mirror of
https://gitlab.com/qemu-project/qemu
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25e5e4c7e9
Make it much more understandable, add a missing iov_cnt argument (number of iovs in the iov), and add comments to it. The new implementation has been extensively tested by splitting a large buffer into many small randomly-sized chunks, sending it over socket to another, slow process and verifying the receiving data is the same. Also add a unit test for iov_send_recv(), sending/ receiving data between two processes over a socketpair using random vectors and random sizes. Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
65 lines
2.4 KiB
C
65 lines
2.4 KiB
C
/*
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* Coroutine-aware I/O functions
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*
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* Copyright (C) 2009-2010 Nippon Telegraph and Telephone Corporation.
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* Copyright (c) 2011, Red Hat, Inc.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu-common.h"
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#include "qemu_socket.h"
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#include "qemu-coroutine.h"
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#include "iov.h"
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ssize_t coroutine_fn
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qemu_co_sendv_recvv(int sockfd, struct iovec *iov, unsigned iov_cnt,
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size_t offset, size_t bytes, bool do_send)
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{
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size_t done = 0;
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ssize_t ret;
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while (done < bytes) {
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ret = iov_send_recv(sockfd, iov, iov_cnt,
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offset + done, bytes - done, do_send);
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if (ret > 0) {
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done += ret;
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} else if (ret < 0) {
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if (errno == EAGAIN) {
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qemu_coroutine_yield();
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} else if (done == 0) {
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return -1;
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} else {
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break;
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}
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} else if (ret == 0 && !do_send) {
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/* write (send) should never return 0.
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* read (recv) returns 0 for end-of-file (-data).
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* In both cases there's little point retrying,
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* but we do for write anyway, just in case */
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break;
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}
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}
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return done;
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}
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ssize_t coroutine_fn
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qemu_co_send_recv(int sockfd, void *buf, size_t bytes, bool do_send)
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{
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struct iovec iov = { .iov_base = buf, .iov_len = bytes };
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return qemu_co_sendv_recvv(sockfd, &iov, 1, 0, bytes, do_send);
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}
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