qemu

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/*
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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/osdep.h"
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#include "qemu/sockets.h"
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#include "qemu/coroutine.h"
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#include "qemu/iov.h"
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#include "qemu/main-loop.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 || errno == EWOULDBLOCK) {
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                qemu_coroutine_yield();
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            } else if (done == 0) {
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                return -errno;
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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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typedef struct {
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    AioContext *ctx;
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    Coroutine *co;
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    int fd;
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} FDYieldUntilData;
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static void fd_coroutine_enter(void *opaque)
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{
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    FDYieldUntilData *data = opaque;
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    aio_set_fd_handler(data->ctx, data->fd, NULL, NULL, NULL, NULL, NULL);
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    qemu_coroutine_enter(data->co);
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}
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void coroutine_fn yield_until_fd_readable(int fd)
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{
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    FDYieldUntilData data;
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    assert(qemu_in_coroutine());
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    data.ctx = qemu_get_current_aio_context();
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    data.co = qemu_coroutine_self();
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    data.fd = fd;
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    aio_set_fd_handler(data.ctx, fd, fd_coroutine_enter, NULL, NULL, NULL,
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                       &data);
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    qemu_coroutine_yield();
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}
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