Implement and use new interface to get rid of hd_qiov. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 20190604161514.262241-13-vsementsov@virtuozzo.com Message-Id: <20190604161514.262241-13-vsementsov@virtuozzo.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
701 lines
18 KiB
C
701 lines
18 KiB
C
/*
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* Helpers for getting linearized buffers from iov / filling buffers into iovs
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*
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* Copyright IBM, Corp. 2007, 2008
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* Copyright (C) 2010 Red Hat, Inc.
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*
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* Author(s):
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* Anthony Liguori <aliguori@us.ibm.com>
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* Amit Shah <amit.shah@redhat.com>
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* Michael Tokarev <mjt@tls.msk.ru>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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* Contributions after 2012-01-13 are licensed under the terms of the
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* GNU GPL, version 2 or (at your option) any later version.
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*/
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#include "qemu/osdep.h"
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#include "qemu-common.h"
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#include "qemu/iov.h"
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#include "qemu/sockets.h"
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#include "qemu/cutils.h"
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size_t iov_from_buf_full(const struct iovec *iov, unsigned int iov_cnt,
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size_t offset, const void *buf, size_t bytes)
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{
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size_t done;
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unsigned int i;
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for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) {
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if (offset < iov[i].iov_len) {
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size_t len = MIN(iov[i].iov_len - offset, bytes - done);
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memcpy(iov[i].iov_base + offset, buf + done, len);
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done += len;
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offset = 0;
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} else {
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offset -= iov[i].iov_len;
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}
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}
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assert(offset == 0);
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return done;
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}
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size_t iov_to_buf_full(const struct iovec *iov, const unsigned int iov_cnt,
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size_t offset, void *buf, size_t bytes)
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{
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size_t done;
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unsigned int i;
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for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) {
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if (offset < iov[i].iov_len) {
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size_t len = MIN(iov[i].iov_len - offset, bytes - done);
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memcpy(buf + done, iov[i].iov_base + offset, len);
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done += len;
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offset = 0;
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} else {
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offset -= iov[i].iov_len;
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}
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}
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assert(offset == 0);
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return done;
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}
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size_t iov_memset(const struct iovec *iov, const unsigned int iov_cnt,
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size_t offset, int fillc, size_t bytes)
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{
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size_t done;
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unsigned int i;
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for (i = 0, done = 0; (offset || done < bytes) && i < iov_cnt; i++) {
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if (offset < iov[i].iov_len) {
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size_t len = MIN(iov[i].iov_len - offset, bytes - done);
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memset(iov[i].iov_base + offset, fillc, len);
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done += len;
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offset = 0;
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} else {
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offset -= iov[i].iov_len;
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}
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}
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assert(offset == 0);
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return done;
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}
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size_t iov_size(const struct iovec *iov, const unsigned int iov_cnt)
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{
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size_t len;
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unsigned int i;
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len = 0;
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for (i = 0; i < iov_cnt; i++) {
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len += iov[i].iov_len;
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}
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return len;
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}
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/* helper function for iov_send_recv() */
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static ssize_t
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do_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt, bool do_send)
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{
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#ifdef CONFIG_POSIX
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ssize_t ret;
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struct msghdr msg;
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memset(&msg, 0, sizeof(msg));
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msg.msg_iov = iov;
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msg.msg_iovlen = iov_cnt;
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do {
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ret = do_send
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? sendmsg(sockfd, &msg, 0)
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: recvmsg(sockfd, &msg, 0);
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} while (ret < 0 && errno == EINTR);
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return ret;
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#else
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/* else send piece-by-piece */
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/*XXX Note: windows has WSASend() and WSARecv() */
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unsigned i = 0;
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ssize_t ret = 0;
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while (i < iov_cnt) {
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ssize_t r = do_send
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? send(sockfd, iov[i].iov_base, iov[i].iov_len, 0)
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: recv(sockfd, iov[i].iov_base, iov[i].iov_len, 0);
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if (r > 0) {
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ret += r;
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} else if (!r) {
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break;
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} else if (errno == EINTR) {
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continue;
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} else {
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/* else it is some "other" error,
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* only return if there was no data processed. */
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if (ret == 0) {
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ret = -1;
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}
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break;
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}
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i++;
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}
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return ret;
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#endif
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}
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ssize_t iov_send_recv(int sockfd, const struct iovec *_iov, unsigned iov_cnt,
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size_t offset, size_t bytes,
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bool do_send)
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{
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ssize_t total = 0;
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ssize_t ret;
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size_t orig_len, tail;
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unsigned niov;
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struct iovec *local_iov, *iov;
