2 * Helpers for getting linearized buffers from iov / filling buffers into iovs
4 * Copyright IBM, Corp. 2007, 2008
5 * Copyright (C) 2010 Red Hat, Inc.
8 * Anthony Liguori <aliguori@us.ibm.com>
9 * Amit Shah <amit.shah@redhat.com>
10 * Michael Tokarev <mjt@tls.msk.ru>
12 * This work is licensed under the terms of the GNU GPL, version 2. See
13 * the COPYING file in the top-level directory.
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.
23 # include <winsock2.h>
25 # include <sys/types.h>
26 # include <sys/socket.h>
29 size_t iov_from_buf(const struct iovec *iov, unsigned int iov_cnt,
30 size_t offset, const void *buf, size_t bytes)
34 for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) {
35 if (offset < iov[i].iov_len) {
36 size_t len = MIN(iov[i].iov_len - offset, bytes - done);
37 memcpy(iov[i].iov_base + offset, buf + done, len);
41 offset -= iov[i].iov_len;
48 size_t iov_to_buf(const struct iovec *iov, const unsigned int iov_cnt,
49 size_t offset, void *buf, size_t bytes)
53 for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) {
54 if (offset < iov[i].iov_len) {
55 size_t len = MIN(iov[i].iov_len - offset, bytes - done);
56 memcpy(buf + done, iov[i].iov_base + offset, len);
60 offset -= iov[i].iov_len;
67 size_t iov_memset(const struct iovec *iov, const unsigned int iov_cnt,
68 size_t offset, int fillc, size_t bytes)
72 for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) {
73 if (offset < iov[i].iov_len) {
74 size_t len = MIN(iov[i].iov_len - offset, bytes - done);
75 memset(iov[i].iov_base + offset, fillc, len);
79 offset -= iov[i].iov_len;
86 size_t iov_size(const struct iovec *iov, const unsigned int iov_cnt)
92 for (i = 0; i < iov_cnt; i++) {
93 len += iov[i].iov_len;
98 /* helper function for iov_send_recv() */
100 do_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt, bool do_send)
105 memset(&msg, 0, sizeof(msg));
107 msg.msg_iovlen = iov_cnt;
110 ? sendmsg(sockfd, &msg, 0)
111 : recvmsg(sockfd, &msg, 0);
112 } while (ret < 0 && errno == EINTR);
115 /* else send piece-by-piece */
116 /*XXX Note: windows has WSASend() and WSARecv() */
119 while (i < iov_cnt) {
121 ? send(sockfd, iov[i].iov_base, iov[i].iov_len, 0)
122 : recv(sockfd, iov[i].iov_base, iov[i].iov_len, 0);
127 } else if (errno == EINTR) {
130 /* else it is some "other" error,
131 * only return if there was no data processed. */
143 ssize_t iov_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt,
144 size_t offset, size_t bytes,
149 size_t orig_len, tail;
153 /* Find the start position, skipping `offset' bytes:
154 * first, skip all full-sized vector elements, */
155 for (niov = 0; niov < iov_cnt && offset >= iov[niov].iov_len; ++niov) {
156 offset -= iov[niov].iov_len;
159 /* niov == iov_cnt would only be valid if bytes == 0, which
160 * we already ruled out in the loop condition. */
161 assert(niov < iov_cnt);
166 /* second, skip `offset' bytes from the (now) first element,
168 iov[0].iov_base += offset;
169 iov[0].iov_len -= offset;
171 /* Find the end position skipping `bytes' bytes: */
172 /* first, skip all full-sized elements */
174 for (niov = 0; niov < iov_cnt && iov[niov].iov_len <= tail; ++niov) {
175 tail -= iov[niov].iov_len;
178 /* second, fixup the last element, and remember the original
180 assert(niov < iov_cnt);
181 assert(iov[niov].iov_len > tail);
182 orig_len = iov[niov].iov_len;
183 iov[niov++].iov_len = tail;
186 ret = do_send_recv(sockfd, iov, niov, do_send);
188 /* Undo the changes above before checking for errors */
190 iov[niov-1].iov_len = orig_len;
193 iov[0].iov_base -= offset;
194 iov[0].iov_len += offset;
198 assert(errno != EINTR);
199 if (errno == EAGAIN && total > 0) {
205 if (ret == 0 && !do_send) {
206 /* recv returns 0 when the peer has performed an orderly
211 /* Prepare for the next iteration */
221 void iov_hexdump(const struct iovec *iov, const unsigned int iov_cnt,
222 FILE *fp, const char *prefix, size_t limit)
228 for (v = 0; v < iov_cnt; v++) {
