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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; | |
114 | while (i < iov_cnt) { | |
25e5e4c7 MT |
115 | ssize_t r = do_send |
116 | ? send(sockfd, iov[i].iov_base, iov[i].iov_len, 0) | |
117 | : recv(sockfd, iov[i].iov_base, iov[i].iov_len, 0); | |
118 | if (r > 0) { | |
119 | ret += r; | |
120 | } else if (!r) { | |
121 | break; | |
122 | } else if (errno == EINTR) { | |
123 | continue; | |
124 | } else { | |
125 | /* else it is some "other" error, | |
126 | * only return if there was no data processed. */ | |
127 | if (ret == 0) { | |
c0958559 | 128 | ret = -1; |
25e5e4c7 MT |
129 | } |
130 | break; | |
131 | } | |
c0958559 | 132 | i++; |
25e5e4c7 | 133 | } |
c0958559 | 134 | return ret; |
25e5e4c7 MT |
135 | #endif |
136 | } | |
137 | ||
6b64640d | 138 | ssize_t iov_send_recv(int sockfd, const struct iovec *_iov, unsigned iov_cnt, |
25e5e4c7 MT |
139 | size_t offset, size_t bytes, |
140 | bool do_send) | |
141 | { | |
83f75c26 | 142 | ssize_t total = 0; |
25e5e4c7 | 143 | ssize_t ret; |
5209d675 | 144 | size_t orig_len, tail; |
f48869ad | 145 | unsigned niov; |
6b64640d WC |
146 | struct iovec *local_iov, *iov; |
147 | ||
148 | if (bytes <= 0) { | |
149 | return 0; | |
150 | } | |
151 | ||
152 | local_iov = g_new0(struct iovec, iov_cnt); | |
153 | iov_copy(local_iov, iov_cnt, _iov, iov_cnt, offset, bytes); | |
154 | offset = 0; | |
155 | iov = local_iov; | |
5209d675 | 156 | |
83f75c26 PB |
157 | while (bytes > 0) { |
158 | /* Find the start position, skipping `offset' bytes: | |
159 | * first, skip all full-sized vector elements, */ | |
160 | for (niov = 0; niov < iov_cnt && offset >= iov[niov].iov_len; ++niov) { | |
161 | offset -= iov[niov].iov_len; | |
162 | } | |
cb6247a7 | 163 | |
83f75c26 PB |
164 | /* niov == iov_cnt would only be valid if bytes == 0, which |
165 | * we already ruled out in the loop condition. */ | |
f48869ad | 166 | assert(niov < iov_cnt); |
83f75c26 PB |
167 | iov += niov; |
168 | iov_cnt -= niov; | |
169 | ||
170 | if (offset) { | |
171 | /* second, skip `offset' bytes from the (now) first element, | |
172 | * undo it on exit */ | |
173 | iov[0].iov_base += offset; | |
174 | iov[0].iov_len -= offset; | |
175 | } | |
176 | /* Find the end position skipping `bytes' bytes: */ | |
177 | /* first, skip all full-sized elements */ | |
178 | tail = bytes; | |
179 | for (niov = 0; niov < iov_cnt && iov[niov].iov_len <= tail; ++niov) { | |
180 | tail -= iov[niov].iov_len; | |
181 | } | |
182 | if (tail) { | |
183 | /* second, fixup the last element, and remember the original | |
184 | * length */ | |
185 | assert(niov < iov_cnt); | |
186 | assert(iov[niov].iov_len > tail); | |
187 | orig_len = iov[niov].iov_len; | |
188 | iov[niov++].iov_len = tail; | |
2be178a4 MT |
189 | ret = do_send_recv(sockfd, iov, niov, do_send); |
190 | /* Undo the changes above before checking for errors */ | |
83f75c26 | 191 | iov[niov-1].iov_len = orig_len; |
2be178a4 MT |
192 | } else { |
193 | ret = do_send_recv(sockfd, iov, niov, do_send); | |
83f75c26 PB |
194 | } |
195 | if (offset) { | |
