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vfs_ceph: use consistent code style when setting errno
[Samba.git] / source3 / lib / sendfile.c
blob69c89d29f3190d5fbce52167faa3e093659b70eb
1 /*
2 Unix SMB/Netbios implementation.
3 Version 2.2.x / 3.0.x
4 sendfile implementations.
5 Copyright (C) Jeremy Allison 2002.
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, see <http://www.gnu.org/licenses/>.
18 */
19
20 /*
21 * This file handles the OS dependent sendfile implementations.
22 * The API is such that it returns -1 on error, else returns the
23 * number of bytes written.
24 */
25
26 #include "includes.h"
27 #include "system/filesys.h"
28
29 #if defined(LINUX_SENDFILE_API)
30
31 #include <sys/sendfile.h>
32
33 #ifndef MSG_MORE
34 #define MSG_MORE 0x8000
35 #endif
36
37 ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset, size_t count)
38 {
39 size_t total=0;
40 ssize_t ret = -1;
41 size_t hdr_len = 0;
42 int old_flags = 0;
43 bool socket_flags_changed = false;
44
45 /*
46 * Send the header first.
47 * Use MSG_MORE to cork the TCP output until sendfile is called.
48 */
49
50 if (header) {
51 hdr_len = header->length;
52 while (total < hdr_len) {
53 ret = sys_send(tofd, header->data + total,hdr_len - total, MSG_MORE);
54 if (ret == -1) {
55 if (errno == EAGAIN || errno == EWOULDBLOCK) {
56 /*
57 * send() must complete before we can
58 * send any other outgoing data on the
59 * socket. Ensure socket is in blocking
60 * mode. For SMB2 by default the socket
61 * is in non-blocking mode.
62 */
63 old_flags = fcntl(tofd, F_GETFL, 0);
64 ret = set_blocking(tofd, true);
65 if (ret == -1) {
66 goto out;
67 }
68 socket_flags_changed = true;
69 continue;
70 }
71 goto out;
72 }
73 total += ret;
74 }
75 }
76
77 total = count;
78 while (total) {
79 ssize_t nwritten;
80 do {
81 nwritten = sendfile(tofd, fromfd, &offset, total);
82 } while (nwritten == -1 && errno == EINTR);
83 if (nwritten == -1) {
84 if (errno == EAGAIN || errno == EWOULDBLOCK) {
85 if (socket_flags_changed) {
86 /*
87 * We're already in blocking
88 * mode. This is an error.
89 */
90 ret = -1;
91 goto out;
92 }
93
94 /*
95 * Sendfile must complete before we can
96 * send any other outgoing data on the socket.
97 * Ensure socket is in blocking mode.
98 * For SMB2 by default the socket is in
99 * non-blocking mode.
100 */
101 old_flags = fcntl(tofd, F_GETFL, 0);
102 ret = set_blocking(tofd, true);
103 if (ret == -1) {
104 goto out;
105 }
106 socket_flags_changed = true;
107 continue;
108 }
109
110 if (errno == ENOSYS || errno == EINVAL) {
111 /* Ok - we're in a world of pain here. We just sent
112 * the header, but the sendfile failed. We have to
113 * emulate the sendfile at an upper layer before we
114 * disable it's use. So we do something really ugly.
115 * We set the errno to a strange value so we can detect
116 * this at the upper level and take care of it without
117 * layer violation. JRA.
118 */
119 errno = EINTR; /* Normally we can never return this. */
120 }
121 ret = -1;
122 goto out;
123 }
124 if (nwritten == 0) {
125 /*
126 * EOF, return a short read
127 */
128 ret = hdr_len + (count - total);
129 goto out;
130 }
131 total -= nwritten;
132 }
133
134 ret = count + hdr_len;
135
136 out:
137
138 if (socket_flags_changed) {
139 int saved_errno = errno;
140 int err;
141
142 /* Restore the old state of the socket. */
143 err = fcntl(tofd, F_SETFL, old_flags);
144 if (err == -1) {
145 return -1;
146 }
147 if (ret == -1) {
148 errno = saved_errno;
149 }
150 }
151
152 return ret;
153 }
154
155 #elif defined(SOLARIS_SENDFILE_API)
156
157 /*
158 * Solaris sendfile code written by Pierre Belanger <belanger@pobox.com>.
