1baacf047SPaolo Bonzini /* 2baacf047SPaolo Bonzini * Helpers for getting linearized buffers from iov / filling buffers into iovs 3baacf047SPaolo Bonzini * 4baacf047SPaolo Bonzini * Copyright IBM, Corp. 2007, 2008 5baacf047SPaolo Bonzini * Copyright (C) 2010 Red Hat, Inc. 6baacf047SPaolo Bonzini * 7baacf047SPaolo Bonzini * Author(s): 8baacf047SPaolo Bonzini * Anthony Liguori <aliguori@us.ibm.com> 9baacf047SPaolo Bonzini * Amit Shah <amit.shah@redhat.com> 10baacf047SPaolo Bonzini * Michael Tokarev <mjt@tls.msk.ru> 11baacf047SPaolo Bonzini * 12baacf047SPaolo Bonzini * This work is licensed under the terms of the GNU GPL, version 2. See 13baacf047SPaolo Bonzini * the COPYING file in the top-level directory. 14baacf047SPaolo Bonzini * 15baacf047SPaolo Bonzini * Contributions after 2012-01-13 are licensed under the terms of the 16baacf047SPaolo Bonzini * GNU GPL, version 2 or (at your option) any later version. 17baacf047SPaolo Bonzini */ 18baacf047SPaolo Bonzini 19aafd7584SPeter Maydell #include "qemu/osdep.h" 20daf015efSMarkus Armbruster #include "qemu-common.h" 21baacf047SPaolo Bonzini #include "qemu/iov.h" 22cc99c6f5SStefan Weil #include "qemu/sockets.h" 23f348b6d1SVeronia Bahaa #include "qemu/cutils.h" 24baacf047SPaolo Bonzini 25ad523bcaSPaolo Bonzini size_t iov_from_buf_full(const struct iovec *iov, unsigned int iov_cnt, 26baacf047SPaolo Bonzini size_t offset, const void *buf, size_t bytes) 27baacf047SPaolo Bonzini { 28baacf047SPaolo Bonzini size_t done; 29baacf047SPaolo Bonzini unsigned int i; 30baacf047SPaolo Bonzini for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) { 31baacf047SPaolo Bonzini if (offset < iov[i].iov_len) { 32baacf047SPaolo Bonzini size_t len = MIN(iov[i].iov_len - offset, bytes - done); 33baacf047SPaolo Bonzini memcpy(iov[i].iov_base + offset, buf + done, len); 34baacf047SPaolo Bonzini done += len; 35baacf047SPaolo Bonzini offset = 0; 36baacf047SPaolo Bonzini } else { 37baacf047SPaolo Bonzini offset -= iov[i].iov_len; 38baacf047SPaolo Bonzini } 39baacf047SPaolo Bonzini } 40baacf047SPaolo Bonzini assert(offset == 0); 41baacf047SPaolo Bonzini return done; 42baacf047SPaolo Bonzini } 43baacf047SPaolo Bonzini 44ad523bcaSPaolo Bonzini size_t iov_to_buf_full(const struct iovec *iov, const unsigned int iov_cnt, 45baacf047SPaolo Bonzini size_t offset, void *buf, size_t bytes) 46baacf047SPaolo Bonzini { 47baacf047SPaolo Bonzini size_t done; 48baacf047SPaolo Bonzini unsigned int i; 49baacf047SPaolo Bonzini for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) { 50baacf047SPaolo Bonzini if (offset < iov[i].iov_len) { 51baacf047SPaolo Bonzini size_t len = MIN(iov[i].iov_len - offset, bytes - done); 52baacf047SPaolo Bonzini memcpy(buf + done, iov[i].iov_base + offset, len); 53baacf047SPaolo Bonzini done += len; 54baacf047SPaolo Bonzini offset = 0; 55baacf047SPaolo Bonzini } else { 56baacf047SPaolo Bonzini offset -= iov[i].iov_len; 57baacf047SPaolo Bonzini } 58baacf047SPaolo Bonzini } 59baacf047SPaolo Bonzini assert(offset == 0); 60baacf047SPaolo Bonzini return done; 61baacf047SPaolo Bonzini } 62baacf047SPaolo Bonzini 63baacf047SPaolo Bonzini size_t iov_memset(const struct iovec *iov, const unsigned int iov_cnt, 64baacf047SPaolo Bonzini size_t offset, int fillc, size_t bytes) 65baacf047SPaolo Bonzini { 66baacf047SPaolo Bonzini size_t done; 67baacf047SPaolo Bonzini unsigned int i; 68baacf047SPaolo Bonzini for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) { 69baacf047SPaolo Bonzini if (offset < iov[i].iov_len) { 70baacf047SPaolo Bonzini size_t len = MIN(iov[i].iov_len - offset, bytes - done); 71baacf047SPaolo Bonzini memset(iov[i].iov_base + offset, fillc, len); 72baacf047SPaolo Bonzini done += len; 73baacf047SPaolo Bonzini offset = 0; 74baacf047SPaolo Bonzini } else { 75baacf047SPaolo Bonzini offset -= iov[i].iov_len; 76baacf047SPaolo Bonzini } 77baacf047SPaolo Bonzini } 78baacf047SPaolo Bonzini assert(offset == 0); 79baacf047SPaolo Bonzini return done; 80baacf047SPaolo Bonzini } 81baacf047SPaolo Bonzini 82baacf047SPaolo Bonzini size_t iov_size(const struct iovec *iov, const unsigned int iov_cnt) 83baacf047SPaolo Bonzini { 84baacf047SPaolo Bonzini size_t len; 85baacf047SPaolo Bonzini unsigned int i; 86baacf047SPaolo Bonzini 87baacf047SPaolo Bonzini len = 0; 88baacf047SPaolo Bonzini for (i = 0; i < iov_cnt; i++) { 89baacf047SPaolo Bonzini len += iov[i].iov_len; 90baacf047SPaolo Bonzini } 91baacf047SPaolo Bonzini return len; 92baacf047SPaolo Bonzini } 93baacf047SPaolo Bonzini 94baacf047SPaolo Bonzini /* helper function for iov_send_recv() */ 95baacf047SPaolo Bonzini static ssize_t 96baacf047SPaolo Bonzini do_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt, bool do_send) 97baacf047SPaolo Bonzini { 989adea5f7SPaolo Bonzini #ifdef CONFIG_POSIX 99baacf047SPaolo Bonzini ssize_t ret; 100baacf047SPaolo Bonzini struct msghdr msg; 101baacf047SPaolo Bonzini memset(&msg, 0, sizeof(msg)); 102baacf047SPaolo Bonzini msg.msg_iov = iov; 103baacf047SPaolo Bonzini msg.msg_iovlen = iov_cnt; 104baacf047SPaolo Bonzini do { 105baacf047SPaolo Bonzini ret = do_send 106baacf047SPaolo Bonzini ? sendmsg(sockfd, &msg, 0) 107baacf047SPaolo Bonzini : recvmsg(sockfd, &msg, 0); 108baacf047SPaolo Bonzini } while (ret < 0 && errno == EINTR); 109baacf047SPaolo Bonzini return ret; 110baacf047SPaolo Bonzini #else 111baacf047SPaolo Bonzini /* else send piece-by-piece */ 112baacf047SPaolo Bonzini /*XXX Note: windows has WSASend() and WSARecv() */ 113baacf047SPaolo Bonzini unsigned i = 0; 114baacf047SPaolo Bonzini ssize_t ret = 0; 115baacf047SPaolo Bonzini while (i < iov_cnt) { 116baacf047SPaolo Bonzini ssize_t r = do_send 117baacf047SPaolo Bonzini ? send(sockfd, iov[i].iov_base, iov[i].iov_len, 0) 118baacf047SPaolo Bonzini : recv(sockfd, iov[i].iov_base, iov[i].iov_len, 0); 119baacf047SPaolo Bonzini if (r > 0) { 120baacf047SPaolo Bonzini ret += r; 121baacf047SPaolo Bonzini } else if (!r) { 122baacf047SPaolo Bonzini break; 123baacf047SPaolo Bonzini } else if (errno == EINTR) { 124baacf047SPaolo Bonzini continue; 125baacf047SPaolo Bonzini } else { 126baacf047SPaolo Bonzini /* else it is some "other" error, 127baacf047SPaolo Bonzini * only return if there was no data processed. */ 128baacf047SPaolo Bonzini if (ret == 0) { 129baacf047SPaolo Bonzini ret = -1; 130baacf047SPaolo Bonzini } 131baacf047SPaolo Bonzini break; 132baacf047SPaolo Bonzini } 133baacf047SPaolo Bonzini i++; 134baacf047SPaolo Bonzini } 135baacf047SPaolo Bonzini return ret; 136baacf047SPaolo Bonzini #endif 137baacf047SPaolo Bonzini } 138baacf047SPaolo Bonzini 1396b64640dSWen Congyang ssize_t iov_send_recv(int sockfd, const struct iovec *_iov, unsigned iov_cnt, 140baacf047SPaolo Bonzini size_t offset, size_t bytes, 141baacf047SPaolo Bonzini bool do_send) 142baacf047SPaolo Bonzini { 14383f75c26SPaolo Bonzini ssize_t total = 0; 144baacf047SPaolo Bonzini ssize_t ret; 1455209d675SPaolo Bonzini size_t orig_len, tail; 146f48869adSPaolo Bonzini unsigned niov; 1476b64640dSWen Congyang struct iovec *local_iov, *iov; 1486b64640dSWen Congyang 1496b64640dSWen Congyang if (bytes <= 0) { 1506b64640dSWen Congyang return 0; 1516b64640dSWen Congyang } 1526b64640dSWen Congyang 1536b64640dSWen Congyang local_iov = g_new0(struct iovec, iov_cnt); 1546b64640dSWen Congyang iov_copy(local_iov, iov_cnt, _iov, iov_cnt, offset, bytes); 1556b64640dSWen Congyang offset = 0; 1566b64640dSWen Congyang iov = local_iov; 1575209d675SPaolo Bonzini 15883f75c26SPaolo Bonzini while (bytes > 0) { 159baacf047SPaolo Bonzini /* Find the start position, skipping `offset' bytes: 160baacf047SPaolo Bonzini * first, skip all full-sized vector elements, */ 161f48869adSPaolo Bonzini for (niov = 0; niov < iov_cnt && offset >= iov[niov].iov_len; ++niov) { 162f48869adSPaolo Bonzini offset -= iov[niov].iov_len; 163baacf047SPaolo Bonzini } 164cb6247a7SPaolo Bonzini 165f48869adSPaolo Bonzini /* niov == iov_cnt would only be valid if bytes == 0, which 16683f75c26SPaolo Bonzini * we already ruled out in the loop condition. */ 167f48869adSPaolo Bonzini assert(niov < iov_cnt); 168f48869adSPaolo Bonzini iov += niov; 169f48869adSPaolo Bonzini iov_cnt -= niov; 170cb6247a7SPaolo Bonzini 171cb6247a7SPaolo Bonzini if (offset) { 172baacf047SPaolo Bonzini /* second, skip `offset' bytes from the (now) first element, 173baacf047SPaolo Bonzini * undo it on exit */ 174cb6247a7SPaolo Bonzini iov[0].iov_base += offset; 175cb6247a7SPaolo Bonzini iov[0].iov_len -= offset; 176baacf047SPaolo Bonzini } 177baacf047SPaolo Bonzini /* Find the end position skipping `bytes' bytes: */ 178baacf047SPaolo Bonzini /* first, skip all full-sized elements */ 1795209d675SPaolo