196 | iov[0].iov_base -= offset; | |
197 | iov[0].iov_len += offset; | |
198 | } | |
199 | ||
200 | if (ret < 0) { | |
201 | assert(errno != EINTR); | |
6b64640d | 202 | g_free(local_iov); |
83f75c26 PB |
203 | if (errno == EAGAIN && total > 0) { |
204 | return total; | |
205 | } | |
206 | return -1; | |
207 | } | |
208 | ||
84004290 MK |
209 | if (ret == 0 && !do_send) { |
210 | /* recv returns 0 when the peer has performed an orderly | |
211 | * shutdown. */ | |
212 | break; | |
213 | } | |
214 | ||
83f75c26 PB |
215 | /* Prepare for the next iteration */ |
216 | offset += ret; | |
217 | total += ret; | |
218 | bytes -= ret; | |
25e5e4c7 | 219 | } |
25e5e4c7 | 220 | |
6b64640d | 221 | g_free(local_iov); |
83f75c26 | 222 | return total; |
25e5e4c7 MT |
223 | } |
224 | ||
225 | ||
3a1dca94 GH |
226 | void iov_hexdump(const struct iovec *iov, const unsigned int iov_cnt, |
227 | FILE *fp, const char *prefix, size_t limit) | |
228 | { | |
6ff66f50 PC |
229 | int v; |
230 | size_t size = 0; | |
231 | char *buf; | |
232 | ||
233 | for (v = 0; v < iov_cnt; v++) { | |
234 | size += iov[v].iov_len; | |
3a1dca94 | 235 | } |
6ff66f50 PC |
236 | size = size > limit ? limit : size; |
237 | buf = g_malloc(size); | |
238 | iov_to_buf(iov, iov_cnt, 0, buf, size); | |
b42581f5 | 239 | qemu_hexdump(fp, prefix, buf, size); |
6ff66f50 | 240 | g_free(buf); |
3a1dca94 | 241 | } |
0191253c | 242 | |
d336336c MT |
243 | unsigned iov_copy(struct iovec *dst_iov, unsigned int dst_iov_cnt, |
244 | const struct iovec *iov, unsigned int iov_cnt, | |
245 | size_t offset, size_t bytes) | |
246 | { | |
247 | size_t len; | |
248 | unsigned int i, j; | |
e911765c SL |
249 | for (i = 0, j = 0; |
250 | i < iov_cnt && j < dst_iov_cnt && (offset || bytes); i++) { | |
d336336c MT |
251 | if (offset >= iov[i].iov_len) { |
252 | offset -= iov[i].iov_len; | |
253 | continue; | |
254 | } | |
255 | len = MIN(bytes, iov[i].iov_len - offset); | |
256 | ||
257 | dst_iov[j].iov_base = iov[i].iov_base + offset; | |
258 | dst_iov[j].iov_len = len; | |
259 | j++; | |
260 | bytes -= len; | |
261 | offset = 0; | |
262 | } | |
263 | assert(offset == 0); | |
264 | return j; | |
265 | } | |
f563a5d7 | 266 | |
0191253c PB |
267 | /* io vectors */ |
268 | ||
269 | void qemu_iovec_init(QEMUIOVector *qiov, int alloc_hint) | |
270 | { | |
e1cf5582 | 271 | qiov->iov = g_new(struct iovec, alloc_hint); |
0191253c PB |
272 | qiov->niov = 0; |
273 | qiov->nalloc = alloc_hint; | |
274 | qiov->size = 0; | |
275 | } | |
276 | ||
277 | void qemu_iovec_init_external(QEMUIOVector *qiov, struct iovec *iov, int niov) | |
278 | { | |
279 | int i; | |
280 | ||
281 | qiov->iov = iov; | |
282 | qiov->niov = niov; | |
283 | qiov->nalloc = -1; | |
284 | qiov->size = 0; | |
285 | for (i = 0; i < niov; i++) | |
286 | qiov->size += iov[i].iov_len; | |
287 | } | |
288 | ||
289 | void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len) | |
290 | { | |
291 | assert(qiov->nalloc != -1); | |
292 | ||
293 | if (qiov->niov == qiov->nalloc) { | |
294 | qiov->nalloc = 2 * qiov->nalloc + 1; | |
