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Commit | Line | Data |
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e4d5639d AS |
1 | /* |
2 | * Helpers for getting linearized buffers from iov / filling buffers into iovs | |
3 | * | |
4 | * Copyright IBM, Corp. 2007, 2008 | |
5 | * Copyright (C) 2010 Red Hat, Inc. | |
6 | * | |
7 | * Author(s): | |
8 | * Anthony Liguori <aliguori@us.ibm.com> | |
9 | * Amit Shah <amit.shah@redhat.com> | |
2278a69e | 10 | * Michael Tokarev <mjt@tls.msk.ru> |
e4d5639d AS |
11 | * |
12 | * This work is licensed under the terms of the GNU GPL, version 2. See | |
13 | * the COPYING file in the top-level directory. | |
6b620ca3 PB |
14 | * |
15 | * Contributions after 2012-01-13 are licensed under the terms of the | |
16 | * GNU GPL, version 2 or (at your option) any later version. | |
e4d5639d AS |
17 | */ |
18 | ||
aafd7584 | 19 | #include "qemu/osdep.h" |
1de7afc9 | 20 | #include "qemu/iov.h" |
cc99c6f5 | 21 | #include "qemu/sockets.h" |
f348b6d1 | 22 | #include "qemu/cutils.h" |
25e5e4c7 | 23 | |
ad523bca PB |
24 | size_t iov_from_buf_full(const struct iovec *iov, unsigned int iov_cnt, |
25 | size_t offset, const void *buf, size_t bytes) | |
e4d5639d | 26 | { |
2278a69e | 27 | size_t done; |
e4d5639d | 28 | unsigned int i; |
2278a69e MT |
29 | for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) { |
30 | if (offset < iov[i].iov_len) { | |
31 | size_t len = MIN(iov[i].iov_len - offset, bytes - done); | |
32 | memcpy(iov[i].iov_base + offset, buf + done, len); | |
33 | done += len; | |
34 | offset = 0; | |
35 | } else { | |
36 | offset -= iov[i].iov_len; | |
348e7b8d | 37 | } |
e4d5639d | 38 | } |
2278a69e MT |
39 | assert(offset == 0); |
40 | return done; | |
e4d5639d | 41 | } |
fa6111f2 | 42 | |
ad523bca PB |
43 | size_t iov_to_buf_full(const struct iovec *iov, const unsigned int iov_cnt, |
44 | size_t offset, void *buf, size_t bytes) | |
fa6111f2 | 45 | { |
2278a69e | 46 | size_t done; |
fa6111f2 | 47 | unsigned int i; |
2278a69e MT |
48 | for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) { |
49 | if (offset < iov[i].iov_len) { | |
50 | size_t len = MIN(iov[i].iov_len - offset, bytes - done); | |
51 | memcpy(buf + done, iov[i].iov_base + offset, len); | |
52 | done += len; | |
53 | offset = 0; | |
54 | } else { | |
55 | offset -= iov[i].iov_len; | |
fa6111f2 | 56 | } |
8d15028e | 57 | } |
2278a69e MT |
58 | assert(offset == 0); |
59 | return done; | |
8d15028e GH |
60 | } |
61 | ||
dcf6f5e1 | 62 | size_t iov_memset(const struct iovec *iov, const unsigned int iov_cnt, |
2278a69e | 63 | size_t offset, int fillc, size_t bytes) |
8d15028e | 64 | { |
2278a69e | 65 | size_t done; |
8d15028e | 66 | unsigned int i; |
2278a69e MT |
67 | for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) { |
68 | if (offset < iov[i].iov_len) { | |
69 | size_t len = MIN(iov[i].iov_len - offset, bytes - done); | |
70 | memset(iov[i].iov_base + offset, fillc, len); | |
71 | done += len; | |
72 | offset = 0; | |
73 | } else { | |
74 | offset -= iov[i].iov_len; | |