Bonzini tail = bytes; 180f48869adSPaolo Bonzini for (niov = 0; niov < iov_cnt && iov[niov].iov_len <= tail; ++niov) { 181f48869adSPaolo Bonzini tail -= iov[niov].iov_len; 182baacf047SPaolo Bonzini } 1835209d675SPaolo Bonzini if (tail) { 1845209d675SPaolo Bonzini /* second, fixup the last element, and remember the original 1855209d675SPaolo Bonzini * length */ 186f48869adSPaolo Bonzini assert(niov < iov_cnt); 187f48869adSPaolo Bonzini assert(iov[niov].iov_len > tail); 188f48869adSPaolo Bonzini orig_len = iov[niov].iov_len; 189f48869adSPaolo Bonzini iov[niov++].iov_len = tail; 190f48869adSPaolo Bonzini ret = do_send_recv(sockfd, iov, niov, do_send); 19183f75c26SPaolo Bonzini /* Undo the changes above before checking for errors */ 192f48869adSPaolo Bonzini iov[niov-1].iov_len = orig_len; 1932be178a4SMichael Tokarev } else { 1942be178a4SMichael Tokarev ret = do_send_recv(sockfd, iov, niov, do_send); 1955209d675SPaolo Bonzini } 196baacf047SPaolo Bonzini if (offset) { 197cb6247a7SPaolo Bonzini iov[0].iov_base -= offset; 198cb6247a7SPaolo Bonzini iov[0].iov_len += offset; 199baacf047SPaolo Bonzini } 200baacf047SPaolo Bonzini 20183f75c26SPaolo Bonzini if (ret < 0) { 20283f75c26SPaolo Bonzini assert(errno != EINTR); 2036b64640dSWen Congyang g_free(local_iov); 20483f75c26SPaolo Bonzini if (errno == EAGAIN && total > 0) { 20583f75c26SPaolo Bonzini return total; 20683f75c26SPaolo Bonzini } 20783f75c26SPaolo Bonzini return -1; 20883f75c26SPaolo Bonzini } 20983f75c26SPaolo Bonzini 21084004290SMORITA Kazutaka if (ret == 0 && !do_send) { 21184004290SMORITA Kazutaka /* recv returns 0 when the peer has performed an orderly 21284004290SMORITA Kazutaka * shutdown. */ 21384004290SMORITA Kazutaka break; 21484004290SMORITA Kazutaka } 21584004290SMORITA Kazutaka 21683f75c26SPaolo Bonzini /* Prepare for the next iteration */ 21783f75c26SPaolo Bonzini offset += ret; 21883f75c26SPaolo Bonzini total += ret; 21983f75c26SPaolo Bonzini bytes -= ret; 22083f75c26SPaolo Bonzini } 22183f75c26SPaolo Bonzini 2226b64640dSWen Congyang g_free(local_iov); 22383f75c26SPaolo Bonzini return total; 224baacf047SPaolo Bonzini } 225baacf047SPaolo Bonzini 226baacf047SPaolo Bonzini 227baacf047SPaolo Bonzini void iov_hexdump(const struct iovec *iov, const unsigned int iov_cnt, 228baacf047SPaolo Bonzini FILE *fp, const char *prefix, size_t limit) 229baacf047SPaolo Bonzini { 2306ff66f50SPeter Crosthwaite int v; 2316ff66f50SPeter Crosthwaite size_t size = 0; 2326ff66f50SPeter Crosthwaite char *buf; 233baacf047SPaolo Bonzini 2346ff66f50SPeter Crosthwaite for (v = 0; v < iov_cnt; v++) { 2356ff66f50SPeter Crosthwaite size += iov[v].iov_len; 236baacf047SPaolo Bonzini } 2376ff66f50SPeter Crosthwaite size = size > limit ? limit : size; 2386ff66f50SPeter Crosthwaite buf = g_malloc(size); 2396ff66f50SPeter Crosthwaite iov_to_buf(iov, iov_cnt, 0, buf, size); 2403568ac2aSEd Maste qemu_hexdump(buf, fp, prefix, size); 2416ff66f50SPeter Crosthwaite g_free(buf); 242baacf047SPaolo Bonzini } 243baacf047SPaolo Bonzini 244baacf047SPaolo Bonzini unsigned iov_copy(struct iovec *dst_iov, unsigned int dst_iov_cnt, 245baacf047SPaolo Bonzini const struct iovec *iov, unsigned int iov_cnt, 246baacf047SPaolo Bonzini size_t offset, size_t bytes) 247baacf047SPaolo Bonzini { 248baacf047SPaolo Bonzini size_t len; 249baacf047SPaolo Bonzini unsigned int i, j; 250e911765cSShmulik Ladkani for (i = 0, j = 0; 251e911765cSShmulik Ladkani i < iov_cnt && j < dst_iov_cnt && (offset || bytes); i++) { 252baacf047SPaolo Bonzini if (offset >= iov[i].iov_len) { 253baacf047SPaolo Bonzini offset -= iov[i].iov_len; 254baacf047SPaolo Bonzini continue; 255baacf047SPaolo Bonzini } 256baacf047SPaolo Bonzini len = MIN(bytes, iov[i].iov_len - offset); 257baacf047SPaolo Bonzini 258baacf047SPaolo Bonzini dst_iov[j].iov_base = iov[i].iov_base + offset; 259baacf047SPaolo Bonzini dst_iov[j].iov_len = len; 260baacf047SPaolo Bonzini j++; 261baacf047SPaolo Bonzini bytes -= len; 262baacf047SPaolo Bonzini offset = 0; 263baacf047SPaolo Bonzini } 264baacf047SPaolo Bonzini assert(offset == 0); 265baacf047SPaolo Bonzini return j; 266baacf047SPaolo Bonzini } 267baacf047SPaolo Bonzini 268baacf047SPaolo Bonzini /* io vectors */ 269baacf047SPaolo Bonzini 270baacf047SPaolo Bonzini void qemu_iovec_init(QEMUIOVector *qiov, int alloc_hint) 