e1cf5582 | 295 | qiov->iov = g_renew(struct iovec, qiov->iov, qiov->nalloc); |
0191253c PB |
296 | } |
297 | qiov->iov[qiov->niov].iov_base = base; | |
298 | qiov->iov[qiov->niov].iov_len = len; | |
299 | qiov->size += len; | |
300 | ++qiov->niov; | |
301 | } | |
302 | ||
303 | /* | |
530c0bbd | 304 | * Concatenates (partial) iovecs from src_iov to the end of dst. |
0191253c PB |
305 | * It starts copying after skipping `soffset' bytes at the |
306 | * beginning of src and adds individual vectors from src to | |
307 | * dst copies up to `sbytes' bytes total, or up to the end | |
530c0bbd | 308 | * of src_iov if it comes first. This way, it is okay to specify |
0191253c PB |
309 | * very large value for `sbytes' to indicate "up to the end |
310 | * of src". | |
311 | * Only vector pointers are processed, not the actual data buffers. | |
312 | */ | |
519661ee PB |
313 | size_t qemu_iovec_concat_iov(QEMUIOVector *dst, |
314 | struct iovec *src_iov, unsigned int src_cnt, | |
315 | size_t soffset, size_t sbytes) | |
0191253c PB |
316 | { |
317 | int i; | |
318 | size_t done; | |
facf98ad AK |
319 | |
320 | if (!sbytes) { | |
519661ee | 321 | return 0; |
facf98ad | 322 | } |
0191253c | 323 | assert(dst->nalloc != -1); |
530c0bbd SH |
324 | for (i = 0, done = 0; done < sbytes && i < src_cnt; i++) { |
325 | if (soffset < src_iov[i].iov_len) { | |
326 | size_t len = MIN(src_iov[i].iov_len - soffset, sbytes - done); | |
327 | qemu_iovec_add(dst, src_iov[i].iov_base + soffset, len); | |
0191253c PB |
328 | done += len; |
329 | soffset = 0; | |
330 | } else { | |
530c0bbd | 331 | soffset -= src_iov[i].iov_len; |
0191253c PB |
332 | } |
333 | } | |
530c0bbd | 334 | assert(soffset == 0); /* offset beyond end of src */ |
519661ee PB |
335 | |
336 | return done; | |
530c0bbd SH |
337 | } |
338 | ||
339 | /* | |
340 | * Concatenates (partial) iovecs from src to the end of dst. | |
341 | * It starts copying after skipping `soffset' bytes at the | |
342 | * beginning of src and adds individual vectors from src to | |
343 | * dst copies up to `sbytes' bytes total, or up to the end | |
344 | * of src if it comes first. This way, it is okay to specify | |
345 | * very large value for `sbytes' to indicate "up to the end | |
346 | * of src". | |
347 | * Only vector pointers are processed, not the actual data buffers. | |
348 | */ | |
349 | void qemu_iovec_concat(QEMUIOVector *dst, | |
350 | QEMUIOVector *src, size_t soffset, size_t sbytes) | |
351 | { | |
352 | qemu_iovec_concat_iov(dst, src->iov, src->niov, soffset, sbytes); | |
0191253c PB |
353 | } |
354 | ||
d953169d VSO |
355 | /* |
356 | * qiov_find_iov | |
357 | * | |
358 | * Return pointer to iovec structure, where byte at @offset in original vector | |
359 | * @iov exactly is. | |
360 | * Set @remaining_offset to be offset inside that iovec to the same byte. | |
361 | */ | |
362 | static struct iovec *iov_skip_offset(struct iovec *iov, size_t offset, | |
363 | size_t *remaining_offset) | |
364 | { | |
365 | while (offset > 0 && offset >= iov->iov_len) { | |
366 | offset -= iov->iov_len; | |
367 | iov++; | |
368 | } | |