8d15028e | 75 | } |
fa6111f2 | 76 | } |
2278a69e MT |
77 | assert(offset == 0); |
78 | return done; | |
fa6111f2 AS |
79 | } |
80 | ||
348e7b8d | 81 | size_t iov_size(const struct iovec *iov, const unsigned int iov_cnt) |
fa6111f2 AS |
82 | { |
83 | size_t len; | |
84 | unsigned int i; | |
85 | ||
86 | len = 0; | |
348e7b8d | 87 | for (i = 0; i < iov_cnt; i++) { |
fa6111f2 AS |
88 | len += iov[i].iov_len; |
89 | } | |
90 | return len; | |
91 | } | |
3a1dca94 | 92 | |
25e5e4c7 MT |
93 | /* helper function for iov_send_recv() */ |
94 | static ssize_t | |
95 | do_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt, bool do_send) | |
96 | { | |
9adea5f7 | 97 | #ifdef CONFIG_POSIX |
25e5e4c7 MT |
98 | ssize_t ret; |
99 | struct msghdr msg; | |
100 | memset(&msg, 0, sizeof(msg)); | |
101 | msg.msg_iov = iov; | |
102 | msg.msg_iovlen = iov_cnt; | |
103 | do { | |
104 | ret = do_send | |
105 | ? sendmsg(sockfd, &msg, 0) | |
106 | : recvmsg(sockfd, &msg, 0); | |
107 | } while (ret < 0 && errno == EINTR); | |
108 | return ret; | |
109 | #else | |
110 | /* else send piece-by-piece */ | |
111 | /*XXX Note: windows has WSASend() and WSARecv() */ | |
c0958559 SW |
112 | unsigned i = 0; |
113 | ssize_t ret = 0; | |
3f08376c | 114 | ssize_t off = 0; |
c0958559 | 115 | while (i < iov_cnt) { |
25e5e4c7 | 116 | ssize_t r = do_send |
3f08376c MAL |
117 | ? send(sockfd, iov[i].iov_base + off, iov[i].iov_len - off, 0) |
118 | : recv(sockfd, iov[i].iov_base + off, iov[i].iov_len - off, 0); | |
25e5e4c7 MT |
119 | if (r > 0) { |
120 | ret += r; | |
3f08376c MAL |
121 | off += r; |
122 | if (off < iov[i].iov_len) { | |
123 | continue; | |
124 | } | |
25e5e4c7 MT |
125 | } else if (!r) { |
126 | break; | |
127 | } else if (errno == EINTR) { | |
128 | continue; | |
129 | } else { | |
130 | /* else it is some "other" error, | |
131 | * only return if there was no data processed. */ | |
132 | if (ret == 0) { | |
c0958559 | 133 | ret = -1; |
25e5e4c7 MT |
134 | } |
135 | break; | |
136 | } | |
3f08376c | 137 | off = 0; |
c0958559 | 138 | i++; |
25e5e4c7 | 139 | } |
c0958559 | 140 | return ret; |
25e5e4c7 MT |
141 | #endif |
142 | } | |
143 | ||
6b64640d | 144 | ssize_t iov_send_recv(int sockfd, const struct iovec *_iov, unsigned iov_cnt, |
25e5e4c7 MT |
145 | size_t offset, size_t bytes, |
146 | bool do_send) | |
147 | { | |
83f75c26 | 148 | ssize_t total = 0; |
25e5e4c7 | 149 | ssize_t ret; |
5209d675 | 150 | size_t orig_len, tail; |
f48869ad | 151 | unsigned niov; |
6b64640d WC |
152 | struct iovec *local_iov, *iov; |
153 | ||
154 | if (bytes <= 0) { | |
155 | return 0; | |
156 | } | |
157 | ||
158 | local_iov = g_new0(struct iovec, iov_cnt); | |
159 | iov_copy(local_iov, iov_cnt, _iov, iov_cnt, offset, bytes); | |
160 | offset = 0; | |
161 | iov = local_iov; | |
5209d675 | 162 | |
83f75c26 PB |
163 | while (bytes > 0) { |
164 | /* Find the start position, skipping `offset' bytes: | |
165 | * first, skip all full-sized vector elements, */ | |
166 | for (niov = 0; niov < iov_cnt && offset >= iov[niov].iov_len; ++niov) { | |