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if (bytes <= 0) {
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return 0;
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}
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local_iov = g_new0(struct iovec, iov_cnt);
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iov_copy(local_iov, iov_cnt, _iov, iov_cnt, offset, bytes);
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offset = 0;
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iov = local_iov;
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while (bytes > 0) {
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/* Find the start position, skipping `offset' bytes:
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* first, skip all full-sized vector elements, */
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for (niov = 0; niov < iov_cnt && offset >= iov[niov].iov_len; ++niov) {
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offset -= iov[niov].iov_len;
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}
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/* niov == iov_cnt would only be valid if bytes == 0, which
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* we already ruled out in the loop condition. */
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assert(niov < iov_cnt);
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iov += niov;
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iov_cnt -= niov;
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if (offset) {
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/* second, skip `offset' bytes from the (now) first element,
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* undo it on exit */
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iov[0].iov_base += offset;
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iov[0].iov_len -= offset;
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}
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/* Find the end position skipping `bytes' bytes: */
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/* first, skip all full-sized elements */
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tail = bytes;
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for (niov = 0; niov < iov_cnt && iov[niov].iov_len <= tail; ++niov) {
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tail -= iov[niov].iov_len;
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}
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if (tail) {
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/* second, fixup the last element, and remember the original
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* length */
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assert(niov < iov_cnt);
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assert(iov[niov].iov_len > tail);
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orig_len = iov[niov].iov_len;
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iov[niov++].iov_len = tail;
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ret = do_send_recv(sockfd, iov, niov, do_send);
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/* Undo the changes above before checking for errors */
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iov[niov-1].iov_len = orig_len;
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} else {
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ret = do_send_recv(sockfd, iov, niov, do_send);
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}
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if (offset) {
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iov[0].iov_base -= offset;
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iov[0].iov_len += offset;
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}
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if (ret < 0) {
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assert(errno != EINTR);
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g_free(local_iov);
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if (errno == EAGAIN && total > 0) {
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return total;
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}
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return -1;
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}
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if (ret == 0 && !do_send) {
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/* recv returns 0 when the peer has performed an orderly
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* shutdown. */
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break;
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}
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/* Prepare for the next iteration */
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offset += ret;
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total += ret;
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bytes -= ret;
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}
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g_free(local_iov);
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return total;
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}
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void iov_hexdump(const struct iovec *iov, const unsigned int iov_cnt,
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FILE *fp, const char *prefix, size_t limit)
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{
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int v;
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size_t size = 0;
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char *buf;
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for (v = 0; v < iov_cnt; v++) {
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size += iov[v].iov_len;
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}
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size = size > limit ? limit : size;
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buf = g_malloc(size);
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iov_to_buf(iov, iov_cnt, 0, buf, size);
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qemu_hexdump(buf, fp, prefix, size);
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g_free(buf);
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}
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unsigned iov_copy(struct iovec *dst_iov, unsigned int dst_iov_cnt,
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const struct iovec *iov, unsigned int iov_cnt,
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size_t offset, size_t bytes)
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{
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size_t len;
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unsigned int i, j;
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for (i = 0, j = 0;
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i < iov_cnt && j < dst_iov_cnt && (offset || bytes); i++) {
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if (offset >= iov[i].iov_len) {
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offset -= iov[i].iov_len;
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continue;
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}
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len = MIN(bytes, iov[i].iov_len - offset);
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dst_iov[j].iov_base = iov[i].iov_base + offset;
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dst_iov[j].iov_len = len;
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j++;
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bytes -= len;
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offset = 0;
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}
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assert(offset == 0);
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return j;
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}
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/* io vectors */
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void qemu_iovec_init(QEMUIOVector *qiov, int alloc_hint)
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{
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qiov->iov = g_new(struct iovec, alloc_hint);
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qiov->niov = 0;
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qiov->nalloc = alloc_hint;
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qiov->size = 0;
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}
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void qemu_iovec_init_external(QEMUIOVector *qiov, struct iovec *iov, int niov)
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{
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int i;
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qiov->iov = iov;
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qiov->niov = niov;
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qiov->nalloc = -1;
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qiov->size = 0;
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for (i = 0; i < niov; i++)
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qiov->size += iov[i].iov_len;
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}
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void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len)
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{
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assert(qiov->nalloc != -1);
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if (qiov->niov == qiov->nalloc) {
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qiov->nalloc = 2 * qiov->nalloc + 1;
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qiov->iov = g_renew(struct iovec, qiov->iov, qiov->nalloc);
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}
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qiov->iov[qiov->niov].iov_base = base;
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qiov->iov[qiov->niov].iov_len = len;
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qiov->size += len;
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++qiov->niov;
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}
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/*
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* Concatenates (partial) iovecs from src_iov to the end of dst.
