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" 20*daf015efSMarkus Armbruster #include "qemu-common.h" 21baacf047SPaolo Bonzini #include "qemu/iov.h" 22cc99c6f5SStefan Weil #include "qemu/sockets.h" 23baacf047SPaolo Bonzini 24ad523bcaSPaolo Bonzini size_t iov_from_buf_full(const struct iovec *iov, unsigned int iov_cnt, 25baacf047SPaolo Bonzini size_t offset, const void *buf, size_t bytes) 26baacf047SPaolo Bonzini { 27baacf047SPaolo Bonzini size_t done; 28baacf047SPaolo Bonzini unsigned int i; 29baacf047SPaolo Bonzini for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) { 30baacf047SPaolo Bonzini if (offset < iov[i].iov_len) { 31baacf047SPaolo Bonzini size_t len = MIN(iov[i].iov_len - offset, bytes - done); 32baacf047SPaolo Bonzini memcpy(iov[i].iov_base + offset, buf + done, len); 33baacf047SPaolo Bonzini done += len; 34baacf047SPaolo Bonzini offset = 0; 35baacf047SPaolo Bonzini } else { 36baacf047SPaolo Bonzini offset -= iov[i].iov_len; 37baacf047SPaolo Bonzini } 38baacf047SPaolo Bonzini } 39baacf047SPaolo Bonzini assert(offset == 0); 40baacf047SPaolo Bonzini return done; 41baacf047SPaolo Bonzini } 42baacf047SPaolo Bonzini 43ad523bcaSPaolo Bonzini size_t iov_to_buf_full(const struct iovec *iov, const unsigned int iov_cnt, 44baacf047SPaolo Bonzini size_t offset, void *buf, size_t bytes) 45baacf047SPaolo Bonzini { 46baacf047SPaolo Bonzini size_t done; 47baacf047SPaolo Bonzini unsigned int i; 48baacf047SPaolo Bonzini for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) { 49baacf047SPaolo Bonzini if (offset < iov[i].iov_len) { 50baacf047SPaolo Bonzini size_t len = MIN(iov[i].iov_len - offset, bytes - done); 51baacf047SPaolo Bonzini memcpy(buf + done, iov[i].iov_base + offset, len); 52baacf047SPaolo Bonzini done += len; 53baacf047SPaolo Bonzini offset = 0; 54baacf047SPaolo Bonzini } else { 55baacf047SPaolo Bonzini offset -= iov[i].iov_len; 56baacf047SPaolo Bonzini } 57baacf047SPaolo Bonzini } 58baacf047SPaolo Bonzini assert(offset == 0); 59baacf047SPaolo Bonzini return done; 60baacf047SPaolo Bonzini } 61baacf047SPaolo Bonzini 62baacf047SPaolo Bonzini size_t iov_memset(const struct iovec *iov, const unsigned int iov_cnt, 63baacf047SPaolo Bonzini size_t offset, int fillc, size_t bytes) 64baacf047SPaolo Bonzini { 65baacf047SPaolo Bonzini size_t done; 66baacf047SPaolo Bonzini unsigned int i; 67baacf047SPaolo Bonzini for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) { 68baacf047SPaolo Bonzini if (offset < iov[i].iov_len) { 69baacf047SPaolo Bonzini size_t len = MIN(iov[i].iov_len - offset, bytes - done); 70baacf047SPaolo Bonzini memset(iov[i].iov_base + offset, fillc, len); 71baacf047SPaolo Bonzini done += len; 72baacf047SPaolo Bonzini offset = 0; 73baacf047SPaolo Bonzini } else { 74baacf047SPaolo Bonzini offset -= iov[i].iov_len; 75baacf047SPaolo Bonzini } 76baacf047SPaolo Bonzini } 77baacf047SPaolo Bonzini assert(offset == 0); 78baacf047SPaolo Bonzini return done; 79baacf047SPaolo Bonzini } 80baacf047SPaolo Bonzini 81baacf047SPaolo Bonzini size_t iov_size(const struct iovec *iov, const unsigned int iov_cnt) 82baacf047SPaolo Bonzini { 83baacf047SPaolo Bonzini size_t len; 84baacf047SPaolo Bonzini unsigned int i; 85baacf047SPaolo Bonzini 86baacf047SPaolo Bonzini len = 0; 87baacf047SPaolo Bonzini for (i = 0; i < iov_cnt; i++) { 88baacf047SPaolo Bonzini len += iov[i].iov_len; 89baacf047SPaolo Bonzini } 90baacf047SPaolo Bonzini return len; 91baacf047SPaolo Bonzini } 92baacf047SPaolo Bonzini 93baacf047SPaolo Bonzini /* helper function for iov_send_recv() */ 94baacf047SPaolo Bonzini static ssize_t 95baacf047SPaolo Bonzini do_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt, bool do_send) 96baacf047SPaolo Bonzini { 979adea5f7SPaolo Bonzini #ifdef CONFIG_POSIX 98baacf047SPaolo Bonzini ssize_t ret; 99baacf047SPaolo Bonzini struct msghdr msg; 100baacf047SPaolo Bonzini memset(&msg, 0, sizeof(msg)); 101baacf047SPaolo Bonzini msg.msg_iov = iov; 102baacf047SPaolo Bonzini msg.msg_iovlen = iov_cnt; 103baacf047SPaolo Bonzini do { 104baacf047SPaolo Bonzini ret = do_send 105baacf047SPaolo Bonzini ? sendmsg(sockfd, &msg, 0) 106baacf047SPaolo Bonzini : recvmsg(sockfd, &msg, 0); 107baacf047SPaolo Bonzini } while (ret < 0 && errno == EINTR); 108baacf047SPaolo Bonzini return ret; 109baacf047SPaolo Bonzini #else 110baacf047SPaolo Bonzini /* else send piece-by-piece */ 111baacf047SPaolo Bonzini /*XXX Note: windows has WSASend() and WSARecv() */ 112baacf047SPaolo Bonzini unsigned i = 0; 113baacf047SPaolo Bonzini ssize_t ret = 0; 114baacf047SPaolo Bonzini while (i < iov_cnt) { 115baacf047SPaolo Bonzini ssize_t r = do_send 116baacf047SPaolo Bonzini ? send(sockfd, iov[i].iov_base, iov[i].iov_len, 0) 117baacf047SPaolo Bonzini : recv(sockfd, iov[i].iov_base, iov[i].iov_len, 0); 118baacf047SPaolo Bonzini if (r > 0) { 119baacf047SPaolo Bonzini ret += r; 120baacf047SPaolo Bonzini } else if (!r) { 121baacf047SPaolo Bonzini break; 122baacf047SPaolo Bonzini } else if (errno == EINTR) { 123baacf047SPaolo Bonzini continue; 124baacf047SPaolo Bonzini } else { 125baacf047SPaolo Bonzini /* else it is some "other" error, 126baacf047SPaolo Bonzini * only return if there was no data processed. */ 127baacf047SPaolo Bonzini if (ret == 0) { 128baacf047SPaolo Bonzini ret = -1; 129baacf047SPaolo Bonzini } 130baacf047SPaolo Bonzini break; 131baacf047SPaolo Bonzini } 132baacf047SPaolo Bonzini i++; 133baacf047SPaolo Bonzini } 134baacf047SPaolo Bonzini return ret; 135baacf047SPaolo Bonzini #endif 136baacf047SPaolo Bonzini } 137baacf047SPaolo Bonzini 1386b64640dSWen Congyang ssize_t iov_send_recv(int sockfd, const struct iovec *_iov, unsigned iov_cnt, 139baacf047SPaolo Bonzini size_t offset, size_t bytes, 140baacf047SPaolo Bonzini bool do_send) 141baacf047SPaolo Bonzini { 14283f75c26SPaolo Bonzini ssize_t total = 0; 143baacf047SPaolo Bonzini ssize_t ret; 1445209d675SPaolo Bonzini size_t orig_len, tail; 145f48869adSPaolo Bonzini unsigned niov; 1466b64640dSWen Congyang struct iovec *local_iov, *iov; 1476b64640dSWen Congyang 1486b64640dSWen Congyang if (bytes <= 0) { 1496b64640dSWen Congyang return 0; 1506b64640dSWen Congyang } 1516b64640dSWen Congyang 1526b64640dSWen Congyang local_iov = g_new0(struct iovec, iov_cnt); 1536b64640dSWen Congyang iov_copy(local_iov, iov_cnt, _iov, iov_cnt, offset, bytes); 1546b64640dSWen Congyang offset = 0; 1556b64640dSWen Congyang iov = local_iov; 1565209d675SPaolo Bonzini 15783f75c26SPaolo Bonzini while (bytes > 0) { 158baacf047SPaolo Bonzini /* Find the start position, skipping `offset' bytes: 159baacf047SPaolo Bonzini * first, skip all full-sized vector elements, */ 160f48869adSPaolo Bonzini for (niov = 0; niov < iov_cnt && offset >= iov[niov].iov_len; ++niov) { 