271baacf047SPaolo Bonzini { 272e1cf5582SMarkus Armbruster qiov->iov = g_new(struct iovec, alloc_hint); 273baacf047SPaolo Bonzini qiov->niov = 0; 274baacf047SPaolo Bonzini qiov->nalloc = alloc_hint; 275baacf047SPaolo Bonzini qiov->size = 0; 276baacf047SPaolo Bonzini } 277baacf047SPaolo Bonzini 278baacf047SPaolo Bonzini void qemu_iovec_init_external(QEMUIOVector *qiov, struct iovec *iov, int niov) 279baacf047SPaolo Bonzini { 280baacf047SPaolo Bonzini int i; 281baacf047SPaolo Bonzini 282baacf047SPaolo Bonzini qiov->iov = iov; 283baacf047SPaolo Bonzini qiov->niov = niov; 284baacf047SPaolo Bonzini qiov->nalloc = -1; 285baacf047SPaolo Bonzini qiov->size = 0; 286baacf047SPaolo Bonzini for (i = 0; i < niov; i++) 287baacf047SPaolo Bonzini qiov->size += iov[i].iov_len; 288baacf047SPaolo Bonzini } 289baacf047SPaolo Bonzini 290baacf047SPaolo Bonzini void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len) 291baacf047SPaolo Bonzini { 292baacf047SPaolo Bonzini assert(qiov->nalloc != -1); 293baacf047SPaolo Bonzini 294baacf047SPaolo Bonzini if (qiov->niov == qiov->nalloc) { 295baacf047SPaolo Bonzini qiov->nalloc = 2 * qiov->nalloc + 1; 296e1cf5582SMarkus Armbruster qiov->iov = g_renew(struct iovec, qiov->iov, qiov->nalloc); 297baacf047SPaolo Bonzini } 298baacf047SPaolo Bonzini qiov->iov[qiov->niov].iov_base = base; 299baacf047SPaolo Bonzini qiov->iov[qiov->niov].iov_len = len; 300baacf047SPaolo Bonzini qiov->size += len; 301baacf047SPaolo Bonzini ++qiov->niov; 302baacf047SPaolo Bonzini } 303baacf047SPaolo Bonzini 304baacf047SPaolo Bonzini /* 305baacf047SPaolo Bonzini * Concatenates (partial) iovecs from src_iov to the end of dst. 306baacf047SPaolo Bonzini * It starts copying after skipping `soffset' bytes at the 307baacf047SPaolo Bonzini * beginning of src and adds individual vectors from src to 308baacf047SPaolo Bonzini * dst copies up to `sbytes' bytes total, or up to the end 309baacf047SPaolo Bonzini * of src_iov if it comes first. This way, it is okay to specify 310baacf047SPaolo Bonzini * very large value for `sbytes' to indicate "up to the end 311baacf047SPaolo Bonzini * of src". 312baacf047SPaolo Bonzini * Only vector pointers are processed, not the actual data buffers. 313baacf047SPaolo Bonzini */ 314519661eeSPaolo Bonzini size_t qemu_iovec_concat_iov(QEMUIOVector *dst, 315baacf047SPaolo Bonzini struct iovec *src_iov, unsigned int src_cnt, 316baacf047SPaolo Bonzini size_t soffset, size_t sbytes) 317baacf047SPaolo Bonzini { 318baacf047SPaolo Bonzini int i; 319baacf047SPaolo Bonzini size_t done; 320facf98adSAneesh Kumar K.V 321facf98adSAneesh Kumar K.V if (!sbytes) { 322519661eeSPaolo Bonzini return 0; 323facf98adSAneesh Kumar K.V } 324baacf047SPaolo Bonzini assert(dst->nalloc != -1); 325baacf047SPaolo Bonzini for (i = 0, done = 0; done < sbytes && i < src_cnt; i++) { 326baacf047SPaolo Bonzini if (soffset < src_iov[i].iov_len) { 327baacf047SPaolo Bonzini size_t len = MIN(src_iov[i].iov_len - soffset, sbytes - done); 328baacf047SPaolo Bonzini qemu_iovec_add(dst, src_iov[i].iov_base + soffset, len); 329baacf047SPaolo Bonzini done += len; 330baacf047SPaolo Bonzini soffset = 0; 331baacf047SPaolo Bonzini } else { 332baacf047SPaolo Bonzini soffset -= src_iov[i].iov_len; 333baacf047SPaolo Bonzini } 334baacf047SPaolo Bonzini } 335baacf047SPaolo Bonzini assert(soffset == 0); /* offset beyond end of src */ 336519661eeSPaolo Bonzini 337519661eeSPaolo Bonzini return done; 338baacf047SPaolo Bonzini } 339baacf047SPaolo Bonzini 340baacf047SPaolo Bonzini /* 341baacf047SPaolo Bonzini * Concatenates (partial) iovecs from src to the end of dst. 342baacf047SPaolo Bonzini * It starts copying after skipping `soffset' bytes at the 343baacf047SPaolo Bonzini * beginning of src and adds individual vectors from src to 344baacf047SPaolo Bonzini * dst copies up to `sbytes' bytes total, or up to the end 345baacf047SPaolo Bonzini * of src if it comes first. This way, it is okay to specify 346baacf047SPaolo Bonzini * very large value for `sbytes' to indicate "up to the end 347baacf047SPaolo Bonzini * of src". 348baacf047SPaolo Bonzini * Only vector pointers are processed, not the actual data buffers. 