Mercurial > hg > nginx
annotate src/os/unix/ngx_linux_aio_read.c @ 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 | f01ab2dbcfdc |
children |
rev | line source |
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3052 | 1 |
2 /* | |
3 * Copyright (C) Igor Sysoev | |
4412 | 4 * Copyright (C) Nginx, Inc. |
3052 | 5 */ |
6 | |
7 | |
8 #include <ngx_config.h> | |
9 #include <ngx_core.h> | |
10 #include <ngx_event.h> | |
11 | |
12 | |
13 extern int ngx_eventfd; | |
14 extern aio_context_t ngx_aio_ctx; | |
15 | |
16 | |
17 static void ngx_file_aio_event_handler(ngx_event_t *ev); | |
18 | |
19 | |
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Fixing Linux AIO syscalls return value handling:
Igor Sysoev <igor@sysoev.ru>
parents:
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20 static int |
3052 | 21 io_submit(aio_context_t ctx, long n, struct iocb **paiocb) |
22 { | |
23 return syscall(SYS_io_submit, ctx, n, paiocb); | |
24 } | |
25 | |
26 | |
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27 ngx_int_t |
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28 ngx_file_aio_init(ngx_file_t *file, ngx_pool_t *pool) |
ccad84a174e0
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29 { |
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Refactored sendfile() AIO preload.
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30 ngx_event_aio_t *aio; |
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31 |
ccad84a174e0
Refactored sendfile() AIO preload.
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32 aio = ngx_pcalloc(pool, sizeof(ngx_event_aio_t)); |
ccad84a174e0
Refactored sendfile() AIO preload.
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33 if (aio == NULL) { |
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34 return NGX_ERROR; |
ccad84a174e0
Refactored sendfile() AIO preload.
Valentin Bartenev <vbart@nginx.com>
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35 } |
ccad84a174e0
Refactored sendfile() AIO preload.
Valentin Bartenev <vbart@nginx.com>
parents:
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36 |
ccad84a174e0
Refactored sendfile() AIO preload.
Valentin Bartenev <vbart@nginx.com>
parents:
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37 aio->file = file; |
ccad84a174e0
Refactored sendfile() AIO preload.
Valentin Bartenev <vbart@nginx.com>
parents:
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38 aio->fd = file->fd; |
ccad84a174e0
Refactored sendfile() AIO preload.
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parents:
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39 aio->event.data = aio; |
ccad84a174e0
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parents:
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40 aio->event.ready = 1; |
ccad84a174e0
Refactored sendfile() AIO preload.
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parents:
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41 aio->event.log = file->log; |
ccad84a174e0
Refactored sendfile() AIO preload.
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parents:
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42 |
ccad84a174e0
Refactored sendfile() AIO preload.
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parents:
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43 file->aio = aio; |
ccad84a174e0
Refactored sendfile() AIO preload.
Valentin Bartenev <vbart@nginx.com>
parents:
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44 |
ccad84a174e0
Refactored sendfile() AIO preload.
Valentin Bartenev <vbart@nginx.com>
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45 return NGX_OK; |
ccad84a174e0
Refactored sendfile() AIO preload.
Valentin Bartenev <vbart@nginx.com>
parents:
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46 } |
ccad84a174e0
Refactored sendfile() AIO preload.
Valentin Bartenev <vbart@nginx.com>
parents:
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changeset
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47 |
ccad84a174e0
Refactored sendfile() AIO preload.
Valentin Bartenev <vbart@nginx.com>
parents:
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48 |
3052 | 49 ssize_t |
50 ngx_file_aio_read(ngx_file_t *file, u_char *buf, size_t size, off_t offset, | |
51 ngx_pool_t *pool) | |
52 { | |
4129
6903dac6ad19
Fixing Linux AIO syscalls return value handling:
Igor Sysoev <igor@sysoev.ru>
parents:
4076
diff
changeset
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53 ngx_err_t err; |
3294
04cfc09b8b8d
export aio presence knowledge to prevent using "aio sendfile",
Igor Sysoev <igor@sysoev.ru>
parents:
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54 struct iocb *piocb[1]; |
04cfc09b8b8d
export aio presence knowledge to prevent using "aio sendfile",
Igor Sysoev <igor@sysoev.ru>
parents:
3052
diff
changeset
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55 ngx_event_t *ev; |
04cfc09b8b8d
export aio presence knowledge to prevent using "aio sendfile",
Igor Sysoev <igor@sysoev.ru>
parents:
3052
diff
changeset
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56 ngx_event_aio_t *aio; |
3052 | 57 |
3294
04cfc09b8b8d
export aio presence knowledge to prevent using "aio sendfile",
Igor Sysoev <igor@sysoev.ru>
parents:
3052
diff
changeset
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58 if (!ngx_file_aio) { |
3052 | 59 return ngx_read_file(file, buf, size, offset); |
60 } | |
61 | |
5980
ccad84a174e0
Refactored sendfile() AIO preload.
Valentin Bartenev <vbart@nginx.com>
parents:
4412
diff
changeset
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62 if (file->aio == NULL && ngx_file_aio_init(file, pool) != NGX_OK) { |
ccad84a174e0
Refactored sendfile() AIO preload.
Valentin Bartenev <vbart@nginx.com>
parents:
4412
diff
changeset
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63 return NGX_ERROR; |
3052 | 64 } |
65 | |
5980
ccad84a174e0
Refactored sendfile() AIO preload.