369 | *remaining_offset = offset; | |
370 | ||
371 | return iov; | |
372 | } | |
373 | ||
374 | /* | |
375 | * qiov_slice | |
376 | * | |
377 | * Find subarray of iovec's, containing requested range. @head would | |
378 | * be offset in first iov (returned by the function), @tail would be | |
379 | * count of extra bytes in last iovec (returned iov + @niov - 1). | |
380 | */ | |
381 | static struct iovec *qiov_slice(QEMUIOVector *qiov, | |
382 | size_t offset, size_t len, | |
383 | size_t *head, size_t *tail, int *niov) | |
384 | { | |
385 | struct iovec *iov, *end_iov; | |
386 | ||
387 | assert(offset + len <= qiov->size); | |
388 | ||
389 | iov = iov_skip_offset(qiov->iov, offset, head); | |
390 | end_iov = iov_skip_offset(iov, *head + len, tail); | |
391 | ||
392 | if (*tail > 0) { | |
393 | assert(*tail < end_iov->iov_len); | |
394 | *tail = end_iov->iov_len - *tail; | |
395 | end_iov++; | |
396 | } | |
397 | ||
398 | *niov = end_iov - iov; | |
399 | ||
400 | return iov; | |
401 | } | |
402 | ||
5396234b VSO |
403 | int qemu_iovec_subvec_niov(QEMUIOVector *qiov, size_t offset, size_t len) |
404 | { | |
405 | size_t head, tail; | |
406 | int niov; | |
407 | ||
408 | qiov_slice(qiov, offset, len, &head, &tail, &niov); | |
409 | ||
410 | return niov; | |
411 | } | |
412 | ||
d953169d VSO |
413 | /* |
414 | * Compile new iovec, combining @head_buf buffer, sub-qiov of @mid_qiov, | |
415 | * and @tail_buf buffer into new qiov. | |
416 | */ | |
4c002cef | 417 | int qemu_iovec_init_extended( |
d953169d VSO |
418 | QEMUIOVector *qiov, |
419 | void *head_buf, size_t head_len, | |
420 | QEMUIOVector *mid_qiov, size_t mid_offset, size_t mid_len, | |
421 | void *tail_buf, size_t tail_len) | |
422 | { | |
423 | size_t mid_head, mid_tail; | |
424 | int total_niov, mid_niov = 0; | |
d38d6de2 | 425 | struct iovec *p, *mid_iov = NULL; |
d953169d | 426 | |
4c002cef VSO |
427 | assert(mid_qiov->niov <= IOV_MAX); |
428 | ||
429 | if (SIZE_MAX - head_len < mid_len || | |
430 | SIZE_MAX - head_len - mid_len < tail_len) | |
431 | { | |
432 | return -EINVAL; | |
433 | } | |
434 | ||
d953169d VSO |
435 | if (mid_len) { |
436 | mid_iov = qiov_slice(mid_qiov, mid_offset, mid_len, | |
437 | &mid_head, &mid_tail, &mid_niov); | |
438 | } | |
439 | ||
440 | total_niov = !!head_len + mid_niov + !!tail_len; | |
4c002cef VSO |
441 | if (total_niov > IOV_MAX) { |
442 | return -EINVAL; | |
443 | } | |
444 | ||
d953169d VSO |
445 | if (total_niov == 1) { |
446 | qemu_iovec_init_buf(qiov, NULL, 0); | |
447 | p = &qiov->local_iov; | |
448 | } else { | |
449 | qiov->niov = qiov->nalloc = total_niov; | |
450 | qiov->size = head_len + mid_len + tail_len; | |
451 | p = qiov->iov = g_new(struct iovec, qiov->niov); | |
452 | } | |
453 | ||
454 | if (head_len) { | |
455 | p->iov_base = head_buf; | |
456 | p->iov_len = head_len; | |
457 | p++; | |
458 | } | |
459 | ||
d38d6de2 VSO |
460 | assert(!mid_niov == !mid_len); |
461 | if (mid_niov) { | |
d953169d VSO |
462 | memcpy(p, mid_iov, mid_niov * sizeof(*p)); |
463 | p[0].iov_base = (uint8_t *)p[0].iov_base + mid_head; | |
464 | p[0].iov_len -= mid_head; | |
