); ngx_pid_t ngx_execute(ngx_cycle_t *cycle, ngx_exec_ctx_t *ctx); ngx_int_t ngx_init_signals(ngx_log_t *log); void ngx_debug_point(void); #if (NGX_HAVE_SCHED_YIELD) #define ngx_sched_yield() sched_yield() #else #define ngx_sched_yield() usleep(1) #endif extern int ngx_argc; extern char **ngx_argv; extern char **ngx_os_argv; extern ngx_pid_t ngx_pid; extern ngx_pid_t ngx_parent; extern ngx_socket_t ngx_channel; extern ngx_int_t ngx_process_slot; extern ngx_int_t ngx_last_process; extern ngx_process_t ngx_processes[NGX_MAX_PROCESSES]; #endif /* _NGX_PROCESS_H_INCLUDED_ */