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* It starts copying after skipping `soffset' bytes at the
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* beginning of src and adds individual vectors from src to
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* dst copies up to `sbytes' bytes total, or up to the end
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* of src_iov if it comes first. This way, it is okay to specify
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* very large value for `sbytes' to indicate "up to the end
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* of src".
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* Only vector pointers are processed, not the actual data buffers.
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*/
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size_t qemu_iovec_concat_iov(QEMUIOVector *dst,
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struct iovec *src_iov, unsigned int src_cnt,
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size_t soffset, size_t sbytes)
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{
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int i;
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size_t done;
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if (!sbytes) {
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return 0;
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}
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assert(dst->nalloc != -1);
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for (i = 0, done = 0; done < sbytes && i < src_cnt; i++) {
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if (soffset < src_iov[i].iov_len) {
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size_t len = MIN(src_iov[i].iov_len - soffset, sbytes - done);
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qemu_iovec_add(dst, src_iov[i].iov_base + soffset, len);
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done += len;
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soffset = 0;
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} else {
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soffset -= src_iov[i].iov_len;
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}
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}
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assert(soffset == 0); /* offset beyond end of src */
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return done;
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}
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/*
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* Concatenates (partial) iovecs from src to the end of dst.
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* It starts copying after skipping `soffset' bytes at the
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* beginning of src and adds individual vectors from src to
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* dst copies up to `sbytes' bytes total, or up to the end
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* of src if it comes first. This way, it is okay to specify
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* very large value for `sbytes' to indicate "up to the end
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* of src".
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* Only vector pointers are processed, not the actual data buffers.
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*/
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void qemu_iovec_concat(QEMUIOVector *dst,
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QEMUIOVector *src, size_t soffset, size_t sbytes)
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{
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qemu_iovec_concat_iov(dst, src->iov, src->niov, soffset, sbytes);
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}
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/*
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* qiov_find_iov
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*
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* Return pointer to iovec structure, where byte at @offset in original vector
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* @iov exactly is.
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* Set @remaining_offset to be offset inside that iovec to the same byte.
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*/
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static struct iovec *iov_skip_offset(struct iovec *iov, size_t offset,
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size_t *remaining_offset)
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{
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while (offset > 0 && offset >= iov->iov_len) {
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offset -= iov->iov_len;
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iov++;
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}
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*remaining_offset = offset;
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return iov;
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}
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/*
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* qiov_slice
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*
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* Find subarray of iovec's, containing requested range. @head would
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* be offset in first iov (returned by the function), @tail would be
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* count of extra bytes in last iovec (returned iov + @niov - 1).
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*/
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static struct iovec *qiov_slice(QEMUIOVector *qiov,
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size_t offset, size_t len,
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size_t *head, size_t *tail, int *niov)
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{
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struct iovec *iov, *end_iov;
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assert(offset + len <= qiov->size);
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iov = iov_skip_offset(qiov->iov, offset, head);
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end_iov = iov_skip_offset(iov, *head + len, tail);
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if (*tail > 0) {
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assert(*tail < end_iov->iov_len);
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*tail = end_iov->iov_len - *tail;
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end_iov++;
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}
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*niov = end_iov - iov;
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return iov;
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}
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int qemu_iovec_subvec_niov(QEMUIOVector *qiov, size_t offset, size_t len)
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{
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size_t head, tail;
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int niov;
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qiov_slice(qiov, offset, len, &head, &tail, &niov);
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return niov;
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}
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/*
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* Compile new iovec, combining @head_buf buffer, sub-qiov of @mid_qiov,
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* and @tail_buf buffer into new qiov.