161f48869adSPaolo Bonzini offset -= iov[niov].iov_len; 162baacf047SPaolo Bonzini } 163cb6247a7SPaolo Bonzini 164f48869adSPaolo Bonzini /* niov == iov_cnt would only be valid if bytes == 0, which 16583f75c26SPaolo Bonzini * we already ruled out in the loop condition. */ 166f48869adSPaolo Bonzini assert(niov < iov_cnt); 167f48869adSPaolo Bonzini iov += niov; 168f48869adSPaolo Bonzini iov_cnt -= niov; 169cb6247a7SPaolo Bonzini 170cb6247a7SPaolo Bonzini if (offset) { 171baacf047SPaolo Bonzini /* second, skip `offset' bytes from the (now) first element, 172baacf047SPaolo Bonzini * undo it on exit */ 173cb6247a7SPaolo Bonzini iov[0].iov_base += offset; 174cb6247a7SPaolo Bonzini iov[0].iov_len -= offset; 175baacf047SPaolo Bonzini } 176baacf047SPaolo Bonzini /* Find the end position skipping `bytes' bytes: */ 177baacf047SPaolo Bonzini /* first, skip all full-sized elements */ 1785209d675SPaolo Bonzini tail = bytes; 179f48869adSPaolo Bonzini for (niov = 0; niov < iov_cnt && iov[niov].iov_len <= tail; ++niov) { 180f48869adSPaolo Bonzini tail -= iov[niov].iov_len; 181baacf047SPaolo Bonzini } 1825209d675SPaolo Bonzini if (tail) { 1835209d675SPaolo Bonzini /* second, fixup the last element, and remember the original 1845209d675SPaolo Bonzini * length */ 185f48869adSPaolo Bonzini assert(niov < iov_cnt); 186f48869adSPaolo Bonzini assert(iov[niov].iov_len > tail); 187f48869adSPaolo Bonzini orig_len = iov[niov].iov_len; 188f48869adSPaolo Bonzini iov[niov++].iov_len = tail; 189f48869adSPaolo Bonzini ret = do_send_recv(sockfd, iov, niov, do_send); 19083f75c26SPaolo Bonzini /* Undo the changes above before checking for errors */ 191f48869adSPaolo Bonzini iov[niov-1].iov_len = orig_len; 1922be178a4SMichael Tokarev } else { 1932be178a4SMichael Tokarev ret = do_send_recv(sockfd, iov, niov, do_send); 1945209d675SPaolo Bonzini } 195baacf047SPaolo Bonzini if (offset) { 196cb6247a7SPaolo Bonzini iov[0].iov_base -= offset; 197cb6247a7SPaolo Bonzini iov[0].iov_len += offset; 198baacf047SPaolo Bonzini } 199baacf047SPaolo Bonzini 20083f75c26SPaolo Bonzini if (ret < 0) { 20183f75c26SPaolo Bonzini assert(errno != EINTR); 2026b64640dSWen Congyang g_free(local_iov); 20383f75c26SPaolo Bonzini if (errno == EAGAIN && total > 0) { 20483f75c26SPaolo Bonzini return total; 20583f75c26SPaolo Bonzini } 20683f75c26SPaolo Bonzini return -1; 20783f75c26SPaolo Bonzini } 20883f75c26SPaolo Bonzini 20984004290SMORITA Kazutaka if (ret == 0 && !do_send) { 21084004290SMORITA Kazutaka /* recv returns 0 when the peer has performed an orderly 21184004290SMORITA Kazutaka * shutdown. */ 21284004290SMORITA Kazutaka break; 21384004290SMORITA Kazutaka } 21484004290SMORITA Kazutaka 21583f75c26SPaolo Bonzini /* Prepare for the next iteration */ 21683f75c26SPaolo Bonzini offset += ret; 21783f75c26SPaolo Bonzini total += ret; 21883f75c26SPaolo Bonzini bytes -= ret; 21983f75c26SPaolo Bonzini } 22083f75c26SPaolo Bonzini 2216b64640dSWen Congyang g_free(local_iov); 22283f75c26SPaolo Bonzini return total; 223baacf047SPaolo Bonzini } 224baacf047SPaolo Bonzini 225baacf047SPaolo Bonzini 226baacf047SPaolo Bonzini void iov_hexdump(const struct iovec *iov, const unsigned int iov_cnt, 227baacf047SPaolo Bonzini FILE *fp, const char *prefix, size_t limit) 228baacf047SPaolo Bonzini { 2296ff66f50SPeter Crosthwaite int v; 2306ff66f50SPeter