Archipelago » qemu

/*

 * Coroutine-aware I/O functions

 *

 * Copyright (C) 2009-2010 Nippon Telegraph and Telephone Corporation.

 * Copyright (c) 2011, Red Hat, Inc.

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#include "qemu-common.h"

#include "qemu/sockets.h"

#include "block/coroutine.h"

#include "qemu/iov.h"

ssize_t coroutine_fn

qemu_co_sendv_recvv(int sockfd, struct iovec *iov, unsigned iov_cnt,

                    size_t offset, size_t bytes, bool do_send)

{

    size_t done = 0;

    ssize_t ret;

    while (done < bytes) {

        ret = iov_send_recv(sockfd, iov, iov_cnt,

                            offset + done, bytes - done, do_send);

        if (ret > 0) {

            done += ret;

        } else if (ret < 0) {

            if (errno == EAGAIN) {

                qemu_coroutine_yield();

            } else if (done == 0) {

                return -1;

            } else {

                break;

            }

        } else if (ret == 0 && !do_send) {

            /* write (send) should never return 0.

             * read (recv) returns 0 for end-of-file (-data).

             * In both cases there's little point retrying,

             * but we do for write anyway, just in case */

            break;

        }

    }

    return done;

}

ssize_t coroutine_fn

qemu_co_send_recv(int sockfd, void *buf, size_t bytes, bool do_send)

{

    struct iovec iov = { .iov_base = buf, .iov_len = bytes };

    return qemu_co_sendv_recvv(sockfd, &iov, 1, 0, bytes, do_send);

}

typedef struct {

    Coroutine *co;

    int fd;

} FDYieldUntilData;

static void fd_coroutine_enter(void *opaque)

{

    FDYieldUntilData *data = opaque;

    qemu_set_fd_handler(data->fd, NULL, NULL, NULL);

    qemu_coroutine_enter(data->co, NULL);

}

void coroutine_fn yield_until_fd_readable(int fd)

{

    FDYieldUntilData data;

    assert(qemu_in_coroutine());

    data.co = qemu_coroutine_self();

    data.fd = fd;

    qemu_set_fd_handler(fd, fd_coroutine_enter, NULL, &data);

    qemu_coroutine_yield();

}