349baacf047SPaolo Bonzini */ 350baacf047SPaolo Bonzini void qemu_iovec_concat(QEMUIOVector *dst, 351baacf047SPaolo Bonzini QEMUIOVector *src, size_t soffset, size_t sbytes) 352baacf047SPaolo Bonzini { 353baacf047SPaolo Bonzini qemu_iovec_concat_iov(dst, src->iov, src->niov, soffset, sbytes); 354baacf047SPaolo Bonzini } 355baacf047SPaolo Bonzini 35643f35cb5SPeter Lieven /* 357*d953169dSVladimir Sementsov-Ogievskiy * qiov_find_iov 358*d953169dSVladimir Sementsov-Ogievskiy * 359*d953169dSVladimir Sementsov-Ogievskiy * Return pointer to iovec structure, where byte at @offset in original vector 360*d953169dSVladimir Sementsov-Ogievskiy * @iov exactly is. 361*d953169dSVladimir Sementsov-Ogievskiy * Set @remaining_offset to be offset inside that iovec to the same byte. 362*d953169dSVladimir Sementsov-Ogievskiy */ 363*d953169dSVladimir Sementsov-Ogievskiy static struct iovec *iov_skip_offset(struct iovec *iov, size_t offset, 364*d953169dSVladimir Sementsov-Ogievskiy size_t *remaining_offset) 365*d953169dSVladimir Sementsov-Ogievskiy { 366*d953169dSVladimir Sementsov-Ogievskiy while (offset > 0 && offset >= iov->iov_len) { 367*d953169dSVladimir Sementsov-Ogievskiy offset -= iov->iov_len; 368*d953169dSVladimir Sementsov-Ogievskiy iov++; 369*d953169dSVladimir Sementsov-Ogievskiy } 370*d953169dSVladimir Sementsov-Ogievskiy *remaining_offset = offset; 371*d953169dSVladimir Sementsov-Ogievskiy 372*d953169dSVladimir Sementsov-Ogievskiy return iov; 373*d953169dSVladimir Sementsov-Ogievskiy } 374*d953169dSVladimir Sementsov-Ogievskiy 375*d953169dSVladimir Sementsov-Ogievskiy /* 376*d953169dSVladimir Sementsov-Ogievskiy * qiov_slice 377*d953169dSVladimir Sementsov-Ogievskiy * 378*d953169dSVladimir Sementsov-Ogievskiy * Find subarray of iovec's, containing requested range. @head would 379*d953169dSVladimir Sementsov-Ogievskiy * be offset in first iov (returned by the function), @tail would be 380*d953169dSVladimir Sementsov-Ogievskiy * count of extra bytes in last iovec (returned iov + @niov - 1). 381*d953169dSVladimir Sementsov-Ogievskiy */ 382*d953169dSVladimir Sementsov-Ogievskiy static struct iovec *qiov_slice(QEMUIOVector *qiov, 383*d953169dSVladimir Sementsov-Ogievskiy size_t offset, size_t len, 384*d953169dSVladimir Sementsov-Ogievskiy size_t *head, size_t *tail, int *niov) 385*d953169dSVladimir Sementsov-Ogievskiy { 386*d953169dSVladimir Sementsov-Ogievskiy struct iovec *iov, *end_iov; 387*d953169dSVladimir Sementsov-Ogievskiy 388*d953169dSVladimir Sementsov-Ogievskiy assert(offset + len <= qiov->size); 389*d953169dSVladimir Sementsov-Ogievskiy 390*d953169dSVladimir Sementsov-Ogievskiy iov = iov_skip_offset(qiov->iov, offset, head); 391*d953169dSVladimir Sementsov-Ogievskiy end_iov = iov_skip_offset(iov, *head + len, tail); 392*d953169dSVladimir Sementsov-Ogievskiy 393*d953169dSVladimir Sementsov-Ogievskiy if (*tail > 0) { 394*d953169dSVladimir Sementsov-Ogievskiy assert(*tail < end_iov->iov_len); 395*d953169dSVladimir Sementsov-Ogievskiy *tail = end_iov->iov_len - *tail; 396*d953169dSVladimir Sementsov-Ogievskiy end_iov++; 397*d953169dSVladimir Sementsov-Ogievskiy } 398*d953169dSVladimir Sementsov-Ogievskiy 399*d953169dSVladimir Sementsov-Ogievskiy *niov = end_iov - iov; 400*d953169dSVladimir Sementsov-Ogievskiy 401*d953169dSVladimir Sementsov-Ogievskiy return iov; 402*d953169dSVladimir Sementsov-Ogievskiy } 403*d953169dSVladimir Sementsov-Ogievskiy 404*d953169dSVladimir Sementsov-Ogievskiy /* 405*d953169dSVladimir Sementsov-Ogievskiy * Compile new iovec, combining @head_buf buffer, sub-qiov of @mid_qiov, 406*d953169dSVladimir Sementsov-Ogievskiy * and @tail_buf buffer into new qiov. 407*d953169dSVladimir Sementsov-Ogievskiy */ 408*d953169dSVladimir Sementsov-Ogievskiy void qemu_iovec_init_extended( 409*d953169dSVladimir Sementsov-Ogievskiy QEMUIOVector *qiov, 410*d953169dSVladimir Sementsov-Ogievskiy void *head_buf, size_t head_len, 411*d953169dSVladimir Sementsov-Ogievskiy QEMUIOVector *mid_qiov, size_t mid_offset, size_t mid_len, 412*d953169dSVladimir Sementsov-Ogievskiy void *tail_buf, size_t tail_len) 413*d953169dSVladimir Sementsov-Ogievskiy { 414*d953169dSVladimir Sementsov-Ogievskiy size_t mid_head, mid_tail; 415*d953169dSVladimir Sementsov-Ogievskiy int total_niov, mid_niov = 0; 416*d953169dSVladimir Sementsov-Ogievskiy struct iovec *p, *mid_iov; 417*d953169dSVladimir Sementsov-Ogievskiy 418*d953169dSVladimir Sementsov-Ogievskiy if (mid_len) { 419*d953169dSVladimir Sementsov-Ogievskiy