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/*
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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/iov.h" |
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#ifdef _WIN32
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# include <windows.h> |
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# include <winsock2.h> |
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#else
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# include <sys/types.h> |
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# include <sys/socket.h> |
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#endif
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size_t iov_from_buf(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(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, 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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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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} |
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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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if (tail) {
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iov[niov-1].iov_len = orig_len;
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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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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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/* 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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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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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; i < iov_cnt && j < dst_iov_cnt && 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_malloc(alloc_hint * sizeof(struct iovec)); |
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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_realloc(qiov->iov, qiov->nalloc * sizeof(struct iovec)); |
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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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void 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;
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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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} |
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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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void qemu_iovec_destroy(QEMUIOVector *qiov)
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{ |
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assert(qiov->nalloc != -1);
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qemu_iovec_reset(qiov); |
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g_free(qiov->iov); |
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qiov->nalloc = 0;
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qiov->iov = NULL;
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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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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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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; |
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*iov_cnt -= 1;
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} |
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*iov = cur; |
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return total;
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} |
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size_t iov_discard_back(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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if (*iov_cnt == 0) { |
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return 0; |
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} |
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cur = iov + (*iov_cnt - 1);
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while (*iov_cnt > 0) { |
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if (cur->iov_len > 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; |
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cur--; |
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*iov_cnt -= 1;
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} |
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return total;
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} |