summaryrefslogtreecommitdiff
path: root/source3/lib/sendfile.c
blob: 46099efd8fea06a619507a52daf6ef20cc3f54e0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
/*
 Unix SMB/Netbios implementation.
 Version 2.2.x / 3.0.x
 sendfile implementations.
 Copyright (C) Jeremy Allison 2002.

 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 3 of the License, or
 (at your option) any later version.
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

/*
 * This file handles the OS dependent sendfile implementations.
 * The API is such that it returns -1 on error, else returns the
 * number of bytes written.
 */

#include "includes.h"

#if defined(LINUX_SENDFILE_API)

#include <sys/sendfile.h>

#ifndef MSG_MORE
#define MSG_MORE 0x8000
#endif

ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, SMB_OFF_T offset, size_t count)
{
	size_t total=0;
	ssize_t ret;
	size_t hdr_len = 0;

	/*
	 * Send the header first.
	 * Use MSG_MORE to cork the TCP output until sendfile is called.
	 */

	if (header) {
		hdr_len = header->length;
		while (total < hdr_len) {
			ret = sys_send(tofd, header->data + total,hdr_len - total, MSG_MORE);
			if (ret == -1)
				return -1;
			total += ret;
		}
	}

	total = count;
	while (total) {
		ssize_t nwritten;
		do {
#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_OFF64_T) && defined(HAVE_SENDFILE64)
			nwritten = sendfile64(tofd, fromfd, &offset, total);
#else
			nwritten = sendfile(tofd, fromfd, &offset, total);
#endif
		} while (nwritten == -1 && errno == EINTR);
		if (nwritten == -1) {
			if (errno == ENOSYS) {
				/* Ok - we're in a world of pain here. We just sent
				 * the header, but the sendfile failed. We have to
				 * emulate the sendfile at an upper layer before we
				 * disable it's use. So we do something really ugly.
				 * We set the errno to a strange value so we can detect
				 * this at the upper level and take care of it without
				 * layer violation. JRA.
				 */
				errno = EINTR; /* Normally we can never return this. */
			}
			return -1;
		}
		if (nwritten == 0)
			return -1; /* I think we're at EOF here... */
		total -= nwritten;
	}
	return count + hdr_len;
}

#elif defined(LINUX_BROKEN_SENDFILE_API)

/*
 * We must use explicit 32 bit types here. This code path means Linux
 * won't do proper 64-bit sendfile. JRA.
 */

extern int32 sendfile (int out_fd, int in_fd, int32 *offset, uint32 count);


#ifndef MSG_MORE
#define MSG_MORE 0x8000
#endif

ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, SMB_OFF_T offset, size_t count)
{
	size_t total=0;
	ssize_t ret;
	ssize_t hdr_len = 0;
	uint32 small_total = 0;
	int32 small_offset;

	/* 
	 * Fix for broken Linux 2.4 systems with no working sendfile64().
	 * If the offset+count > 2 GB then pretend we don't have the
	 * system call sendfile at all. The upper layer catches this
	 * and uses a normal read. JRA.
	 */

	if ((sizeof(SMB_OFF_T) >= 8) && (offset + count > (SMB_OFF_T)0x7FFFFFFF)) {
		errno = ENOSYS;
		return -1;
	}

	/*
	 * Send the header first.
	 * Use MSG_MORE to cork the TCP output until sendfile is called.
	 */

	if (header) {
		hdr_len = header->length;
		while (total < hdr_len) {
			ret = sys_send(tofd, header->data + total,hdr_len - total, MSG_MORE);
			if (ret == -1)
				return -1;
			total += ret;
		}
	}

	small_total = (uint32)count;
	small_offset = (int32)offset;

	while (small_total) {
		int32 nwritten;
		do {
			nwritten = sendfile(tofd, fromfd, &small_offset, small_total);
		} while (nwritten == -1 && errno == EINTR);
		if (nwritten == -1) {
			if (errno == ENOSYS) {
				/* Ok - we're in a world of pain here. We just sent
				 * the header, but the sendfile failed. We have to
				 * emulate the sendfile at an upper layer before we
				 * disable it's use. So we do something really ugly.
				 * We set the errno to a strange value so we can detect
				 * this at the upper level and take care of it without
				 * layer violation. JRA.
				 */
				errno = EINTR; /* Normally we can never return this. */
			}
			return -1;
		}
		if (nwritten == 0)
			return -1; /* I think we're at EOF here... */
		small_total -= nwritten;
	}
	return count + hdr_len;
}