Crosthwaite size_t size = 0; 2316ff66f50SPeter Crosthwaite char *buf; 232baacf047SPaolo Bonzini 2336ff66f50SPeter Crosthwaite for (v = 0; v < iov_cnt; v++) { 2346ff66f50SPeter Crosthwaite size += iov[v].iov_len; 235baacf047SPaolo Bonzini } 2366ff66f50SPeter Crosthwaite size = size > limit ? limit : size; 2376ff66f50SPeter Crosthwaite buf = g_malloc(size); 2386ff66f50SPeter Crosthwaite iov_to_buf(iov, iov_cnt, 0, buf, size); 2393568ac2aSEd Maste qemu_hexdump(buf, fp, prefix, size); 2406ff66f50SPeter Crosthwaite g_free(buf); 241baacf047SPaolo Bonzini } 242baacf047SPaolo Bonzini 243baacf047SPaolo Bonzini unsigned iov_copy(struct iovec *dst_iov, unsigned int dst_iov_cnt, 244baacf047SPaolo Bonzini const struct iovec *iov, unsigned int iov_cnt, 245baacf047SPaolo Bonzini size_t offset, size_t bytes) 246baacf047SPaolo Bonzini { 247baacf047SPaolo Bonzini size_t len; 248baacf047SPaolo Bonzini unsigned int i, j; 249baacf047SPaolo Bonzini for (i = 0, j = 0; i < iov_cnt && j < dst_iov_cnt && bytes; i++) { 250baacf047SPaolo Bonzini if (offset >= iov[i].iov_len) { 251baacf047SPaolo Bonzini offset -= iov[i].iov_len; 252baacf047SPaolo Bonzini continue; 253baacf047SPaolo Bonzini } 254baacf047SPaolo Bonzini len = MIN(bytes, iov[i].iov_len - offset); 255baacf047SPaolo Bonzini 256baacf047SPaolo Bonzini dst_iov[j].iov_base = iov[i].iov_base + offset; 257baacf047SPaolo Bonzini dst_iov[j].iov_len = len; 258baacf047SPaolo Bonzini j++; 259baacf047SPaolo Bonzini bytes -= len; 260baacf047SPaolo Bonzini offset = 0; 261baacf047SPaolo Bonzini } 262baacf047SPaolo Bonzini assert(offset == 0); 263baacf047SPaolo Bonzini return j; 264baacf047SPaolo Bonzini } 265baacf047SPaolo Bonzini 266baacf047SPaolo Bonzini /* io vectors */ 267baacf047SPaolo Bonzini 268baacf047SPaolo Bonzini void qemu_iovec_init(QEMUIOVector *qiov, int alloc_hint) 269baacf047SPaolo Bonzini { 270e1cf5582SMarkus Armbruster qiov->iov = g_new(struct iovec, alloc_hint); 271baacf047SPaolo Bonzini qiov->niov = 0; 272baacf047SPaolo Bonzini qiov->nalloc = alloc_hint; 273baacf047SPaolo Bonzini qiov->size = 0; 274baacf047SPaolo Bonzini } 275baacf047SPaolo Bonzini 276baacf047SPaolo Bonzini void qemu_iovec_init_external(QEMUIOVector *qiov, struct iovec *iov, int niov) 277baacf047SPaolo Bonzini { 278baacf047SPaolo Bonzini int i; 279baacf047SPaolo Bonzini 280baacf047SPaolo Bonzini qiov->iov = iov; 281baacf047SPaolo Bonzini qiov->niov = niov; 282baacf047SPaolo Bonzini qiov->nalloc = -1; 283baacf047SPaolo Bonzini qiov->size = 0; 284baacf047SPaolo Bonzini for (i = 0; i < niov; i++) 285baacf047SPaolo Bonzini qiov->size += iov[i].iov_len; 286baacf047SPaolo Bonzini } 287baacf047SPaolo Bonzini 288baacf047SPaolo Bonzini void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len) 289baacf047SPaolo Bonzini { 290baacf047SPaolo Bonzini assert(qiov->nalloc != -1); 291baacf047SPaolo Bonzini 292baacf047SPaolo Bonzini if (qiov->niov == qiov->nalloc) { 293baacf047SPaolo Bonzini qiov->nalloc = 2 * qiov->nalloc + 1; 294e1cf5582SMarkus Armbruster qiov->iov = g_renew(struct iovec, qiov->iov, qiov->nalloc); 295baacf047SPaolo Bonzini } 296baacf047SPaolo Bonzini qiov->iov[qiov->niov].iov_base = base; 297baacf047SPaolo Bonzini qiov->iov[qiov->niov].iov_len = len; 298baacf047SPaolo Bonzini qiov->size += len; 299baacf047SPaolo Bonzini ++qiov->niov; 300baacf047SPaolo Bonzini } 301baacf047SPaolo