167 | offset -= iov[niov].iov_len; | |
168 | } | |
cb6247a7 | 169 | |
83f75c26 PB |
170 | /* niov == iov_cnt would only be valid if bytes == 0, which |
171 | * we already ruled out in the loop condition. */ | |
f48869ad | 172 | assert(niov < iov_cnt); |
83f75c26 PB |
173 | iov += niov; |
174 | iov_cnt -= niov; | |
175 | ||
176 | if (offset) { | |
177 | /* second, skip `offset' bytes from the (now) first element, | |
178 | * undo it on exit */ | |
179 | iov[0].iov_base += offset; | |
180 | iov[0].iov_len -= offset; | |
181 | } | |
182 | /* Find the end position skipping `bytes' bytes: */ | |
183 | /* first, skip all full-sized elements */ | |
184 | tail = bytes; | |
185 | for (niov = 0; niov < iov_cnt && iov[niov].iov_len <= tail; ++niov) { | |
186 | tail -= iov[niov].iov_len; | |
187 | } | |
188 | if (tail) { | |
189 | /* second, fixup the last element, and remember the original | |
190 | * length */ | |
191 | assert(niov < iov_cnt); | |
192 | assert(iov[niov].iov_len > tail); | |
193 | orig_len = iov[niov].iov_len; | |
194 | iov[niov++].iov_len = tail; | |
2be178a4 MT |
195 | ret = do_send_recv(sockfd, iov, niov, do_send); |
196 | /* Undo the changes above before checking for errors */ | |
83f75c26 | 197 | iov[niov-1].iov_len = orig_len; |
2be178a4 MT |
198 | } else { |
199 | ret = do_send_recv(sockfd, iov, niov, do_send); | |
83f75c26 PB |
200 | } |
201 | if (offset) { | |
202 | iov[0].iov_base -= offset; | |
203 | iov[0].iov_len += offset; | |
204 | } | |
205 | ||
206 | if (ret < 0) { | |
207 | assert(errno != EINTR); | |
6b64640d | 208 | g_free(local_iov); |
83f75c26 PB |
209 | if (errno == EAGAIN && total > 0) { |
210 | return total; | |
211 | } | |
212 | return -1; | |
213 | } | |
214 | ||
84004290 MK |
215 | if (ret == 0 && !do_send) { |
216 | /* recv returns 0 when the peer has performed an orderly | |
217 | * shutdown. */ | |
218 | break; | |
219 | } | |
220 | ||
83f75c26 PB |
221 | /* Prepare for the next iteration */ |
222 | offset += ret; | |
223 | total += ret; | |
224 | bytes -= ret; | |
25e5e4c7 | 225 | } |
25e5e4c7 | 226 | |
6b64640d | 227 | g_free(local_iov); |
83f75c26 | 228 | return total; |
25e5e4c7 MT |
229 | } |
230 | ||
231 | ||
3a1dca94 GH |
232 | void iov_hexdump(const struct iovec *iov, const unsigned int iov_cnt, |
233 | FILE *fp, const char *prefix, size_t limit) | |
234 | { | |
6ff66f50 PC |
235 | int v; |
236 | size_t size = 0; | |
237 | char *buf; | |
238 | ||
239 | for (v = 0; v < iov_cnt; v++) { | |
240 | size += iov[v].iov_len; | |
3a1dca94 | 241 | } |
6ff66f50 PC |
242 | size = size > limit ? limit : size; |
243 | buf = g_malloc(size); | |
244 | iov_to_buf(iov, iov_cnt, 0, buf, size); | |
b42581f5 | 245 | qemu_hexdump(fp, prefix, buf, size); |
6ff66f50 | 246 | g_free(buf); |
3a1dca94 | 247 | } |
0191253c | 248 | |
d336336c MT |
249 | unsigned iov_copy(struct iovec *dst_iov, unsigned int dst_iov_cnt, |
250 | const struct iovec *iov, unsigned int iov_cnt, | |
251 | size_t offset, size_t bytes) | |
252 | { | |
253 | size_t len; | |
254 | unsigned int i, j; | |