465 | p[mid_niov - 1].iov_len -= mid_tail; | |
466 | p += mid_niov; | |
467 | } | |
468 | ||
469 | if (tail_len) { | |
470 | p->iov_base = tail_buf; | |
471 | p->iov_len = tail_len; | |
472 | } | |
4c002cef VSO |
473 | |
474 | return 0; | |
d953169d VSO |
475 | } |
476 | ||
43f35cb5 | 477 | /* |
f76889e7 | 478 | * Check if the contents of subrange of qiov data is all zeroes. |
43f35cb5 | 479 | */ |
f76889e7 | 480 | bool qemu_iovec_is_zero(QEMUIOVector *qiov, size_t offset, size_t bytes) |
43f35cb5 | 481 | { |
f76889e7 VSO |
482 | struct iovec *iov; |
483 | size_t current_offset; | |
484 | ||
485 | assert(offset + bytes <= qiov->size); | |
486 | ||
487 | iov = iov_skip_offset(qiov->iov, offset, ¤t_offset); | |
488 | ||
489 | while (bytes) { | |
490 | uint8_t *base = (uint8_t *)iov->iov_base + current_offset; | |
491 | size_t len = MIN(iov->iov_len - current_offset, bytes); | |
492 | ||
493 | if (!buffer_is_zero(base, len)) { | |
43f35cb5 PL |
494 | return false; |
495 | } | |
f76889e7 VSO |
496 | |
497 | current_offset = 0; | |
498 | bytes -= len; | |
499 | iov++; | |
43f35cb5 | 500 | } |
f76889e7 | 501 | |
43f35cb5 PL |
502 | return true; |
503 | } | |
504 | ||
d953169d VSO |
505 | void qemu_iovec_init_slice(QEMUIOVector *qiov, QEMUIOVector *source, |
506 | size_t offset, size_t len) | |
507 | { | |
4c002cef VSO |
508 | int ret; |
509 | ||
510 | assert(source->size >= len); | |
511 | assert(source->size - len >= offset); | |
512 | ||
513 | /* We shrink the request, so we can't overflow neither size_t nor MAX_IOV */ | |
514 | ret = qemu_iovec_init_extended(qiov, NULL, 0, source, offset, len, NULL, 0); | |
515 | assert(ret == 0); | |
d953169d VSO |
516 | } |
517 | ||
0191253c PB |
518 | void qemu_iovec_destroy(QEMUIOVector *qiov) |
519 | { | |
d953169d VSO |
520 | if (qiov->nalloc != -1) { |
521 | g_free(qiov->iov); | |
522 | } | |
0191253c | 523 | |
d953169d | 524 | memset(qiov, 0, sizeof(*qiov)); |
0191253c PB |
525 | } |
526 | ||
527 | void qemu_iovec_reset(QEMUIOVector *qiov) | |
528 | { | |
529 | assert(qiov->nalloc != -1); | |
530 | ||
531 | qiov->niov = 0; | |
532 | qiov->size = 0; | |
533 | } | |
534 | ||
535 | size_t qemu_iovec_to_buf(QEMUIOVector *qiov, size_t offset, | |
536 | void *buf, size_t bytes) | |
537 | { | |
538 | return iov_to_buf(qiov->iov, qiov->niov, offset, buf, bytes); | |
539 | } | |
540 | ||
541 | size_t qemu_iovec_from_buf(QEMUIOVector *qiov, size_t offset, | |
542 | const void *buf, size_t bytes) | |
543 | { | |
544 | return iov_from_buf(qiov->iov, qiov->niov, offset, buf, bytes); | |
545 | } | |
546 | ||
547 | size_t qemu_iovec_memset(QEMUIOVector *qiov, size_t offset, | |
548 | int fillc, size_t bytes) | |
549 | { | |
550 | return iov_memset(qiov->iov, qiov->niov, offset, fillc, bytes); | |
551 | } | |
d0277635 | 552 | |
f70d7f7e BC |
553 | /** |
554 | * Check that I/O vector contents are identical | |
555 | * | |
556 | * The IO vectors must have the same structure (same length of all parts). | |
557 | * A typical usage is to compare vectors created with qemu_iovec_clone(). | |
558 | * | |
