254 lines
6.9 KiB
C
254 lines
6.9 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 "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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#if defined CONFIG_IOVEC && defined 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 ret;
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unsigned si, ei; /* start and end indexes */
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if (bytes == 0) {
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/* Catch the do-nothing case early, as otherwise we will pass an
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* empty iovec to sendmsg/recvmsg(), and not all implementations
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* accept this.
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*/
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return 0;
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}
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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 (si = 0; si < iov_cnt && offset >= iov[si].iov_len; ++si) {
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offset -= iov[si].iov_len;
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}
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if (offset) {
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assert(si < iov_cnt);
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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[si].iov_base += offset;
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iov[si].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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for (ei = si; ei < iov_cnt && iov[ei].iov_len <= bytes; ++ei) {
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bytes -= iov[ei].iov_len;
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}
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if (bytes) {
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/* second, fixup the last element, and remember
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* the length we've cut from the end of it in `bytes' */
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size_t tail;
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assert(ei < iov_cnt);
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assert(iov[ei].iov_len > bytes);
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tail = iov[ei].iov_len - bytes;
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iov[ei].iov_len = bytes;
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bytes = tail; /* bytes is now equal to the tail size */
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++ei;
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}
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ret = do_send_recv(sockfd, iov + si, ei - si, do_send);
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/* Undo the changes above */
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if (offset) {
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iov[si].iov_base -= offset;
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iov[si].iov_len += offset;
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}
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if (bytes) {
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iov[ei-1].iov_len += bytes;
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}
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return ret;
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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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unsigned int i, v, b;
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uint8_t *c;
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c = iov[0].iov_base;
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for (i = 0, v = 0, b = 0; b < limit; i++, b++) {
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if (i == iov[v].iov_len) {
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i = 0; v++;
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if (v == iov_cnt) {
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break;
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}
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c = iov[v].iov_base;
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}
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if ((b % 16) == 0) {
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fprintf(fp, "%s: %04x:", prefix, b);
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}
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if ((b % 4) == 0) {
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fprintf(fp, " ");
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}
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fprintf(fp, " %02x", c[i]);
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if ((b % 16) == 15) {
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fprintf(fp, "\n");
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}
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}
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if ((b % 16) != 0) {
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fprintf(fp, "\n");
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}
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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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