159 */
160
161 #include <sys/sendfile.h>
162
163 ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset, size_t count)
164 {
165 int sfvcnt;
166 size_t total, xferred;
167 struct sendfilevec vec[2];
168 ssize_t hdr_len = 0;
169 int old_flags = 0;
170 ssize_t ret = -1;
171 bool socket_flags_changed = false;
172
173 if (header) {
174 sfvcnt = 2;
175
176 vec[0].sfv_fd = SFV_FD_SELF;
177 vec[0].sfv_flag = 0;
178 vec[0].sfv_off = (off_t)header->data;
179 vec[0].sfv_len = hdr_len = header->length;
180
181 vec[1].sfv_fd = fromfd;
182 vec[1].sfv_flag = 0;
183 vec[1].sfv_off = offset;
184 vec[1].sfv_len = count;
185
186 } else {
187 sfvcnt = 1;
188
189 vec[0].sfv_fd = fromfd;
190 vec[0].sfv_flag = 0;
191 vec[0].sfv_off = offset;
192 vec[0].sfv_len = count;
193 }
194
195 total = count + hdr_len;
196
197 while (total) {
198 ssize_t nwritten;
199
200 /*
201 * Although not listed in the API error returns, this is almost certainly
202 * a slow system call and will be interrupted by a signal with EINTR. JRA.
203 */
204
205 xferred = 0;
206
207 nwritten = sendfilev(tofd, vec, sfvcnt, &xferred);
208 if (nwritten == -1 && errno == EINTR) {
209 if (xferred == 0)
210 continue; /* Nothing written yet. */
211 else
212 nwritten = xferred;
213 }
214
215 if (nwritten == -1) {
216 if (errno == EAGAIN || errno == EWOULDBLOCK) {
217 /*
218 * Sendfile must complete before we can
219 * send any other outgoing data on the socket.
220 * Ensure socket is in blocking mode.
221 * For SMB2 by default the socket is in
222 * non-blocking mode.
223 */
224 old_flags = fcntl(tofd, F_GETFL, 0);
225 ret = set_blocking(tofd, true);
226 if (ret == -1) {
227 goto out;
228 }
229 socket_flags_changed = true;
230 continue;
231 }
232 ret = -1;
233 goto out;
234 }
235 if (nwritten == 0) {
236 ret = -1;
237 goto out; /* I think we're at EOF here... */
238 }
239
240 /*
241 * If this was a short (signal interrupted) write we may need
242 * to subtract it from the header data, or null out the header
243 * data altogether if we wrote more than vec[0].sfv_len bytes.
244 * We move vec[1].* to vec[0].* and set sfvcnt to 1
245 */
246
247 if (sfvcnt == 2 && nwritten >= vec[0].sfv_len) {
248 vec[1].sfv_off += nwritten - vec[0].sfv_len;
249 vec[1].sfv_len -= nwritten - vec[0].sfv_len;
250
251 /* Move vec[1].* to vec[0].* and set sfvcnt to 1 */
252 vec[0] = vec[1];
253 sfvcnt = 1;
254 } else {
255 vec[0].sfv_off += nwritten;
256 vec[0].sfv_len -= nwritten;
257 }
258 total -= nwritten;
259 }
260 ret = count + hdr_len;
261
262 out:
263
264 if (socket_flags_changed) {
265 int saved_errno;
266 int err;
267
268 if (ret == -1) {
269 saved_errno = errno;
270 }
271 /* Restore the old state of the socket. */
272 err = fcntl(tofd, F_SETFL, old_flags);
273 if (err == -1) {
274 return -1;
275 }
276 if (ret == -1) {
277 errno = saved_errno;
278 }
279 }
280
281 return ret;
282 }
283
284 #elif defined(HPUX_SENDFILE_API)
285
286 #include <sys/socket.h>
287 #include <sys/uio.h>
288
289 ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset, size_t count)
290 {
291 size_t total=0;
292 struct iovec hdtrl[2];
293 size_t hdr_len = 0;
294 int old_flags = 0;
295 ssize_t ret = -1;
296 bool socket_flags_changed = false;
297
298 if (header) {
299 /* Set up the header/trailer iovec. */
300 hdtrl[0].iov_base = (void *)header->data;
301 hdtrl[0].iov_len = hdr_len = header->length;
302 } else {
303 hdtrl[0].iov_base = NULL;
304 hdtrl[0].iov_len = hdr_len = 0;
305 }
306 hdtrl[1].iov_base = NULL;
307 hdtrl[1].iov_len = 0;
308
309 total = count;
310 while (total + hdtrl[0].iov_len) {
311 ssize_t nwritten;
312
313 /*
314 * HPUX guarantees that if any data was written before
315 * a signal interrupt then sendfile returns the number of
316 * bytes written (which may be less than requested) not -1.
