1
2 /*
3 * Copyright (C) Igor Sysoev
4 * Copyright (C) Nginx, Inc.
5 */
6
7
8 #include <ngx_config.h>
9 #include <ngx_core.h>
10 #include <ngx_event.h>
11
12
13 /*
14 * Although FreeBSD sendfile() allows to pass a header and a trailer,
15 * it cannot send a header with a part of the file in one packet until
16 * FreeBSD 5.3. Besides, over the fast ethernet connection sendfile()
17 * may send the partially filled packets, i.e. the 8 file pages may be sent
18 * as the 11 full 1460-bytes packets, then one incomplete 324-bytes packet,
19 * and then again the 11 full 1460-bytes packets.
20 *
21 * Therefore we use the TCP_NOPUSH option (similar to Linux's TCP_CORK)
22 * to postpone the sending - it not only sends a header and the first part of
23 * the file in one packet, but also sends the file pages in the full packets.
24 *
25 * But until FreeBSD 4.5 turning TCP_NOPUSH off does not flush a pending
26 * data that less than MSS, so that data may be sent with 5 second delay.
27 * So we do not use TCP_NOPUSH on FreeBSD prior to 4.5, although it can be used
28 * for non-keepalive HTTP connections.
29 */
30
31
32 ngx_chain_t *
ngx_freebsd_sendfile_chain(ngx_connection_t * c,ngx_chain_t * in,off_t limit)33 ngx_freebsd_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
34 {
35 int rc, flags;
36 off_t send, prev_send, sent;
37 size_t file_size;
38 ssize_t n;
39 ngx_uint_t eintr, eagain;
40 ngx_err_t err;
41 ngx_buf_t *file;
42 ngx_event_t *wev;
43 ngx_chain_t *cl;
44 ngx_iovec_t header, trailer;
45 struct sf_hdtr hdtr;
46 struct iovec headers[NGX_IOVS_PREALLOCATE];
47 struct iovec trailers[NGX_IOVS_PREALLOCATE];
48 #if (NGX_HAVE_AIO_SENDFILE)
49 ngx_uint_t ebusy;
50 ngx_event_aio_t *aio;
51 #endif
52
53 wev = c->write;
54
55 if (!wev->ready) {
56 return in;
57 }
58
59 #if (NGX_HAVE_KQUEUE)
60
61 if ((ngx_event_flags & NGX_USE_KQUEUE_EVENT) && wev->pending_eof) {
62 (void) ngx_connection_error(c, wev->kq_errno,
63 "kevent() reported about an closed connection");
64 wev->error = 1;
65 return NGX_CHAIN_ERROR;
66 }
67
68 #endif
69
70 /* the maximum limit size is the maximum size_t value - the page size */
71
72 if (limit == 0 || limit > (off_t) (NGX_MAX_SIZE_T_VALUE - ngx_pagesize)) {
73 limit = NGX_MAX_SIZE_T_VALUE - ngx_pagesize;
74 }
75
76 send = 0;
77 eagain = 0;
78 flags = 0;
79
80 #if (NGX_HAVE_AIO_SENDFILE && NGX_SUPPRESS_WARN)
81 aio = NULL;
82 file = NULL;
83 #endif
84
85 header.iovs = headers;
86 header.nalloc = NGX_IOVS_PREALLOCATE;
87
88 trailer.iovs = trailers;
89 trailer.nalloc = NGX_IOVS_PREALLOCATE;
90
91 for ( ;; ) {
92 eintr = 0;
93 #if (NGX_HAVE_AIO_SENDFILE)
94 ebusy = 0;
95 #endif
96 prev_send = send;
97
98 /* create the header iovec and coalesce the neighbouring bufs */
99
100 cl = ngx_output_chain_to_iovec(&header, in, limit - send, c->log);
101
102 if (cl == NGX_CHAIN_ERROR) {
103 return NGX_CHAIN_ERROR;
104 }
105
106 send += header.size;
107
108 if (cl && cl->buf->in_file && send < limit) {
109 file = cl->buf;
110
111 /* coalesce the neighbouring file bufs */
112
113 file_size = (size_t) ngx_chain_coalesce_file(&cl, limit - send);
114
115 send += file_size;
116
117 if (send < limit) {
118
119 /*
120 * create the trailer iovec and coalesce the neighbouring bufs
121 */
122
123 cl = ngx_output_chain_to_iovec(&trailer, cl, limit - send,
124 c->log);
125 if (cl == NGX_CHAIN_ERROR) {
126 return NGX_CHAIN_ERROR;
127 }
128
129 send += trailer.size;
130
131 } else {
132 trailer.count = 0;
133 }
134
135 if (ngx_freebsd_use_tcp_nopush
136 && c->tcp_nopush == NGX_TCP_NOPUSH_UNSET)
137 {
138 if (ngx_tcp_nopush(c->fd) == -1) {
139 err = ngx_socket_errno;
140
141 /*
142 * there is a tiny chance to be interrupted, however,
143 * we continue a processing without the TCP_NOPUSH
144 */
145
146 if (err != NGX_EINTR) {
147 wev->error = 1;