#elif defined(SOLARIS_SENDFILE_API)

/*
 * Solaris sendfile code written by Pierre Belanger <belanger@pobox.com>.
 */

#include <sys/sendfile.h>

ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, SMB_OFF_T offset, size_t count)
{
	int sfvcnt;
	size_t total, xferred;
	struct sendfilevec vec[2];
	ssize_t hdr_len = 0;

	if (header) {
		sfvcnt = 2;

		vec[0].sfv_fd = SFV_FD_SELF;
		vec[0].sfv_flag = 0;
		vec[0].sfv_off = (off_t)header->data;
		vec[0].sfv_len = hdr_len = header->length;

		vec[1].sfv_fd = fromfd;
		vec[1].sfv_flag = 0;
		vec[1].sfv_off = offset;
		vec[1].sfv_len = count;

	} else {
		sfvcnt = 1;

		vec[0].sfv_fd = fromfd;
		vec[0].sfv_flag = 0;
		vec[0].sfv_off = offset;
		vec[0].sfv_len = count;
	}

	total = count + hdr_len;

	while (total) {
		ssize_t nwritten;

		/*
		 * Although not listed in the API error returns, this is almost certainly
		 * a slow system call and will be interrupted by a signal with EINTR. JRA.
		 */

		xferred = 0;

#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_OFF64_T) && defined(HAVE_SENDFILEV64)
			nwritten = sendfilev64(tofd, vec, sfvcnt, &xferred);
#else
			nwritten = sendfilev(tofd, vec, sfvcnt, &xferred);
#endif
		if (nwritten == -1 && errno == EINTR) {
			if (xferred == 0)
				continue; /* Nothing written yet. */
			else
				nwritten = xferred;
		}

		if (nwritten == -1)
			return -1;
		if (nwritten == 0)
			return -1; /* I think we're at EOF here... */

		/*
		 * If this was a short (signal interrupted) write we may need
		 * to subtract it from the header data, or null out the header
		 * data altogether if we wrote more than vec[0].sfv_len bytes.
		 * We move vec[1].* to vec[0].* and set sfvcnt to 1
		 */

		if (sfvcnt == 2 && nwritten >= vec[0].sfv_len) {
			vec[1].sfv_off += nwritten - vec[0].sfv_len;
			vec[1].sfv_len -= nwritten - vec[0].sfv_len;

			/* Move vec[1].* to vec[0].* and set sfvcnt to 1 */
			vec[0] = vec[1];
			sfvcnt = 1;
		} else {
			vec[0].sfv_off += nwritten;
			vec[0].sfv_len -= nwritten;
		}
		total -= nwritten;
	}
	return count + hdr_len;
}

#elif defined(HPUX_SENDFILE_API)

#include <sys/socket.h>
#include <sys/uio.h>

ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, SMB_OFF_T offset, size_t count)
{
	size_t total=0;
	struct iovec hdtrl[2];
	size_t hdr_len = 0;

	if (header) {
		/* Set up the header/trailer iovec. */
		hdtrl[0].iov_base = header->data;
		hdtrl[0].iov_len = hdr_len = header->length;
	} else {
		hdtrl[0].iov_base = NULL;
		hdtrl[0].iov_len = hdr_len = 0;
	}
	hdtrl[1].iov_base = NULL;
	hdtrl[1].iov_len = 0;

	total = count;
	while (total + hdtrl[0].iov_len) {
		ssize_t nwritten;

		/*
		 * HPUX guarantees that if any data was written before
		 * a signal interrupt then sendfile returns the number of
		 * bytes written (which may be less than requested) not -1.
		 * nwritten includes the header data sent.
		 */

		do {
#if defined(HAVE_EXPLICIT_LARGEFILE_SUPPORT) && defined(HAVE_OFF64_T) && defined(HAVE_SENDFILE64)
			nwritten = sendfile64(tofd, fromfd, offset, total, &hdtrl[0], 0);
#else
			nwritten = sendfile(tofd, fromfd, offset, total, &hdtrl[0], 0);
#endif
		} while (nwritten == -1 && errno == EINTR);
		if (nwritten == -1)
			return -1;
		if (nwritten == 0)
			return -1; /* I think we're at EOF here... */

