Mercurial > hg > nginx
annotate src/core/ngx_shmtx.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 | 512c741fa841 |
children |
rev | line source |
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611 | 1 |
2 /* | |
3 * Copyright (C) Igor Sysoev | |
4412 | 4 * Copyright (C) Nginx, Inc. |
611 | 5 */ |
6 | |
7 | |
8 #ifndef _NGX_SHMTX_H_INCLUDED_ | |
9 #define _NGX_SHMTX_H_INCLUDED_ | |
10 | |
11 | |
12 #include <ngx_config.h> | |
13 #include <ngx_core.h> | |
14 | |
15 | |
16 typedef struct { | |
4309
3f6040cd731e
Added shmtx interface to forcibly unlock mutexes.
Maxim Dounin <mdounin@mdounin.ru>
parents:
3909
diff
changeset
|
17 ngx_atomic_t lock; |
3f6040cd731e
Added shmtx interface to forcibly unlock mutexes.
Maxim Dounin <mdounin@mdounin.ru>
parents:
3909
diff
changeset
|
18 #if (NGX_HAVE_POSIX_SEM) |
3f6040cd731e
Added shmtx interface to forcibly unlock mutexes.
Maxim Dounin <mdounin@mdounin.ru>
parents:
3909
diff
changeset
|
19 ngx_atomic_t wait; |
3f6040cd731e
Added shmtx interface to forcibly unlock mutexes.
Maxim Dounin <mdounin@mdounin.ru>
parents:
3909
diff
changeset
|
20 #endif |
3f6040cd731e
Added shmtx interface to forcibly unlock mutexes.
Maxim Dounin <mdounin@mdounin.ru>
parents:
3909
diff
changeset
|
21 } ngx_shmtx_sh_t; |
3f6040cd731e
Added shmtx interface to forcibly unlock mutexes.
Maxim Dounin <mdounin@mdounin.ru>
parents:
3909
diff
changeset
|
22 |
3f6040cd731e
Added shmtx interface to forcibly unlock mutexes.
Maxim Dounin <mdounin@mdounin.ru>
parents:
3909
diff
changeset
|
23 |
3f6040cd731e
Added shmtx interface to forcibly unlock mutexes.
Maxim Dounin <mdounin@mdounin.ru>
parents:
3909
diff
changeset
|
24 typedef struct { |
611 | 25 #if (NGX_HAVE_ATOMIC_OPS) |
26 ngx_atomic_t *lock; | |
3909
0daede16d68b
use POSIX semaphores in shmtx instead of sched_yield()
Igor Sysoev <igor@sysoev.ru>
parents:
2563
diff
changeset
|
27 #if (NGX_HAVE_POSIX_SEM) |
4309
3f6040cd731e
Added shmtx interface to forcibly unlock mutexes.
Maxim Dounin <mdounin@mdounin.ru>
parents:
3909
diff
changeset
|
28 ngx_atomic_t *wait; |
3909
0daede16d68b
use POSIX semaphores in shmtx instead of sched_yield()
Igor Sysoev <igor@sysoev.ru>
parents:
2563
diff
changeset
|
29 ngx_uint_t semaphore; |
0daede16d68b
use POSIX semaphores in shmtx instead of sched_yield()
Igor Sysoev <igor@sysoev.ru>
parents:
2563
diff
changeset
|
30 sem_t sem; |
0daede16d68b
use POSIX semaphores in shmtx instead of sched_yield()
Igor Sysoev <igor@sysoev.ru>
parents:
2563
diff
changeset
|
31 #endif |
611 | 32 #else |
33 ngx_fd_t fd; | |
34 u_char *name; | |
35 #endif | |
3909
0daede16d68b
use POSIX semaphores in shmtx instead of sched_yield()
Igor Sysoev <igor@sysoev.ru>
parents:
2563
diff
changeset
|
36 ngx_uint_t spin; |
611 | 37 } ngx_shmtx_t; |
38 | |
39 | |
4309
3f6040cd731e
Added shmtx interface to forcibly unlock mutexes.
Maxim Dounin <mdounin@mdounin.ru>
parents:
3909
diff
changeset
|
40 ngx_int_t ngx_shmtx_create(ngx_shmtx_t *mtx, ngx_shmtx_sh_t *addr, |
3f6040cd731e
Added shmtx interface to forcibly unlock mutexes.
Maxim Dounin <mdounin@mdounin.ru>
parents:
3909
diff
changeset
|
41 u_char *name); |
4738
512c741fa841
Fixed typo in a function name.
Ruslan Ermilov <ru@nginx.com>
parents:
4412
diff
changeset
|
42 void ngx_shmtx_destroy(ngx_shmtx_t *mtx); |
3909
0daede16d68b
use POSIX semaphores in shmtx instead of sched_yield()
Igor Sysoev <igor@sysoev.ru>
parents:
2563
diff
changeset
|
43 ngx_uint_t ngx_shmtx_trylock(ngx_shmtx_t *mtx); |
0daede16d68b
use POSIX semaphores in shmtx instead of sched_yield()
Igor Sysoev <igor@sysoev.ru>
parents:
2563
diff
changeset
|
44 void ngx_shmtx_lock(ngx_shmtx_t *mtx); |
0daede16d68b
use POSIX semaphores in shmtx instead of sched_yield()
Igor Sysoev <igor@sysoev.ru>
parents:
2563
diff
changeset
|
45 void ngx_shmtx_unlock(ngx_shmtx_t *mtx); |
4309
3f6040cd731e
Added shmtx interface to forcibly unlock mutexes.
Maxim Dounin <mdounin@mdounin.ru>
parents:
3909
diff
changeset
|
46 ngx_uint_t ngx_shmtx_force_unlock(ngx_shmtx_t *mtx, ngx_pid_t pid); |
611 | 47 |
48 | |
49 #endif /* _NGX_SHMTX_H_INCLUDED_ */ |