e911765c SL |
255 | for (i = 0, j = 0; |
256 | i < iov_cnt && j < dst_iov_cnt && (offset || bytes); i++) { | |
d336336c MT |
257 | if (offset >= iov[i].iov_len) { |
258 | offset -= iov[i].iov_len; | |
259 | continue; | |
260 | } | |
261 | len = MIN(bytes, iov[i].iov_len - offset); | |
262 | ||
263 | dst_iov[j].iov_base = iov[i].iov_base + offset; | |
264 | dst_iov[j].iov_len = len; | |
265 | j++; | |
266 | bytes -= len; | |
267 | offset = 0; | |
268 | } | |
269 | assert(offset == 0); | |
270 | return j; | |
271 | } | |
f563a5d7 | 272 | |
0191253c PB |
273 | /* io vectors */ |
274 | ||
275 | void qemu_iovec_init(QEMUIOVector *qiov, int alloc_hint) | |
276 | { | |
e1cf5582 | 277 | qiov->iov = g_new(struct iovec, alloc_hint); |
0191253c PB |
278 | qiov->niov = 0; |
279 | qiov->nalloc = alloc_hint; | |
280 | qiov->size = 0; | |
281 | } | |
282 | ||
283 | void qemu_iovec_init_external(QEMUIOVector *qiov, struct iovec *iov, int niov) | |
284 | { | |
285 | int i; | |
286 | ||
287 | qiov->iov = iov; | |
288 | qiov->niov = niov; | |
289 | qiov->nalloc = -1; | |
290 | qiov->size = 0; | |
291 | for (i = 0; i < niov; i++) | |
292 | qiov->size += iov[i].iov_len; | |
293 | } | |
294 | ||
295 | void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len) | |
296 | { | |
297 | assert(qiov->nalloc != -1); | |
298 | ||
299 | if (qiov->niov == qiov->nalloc) { | |
300 | qiov->nalloc = 2 * qiov->nalloc + 1; | |
e1cf5582 | 301 | qiov->iov = g_renew(struct iovec, qiov->iov, qiov->nalloc); |
0191253c PB |
302 | } |
303 | qiov->iov[qiov->niov].iov_base = base; | |
304 | qiov->iov[qiov->niov].iov_len = len; | |
305 | qiov->size += len; | |
306 | ++qiov->niov; | |
307 | } | |
308 | ||
309 | /* | |
530c0bbd | 310 | * Concatenates (partial) iovecs from src_iov to the end of dst. |
0191253c PB |
311 | * It starts copying after skipping `soffset' bytes at the |
312 | * beginning of src and adds individual vectors from src to | |
313 | * dst copies up to `sbytes' bytes total, or up to the end | |
530c0bbd | 314 | * of src_iov if it comes first. This way, it is okay to specify |
0191253c PB |
315 | * very large value for `sbytes' to indicate "up to the end |
316 | * of src". | |
317 | * Only vector pointers are processed, not the actual data buffers. | |
318 | */ | |
519661ee PB |
319 | size_t qemu_iovec_concat_iov(QEMUIOVector *dst, |
320 | struct iovec *src_iov, unsigned int src_cnt, | |
321 | size_t soffset, size_t sbytes) | |
0191253c PB |
322 | { |
323 | int i; | |
324 | size_t done; | |
facf98ad AK |
325 | |
326 | if (!sbytes) { | |
519661ee | 327 | return 0; |
facf98ad | 328 | } |
0191253c | 329 | assert(dst->nalloc != -1); |
530c0bbd SH |
330 | for (i = 0, done = 0; done < sbytes && i < src_cnt; i++) { |
331 | if (soffset < src_iov[i].iov_len) { | |
332 | size_t len = MIN(src_iov[i].iov_len - soffset, sbytes - done); | |
333 | qemu_iovec_add(dst, src_iov[i].iov_base + soffset, len); | |
0191253c PB |
334 | done += len; |
335 | soffset = 0; | |
336 | } else { | |
530c0bbd | 337 | soffset -= src_iov[i].iov_len; |