559 | * @a: I/O vector | |
560 | * @b: I/O vector | |
561 | * @ret: Offset to first mismatching byte or -1 if match | |
562 | */ | |
563 | ssize_t qemu_iovec_compare(QEMUIOVector *a, QEMUIOVector *b) | |
564 | { | |
565 | int i; | |
566 | ssize_t offset = 0; | |
567 | ||
568 | assert(a->niov == b->niov); | |
569 | for (i = 0; i < a->niov; i++) { | |
570 | size_t len = 0; | |
571 | uint8_t *p = (uint8_t *)a->iov[i].iov_base; | |
572 | uint8_t *q = (uint8_t *)b->iov[i].iov_base; | |
573 | ||
574 | assert(a->iov[i].iov_len == b->iov[i].iov_len); | |
575 | while (len < a->iov[i].iov_len && *p++ == *q++) { | |
576 | len++; | |
577 | } | |
578 | ||
579 | offset += len; | |
580 | ||
581 | if (len != a->iov[i].iov_len) { | |
582 | return offset; | |
583 | } | |
584 | } | |
585 | return -1; | |
586 | } | |
587 | ||
588 | typedef struct { | |
589 | int src_index; | |
590 | struct iovec *src_iov; | |
591 | void *dest_base; | |
592 | } IOVectorSortElem; | |
593 | ||
594 | static int sortelem_cmp_src_base(const void *a, const void *b) | |
595 | { | |
596 | const IOVectorSortElem *elem_a = a; | |
597 | const IOVectorSortElem *elem_b = b; | |
598 | ||
599 | /* Don't overflow */ | |
600 | if (elem_a->src_iov->iov_base < elem_b->src_iov->iov_base) { | |
601 | return -1; | |
602 | } else if (elem_a->src_iov->iov_base > elem_b->src_iov->iov_base) { | |
603 | return 1; | |
604 | } else { | |
605 | return 0; | |
606 | } | |
607 | } | |
608 | ||
609 | static int sortelem_cmp_src_index(const void *a, const void *b) | |
610 | { | |
611 | const IOVectorSortElem *elem_a = a; | |
612 | const IOVectorSortElem *elem_b = b; | |
613 | ||
614 | return elem_a->src_index - elem_b->src_index; | |
615 | } | |
616 | ||
617 | /** | |
618 | * Copy contents of I/O vector | |
619 | * | |
620 | * The relative relationships of overlapping iovecs are preserved. This is | |
621 | * necessary to ensure identical semantics in the cloned I/O vector. | |
622 | */ | |
623 | void qemu_iovec_clone(QEMUIOVector *dest, const QEMUIOVector *src, void *buf) | |
624 | { | |
625 | IOVectorSortElem sortelems[src->niov]; | |
626 | void *last_end; | |
627 | int i; | |
628 | ||
629 | /* Sort by source iovecs by base address */ | |
630 | for (i = 0; i < src->niov; i++) { | |
631 | sortelems[i].src_index = i; | |
632 | sortelems[i].src_iov = &src->iov[i]; | |
633 | } | |
634 | qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_base); | |
635 | ||
636 | /* Allocate buffer space taking into account overlapping iovecs */ | |
637 | last_end = NULL; | |
638 | for (i = 0; i < src->niov; i++) { | |
639 | struct iovec *cur = sortelems[i].src_iov; | |
640 | ptrdiff_t rewind = 0; | |
641 | ||
642 | /* Detect overlap */ | |
643 | if (last_end && last_end > cur->iov_base) { | |
644 | rewind = last_end - cur->iov_base; | |
645 | } | |
646 | ||
647 | sortelems[i].dest_base = buf - rewind; | |
648 | buf += cur->iov_len - MIN(rewind, cur->iov_len); | |
649 | last_end = MAX(cur->iov_base + cur->iov_len, last_end); | |
650 | } | |
651 | ||
652 | /* Sort by source iovec index and build destination iovec */ | |