mid_iov = qiov_slice(mid_qiov, mid_offset, mid_len, 420*d953169dSVladimir Sementsov-Ogievskiy &mid_head, &mid_tail, &mid_niov); 421*d953169dSVladimir Sementsov-Ogievskiy } 422*d953169dSVladimir Sementsov-Ogievskiy 423*d953169dSVladimir Sementsov-Ogievskiy total_niov = !!head_len + mid_niov + !!tail_len; 424*d953169dSVladimir Sementsov-Ogievskiy if (total_niov == 1) { 425*d953169dSVladimir Sementsov-Ogievskiy qemu_iovec_init_buf(qiov, NULL, 0); 426*d953169dSVladimir Sementsov-Ogievskiy p = &qiov->local_iov; 427*d953169dSVladimir Sementsov-Ogievskiy } else { 428*d953169dSVladimir Sementsov-Ogievskiy qiov->niov = qiov->nalloc = total_niov; 429*d953169dSVladimir Sementsov-Ogievskiy qiov->size = head_len + mid_len + tail_len; 430*d953169dSVladimir Sementsov-Ogievskiy p = qiov->iov = g_new(struct iovec, qiov->niov); 431*d953169dSVladimir Sementsov-Ogievskiy } 432*d953169dSVladimir Sementsov-Ogievskiy 433*d953169dSVladimir Sementsov-Ogievskiy if (head_len) { 434*d953169dSVladimir Sementsov-Ogievskiy p->iov_base = head_buf; 435*d953169dSVladimir Sementsov-Ogievskiy p->iov_len = head_len; 436*d953169dSVladimir Sementsov-Ogievskiy p++; 437*d953169dSVladimir Sementsov-Ogievskiy } 438*d953169dSVladimir Sementsov-Ogievskiy 439*d953169dSVladimir Sementsov-Ogievskiy if (mid_len) { 440*d953169dSVladimir Sementsov-Ogievskiy memcpy(p, mid_iov, mid_niov * sizeof(*p)); 441*d953169dSVladimir Sementsov-Ogievskiy p[0].iov_base = (uint8_t *)p[0].iov_base + mid_head; 442*d953169dSVladimir Sementsov-Ogievskiy p[0].iov_len -= mid_head; 443*d953169dSVladimir Sementsov-Ogievskiy p[mid_niov - 1].iov_len -= mid_tail; 444*d953169dSVladimir Sementsov-Ogievskiy p += mid_niov; 445*d953169dSVladimir Sementsov-Ogievskiy } 446*d953169dSVladimir Sementsov-Ogievskiy 447*d953169dSVladimir Sementsov-Ogievskiy if (tail_len) { 448*d953169dSVladimir Sementsov-Ogievskiy p->iov_base = tail_buf; 449*d953169dSVladimir Sementsov-Ogievskiy p->iov_len = tail_len; 450*d953169dSVladimir Sementsov-Ogievskiy } 451*d953169dSVladimir Sementsov-Ogievskiy } 452*d953169dSVladimir Sementsov-Ogievskiy 453*d953169dSVladimir Sementsov-Ogievskiy /* 45443f35cb5SPeter Lieven * Check if the contents of the iovecs are all zero 45543f35cb5SPeter Lieven */ 45643f35cb5SPeter Lieven bool qemu_iovec_is_zero(QEMUIOVector *qiov) 45743f35cb5SPeter Lieven { 45843f35cb5SPeter Lieven int i; 45943f35cb5SPeter Lieven for (i = 0; i < qiov->niov; i++) { 46043f35cb5SPeter Lieven size_t offs = QEMU_ALIGN_DOWN(qiov->iov[i].iov_len, 4 * sizeof(long)); 46143f35cb5SPeter Lieven uint8_t *ptr = qiov->iov[i].iov_base; 46243f35cb5SPeter Lieven if (offs && !buffer_is_zero(qiov->iov[i].iov_base, offs)) { 46343f35cb5SPeter Lieven return false; 46443f35cb5SPeter Lieven } 46543f35cb5SPeter Lieven for (; offs < qiov->iov[i].iov_len; offs++) { 46643f35cb5SPeter Lieven if (ptr[offs]) { 46743f35cb5SPeter Lieven return false; 46843f35cb5SPeter Lieven } 46943f35cb5SPeter Lieven } 47043f35cb5SPeter Lieven } 47143f35cb5SPeter Lieven return true; 47243f35cb5SPeter Lieven } 47343f35cb5SPeter Lieven 474*d953169dSVladimir Sementsov-Ogievskiy void qemu_iovec_init_slice(QEMUIOVector *qiov, QEMUIOVector *source, 475*d953169dSVladimir Sementsov-Ogievskiy size_t offset, size_t len) 476*d953169dSVladimir Sementsov-Ogievskiy { 477*d953169dSVladimir Sementsov-Ogievskiy qemu_iovec_init_extended(qiov, NULL, 0, source, offset, len, NULL, 0); 478*d953169dSVladimir Sementsov-Ogievskiy } 479*d953169dSVladimir Sementsov-Ogievskiy 480baacf047SPaolo Bonzini void qemu_iovec_destroy(QEMUIOVector *qiov) 481baacf047SPaolo Bonzini { 482*d953169dSVladimir Sementsov-Ogievskiy if (qiov->nalloc != -1) { 483baacf047SPaolo Bonzini g_free(qiov->iov); 484*d953169dSVladimir Sementsov-Ogievskiy } 485*d953169dSVladimir Sementsov-Ogievskiy 486*d953169dSVladimir Sementsov-Ogievskiy memset(qiov, 0, sizeof(*qiov)); 487baacf047SPaolo Bonzini } 488baacf047SPaolo Bonzini 489baacf047SPaolo Bonzini void qemu_iovec_reset(QEMUIOVector *qiov) 490baacf047SPaolo Bonzini { 491baacf047SPaolo Bonzini assert(qiov->nalloc != -1); 492baacf047SPaolo Bonzini 493baacf047SPaolo Bonzini qiov->niov = 0; 494baacf047SPaolo Bonzini qiov->size = 0; 495baacf047SPaolo Bonzini } 496baacf047SPaolo Bonzini 497baacf047SPaolo Bonzini size_t qemu_iovec_to_buf(QEMUIOVector *qiov, size_t offset, 