0191253c PB |
338 | } |
339 | } | |
530c0bbd | 340 | assert(soffset == 0); /* offset beyond end of src */ |
519661ee PB |
341 | |
342 | return done; | |
530c0bbd SH |
343 | } |
344 | ||
345 | /* | |
346 | * Concatenates (partial) iovecs from src to the end of dst. | |
347 | * It starts copying after skipping `soffset' bytes at the | |
348 | * beginning of src and adds individual vectors from src to | |
349 | * dst copies up to `sbytes' bytes total, or up to the end | |
350 | * of src if it comes first. This way, it is okay to specify | |
351 | * very large value for `sbytes' to indicate "up to the end | |
352 | * of src". | |
353 | * Only vector pointers are processed, not the actual data buffers. | |
354 | */ | |
355 | void qemu_iovec_concat(QEMUIOVector *dst, | |
356 | QEMUIOVector *src, size_t soffset, size_t sbytes) | |
357 | { | |
358 | qemu_iovec_concat_iov(dst, src->iov, src->niov, soffset, sbytes); | |
0191253c PB |
359 | } |
360 | ||
d953169d VSO |
361 | /* |
362 | * qiov_find_iov | |
363 | * | |
364 | * Return pointer to iovec structure, where byte at @offset in original vector | |
365 | * @iov exactly is. | |
366 | * Set @remaining_offset to be offset inside that iovec to the same byte. | |
367 | */ | |
368 | static struct iovec *iov_skip_offset(struct iovec *iov, size_t offset, | |
369 | size_t *remaining_offset) | |
370 | { | |
371 | while (offset > 0 && offset >= iov->iov_len) { | |
372 | offset -= iov->iov_len; | |
373 | iov++; | |
374 | } | |
375 | *remaining_offset = offset; | |
376 | ||
377 | return iov; | |
378 | } | |
379 | ||
380 | /* | |
3d06cea8 | 381 | * qemu_iovec_slice |
d953169d VSO |
382 | * |
383 | * Find subarray of iovec's, containing requested range. @head would | |
384 | * be offset in first iov (returned by the function), @tail would be | |
385 | * count of extra bytes in last iovec (returned iov + @niov - 1). | |
386 | */ | |
3d06cea8 HC |
387 | struct iovec *qemu_iovec_slice(QEMUIOVector *qiov, |
388 | size_t offset, size_t len, | |
389 | size_t *head, size_t *tail, int *niov) | |
d953169d VSO |
390 | { |
391 | struct iovec *iov, *end_iov; | |
392 | ||
393 | assert(offset + len <= qiov->size); | |
394 | ||
395 | iov = iov_skip_offset(qiov->iov, offset, head); | |
396 | end_iov = iov_skip_offset(iov, *head + len, tail); | |
397 | ||
398 | if (*tail > 0) { | |
399 | assert(*tail < end_iov->iov_len); | |
400 | *tail = end_iov->iov_len - *tail; | |
401 | end_iov++; | |
402 | } | |
403 | ||
404 | *niov = end_iov - iov; | |
405 | ||
406 | return iov; | |
407 | } | |
408 | ||
5396234b VSO |
409 | int qemu_iovec_subvec_niov(QEMUIOVector *qiov, size_t offset, size_t len) |
410 | { | |
411 | size_t head, tail; | |
412 | int niov; | |
413 | ||
3d06cea8 | 414 | qemu_iovec_slice(qiov, offset, len, &head, &tail, &niov); |
5396234b VSO |
415 | |
416 | return niov; | |
417 | } | |
418 | ||
43f35cb5 | 419 | /* |
f76889e7 | 420 | * Check if the contents of subrange of qiov data is all zeroes. |
43f35cb5 | 421 | */ |
f76889e7 | 422 | bool qemu_iovec_is_zero(QEMUIOVector *qiov, size_t offset, size_t bytes) |