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*/
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void qemu_iovec_init_extended(
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QEMUIOVector *qiov,
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void *head_buf, size_t head_len,
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QEMUIOVector *mid_qiov, size_t mid_offset, size_t mid_len,
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void *tail_buf, size_t tail_len)
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{
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size_t mid_head, mid_tail;
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int total_niov, mid_niov = 0;
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struct iovec *p, *mid_iov;
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if (mid_len) {
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mid_iov = qiov_slice(mid_qiov, mid_offset, mid_len,
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&mid_head, &mid_tail, &mid_niov);
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}
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total_niov = !!head_len + mid_niov + !!tail_len;
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if (total_niov == 1) {
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qemu_iovec_init_buf(qiov, NULL, 0);
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p = &qiov->local_iov;
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} else {
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qiov->niov = qiov->nalloc = total_niov;
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qiov->size = head_len + mid_len + tail_len;
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p = qiov->iov = g_new(struct iovec, qiov->niov);
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}
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if (head_len) {
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p->iov_base = head_buf;
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p->iov_len = head_len;
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p++;
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}
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if (mid_len) {
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memcpy(p, mid_iov, mid_niov * sizeof(*p));
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p[0].iov_base = (uint8_t *)p[0].iov_base + mid_head;
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p[0].iov_len -= mid_head;
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p[mid_niov - 1].iov_len -= mid_tail;
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p += mid_niov;
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}
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if (tail_len) {
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p->iov_base = tail_buf;
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p->iov_len = tail_len;
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}
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}
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/*
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* Check if the contents of subrange of qiov data is all zeroes.
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*/
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bool qemu_iovec_is_zero(QEMUIOVector *qiov, size_t offset, size_t bytes)
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{
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struct iovec *iov;
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size_t current_offset;
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assert(offset + bytes <= qiov->size);
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iov = iov_skip_offset(qiov->iov, offset, ¤t_offset);
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while (bytes) {
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uint8_t *base = (uint8_t *)iov->iov_base + current_offset;
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size_t len = MIN(iov->iov_len - current_offset, bytes);
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if (!buffer_is_zero(base, len)) {
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return false;
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}
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current_offset = 0;
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bytes -= len;
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iov++;
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}
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return true;
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}
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void qemu_iovec_init_slice(QEMUIOVector *qiov, QEMUIOVector *source,
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size_t offset, size_t len)
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{
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qemu_iovec_init_extended(qiov, NULL, 0, source, offset, len, NULL, 0);
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}
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void qemu_iovec_destroy(QEMUIOVector *qiov)
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{
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if (qiov->nalloc != -1) {
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g_free(qiov->iov);
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}
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memset(qiov, 0, sizeof(*qiov));
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}
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void qemu_iovec_reset(QEMUIOVector *qiov)
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{
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assert(qiov->nalloc != -1);
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qiov->niov = 0;
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qiov->size = 0;
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}
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size_t qemu_iovec_to_buf(QEMUIOVector *qiov, size_t offset,
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void *buf, size_t bytes)
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{
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return iov_to_buf(qiov->iov, qiov->niov, offset, buf, bytes);
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}
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size_t qemu_iovec_from_buf(QEMUIOVector *qiov, size_t offset,
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const void *buf, size_t bytes)
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{
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return iov_from_buf(qiov->iov, qiov->niov, offset, buf, bytes);
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}
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size_t qemu_iovec_memset(QEMUIOVector *qiov, size_t offset,
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int fillc, size_t bytes)
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{
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return iov_memset(qiov->iov, qiov->niov, offset, fillc, bytes);
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}
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/**
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* Check that I/O vector contents are identical
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*
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* The IO vectors must have the same structure (same length of all parts).
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* A typical usage is to compare vectors created with qemu_iovec_clone().