317 * nwritten includes the header data sent.
318 */
319
320 do {
321 nwritten = sendfile(tofd, fromfd, offset, total, &hdtrl[0], 0);
322 } while (nwritten == -1 && errno == EINTR);
323 if (nwritten == -1) {
324 if (errno == EAGAIN || errno == EWOULDBLOCK) {
325 /*
326 * Sendfile must complete before we can
327 * send any other outgoing data on the socket.
328 * Ensure socket is in blocking mode.
329 * For SMB2 by default the socket is in
330 * non-blocking mode.
331 */
332 old_flags = fcntl(tofd, F_GETFL, 0);
333 ret = set_blocking(tofd, true);
334 if (ret == -1) {
335 goto out;
336 }
337 socket_flags_changed = true;
338 continue;
339 }
340 ret = -1;
341 goto out;
342 }
343 if (nwritten == 0) {
344 ret = -1; /* I think we're at EOF here... */
345 goto out;
346 }
347
348 /*
349 * If this was a short (signal interrupted) write we may need
350 * to subtract it from the header data, or null out the header
351 * data altogether if we wrote more than hdtrl[0].iov_len bytes.
352 * We change nwritten to be the number of file bytes written.
353 */
354
355 if (hdtrl[0].iov_base && hdtrl[0].iov_len) {
356 if (nwritten >= hdtrl[0].iov_len) {
357 nwritten -= hdtrl[0].iov_len;
358 hdtrl[0].iov_base = NULL;
359 hdtrl[0].iov_len = 0;
360 } else {
361 /* iov_base is defined as a void *... */
362 hdtrl[0].iov_base = (void *)(((char *)hdtrl[0].iov_base) + nwritten);
363 hdtrl[0].iov_len -= nwritten;
364 nwritten = 0;
365 }
366 }
367 total -= nwritten;
368 offset += nwritten;
369 }
370 ret = count + hdr_len;
371
372 out:
373
374 if (socket_flags_changed) {
375 int saved_errno;
376 int err;
377
378 if (ret == -1) {
379 saved_errno = errno;
380 }
381 /* Restore the old state of the socket. */
382 err = fcntl(tofd, F_SETFL, old_flags);
383 if (err == -1) {
384 return -1;
385 }
386 if (ret == -1) {
387 errno = saved_errno;
388 }
389 }
390
391 return ret;
392 }
393
394 #elif defined(FREEBSD_SENDFILE_API) || defined(DARWIN_SENDFILE_API)
395
396 #include <sys/types.h>
397 #include <sys/socket.h>
398 #include <sys/uio.h>
399
400 ssize_t sys_sendfile(int tofd, int fromfd,
401 const DATA_BLOB *header, off_t offset, size_t count)
402 {
403 struct sf_hdtr sf_header = {0};
404 struct iovec io_header = {0};
405 int old_flags = 0;
406
407 off_t nwritten;
408 ssize_t ret = -1;
409 bool socket_flags_changed = false;
410
411 if (header) {
412 sf_header.headers = &io_header;
413 sf_header.hdr_cnt = 1;
414 io_header.iov_base = header->data;
415 io_header.iov_len = header->length;
416 sf_header.trailers = NULL;
417 sf_header.trl_cnt = 0;
418 }
419
420 while (count != 0) {
421
422 nwritten = count;
423 #if defined(DARWIN_SENDFILE_API)
424 /* Darwin recycles nwritten as a value-result parameter, apart from that this
425 sendfile implementation is quite the same as the FreeBSD one */
426 ret = sendfile(fromfd, tofd, offset, &nwritten, &sf_header, 0);
427 #else
428 ret = sendfile(fromfd, tofd, offset, count, &sf_header, &nwritten, 0);
429 #endif
430 if (ret == -1 && errno != EINTR) {
431 if (errno == EAGAIN || errno == EWOULDBLOCK) {
432 /*
433 * Sendfile must complete before we can
434 * send any other outgoing data on the socket.
435 * Ensure socket is in blocking mode.
436 * For SMB2 by default the socket is in
437 * non-blocking mode.