43f35cb5 | 423 | { |
f76889e7 VSO |
424 | struct iovec *iov; |
425 | size_t current_offset; | |
426 | ||
427 | assert(offset + bytes <= qiov->size); | |
428 | ||
429 | iov = iov_skip_offset(qiov->iov, offset, ¤t_offset); | |
430 | ||
431 | while (bytes) { | |
432 | uint8_t *base = (uint8_t *)iov->iov_base + current_offset; | |
433 | size_t len = MIN(iov->iov_len - current_offset, bytes); | |
434 | ||
435 | if (!buffer_is_zero(base, len)) { | |
43f35cb5 PL |
436 | return false; |
437 | } | |
f76889e7 VSO |
438 | |
439 | current_offset = 0; | |
440 | bytes -= len; | |
441 | iov++; | |
43f35cb5 | 442 | } |
f76889e7 | 443 | |
43f35cb5 PL |
444 | return true; |
445 | } | |
446 | ||
d953169d VSO |
447 | void qemu_iovec_init_slice(QEMUIOVector *qiov, QEMUIOVector *source, |
448 | size_t offset, size_t len) | |
449 | { | |
cc63f6f6 HC |
450 | struct iovec *slice_iov; |
451 | int slice_niov; | |
452 | size_t slice_head, slice_tail; | |
4c002cef VSO |
453 | |
454 | assert(source->size >= len); | |
455 | assert(source->size - len >= offset); | |
456 | ||
cc63f6f6 HC |
457 | slice_iov = qemu_iovec_slice(source, offset, len, |
458 | &slice_head, &slice_tail, &slice_niov); | |
459 | if (slice_niov == 1) { | |
460 | qemu_iovec_init_buf(qiov, slice_iov[0].iov_base + slice_head, len); | |
461 | } else { | |
462 | qemu_iovec_init(qiov, slice_niov); | |
463 | qemu_iovec_concat_iov(qiov, slice_iov, slice_niov, slice_head, len); | |
464 | } | |
d953169d VSO |
465 | } |
466 | ||
0191253c PB |
467 | void qemu_iovec_destroy(QEMUIOVector *qiov) |
468 | { | |
d953169d VSO |
469 | if (qiov->nalloc != -1) { |
470 | g_free(qiov->iov); | |
471 | } | |
0191253c | 472 | |
d953169d | 473 | memset(qiov, 0, sizeof(*qiov)); |
0191253c PB |
474 | } |
475 | ||
476 | void qemu_iovec_reset(QEMUIOVector *qiov) | |
477 | { | |
478 | assert(qiov->nalloc != -1); | |
479 | ||
480 | qiov->niov = 0; | |
481 | qiov->size = 0; | |
482 | } | |
483 | ||
484 | size_t qemu_iovec_to_buf(QEMUIOVector *qiov, size_t offset, | |
485 | void *buf, size_t bytes) | |
486 | { | |
487 | return iov_to_buf(qiov->iov, qiov->niov, offset, buf, bytes); | |
488 | } | |
489 | ||
490 | size_t qemu_iovec_from_buf(QEMUIOVector *qiov, size_t offset, | |
491 | const void *buf, size_t bytes) | |
492 | { | |
493 | return iov_from_buf(qiov->iov, qiov->niov, offset, buf, bytes); | |
494 | } | |
495 | ||
496 | size_t qemu_iovec_memset(QEMUIOVector *qiov, size_t offset, | |
497 | int fillc, size_t bytes) | |
498 | { | |
499 | return iov_memset(qiov->iov, qiov->niov, offset, fillc, bytes); | |
500 | } | |
d0277635 | 501 | |
f70d7f7e BC |
502 | /** |
503 | * Check that I/O vector contents are identical | |
504 | * | |
505 | * The IO vectors must have the same structure (same length of all parts). | |
506 | * A typical usage is to compare vectors created with qemu_iovec_clone(). | |
507 | * | |
508 | * @a: I/O vector | |
509 | * @b: I/O vector | |
510 | * @ret: Offset to first mismatching byte or -1 if match | |
511 | */ | |