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*
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* @a: I/O vector
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* @b: I/O vector
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* @ret: Offset to first mismatching byte or -1 if match
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*/
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ssize_t qemu_iovec_compare(QEMUIOVector *a, QEMUIOVector *b)
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{
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int i;
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ssize_t offset = 0;
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assert(a->niov == b->niov);
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for (i = 0; i < a->niov; i++) {
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size_t len = 0;
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uint8_t *p = (uint8_t *)a->iov[i].iov_base;
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uint8_t *q = (uint8_t *)b->iov[i].iov_base;
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assert(a->iov[i].iov_len == b->iov[i].iov_len);
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while (len < a->iov[i].iov_len && *p++ == *q++) {
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len++;
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}
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offset += len;
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if (len != a->iov[i].iov_len) {
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return offset;
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}
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}
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return -1;
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}
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typedef struct {
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int src_index;
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struct iovec *src_iov;
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void *dest_base;
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} IOVectorSortElem;
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static int sortelem_cmp_src_base(const void *a, const void *b)
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{
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const IOVectorSortElem *elem_a = a;
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const IOVectorSortElem *elem_b = b;
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/* Don't overflow */
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if (elem_a->src_iov->iov_base < elem_b->src_iov->iov_base) {
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return -1;
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} else if (elem_a->src_iov->iov_base > elem_b->src_iov->iov_base) {
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return 1;
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} else {
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return 0;
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}
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}
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static int sortelem_cmp_src_index(const void *a, const void *b)
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{
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const IOVectorSortElem *elem_a = a;
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const IOVectorSortElem *elem_b = b;
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return elem_a->src_index - elem_b->src_index;
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}
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/**
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* Copy contents of I/O vector
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*
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* The relative relationships of overlapping iovecs are preserved. This is
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* necessary to ensure identical semantics in the cloned I/O vector.
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*/
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void qemu_iovec_clone(QEMUIOVector *dest, const QEMUIOVector *src, void *buf)
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{
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IOVectorSortElem sortelems[src->niov];
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void *last_end;
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int i;
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/* Sort by source iovecs by base address */
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for (i = 0; i < src->niov; i++) {
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sortelems[i].src_index = i;
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sortelems[i].src_iov = &src->iov[i];
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}
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qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_base);
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/* Allocate buffer space taking into account overlapping iovecs */
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last_end = NULL;
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for (i = 0; i < src->niov; i++) {
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struct iovec *cur = sortelems[i].src_iov;
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ptrdiff_t rewind = 0;
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/* Detect overlap */
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if (last_end && last_end > cur->iov_base) {
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rewind = last_end - cur->iov_base;
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}
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sortelems[i].dest_base = buf - rewind;
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buf += cur->iov_len - MIN(rewind, cur->iov_len);
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last_end = MAX(cur->iov_base + cur->iov_len, last_end);
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}
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/* Sort by source iovec index and build destination iovec */
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qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_index);
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for (i = 0; i < src->niov; i++) {
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qemu_iovec_add(dest, sortelems[i].dest_base, src->iov[i].iov_len);
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}
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}
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size_t iov_discard_front(struct iovec **iov, unsigned int *iov_cnt,
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size_t bytes)
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|
{
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size_t total = 0;
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struct iovec *cur;
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|
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for (cur = *iov; *iov_cnt > 0; cur++) {
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if (cur->iov_len > bytes) {
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cur->iov_base += bytes;
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cur->iov_len -= bytes;
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total += bytes;
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break;
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}
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|
bytes -= cur->iov_len;
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total += cur->iov_len;
|
|
*iov_cnt -= 1;
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|
}
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|
*iov = cur;
|
|
return total;
|
|
}
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size_t iov_discard_back(struct iovec *iov, unsigned int *iov_cnt,
|
|
size_t bytes)
|
|
{
|
|
size_t total = 0;
|
|
struct iovec *cur;
|
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|
|
if (*iov_cnt == 0) {
|
|
return 0;
|
|
}
|
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|
|
cur = iov + (*iov_cnt - 1);
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|
|
while (*iov_cnt > 0) {
|
|
if (cur->iov_len > bytes) {
|
|
cur->iov_len -= bytes;
|
|
total += bytes;
|
|
break;
|
|
}
|
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|
|
bytes -= cur->iov_len;
|
|
total += cur->iov_len;
|
|
cur--;
|
|
*iov_cnt -= 1;
|
|
}
|
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|
|
return total;
|
|
}
|
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|
|
void qemu_iovec_discard_back(QEMUIOVector *qiov, size_t bytes)
|
|
{
|
|
size_t total;
|
|
unsigned int niov = qiov->niov;
|
|
|
|
assert(qiov->size >= bytes);
|
|
total = iov_discard_back(qiov->iov, &niov, bytes);
|
|
assert(total == bytes);
|
|
|
|
qiov->niov = niov;
|
|
qiov->size -= bytes;
|
|
}
|