438 */
439 old_flags = fcntl(tofd, F_GETFL, 0);
440 ret = set_blocking(tofd, true);
441 if (ret == -1) {
442 goto out;
443 }
444 socket_flags_changed = true;
445 continue;
446 }
447 /* Send failed, we are toast. */
448 ret = -1;
449 goto out;
450 }
451
452 if (nwritten == 0) {
453 /* EOF of offset is after EOF. */
454 break;
455 }
456
457 if (sf_header.hdr_cnt) {
458 if (io_header.iov_len <= nwritten) {
459 /* Entire header was sent. */
460 sf_header.headers = NULL;
461 sf_header.hdr_cnt = 0;
462 nwritten -= io_header.iov_len;
463 } else {
464 /* Partial header was sent. */
465 io_header.iov_len -= nwritten;
466 io_header.iov_base =
467 ((uint8_t *)io_header.iov_base) + nwritten;
468 nwritten = 0;
469 }
470 }
471
472 offset += nwritten;
473 count -= nwritten;
474 }
475
476 ret = nwritten;
477
478 out:
479
480 if (socket_flags_changed) {
481 int saved_errno;
482 int err;
483
484 if (ret == -1) {
485 saved_errno = errno;
486 }
487 /* Restore the old state of the socket. */
488 err = fcntl(tofd, F_SETFL, old_flags);
489 if (err == -1) {
490 return -1;
491 }
492 if (ret == -1) {
493 errno = saved_errno;
494 }
495 }
496
497 return ret;
498 }
499
500 #elif defined(AIX_SENDFILE_API)
501
502 /* BEGIN AIX SEND_FILE */
503
504 /* Contributed by William Jojo <jojowil@hvcc.edu> */
505 #include <sys/socket.h>
506
507 ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset, size_t count)
508 {
509 struct sf_parms hdtrl;
510 int old_flags = 0;
511 ssize_t ret = -1;
512 bool socket_flags_changed = false;
513
514 /* Set up the header/trailer struct params. */
515 if (header) {
516 hdtrl.header_data = header->data;
517 hdtrl.header_length = header->length;
518 } else {
519 hdtrl.header_data = NULL;
520 hdtrl.header_length = 0;
521 }
522 hdtrl.trailer_data = NULL;
523 hdtrl.trailer_length = 0;
524
525 hdtrl.file_descriptor = fromfd;
526 hdtrl.file_offset = offset;
527 hdtrl.file_bytes = count;
528
529 while ( hdtrl.file_bytes + hdtrl.header_length ) {
530 /*
531 Return Value
532
533 There are three possible return values from send_file:
534
535 Value Description
536
537 -1 an error has occurred, errno contains the error code.
538
539 0 the command has completed successfully.
540
541 1 the command was completed partially, some data has been
542 transmitted but the command has to return for some reason,
543 for example, the command was interrupted by signals.
544 */
545 do {
546 ret = send_file(&tofd, &hdtrl, 0);
547 } while ((ret == 1) || (ret == -1 && errno == EINTR));
548 if ( ret == -1 ) {
549 if (errno == EAGAIN || errno == EWOULDBLOCK) {
550 /*
551 * Sendfile must complete before we can
552 * send any other outgoing data on the socket.
553 * Ensure socket is in blocking mode.
554 * For SMB2 by default the socket is in
555 * non-blocking mode.
556 */
557 old_flags = fcntl(tofd, F_GETFL, 0);
558 ret = set_blocking(tofd, true);
559 if (ret == -1) {
560 goto out;
561 }
562 socket_flags_changed = true;
563 continue;
564 }
565 goto out;
566 }
567 }
568
569 ret = count + header->length;
570
571 out:
572
573 if (socket_flags_changed) {
574 int saved_errno;
575 int err;
576
577 if (ret == -1) {
578 saved_errno = errno;
579 }
580 /* Restore the old state of the socket. */
581 err = fcntl(tofd, F_SETFL, old_flags);
582 if (err == -1) {
583 return -1;
584 }
585 if (ret == -1) {
586 errno = saved_errno;
587 }
588 }
589
590 return ret;
591 }
592 /* END AIX SEND_FILE */
593
594 #else /* No sendfile implementation. Return error. */
595
596 ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset, size_t count)
597 {
598 /* No sendfile syscall. */
599 errno = ENOSYS;
600 return -1;
601 }
602 #endif
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