512 | ssize_t qemu_iovec_compare(QEMUIOVector *a, QEMUIOVector *b) | |
513 | { | |
514 | int i; | |
515 | ssize_t offset = 0; | |
516 | ||
517 | assert(a->niov == b->niov); | |
518 | for (i = 0; i < a->niov; i++) { | |
519 | size_t len = 0; | |
520 | uint8_t *p = (uint8_t *)a->iov[i].iov_base; | |
521 | uint8_t *q = (uint8_t *)b->iov[i].iov_base; | |
522 | ||
523 | assert(a->iov[i].iov_len == b->iov[i].iov_len); | |
524 | while (len < a->iov[i].iov_len && *p++ == *q++) { | |
525 | len++; | |
526 | } | |
527 | ||
528 | offset += len; | |
529 | ||
530 | if (len != a->iov[i].iov_len) { | |
531 | return offset; | |
532 | } | |
533 | } | |
534 | return -1; | |
535 | } | |
536 | ||
537 | typedef struct { | |
538 | int src_index; | |
539 | struct iovec *src_iov; | |
540 | void *dest_base; | |
541 | } IOVectorSortElem; | |
542 | ||
543 | static int sortelem_cmp_src_base(const void *a, const void *b) | |
544 | { | |
545 | const IOVectorSortElem *elem_a = a; | |
546 | const IOVectorSortElem *elem_b = b; | |
547 | ||
548 | /* Don't overflow */ | |
549 | if (elem_a->src_iov->iov_base < elem_b->src_iov->iov_base) { | |
550 | return -1; | |
551 | } else if (elem_a->src_iov->iov_base > elem_b->src_iov->iov_base) { | |
552 | return 1; | |
553 | } else { | |
554 | return 0; | |
555 | } | |
556 | } | |
557 | ||
558 | static int sortelem_cmp_src_index(const void *a, const void *b) | |
559 | { | |
560 | const IOVectorSortElem *elem_a = a; | |
561 | const IOVectorSortElem *elem_b = b; | |
562 | ||
563 | return elem_a->src_index - elem_b->src_index; | |
564 | } | |
565 | ||
566 | /** | |
567 | * Copy contents of I/O vector | |
568 | * | |
569 | * The relative relationships of overlapping iovecs are preserved. This is | |
570 | * necessary to ensure identical semantics in the cloned I/O vector. | |
571 | */ | |
572 | void qemu_iovec_clone(QEMUIOVector *dest, const QEMUIOVector *src, void *buf) | |
573 | { | |
522a9b94 | 574 | g_autofree IOVectorSortElem *sortelems = g_new(IOVectorSortElem, src->niov); |
f70d7f7e BC |
575 | void *last_end; |
576 | int i; | |
577 | ||
578 | /* Sort by source iovecs by base address */ | |
579 | for (i = 0; i < src->niov; i++) { | |
580 | sortelems[i].src_index = i; | |
581 | sortelems[i].src_iov = &src->iov[i]; | |
582 | } | |
583 | qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_base); | |
584 | ||
585 | /* Allocate buffer space taking into account overlapping iovecs */ | |
586 | last_end = NULL; | |
587 | for (i = 0; i < src->niov; i++) { | |
588 | struct iovec *cur = sortelems[i].src_iov; | |
589 | ptrdiff_t rewind = 0; | |
590 | ||
591 | /* Detect overlap */ | |
592 | if (last_end && last_end > cur->iov_base) { | |
593 | rewind = last_end - cur->iov_base; | |
594 | } | |
595 | ||
596 | sortelems[i].dest_base = buf - rewind; | |
597 | buf += cur->iov_len - MIN(rewind, cur->iov_len); | |
598 | last_end = MAX(cur->iov_base + cur->iov_len, last_end); | |
599 | } | |
600 | ||
601 | /* Sort by source iovec index and build destination iovec */ | |
602 | qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_index); | |