Valentin Bartenev <vbart@nginx.com>
parents:
4412
diff
changeset
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66 aio = file->aio; |
3052 | 67 ev = &aio->event; |
68 | |
69 if (!ev->ready) { | |
70 ngx_log_error(NGX_LOG_ALERT, file->log, 0, | |
71 "second aio post for \"%V\"", &file->name); | |
72 return NGX_AGAIN; | |
73 } | |
74 | |
75 ngx_log_debug4(NGX_LOG_DEBUG_CORE, file->log, 0, | |
6480 | 76 "aio complete:%d @%O:%uz %V", |
3052 | 77 ev->complete, offset, size, &file->name); |
78 | |
79 if (ev->complete) { | |
80 ev->active = 0; | |
81 ev->complete = 0; | |
82 | |
83 if (aio->res >= 0) { | |
84 ngx_set_errno(0); | |
85 return aio->res; | |
86 } | |
87 | |
88 ngx_set_errno(-aio->res); | |
4076
37da005a5808
Bugfix: open_file_cache lost is_directio flag.
Maxim Dounin <mdounin@mdounin.ru>
parents:
3777
diff
changeset
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89 |
37da005a5808
Bugfix: open_file_cache lost is_directio flag.
Maxim Dounin <mdounin@mdounin.ru>
parents:
3777
diff
changeset
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90 ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno, |
37da005a5808
Bugfix: open_file_cache lost is_directio flag.
Maxim Dounin <mdounin@mdounin.ru>
parents:
3777
diff
changeset
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91 "aio read \"%s\" failed", file->name.data); |
37da005a5808
Bugfix: open_file_cache lost is_directio flag.
Maxim Dounin <mdounin@mdounin.ru>
parents:
3777
diff
changeset
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92 |
3052 | 93 return NGX_ERROR; |
94 } | |
95 | |
96 ngx_memzero(&aio->aiocb, sizeof(struct iocb)); | |
97 | |
98 aio->aiocb.aio_data = (uint64_t) (uintptr_t) ev; | |
99 aio->aiocb.aio_lio_opcode = IOCB_CMD_PREAD; | |
100 aio->aiocb.aio_fildes = file->fd; | |
101 aio->aiocb.aio_buf = (uint64_t) (uintptr_t) buf; | |
102 aio->aiocb.aio_nbytes = size; | |
103 aio->aiocb.aio_offset = offset; | |
104 aio->aiocb.aio_flags = IOCB_FLAG_RESFD; | |
105 aio->aiocb.aio_resfd = ngx_eventfd; | |
106 | |
107 ev->handler = ngx_file_aio_event_handler; | |
108 | |
109 piocb[0] = &aio->aiocb; | |
110 | |
4129
6903dac6ad19
Fixing Linux AIO syscalls return value handling:
Igor Sysoev <igor@sysoev.ru>
parents:
4076
diff
changeset
|
111 if (io_submit(ngx_aio_ctx, 1, piocb) == 1) { |
3777
cd04f652478c
update event flags after successful io_submit()
Igor Sysoev <igor@sysoev.ru>
parents:
3294
diff
changeset
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112 ev->active = 1; |
cd04f652478c
update event flags after successful io_submit()
Igor Sysoev <igor@sysoev.ru>
parents:
3294
diff
changeset
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113 ev->ready = 0; |
cd04f652478c
update event flags after successful io_submit()
Igor Sysoev <igor@sysoev.ru>
parents:
3294
diff
changeset
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114 ev->complete = 0; |
cd04f652478c
update event flags after successful io_submit()
Igor Sysoev <igor@sysoev.ru>
parents:
3294
diff
changeset
|
115 |
3052 | 116 return NGX_AGAIN; |
117 } | |
118 | |
4129
6903dac6ad19
Fixing Linux AIO syscalls return value handling:
Igor Sysoev <igor@sysoev.ru>
parents:
4076
diff
changeset
|
119 err = ngx_errno; |
3052 | 120 |
4129
6903dac6ad19
Fixing Linux AIO syscalls return value handling:
Igor Sysoev <igor@sysoev.ru>
parents:
4076
diff
changeset
|
121 if (err == NGX_EAGAIN) { |
3052 | 122 return ngx_read_file(file, buf, size, offset); |
123 } | |
124 | |
4129
6903dac6ad19
Fixing Linux AIO syscalls return value handling:
Igor Sysoev <igor@sysoev.ru>
parents:
4076
diff
changeset
|
125 ngx_log_error(NGX_LOG_CRIT, file->log, err, |
3052 | 126 "io_submit(\"%V\") failed", &file->name); |
127 | |
4129
6903dac6ad19
Fixing Linux AIO syscalls return value handling:
Igor Sysoev <igor@sysoev.ru>
parents:
4076
diff
changeset
|
128 if (err == NGX_ENOSYS) { |
3294
04cfc09b8b8d
export aio presence knowledge to prevent using "aio sendfile",
Igor Sysoev <igor@sysoev.ru>
parents:
3052
diff
changeset
|
129 ngx_file_aio = 0; |
3052 | 130 return ngx_read_file(file, buf, size, offset); |
131 } | |
132 | |
133 return NGX_ERROR; | |
134 } | |
135 | |
136 | |
137 static void | |
138 ngx_file_aio_event_handler(ngx_event_t *ev) | |
139 { | |
140 ngx_event_aio_t *aio; | |
141 | |
142 aio = ev->data; | |
143 | |
144 ngx_log_debug2(NGX_LOG_DEBUG_CORE, ev->log, 0, | |
145 "aio event handler fd:%d %V", aio->fd, &aio->file->name); | |
146 | |
147 aio->handler(ev); | |
148 } |