498baacf047SPaolo Bonzini void *buf, size_t bytes) 499baacf047SPaolo Bonzini { 500baacf047SPaolo Bonzini return iov_to_buf(qiov->iov, qiov->niov, offset, buf, bytes); 501baacf047SPaolo Bonzini } 502baacf047SPaolo Bonzini 503baacf047SPaolo Bonzini size_t qemu_iovec_from_buf(QEMUIOVector *qiov, size_t offset, 504baacf047SPaolo Bonzini const void *buf, size_t bytes) 505baacf047SPaolo Bonzini { 506baacf047SPaolo Bonzini return iov_from_buf(qiov->iov, qiov->niov, offset, buf, bytes); 507baacf047SPaolo Bonzini } 508baacf047SPaolo Bonzini 509baacf047SPaolo Bonzini size_t qemu_iovec_memset(QEMUIOVector *qiov, size_t offset, 510baacf047SPaolo Bonzini int fillc, size_t bytes) 511baacf047SPaolo Bonzini { 512baacf047SPaolo Bonzini return iov_memset(qiov->iov, qiov->niov, offset, fillc, bytes); 513baacf047SPaolo Bonzini } 514baacf047SPaolo Bonzini 515f70d7f7eSBenoît Canet /** 516f70d7f7eSBenoît Canet * Check that I/O vector contents are identical 517f70d7f7eSBenoît Canet * 518f70d7f7eSBenoît Canet * The IO vectors must have the same structure (same length of all parts). 519f70d7f7eSBenoît Canet * A typical usage is to compare vectors created with qemu_iovec_clone(). 520f70d7f7eSBenoît Canet * 521f70d7f7eSBenoît Canet * @a: I/O vector 522f70d7f7eSBenoît Canet * @b: I/O vector 523f70d7f7eSBenoît Canet * @ret: Offset to first mismatching byte or -1 if match 524f70d7f7eSBenoît Canet */ 525f70d7f7eSBenoît Canet ssize_t qemu_iovec_compare(QEMUIOVector *a, QEMUIOVector *b) 526f70d7f7eSBenoît Canet { 527f70d7f7eSBenoît Canet int i; 528f70d7f7eSBenoît Canet ssize_t offset = 0; 529f70d7f7eSBenoît Canet 530f70d7f7eSBenoît Canet assert(a->niov == b->niov); 531f70d7f7eSBenoît Canet for (i = 0; i < a->niov; i++) { 532f70d7f7eSBenoît Canet size_t len = 0; 533f70d7f7eSBenoît Canet uint8_t *p = (uint8_t *)a->iov[i].iov_base; 534f70d7f7eSBenoît Canet uint8_t *q = (uint8_t *)b->iov[i].iov_base; 535f70d7f7eSBenoît Canet 536f70d7f7eSBenoît Canet assert(a->iov[i].iov_len == b->iov[i].iov_len); 537f70d7f7eSBenoît Canet while (len < a->iov[i].iov_len && *p++ == *q++) { 538f70d7f7eSBenoît Canet len++; 539f70d7f7eSBenoît Canet } 540f70d7f7eSBenoît Canet 541f70d7f7eSBenoît Canet offset += len; 542f70d7f7eSBenoît Canet 543f70d7f7eSBenoît Canet if (len != a->iov[i].iov_len) { 544f70d7f7eSBenoît Canet return offset; 545f70d7f7eSBenoît Canet } 546f70d7f7eSBenoît Canet } 547f70d7f7eSBenoît Canet return -1; 548f70d7f7eSBenoît Canet } 549f70d7f7eSBenoît Canet 550f70d7f7eSBenoît Canet typedef struct { 551f70d7f7eSBenoît Canet int src_index; 552f70d7f7eSBenoît Canet struct iovec *src_iov; 553f70d7f7eSBenoît Canet void *dest_base; 554f70d7f7eSBenoît Canet } IOVectorSortElem; 555f70d7f7eSBenoît Canet 556f70d7f7eSBenoît Canet static int sortelem_cmp_src_base(const void *a, const void *b) 557f70d7f7eSBenoît Canet { 558f70d7f7eSBenoît Canet const IOVectorSortElem *elem_a = a; 559f70d7f7eSBenoît Canet const IOVectorSortElem *elem_b = b; 560f70d7f7eSBenoît Canet 561f70d7f7eSBenoît Canet /* Don't overflow */ 562f70d7f7eSBenoît Canet if (elem_a->src_iov->iov_base < elem_b->src_iov->iov_base) { 563f70d7f7eSBenoît Canet return -1; 564f70d7f7eSBenoît Canet } else if (elem_a->src_iov->iov_base > elem_b->src_iov->iov_base) { 565f70d7f7eSBenoît Canet return 1; 566f70d7f7eSBenoît Canet } else { 567f70d7f7eSBenoît Canet return 0; 568f70d7f7eSBenoît Canet } 569f70d7f7eSBenoît Canet } 570f70d7f7eSBenoît Canet 571f70d7f7eSBenoît Canet static int sortelem_cmp_src_index(const void *a, const void *b) 572f70d7f7eSBenoît Canet { 573f70d7f7eSBenoît Canet const IOVectorSortElem *elem_a = a; 574f70d7f7eSBenoît Canet const IOVectorSortElem *elem_b = b; 575f70d7f7eSBenoît Canet 576f70d7f7eSBenoît Canet return elem_a->src_index - elem_b->src_index; 577f70d7f7eSBenoît Canet } 578f70d7f7eSBenoît Canet 579f70d7f7eSBenoît Canet /** 580f70d7f7eSBenoît Canet * Copy contents of I/O vector 581f70d7f7eSBenoît Canet * 582f70d7f7eSBenoît Canet * The relative relationships of overlapping iovecs are preserved. This is 583f70d7f7eSBenoît Canet * necessary to ensure identical semantics in the cloned I/O vector. 