603 | for (i = 0; i < src->niov; i++) { | |
604 | qemu_iovec_add(dest, sortelems[i].dest_base, src->iov[i].iov_len); | |
605 | } | |
606 | } | |
607 | ||
9dd6f7c2 SH |
608 | void iov_discard_undo(IOVDiscardUndo *undo) |
609 | { | |
610 | /* Restore original iovec if it was modified */ | |
611 | if (undo->modified_iov) { | |
612 | *undo->modified_iov = undo->orig; | |
613 | } | |
614 | } | |
615 | ||
616 | size_t iov_discard_front_undoable(struct iovec **iov, | |
617 | unsigned int *iov_cnt, | |
618 | size_t bytes, | |
619 | IOVDiscardUndo *undo) | |
d0277635 SH |
620 | { |
621 | size_t total = 0; | |
622 | struct iovec *cur; | |
623 | ||
9dd6f7c2 SH |
624 | if (undo) { |
625 | undo->modified_iov = NULL; | |
626 | } | |
627 | ||
d0277635 SH |
628 | for (cur = *iov; *iov_cnt > 0; cur++) { |
629 | if (cur->iov_len > bytes) { | |
9dd6f7c2 SH |
630 | if (undo) { |
631 | undo->modified_iov = cur; | |
632 | undo->orig = *cur; | |
633 | } | |
634 | ||
d0277635 SH |
635 | cur->iov_base += bytes; |
636 | cur->iov_len -= bytes; | |
637 | total += bytes; | |
638 | break; | |
639 | } | |
640 | ||
641 | bytes -= cur->iov_len; | |
642 | total += cur->iov_len; | |
643 | *iov_cnt -= 1; | |
644 | } | |
645 | ||
646 | *iov = cur; | |
647 | return total; | |
648 | } | |
649 | ||
9dd6f7c2 SH |
650 | size_t iov_discard_front(struct iovec **iov, unsigned int *iov_cnt, |
651 | size_t bytes) | |
652 | { | |
653 | return iov_discard_front_undoable(iov, iov_cnt, bytes, NULL); | |
654 | } | |
655 | ||
656 | size_t iov_discard_back_undoable(struct iovec *iov, | |
657 | unsigned int *iov_cnt, | |
658 | size_t bytes, | |
659 | IOVDiscardUndo *undo) | |
d0277635 SH |
660 | { |
661 | size_t total = 0; | |
662 | struct iovec *cur; | |
663 | ||
9dd6f7c2 SH |
664 | if (undo) { |
665 | undo->modified_iov = NULL; | |
666 | } | |
667 | ||
d0277635 SH |
668 | if (*iov_cnt == 0) { |
669 | return 0; | |
670 | } | |
671 | ||
672 | cur = iov + (*iov_cnt - 1); | |
673 | ||
674 | while (*iov_cnt > 0) { | |
675 | if (cur->iov_len > bytes) { | |
9dd6f7c2 SH |
676 | if (undo) { |
677 | undo->modified_iov = cur; | |
678 | undo->orig = *cur; | |
679 | } | |
680 | ||
d0277635 SH |
681 | cur->iov_len -= bytes; |
682 | total += bytes; | |
683 | break; | |
684 | } | |
685 | ||
686 | bytes -= cur->iov_len; | |
687 | total += cur->iov_len; | |
688 | cur--; | |
689 | *iov_cnt -= 1; | |
690 | } | |
691 | ||
692 | return total; | |
693 | } | |
58f423fb | 694 | |
9dd6f7c2 SH |
695 | size_t iov_discard_back(struct iovec *iov, unsigned int *iov_cnt, |
696 | size_t bytes) | |
697 | { | |
698 | return iov_discard_back_undoable(iov, iov_cnt, bytes, NULL); | |
699 | } | |
700 | ||
58f423fb KW |
701 | void qemu_iovec_discard_back(QEMUIOVector *qiov, size_t bytes) |
702 | { | |
703 | size_t total; | |
704 | unsigned int niov = qiov->niov; | |
705 | ||
706 | assert(qiov->size >= bytes); | |
707 | total = iov_discard_back(qiov->iov, &niov, bytes); | |
708 | assert(total == bytes); | |
709 | ||
710 | qiov->niov = niov; | |
711 | qiov->size -= bytes; | |
712 | } |