Bonzini 302baacf047SPaolo Bonzini /* 303baacf047SPaolo Bonzini * Concatenates (partial) iovecs from src_iov to the end of dst. 304baacf047SPaolo Bonzini * It starts copying after skipping `soffset' bytes at the 305baacf047SPaolo Bonzini * beginning of src and adds individual vectors from src to 306baacf047SPaolo Bonzini * dst copies up to `sbytes' bytes total, or up to the end 307baacf047SPaolo Bonzini * of src_iov if it comes first. This way, it is okay to specify 308baacf047SPaolo Bonzini * very large value for `sbytes' to indicate "up to the end 309baacf047SPaolo Bonzini * of src". 310baacf047SPaolo Bonzini * Only vector pointers are processed, not the actual data buffers. 311baacf047SPaolo Bonzini */ 312519661eeSPaolo Bonzini size_t qemu_iovec_concat_iov(QEMUIOVector *dst, 313baacf047SPaolo Bonzini struct iovec *src_iov, unsigned int src_cnt, 314baacf047SPaolo Bonzini size_t soffset, size_t sbytes) 315baacf047SPaolo Bonzini { 316baacf047SPaolo Bonzini int i; 317baacf047SPaolo Bonzini size_t done; 318facf98adSAneesh Kumar K.V 319facf98adSAneesh Kumar K.V if (!sbytes) { 320519661eeSPaolo Bonzini return 0; 321facf98adSAneesh Kumar K.V } 322baacf047SPaolo Bonzini assert(dst->nalloc != -1); 323baacf047SPaolo Bonzini for (i = 0, done = 0; done < sbytes && i < src_cnt; i++) { 324baacf047SPaolo Bonzini if (soffset < src_iov[i].iov_len) { 325baacf047SPaolo Bonzini size_t len = MIN(src_iov[i].iov_len - soffset, sbytes - done); 326baacf047SPaolo Bonzini qemu_iovec_add(dst, src_iov[i].iov_base + soffset, len); 327baacf047SPaolo Bonzini done += len; 328baacf047SPaolo Bonzini soffset = 0; 329baacf047SPaolo Bonzini } else { 330baacf047SPaolo Bonzini soffset -= src_iov[i].iov_len; 331baacf047SPaolo Bonzini } 332baacf047SPaolo Bonzini } 333baacf047SPaolo Bonzini assert(soffset == 0); /* offset beyond end of src */ 334519661eeSPaolo Bonzini 335519661eeSPaolo Bonzini return done; 336baacf047SPaolo Bonzini } 337baacf047SPaolo Bonzini 338baacf047SPaolo Bonzini /* 339baacf047SPaolo Bonzini * Concatenates (partial) iovecs from src to the end of dst. 340baacf047SPaolo Bonzini * It starts copying after skipping `soffset' bytes at the 341baacf047SPaolo Bonzini * beginning of src and adds individual vectors from src to 342baacf047SPaolo Bonzini * dst copies up to `sbytes' bytes total, or up to the end 343baacf047SPaolo Bonzini * of src if it comes first. This way, it is okay to specify 344baacf047SPaolo Bonzini * very large value for `sbytes' to indicate "up to the end 345baacf047SPaolo Bonzini * of src". 346baacf047SPaolo Bonzini * Only vector pointers are processed, not the actual data buffers. 347baacf047SPaolo Bonzini */ 348baacf047SPaolo Bonzini void qemu_iovec_concat(QEMUIOVector *dst, 349baacf047SPaolo Bonzini QEMUIOVector *src, size_t soffset, size_t sbytes) 350baacf047SPaolo Bonzini { 351baacf047SPaolo Bonzini qemu_iovec_concat_iov(dst, src->iov, src->niov, soffset, sbytes); 352baacf047SPaolo Bonzini } 353baacf047SPaolo Bonzini 35443f35cb5SPeter Lieven /* 35543f35cb5SPeter Lieven * Check if the contents of the iovecs are all zero 35643f35cb5SPeter Lieven */ 35743f35cb5SPeter Lieven bool qemu_iovec_is_zero(QEMUIOVector *qiov) 35843f35cb5SPeter Lieven { 35943f35cb5SPeter Lieven int i; 36043f35cb5SPeter Lieven for (i = 0; i < qiov->niov; i++) { 36143f35cb5SPeter Lieven size_t offs = QEMU_ALIGN_DOWN(qiov->iov[i].iov_len, 4 * sizeof(long)); 36243f35cb5SPeter Lieven uint8_t *ptr = qiov->iov[i].iov_base; 36343f35cb5SPeter Lieven if (offs && !buffer_is_zero(qiov->iov[i].iov_base, offs)) { 36443f35cb5SPeter Lieven return false; 36543f35cb5SPeter Lieven } 36643f35cb5SPeter Lieven for (; offs < qiov->iov[i].iov_len; offs++) { 36743f35cb5SPeter Lieven if (ptr[offs]) { 36843f35cb5SPeter Lieven return false; 36943f35cb5SPeter Lieven } 37043f35cb5SPeter Lieven } 37143f35cb5SPeter Lieven } 37243f35cb5SPeter Lieven return true; 37343f35cb5SPeter Lieven } 37443f35cb5SPeter Lieven 375baacf047SPaolo Bonzini void qemu_iovec_destroy(QEMUIOVector *qiov) 376baacf047SPaolo Bonzini { 377baacf047SPaolo Bonzini assert(qiov->nalloc != -1); 378baacf047SPaolo Bonzini 379baacf047SPaolo Bonzini qemu_iovec_reset(qiov); 380baacf047SPaolo Bonzini g_free(qiov->iov); 381baacf047SPaolo Bonzini qiov->nalloc = 0; 382baacf047SPaolo Bonzini qiov->iov = NULL; 383baacf047SPaolo Bonzini } 384baacf047SPaolo Bonzini 385baacf047SPaolo Bonzini void qemu_iovec_reset(QEMUIOVector *qiov) 386baacf047SPaolo Bonzini { 387baacf047SPaolo Bonzini assert(qiov->nalloc != -1); 388baacf047SPaolo Bonzini 389baacf047SPaolo Bonzini qiov->niov = 0; 390baacf047SPaolo Bonzini qiov->size = 0; 391baacf047SPaolo Bonzini } 392baacf047SPaolo Bonzini 393baacf047SPaolo Bonzini size_t qemu_iovec_to_buf(QEMUIOVector *qiov, size_t offset, 394baacf047SPaolo Bonzini void *buf, size_t bytes) 395baacf047SPaolo Bonzini { 396baacf047SPaolo Bonzini return iov_to_buf(qiov->iov, qiov->niov, offset, buf, bytes); 397baacf047SPaolo Bonzini } 398baacf047SPaolo Bonzini 399baacf047SPaolo Bonzini size_t qemu_iovec_from_buf(QEMUIOVector *qiov, size_t offset, 400baacf047SPaolo Bonzini const void *buf, size_t bytes) 401baacf047SPaolo Bonzini { 402baacf047SPaolo Bonzini return iov_from_buf(qiov->iov, qiov->niov, offset, buf, bytes); 403baacf047SPaolo Bonzini } 404baacf047SPaolo Bonzini 405baacf047SPaolo Bonzini size_t qemu_iovec_memset(QEMUIOVector *qiov, size_t offset, 406baacf047SPaolo Bonzini int fillc, size_t bytes) 407baacf047SPaolo Bonzini { 408baacf047SPaolo Bonzini return iov_memset(qiov->iov, qiov->niov, offset, fillc, bytes); 409baacf047SPaolo Bonzini } 410baacf047SPaolo Bonzini 411f70d7f7eSBenoît Canet /** 412f70d7f7eSBenoît Canet * Check that I/O vector contents are identical 413f70d7f7eSBenoît Canet * 414f70d7f7eSBenoît Canet * The IO vectors must have the same structure (same length of all parts). 415f70d7f7eSBenoît Canet * A typical usage is to compare vectors created with qemu_iovec_clone(). 416f70d7f7eSBenoît Canet * 417f70d7f7eSBenoît Canet * @a: I/O vector 418f70d7f7eSBenoît Canet * @b: I/O vector 419f70d7f7eSBenoît Canet * @ret: Offset to first mismatching byte or -1 if match 420f70d7f7eSBenoît Canet */ 421f70d7f7eSBenoît Canet ssize_t qemu_iovec_compare(QEMUIOVector *a, QEMUIOVector *b) 422f70d7f7eSBenoît Canet { 423f70d7f7eSBenoît Canet int i; 424f70d7f7eSBenoît Canet ssize_t offset = 0; 425f70d7f7eSBenoît Canet 426f70d7f7eSBenoît Canet assert(a->niov == b->niov); 427f70d7f7eSBenoît Canet for (i = 0; i < a->niov; i++) { 428f70d7f7eSBenoît Canet size_t len = 0; 429f70d7f7eSBenoît Canet uint8_t *p = (uint8_t *)a->iov[i].iov_base; 430f70d7f7eSBenoît Canet uint8_t *q = (uint8_t *)b->iov[i].iov_base; 431f70d7f7eSBenoît Canet 432f70d7f7eSBenoît