148 (void) ngx_connection_error(c, err,
149 ngx_tcp_nopush_n " failed");
150 return NGX_CHAIN_ERROR;
151 }
152
153 } else {
154 c->tcp_nopush = NGX_TCP_NOPUSH_SET;
155
156 ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, 0,
157 "tcp_nopush");
158 }
159 }
160
161 /*
162 * sendfile() does unneeded work if sf_hdtr's count is 0,
163 * but corresponding pointer is not NULL
164 */
165
166 hdtr.headers = header.count ? header.iovs : NULL;
167 hdtr.hdr_cnt = header.count;
168 hdtr.trailers = trailer.count ? trailer.iovs : NULL;
169 hdtr.trl_cnt = trailer.count;
170
171 /*
172 * the "nbytes bug" of the old sendfile() syscall:
173 * http://bugs.freebsd.org/33771
174 */
175
176 if (!ngx_freebsd_sendfile_nbytes_bug) {
177 header.size = 0;
178 }
179
180 sent = 0;
181
182 #if (NGX_HAVE_AIO_SENDFILE)
183 aio = file->file->aio;
184 flags = (aio && aio->preload_handler) ? SF_NODISKIO : 0;
185 #endif
186
187 rc = sendfile(file->file->fd, c->fd, file->file_pos,
188 file_size + header.size, &hdtr, &sent, flags);
189
190 if (rc == -1) {
191 err = ngx_errno;
192
193 switch (err) {
194 case NGX_EAGAIN:
195 eagain = 1;
196 break;
197
198 case NGX_EINTR:
199 eintr = 1;
200 break;
201
202 #if (NGX_HAVE_AIO_SENDFILE)
203 case NGX_EBUSY:
204 ebusy = 1;
205 break;
206 #endif
207
208 default:
209 wev->error = 1;
210 (void) ngx_connection_error(c, err, "sendfile() failed");
211 return NGX_CHAIN_ERROR;
212 }
213
214 ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, err,
215 "sendfile() sent only %O bytes", sent);
216
217 /*
218 * sendfile() in FreeBSD 3.x-4.x may return value >= 0
219 * on success, although only 0 is documented
220 */
221
222 } else if (rc >= 0 && sent == 0) {
223
224 /*
225 * if rc is OK and sent equal to zero, then someone
226 * has truncated the file, so the offset became beyond
227 * the end of the file
228 */
229
230 ngx_log_error(NGX_LOG_ALERT, c->log, 0,
231 "sendfile() reported that \"%s\" was truncated at %O",
232 file->file->name.data, file->file_pos);
233
234 return NGX_CHAIN_ERROR;
235 }
236
237 ngx_log_debug4(NGX_LOG_DEBUG_EVENT, c->log, 0,
238 "sendfile: %d, @%O %O:%uz",
239 rc, file->file_pos, sent, file_size + header.size);
240
241 } else {
242 n = ngx_writev(c, &header);
243
244 if (n == NGX_ERROR) {
245 return NGX_CHAIN_ERROR;
246 }
247
248 sent = (n == NGX_AGAIN) ? 0 : n;
249 }
250
251 c->sent += sent;
252
253 in = ngx_chain_update_sent(in, sent);
254
255 #if (NGX_HAVE_AIO_SENDFILE)
256
257 if (ebusy) {
258 if (aio->event.active) {
259 /*
260 * tolerate duplicate calls; they can happen due to subrequests
261 * or multiple calls of the next body filter from a filter
262 */
263
264 if (sent) {
265 c->busy_count = 0;
266 }
267
268 return in;
269 }
270
271 if (sent == 0) {
272 c->busy_count++;
273
274 if (c->busy_count > 2) {
275 ngx_log_error(NGX_LOG_ALERT, c->log, 0,
276 "sendfile(%V) returned busy again",
277 &file->file->name);
278
279 c->busy_count = 0;
280 aio->preload_handler = NULL;
281
282 send = prev_send;
283 continue;
284 }
285
286 } else {
287 c->busy_count = 0;
288 }
289
290 n = aio->preload_handler(file);
291
292 if (n > 0) {
293 send = prev_send + sent;
294 continue;
295 }
296
297 return in;
298 }
299
300 if (flags == SF_NODISKIO) {
301 c->busy_count = 0;
302 }
303
304 #endif
305
306 if (eagain) {
307
308 /*
309 * sendfile() may return EAGAIN, even if it has sent a whole file
310 * part, it indicates that the successive sendfile() call would
311 * return EAGAIN right away and would not send anything.
312 * We use it as a hint.
313 */
314
315 wev->ready = 0;
316 return in;
317 }
318
319 if (eintr) {
320 send = prev_send + sent;
321 continue;
322 }
323
324 if (send - prev_send != sent) {
325 wev->ready = 0;
326 return in;
327 }
328
329 if (send >= limit || in == NULL) {
330 return in;
331 }
332 }
333 }
334