Mercurial > hg > nginx
annotate src/core/ngx_queue.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 | 3038bd4d7816 |
children |
rev | line source |
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1646 | 1 |
2 /* | |
3 * Copyright (C) Igor Sysoev | |
4412 | 4 * Copyright (C) Nginx, Inc. |
1646 | 5 */ |
6 | |
7 | |
8 #include <ngx_config.h> | |
9 #include <ngx_core.h> | |
10 | |
11 | |
12 #ifndef _NGX_QUEUE_H_INCLUDED_ | |
13 #define _NGX_QUEUE_H_INCLUDED_ | |
14 | |
15 | |
16 typedef struct ngx_queue_s ngx_queue_t; | |
17 | |
18 struct ngx_queue_s { | |
19 ngx_queue_t *prev; | |
20 ngx_queue_t *next; | |
21 }; | |
22 | |
23 | |
1684 | 24 #define ngx_queue_init(q) \ |
25 (q)->prev = q; \ | |
1763 | 26 (q)->next = q |
1684 | 27 |
28 | |
1646 | 29 #define ngx_queue_empty(h) \ |
30 (h == (h)->prev) | |
31 | |
32 | |
33 #define ngx_queue_insert_head(h, x) \ | |
34 (x)->next = (h)->next; \ | |
35 (x)->next->prev = x; \ | |
36 (x)->prev = h; \ | |
37 (h)->next = x | |
38 | |
39 | |
2026 | 40 #define ngx_queue_insert_after ngx_queue_insert_head |
41 | |
42 | |
43 #define ngx_queue_insert_tail(h, x) \ | |
44 (x)->prev = (h)->prev; \ | |
45 (x)->prev->next = x; \ | |
46 (x)->next = h; \ | |
47 (h)->prev = x | |
48 | |
49 | |
9167
3038bd4d7816
Core: changed ngx_queue_sort() to use merge sort.
Maxim Dounin <mdounin@mdounin.ru>
parents:
4412
diff
changeset
|
50 #define ngx_queue_insert_before ngx_queue_insert_tail |
3038bd4d7816
Core: changed ngx_queue_sort() to use merge sort.
Maxim Dounin <mdounin@mdounin.ru>
parents:
4412
diff
changeset
|
51 |
3038bd4d7816
Core: changed ngx_queue_sort() to use merge sort.
Maxim Dounin <mdounin@mdounin.ru>
parents:
4412
diff
changeset
|
52 |
1646 | 53 #define ngx_queue_head(h) \ |
54 (h)->next | |
55 | |
56 | |
57 #define ngx_queue_last(h) \ | |
58 (h)->prev | |
59 | |
60 | |
2026 | 61 #define ngx_queue_sentinel(h) \ |
62 (h) | |
63 | |
64 | |
65 #define ngx_queue_next(q) \ | |
66 (q)->next | |
67 | |
68 | |
69 #define ngx_queue_prev(q) \ | |
70 (q)->prev | |
71 | |
72 | |
1646 | 73 #if (NGX_DEBUG) |
74 | |
75 #define ngx_queue_remove(x) \ | |
76 (x)->next->prev = (x)->prev; \ | |
77 (x)->prev->next = (x)->next; \ | |
78 (x)->prev = NULL; \ | |
79 (x)->next = NULL | |
80 | |
81 #else | |
82 | |
83 #define ngx_queue_remove(x) \ | |
84 (x)->next->prev = (x)->prev; \ | |
85 (x)->prev->next = (x)->next | |
86 | |
87 #endif | |
88 | |
89 | |
2026 | 90 #define ngx_queue_split(h, q, n) \ |
91 (n)->prev = (h)->prev; \ | |
92 (n)->prev->next = n; \ | |
93 (n)->next = q; \ | |
94 (h)->prev = (q)->prev; \ | |
95 (h)->prev->next = h; \ | |
96 (q)->prev = n; | |
97 | |
98 | |
99 #define ngx_queue_add(h, n) \ | |
100 (h)->prev->next = (n)->next; \ | |
101 (n)->next->prev = (h)->prev; \ | |
102 (h)->prev = (n)->prev; \ | |
103 (h)->prev->next = h; | |
104 | |
105 | |
1646 | 106 #define ngx_queue_data(q, type, link) \ |
107 (type *) ((u_char *) q - offsetof(type, link)) | |
108 | |
109 | |
2026 | 110 ngx_queue_t *ngx_queue_middle(ngx_queue_t *queue); |
111 void ngx_queue_sort(ngx_queue_t *queue, | |
112 ngx_int_t (*cmp)(const ngx_queue_t *, const ngx_queue_t *)); | |
113 | |
114 | |
1646 | 115 #endif /* _NGX_QUEUE_H_INCLUDED_ */ |