229 size += iov[v].iov_len;
231 size = size > limit ? limit : size;
232 buf = g_malloc(size);
233 iov_to_buf(iov, iov_cnt, 0, buf, size);
234 qemu_hexdump(buf, fp, prefix, size);
238 unsigned iov_copy(struct iovec *dst_iov, unsigned int dst_iov_cnt,
239 const struct iovec *iov, unsigned int iov_cnt,
240 size_t offset, size_t bytes)
244 for (i = 0, j = 0; i < iov_cnt && j < dst_iov_cnt && bytes; i++) {
245 if (offset >= iov[i].iov_len) {
246 offset -= iov[i].iov_len;
249 len = MIN(bytes, iov[i].iov_len - offset);
251 dst_iov[j].iov_base = iov[i].iov_base + offset;
252 dst_iov[j].iov_len = len;
263 void qemu_iovec_init(QEMUIOVector *qiov, int alloc_hint)
265 qiov->iov = g_malloc(alloc_hint * sizeof(struct iovec));
267 qiov->nalloc = alloc_hint;
271 void qemu_iovec_init_external(QEMUIOVector *qiov, struct iovec *iov, int niov)
279 for (i = 0; i < niov; i++)
280 qiov->size += iov[i].iov_len;
283 void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len)
285 assert(qiov->nalloc != -1);
287 if (qiov->niov == qiov->nalloc) {
288 qiov->nalloc = 2 * qiov->nalloc + 1;
289 qiov->iov = g_realloc(qiov->iov, qiov->nalloc * sizeof(struct iovec));
291 qiov->iov[qiov->niov].iov_base = base;
292 qiov->iov[qiov->niov].iov_len = len;
298 * Concatenates (partial) iovecs from src_iov to the end of dst.
299 * It starts copying after skipping `soffset' bytes at the
300 * beginning of src and adds individual vectors from src to
301 * dst copies up to `sbytes' bytes total, or up to the end
302 * of src_iov if it comes first. This way, it is okay to specify
303 * very large value for `sbytes' to indicate "up to the end
305 * Only vector pointers are processed, not the actual data buffers.
307 void qemu_iovec_concat_iov(QEMUIOVector *dst,
308 struct iovec *src_iov, unsigned int src_cnt,
309 size_t soffset, size_t sbytes)
317 assert(dst->nalloc != -1);
318 for (i = 0, done = 0; done < sbytes && i < src_cnt; i++) {
319 if (soffset < src_iov[i].iov_len) {
320 size_t len = MIN(src_iov[i].iov_len - soffset, sbytes - done);
321 qemu_iovec_add(dst, src_iov[i].iov_base + soffset, len);
325 soffset -= src_iov[i].iov_len;
328 assert(soffset == 0); /* offset beyond end of src */
332 * Concatenates (partial) iovecs from src to the end of dst.
333 * It starts copying after skipping `soffset' bytes at the
334 * beginning of src and adds individual vectors from src to
335 * dst copies up to `sbytes' bytes total, or up to the end
336 * of src if it comes first. This way, it is okay to specify
337 * very large value for `sbytes' to indicate "up to the end
339 * Only vector pointers are processed, not the actual data buffers.
341 void qemu_iovec_concat(QEMUIOVector *dst,
342 QEMUIOVector *src, size_t soffset, size_t sbytes)
344 qemu_iovec_concat_iov(dst, src->iov, src->niov, soffset, sbytes);
347 void qemu_iovec_destroy(QEMUIOVector *qiov)
349 assert(qiov->nalloc != -1);
351 qemu_iovec_reset(qiov);
357 void qemu_iovec_reset(QEMUIOVector *qiov)
359 assert(qiov->nalloc != -1);
365 size_t qemu_iovec_to_buf(QEMUIOVector *qiov, size_t offset,
366 void *buf, size_t bytes)
368 return iov_to_buf(qiov->iov, qiov->niov, offset, buf, bytes);
371 size_t qemu_iovec_from_buf(QEMUIOVector *qiov, size_t offset,
372 const void *buf, size_t bytes)
374 return iov_from_buf(qiov->iov, qiov->niov, offset, buf, bytes);
377 size_t qemu_iovec_memset(QEMUIOVector *qiov, size_t offset,
378 int fillc, size_t bytes)
380 return iov_memset(qiov->iov, qiov->niov, offset, fillc, bytes);
383 size_t iov_discard_front(struct iovec **iov, unsigned int *iov_cnt,
389 for (cur = *iov; *iov_cnt > 0; cur++) {
390 if (cur->iov_len > bytes) {
391 cur->iov_base += bytes;
392 cur->iov_len -= bytes;
397 bytes -= cur->iov_len;
398 total += cur->iov_len;
406 size_t iov_discard_back(struct iovec *iov, unsigned int *iov_cnt,
416 cur = iov + (*iov_cnt - 1);
418 while (*iov_cnt > 0) {
419 if (cur->iov_len > bytes) {
420 cur->iov_len -= bytes;
425 bytes -= cur->iov_len;
426 total += cur->iov_len;