Canet assert(a->iov[i].iov_len == b->iov[i].iov_len); 433f70d7f7eSBenoît Canet while (len < a->iov[i].iov_len && *p++ == *q++) { 434f70d7f7eSBenoît Canet len++; 435f70d7f7eSBenoît Canet } 436f70d7f7eSBenoît Canet 437f70d7f7eSBenoît Canet offset += len; 438f70d7f7eSBenoît Canet 439f70d7f7eSBenoît Canet if (len != a->iov[i].iov_len) { 440f70d7f7eSBenoît Canet return offset; 441f70d7f7eSBenoît Canet } 442f70d7f7eSBenoît Canet } 443f70d7f7eSBenoît Canet return -1; 444f70d7f7eSBenoît Canet } 445f70d7f7eSBenoît Canet 446f70d7f7eSBenoît Canet typedef struct { 447f70d7f7eSBenoît Canet int src_index; 448f70d7f7eSBenoît Canet struct iovec *src_iov; 449f70d7f7eSBenoît Canet void *dest_base; 450f70d7f7eSBenoît Canet } IOVectorSortElem; 451f70d7f7eSBenoît Canet 452f70d7f7eSBenoît Canet static int sortelem_cmp_src_base(const void *a, const void *b) 453f70d7f7eSBenoît Canet { 454f70d7f7eSBenoît Canet const IOVectorSortElem *elem_a = a; 455f70d7f7eSBenoît Canet const IOVectorSortElem *elem_b = b; 456f70d7f7eSBenoît Canet 457f70d7f7eSBenoît Canet /* Don't overflow */ 458f70d7f7eSBenoît Canet if (elem_a->src_iov->iov_base < elem_b->src_iov->iov_base) { 459f70d7f7eSBenoît Canet return -1; 460f70d7f7eSBenoît Canet } else if (elem_a->src_iov->iov_base > elem_b->src_iov->iov_base) { 461f70d7f7eSBenoît Canet return 1; 462f70d7f7eSBenoît Canet } else { 463f70d7f7eSBenoît Canet return 0; 464f70d7f7eSBenoît Canet } 465f70d7f7eSBenoît Canet } 466f70d7f7eSBenoît Canet 467f70d7f7eSBenoît Canet static int sortelem_cmp_src_index(const void *a, const void *b) 468f70d7f7eSBenoît Canet { 469f70d7f7eSBenoît Canet const IOVectorSortElem *elem_a = a; 470f70d7f7eSBenoît Canet const IOVectorSortElem *elem_b = b; 471f70d7f7eSBenoît Canet 472f70d7f7eSBenoît Canet return elem_a->src_index - elem_b->src_index; 473f70d7f7eSBenoît Canet } 474f70d7f7eSBenoît Canet 475f70d7f7eSBenoît Canet /** 476f70d7f7eSBenoît Canet * Copy contents of I/O vector 477f70d7f7eSBenoît Canet * 478f70d7f7eSBenoît Canet * The relative relationships of overlapping iovecs are preserved. This is 479f70d7f7eSBenoît Canet * necessary to ensure identical semantics in the cloned I/O vector. 480f70d7f7eSBenoît Canet */ 481f70d7f7eSBenoît Canet void qemu_iovec_clone(QEMUIOVector *dest, const QEMUIOVector *src, void *buf) 482f70d7f7eSBenoît Canet { 483f70d7f7eSBenoît Canet IOVectorSortElem sortelems[src->niov]; 484f70d7f7eSBenoît Canet void *last_end; 485f70d7f7eSBenoît Canet int i; 486f70d7f7eSBenoît Canet 487f70d7f7eSBenoît Canet /* Sort by source iovecs by base address */ 488f70d7f7eSBenoît Canet for (i = 0; i < src->niov; i++) { 489f70d7f7eSBenoît Canet sortelems[i].src_index = i; 490f70d7f7eSBenoît Canet sortelems[i].src_iov = &src->iov[i]; 491f70d7f7eSBenoît Canet } 492f70d7f7eSBenoît Canet qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_base); 493f70d7f7eSBenoît Canet 494f70d7f7eSBenoît Canet /* Allocate buffer space taking into account overlapping iovecs */ 495f70d7f7eSBenoît Canet last_end = NULL; 496f70d7f7eSBenoît Canet for (i = 0; i < src->niov; i++) { 497f70d7f7eSBenoît Canet struct iovec *cur = sortelems[i].src_iov; 498f70d7f7eSBenoît Canet ptrdiff_t rewind = 0; 499f70d7f7eSBenoît Canet 500f70d7f7eSBenoît Canet /* Detect overlap */ 501f70d7f7eSBenoît Canet if (last_end && last_end > cur->iov_base) { 502f70d7f7eSBenoît Canet