584f70d7f7eSBenoît Canet */ 585f70d7f7eSBenoît Canet void qemu_iovec_clone(QEMUIOVector *dest, const QEMUIOVector *src, void *buf) 586f70d7f7eSBenoît Canet { 587f70d7f7eSBenoît Canet IOVectorSortElem sortelems[src->niov]; 588f70d7f7eSBenoît Canet void *last_end; 589f70d7f7eSBenoît Canet int i; 590f70d7f7eSBenoît Canet 591f70d7f7eSBenoît Canet /* Sort by source iovecs by base address */ 592f70d7f7eSBenoît Canet for (i = 0; i < src->niov; i++) { 593f70d7f7eSBenoît Canet sortelems[i].src_index = i; 594f70d7f7eSBenoît Canet sortelems[i].src_iov = &src->iov[i]; 595f70d7f7eSBenoît Canet } 596f70d7f7eSBenoît Canet qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_base); 597f70d7f7eSBenoît Canet 598f70d7f7eSBenoît Canet /* Allocate buffer space taking into account overlapping iovecs */ 599f70d7f7eSBenoît Canet last_end = NULL; 600f70d7f7eSBenoît Canet for (i = 0; i < src->niov; i++) { 601f70d7f7eSBenoît Canet struct iovec *cur = sortelems[i].src_iov; 602f70d7f7eSBenoît Canet ptrdiff_t rewind = 0; 603f70d7f7eSBenoît Canet 604f70d7f7eSBenoît Canet /* Detect overlap */ 605f70d7f7eSBenoît Canet if (last_end && last_end > cur->iov_base) { 606f70d7f7eSBenoît Canet rewind = last_end - cur->iov_base; 607f70d7f7eSBenoît Canet } 608f70d7f7eSBenoît Canet 609f70d7f7eSBenoît Canet sortelems[i].dest_base = buf - rewind; 610f70d7f7eSBenoît Canet buf += cur->iov_len - MIN(rewind, cur->iov_len); 611f70d7f7eSBenoît Canet last_end = MAX(cur->iov_base + cur->iov_len, last_end); 612f70d7f7eSBenoît Canet } 613f70d7f7eSBenoît Canet 614f70d7f7eSBenoît Canet /* Sort by source iovec index and build destination iovec */ 615f70d7f7eSBenoît Canet qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_index); 616f70d7f7eSBenoît Canet for (i = 0; i < src->niov; i++) { 617f70d7f7eSBenoît Canet qemu_iovec_add(dest, sortelems[i].dest_base, src->iov[i].iov_len); 618f70d7f7eSBenoît Canet } 619f70d7f7eSBenoît Canet } 620f70d7f7eSBenoît Canet 621baacf047SPaolo Bonzini size_t iov_discard_front(struct iovec **iov, unsigned int *iov_cnt, 622baacf047SPaolo Bonzini size_t bytes) 623baacf047SPaolo Bonzini { 624baacf047SPaolo Bonzini size_t total = 0; 625baacf047SPaolo Bonzini struct iovec *cur; 626baacf047SPaolo Bonzini 627baacf047SPaolo Bonzini for (cur = *iov; *iov_cnt > 0; cur++) { 628baacf047SPaolo Bonzini if (cur->iov_len > bytes) { 629baacf047SPaolo Bonzini cur->iov_base += bytes; 630baacf047SPaolo Bonzini cur->iov_len -= bytes; 631baacf047SPaolo Bonzini total += bytes; 632baacf047SPaolo Bonzini break; 633baacf047SPaolo Bonzini } 634baacf047SPaolo Bonzini 635baacf047SPaolo Bonzini bytes -= cur->iov_len; 636baacf047SPaolo Bonzini total += cur->iov_len; 637baacf047SPaolo Bonzini *iov_cnt -= 1; 638baacf047SPaolo Bonzini } 639baacf047SPaolo Bonzini 640baacf047SPaolo Bonzini *iov = cur; 641baacf047SPaolo Bonzini return total; 642baacf047SPaolo Bonzini } 643baacf047SPaolo Bonzini 644baacf047SPaolo Bonzini size_t iov_discard_back(struct iovec *iov, unsigned int *iov_cnt, 645baacf047SPaolo Bonzini size_t bytes) 646baacf047SPaolo Bonzini { 647baacf047SPaolo Bonzini size_t total = 0; 648baacf047SPaolo Bonzini struct iovec *cur; 649baacf047SPaolo Bonzini 650baacf047SPaolo Bonzini if (*iov_cnt == 0) { 651baacf047SPaolo Bonzini return 0; 652baacf047SPaolo Bonzini } 653baacf047SPaolo Bonzini 654baacf047SPaolo Bonzini cur = iov + (*iov_cnt - 1); 655baacf047SPaolo Bonzini 656baacf047SPaolo Bonzini while (*iov_cnt > 0) { 657baacf047SPaolo Bonzini if (cur->iov_len > bytes) { 658baacf047SPaolo Bonzini cur->iov_len -= bytes; 659baacf047SPaolo Bonzini total += bytes; 660baacf047SPaolo Bonzini break; 661baacf047SPaolo Bonzini } 662baacf047SPaolo Bonzini 663baacf047SPaolo Bonzini bytes -= cur->iov_len; 664baacf047SPaolo Bonzini total += cur->iov_len; 665baacf047SPaolo Bonzini cur--; 666baacf047SPaolo Bonzini *iov_cnt -= 1; 667baacf047SPaolo Bonzini } 668baacf047SPaolo Bonzini 669baacf047SPaolo Bonzini return total; 670baacf047SPaolo Bonzini } 67158f423fbSKevin Wolf 67258f423fbSKevin Wolf void qemu_iovec_discard_back(QEMUIOVector *qiov, size_t bytes) 67358f423fbSKevin Wolf { 67458f423fbSKevin Wolf size_t total; 67558f423fbSKevin Wolf unsigned int niov = qiov->niov; 67658f423fbSKevin Wolf 67758f423fbSKevin Wolf assert(qiov->size >= bytes); 67858f423fbSKevin Wolf total = iov_discard_back(qiov->iov, &niov, bytes); 67958f423fbSKevin Wolf assert(total == bytes); 68058f423fbSKevin Wolf 68158f423fbSKevin Wolf qiov->niov = niov; 68258f423fbSKevin Wolf qiov->size -= bytes; 68358f423fbSKevin Wolf } 684