653 | qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_index); | |
654 | for (i = 0; i < src->niov; i++) { | |
655 | qemu_iovec_add(dest, sortelems[i].dest_base, src->iov[i].iov_len); | |
656 | } | |
657 | } | |
658 | ||
9dd6f7c2 SH |
659 | void iov_discard_undo(IOVDiscardUndo *undo) |
660 | { | |
661 | /* Restore original iovec if it was modified */ | |
662 | if (undo->modified_iov) { | |
663 | *undo->modified_iov = undo->orig; | |
664 | } | |
665 | } | |
666 | ||
667 | size_t iov_discard_front_undoable(struct iovec **iov, | |
668 | unsigned int *iov_cnt, | |
669 | size_t bytes, | |
670 | IOVDiscardUndo *undo) | |
d0277635 SH |
671 | { |
672 | size_t total = 0; | |
673 | struct iovec *cur; | |
674 | ||
9dd6f7c2 SH |
675 | if (undo) { |
676 | undo->modified_iov = NULL; | |
677 | } | |
678 | ||
d0277635 SH |
679 | for (cur = *iov; *iov_cnt > 0; cur++) { |
680 | if (cur->iov_len > bytes) { | |
9dd6f7c2 SH |
681 | if (undo) { |
682 | undo->modified_iov = cur; | |
683 | undo->orig = *cur; | |
684 | } | |
685 | ||
d0277635 SH |
686 | cur->iov_base += bytes; |
687 | cur->iov_len -= bytes; | |
688 | total += bytes; | |
689 | break; | |
690 | } | |
691 | ||
692 | bytes -= cur->iov_len; | |
693 | total += cur->iov_len; | |
694 | *iov_cnt -= 1; | |
695 | } | |
696 | ||
697 | *iov = cur; | |
698 | return total; | |
699 | } | |
700 | ||
9dd6f7c2 SH |
701 | size_t iov_discard_front(struct iovec **iov, unsigned int *iov_cnt, |
702 | size_t bytes) | |
703 | { | |
704 | return iov_discard_front_undoable(iov, iov_cnt, bytes, NULL); | |
705 | } | |
706 | ||
707 | size_t iov_discard_back_undoable(struct iovec *iov, | |
708 | unsigned int *iov_cnt, | |
709 | size_t bytes, | |
710 | IOVDiscardUndo *undo) | |
d0277635 SH |
711 | { |
712 | size_t total = 0; | |
713 | struct iovec *cur; | |
714 | ||
9dd6f7c2 SH |
715 | if (undo) { |
716 | undo->modified_iov = NULL; | |
717 | } | |
718 | ||
d0277635 SH |
719 | if (*iov_cnt == 0) { |
720 | return 0; | |
721 | } | |
722 | ||
723 | cur = iov + (*iov_cnt - 1); | |
724 | ||
725 | while (*iov_cnt > 0) { | |
726 | if (cur->iov_len > bytes) { | |
9dd6f7c2 SH |
727 | if (undo) { |
728 | undo->modified_iov = cur; | |
729 | undo->orig = *cur; | |
730 | } | |
731 | ||
d0277635 SH |
732 | cur->iov_len -= bytes; |
733 | total += bytes; | |
734 | break; | |
735 | } | |
736 | ||
737 | bytes -= cur->iov_len; | |
738 | total += cur->iov_len; | |
739 | cur--; | |
740 | *iov_cnt -= 1; | |
741 | } | |
742 | ||
743 | return total; | |
744 | } | |
58f423fb | 745 | |
9dd6f7c2 SH |
746 | size_t iov_discard_back(struct iovec *iov, unsigned int *iov_cnt, |
747 | size_t bytes) | |
748 | { | |
749 | return iov_discard_back_undoable(iov, iov_cnt, bytes, NULL); | |
750 | } | |
751 | ||
58f423fb KW |
752 | void qemu_iovec_discard_back(QEMUIOVector *qiov, size_t bytes) |
753 | { | |
754 | size_t total; | |
755 | unsigned int niov = qiov->niov; | |
756 | ||
757 | assert(qiov->size >= bytes); | |
758 | total = iov_discard_back(qiov->iov, &niov, bytes); | |
759 | assert(total == bytes); | |
760 | ||
761 | qiov->niov = niov; | |
762 | qiov->size -= bytes; | |
763 | } |