rewind = last_end - cur->iov_base; 503f70d7f7eSBenoît Canet } 504f70d7f7eSBenoît Canet 505f70d7f7eSBenoît Canet sortelems[i].dest_base = buf - rewind; 506f70d7f7eSBenoît Canet buf += cur->iov_len - MIN(rewind, cur->iov_len); 507f70d7f7eSBenoît Canet last_end = MAX(cur->iov_base + cur->iov_len, last_end); 508f70d7f7eSBenoît Canet } 509f70d7f7eSBenoît Canet 510f70d7f7eSBenoît Canet /* Sort by source iovec index and build destination iovec */ 511f70d7f7eSBenoît Canet qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_index); 512f70d7f7eSBenoît Canet for (i = 0; i < src->niov; i++) { 513f70d7f7eSBenoît Canet qemu_iovec_add(dest, sortelems[i].dest_base, src->iov[i].iov_len); 514f70d7f7eSBenoît Canet } 515f70d7f7eSBenoît Canet } 516f70d7f7eSBenoît Canet 517baacf047SPaolo Bonzini size_t iov_discard_front(struct iovec **iov, unsigned int *iov_cnt, 518baacf047SPaolo Bonzini size_t bytes) 519baacf047SPaolo Bonzini { 520baacf047SPaolo Bonzini size_t total = 0; 521baacf047SPaolo Bonzini struct iovec *cur; 522baacf047SPaolo Bonzini 523baacf047SPaolo Bonzini for (cur = *iov; *iov_cnt > 0; cur++) { 524baacf047SPaolo Bonzini if (cur->iov_len > bytes) { 525baacf047SPaolo Bonzini cur->iov_base += bytes; 526baacf047SPaolo Bonzini cur->iov_len -= bytes; 527baacf047SPaolo Bonzini total += bytes; 528baacf047SPaolo Bonzini break; 529baacf047SPaolo Bonzini } 530baacf047SPaolo Bonzini 531baacf047SPaolo Bonzini bytes -= cur->iov_len; 532baacf047SPaolo Bonzini total += cur->iov_len; 533baacf047SPaolo Bonzini *iov_cnt -= 1; 534baacf047SPaolo Bonzini } 535baacf047SPaolo Bonzini 536baacf047SPaolo Bonzini *iov = cur; 537baacf047SPaolo Bonzini return total; 538baacf047SPaolo Bonzini } 539baacf047SPaolo Bonzini 540baacf047SPaolo Bonzini size_t iov_discard_back(struct iovec *iov, unsigned int *iov_cnt, 541baacf047SPaolo Bonzini size_t bytes) 542baacf047SPaolo Bonzini { 543baacf047SPaolo Bonzini size_t total = 0; 544baacf047SPaolo Bonzini struct iovec *cur; 545baacf047SPaolo Bonzini 546baacf047SPaolo Bonzini if (*iov_cnt == 0) { 547baacf047SPaolo Bonzini return 0; 548baacf047SPaolo Bonzini } 549baacf047SPaolo Bonzini 550baacf047SPaolo Bonzini cur = iov + (*iov_cnt - 1); 551baacf047SPaolo Bonzini 552baacf047SPaolo Bonzini while (*iov_cnt > 0) { 553baacf047SPaolo Bonzini if (cur->iov_len > bytes) { 554baacf047SPaolo Bonzini cur->iov_len -= bytes; 555baacf047SPaolo Bonzini total += bytes; 556baacf047SPaolo Bonzini break; 557baacf047SPaolo Bonzini } 558baacf047SPaolo Bonzini 559baacf047SPaolo Bonzini bytes -= cur->iov_len; 560baacf047SPaolo Bonzini total += cur->iov_len; 561baacf047SPaolo Bonzini cur--; 562baacf047SPaolo Bonzini *iov_cnt -= 1; 563baacf047SPaolo Bonzini } 564baacf047SPaolo Bonzini 565baacf047SPaolo Bonzini return total; 566baacf047SPaolo Bonzini } 56758f423fbSKevin Wolf 56858f423fbSKevin Wolf void qemu_iovec_discard_back(QEMUIOVector *qiov, size_t bytes) 56958f423fbSKevin Wolf { 57058f423fbSKevin Wolf size_t total; 57158f423fbSKevin Wolf unsigned int niov = qiov->niov; 57258f423fbSKevin Wolf 57358f423fbSKevin Wolf assert(qiov->size >= bytes); 57458f423fbSKevin Wolf total = iov_discard_back(qiov->iov, &niov, bytes); 57558f423fbSKevin Wolf assert(total == bytes); 57658f423fbSKevin Wolf 57758f423fbSKevin Wolf qiov->niov = niov; 57858f423fbSKevin Wolf qiov->size -= bytes; 57958f423fbSKevin Wolf } 580