		/*
		 * If this was a short (signal interrupted) write we may need
		 * to subtract it from the header data, or null out the header
		 * data altogether if we wrote more than hdtrl[0].iov_len bytes.
		 * We change nwritten to be the number of file bytes written.
		 */

		if (hdtrl[0].iov_base && hdtrl[0].iov_len) {
			if (nwritten >= hdtrl[0].iov_len) {
				nwritten -= hdtrl[0].iov_len;
				hdtrl[0].iov_base = NULL;
				hdtrl[0].iov_len = 0;
			} else {
				/* iov_base is defined as a void *... */
				hdtrl[0].iov_base = ((char *)hdtrl[0].iov_base) + nwritten;
				hdtrl[0].iov_len -= nwritten;
				nwritten = 0;
			}
		}
		total -= nwritten;
		offset += nwritten;
	}
	return count + hdr_len;
}

#elif defined(FREEBSD_SENDFILE_API)

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/uio.h>

ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, SMB_OFF_T offset, size_t count)
{
	size_t total=0;
	struct sf_hdtr hdr;
	struct iovec hdtrl;
	size_t hdr_len = 0;

	hdr.headers = &hdtrl;
	hdr.hdr_cnt = 1;
	hdr.trailers = NULL;
	hdr.trl_cnt = 0;

	/* Set up the header iovec. */
	if (header) {
		hdtrl.iov_base = header->data;
		hdtrl.iov_len = hdr_len = header->length;
	} else {
		hdtrl.iov_base = NULL;
		hdtrl.iov_len = 0;
	}

	total = count;
	while (total + hdtrl.iov_len) {
		SMB_OFF_T nwritten;
		int ret;

		/*
		 * FreeBSD sendfile returns 0 on success, -1 on error.
		 * Remember, the tofd and fromfd are reversed..... :-).
		 * nwritten includes the header data sent.
		 */

		do {
			ret = sendfile(fromfd, tofd, offset, total, &hdr, &nwritten, 0);
		} while (ret == -1 && errno == EINTR);
		if (ret == -1)
			return -1;

		if (nwritten == 0)
			return -1; /* I think we're at EOF here... */

		/*
		 * If this was a short (signal interrupted) write we may need
		 * to subtract it from the header data, or null out the header
		 * data altogether if we wrote more than hdtrl.iov_len bytes.
		 * We change nwritten to be the number of file bytes written.
		 */

		if (hdtrl.iov_base && hdtrl.iov_len) {
			if (nwritten >= hdtrl.iov_len) {
				nwritten -= hdtrl.iov_len;
				hdtrl.iov_base = NULL;
				hdtrl.iov_len = 0;
			} else {
				hdtrl.iov_base += nwritten;
				hdtrl.iov_len -= nwritten;
				nwritten = 0;
			}
		}
		total -= nwritten;
		offset += nwritten;
	}
	return count + hdr_len;
}

#elif defined(AIX_SENDFILE_API)

/* BEGIN AIX SEND_FILE */

/* Contributed by William Jojo <jojowil@hvcc.edu> */
#include <sys/socket.h>

ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, SMB_OFF_T offset, size_t count)
{
	struct sf_parms hdtrl;

	/* Set up the header/trailer struct params. */
	if (header) {
		hdtrl.header_data = header->data;
		hdtrl.header_length = header->length;
	} else {
		hdtrl.header_data = NULL;
		hdtrl.header_length = 0;
	}
	hdtrl.trailer_data = NULL;
	hdtrl.trailer_length = 0;

	hdtrl.file_descriptor = fromfd;
	hdtrl.file_offset = offset;
	hdtrl.file_bytes = count;

	while ( hdtrl.file_bytes + hdtrl.header_length ) {
		ssize_t ret;

		/*
		 Return Value

		 There are three possible return values from send_file:

		 Value Description

		 -1 an error has occurred, errno contains the error code.

		 0 the command has completed successfully.

		 1 the command was completed partially, some data has been
		 transmitted but the command has to return for some reason,
		 for example, the command was interrupted by signals.
		*/
		do {
			ret = send_file(&tofd, &hdtrl, 0);
		} while ( (ret == 1) || (ret == -1 && errno == EINTR) );
		if ( ret == -1 )
			return -1;
	}

	return count + header->length;
}
/* END AIX SEND_FILE */

#else /* No sendfile implementation. Return error. */

ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, SMB_OFF_T offset, size_t count)
{
	/* No sendfile syscall. */
	errno = ENOSYS;
	return -1;
}
#endif