qemu

FORK: QEMU emulator
git clone https://git.neptards.moe/neptards/qemu.git
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qemu-coroutine-io.c (3211B)

      1 /*
      2  * Coroutine-aware I/O functions
      3  *
      4  * Copyright (C) 2009-2010 Nippon Telegraph and Telephone Corporation.
      5  * Copyright (c) 2011, Red Hat, Inc.
      6  *
      7  * Permission is hereby granted, free of charge, to any person obtaining a copy
      8  * of this software and associated documentation files (the "Software"), to deal
      9  * in the Software without restriction, including without limitation the rights
     10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     11  * copies of the Software, and to permit persons to whom the Software is
     12  * furnished to do so, subject to the following conditions:
     13  *
     14  * The above copyright notice and this permission notice shall be included in
     15  * all copies or substantial portions of the Software.
     16  *
     17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
     20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
     22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
     23  * THE SOFTWARE.
     24  */
     25 #include "qemu/osdep.h"
     26 #include "qemu/sockets.h"
     27 #include "qemu/coroutine.h"
     28 #include "qemu/iov.h"
     29 #include "qemu/main-loop.h"
     30 
     31 ssize_t coroutine_fn
     32 qemu_co_sendv_recvv(int sockfd, struct iovec *iov, unsigned iov_cnt,
     33                     size_t offset, size_t bytes, bool do_send)
     34 {
     35     size_t done = 0;
     36     ssize_t ret;
     37     while (done < bytes) {
     38         ret = iov_send_recv(sockfd, iov, iov_cnt,
     39                             offset + done, bytes - done, do_send);
     40         if (ret > 0) {
     41             done += ret;
     42         } else if (ret < 0) {
     43             if (errno == EAGAIN || errno == EWOULDBLOCK) {
     44                 qemu_coroutine_yield();
     45             } else if (done == 0) {
     46                 return -errno;
     47             } else {
     48                 break;
     49             }
     50         } else if (ret == 0 && !do_send) {
     51             /* write (send) should never return 0.
     52              * read (recv) returns 0 for end-of-file (-data).
     53              * In both cases there's little point retrying,
     54              * but we do for write anyway, just in case */
     55             break;
     56         }
     57     }
     58     return done;
     59 }
     60 
     61 ssize_t coroutine_fn
     62 qemu_co_send_recv(int sockfd, void *buf, size_t bytes, bool do_send)
     63 {
     64     struct iovec iov = { .iov_base = buf, .iov_len = bytes };
     65     return qemu_co_sendv_recvv(sockfd, &iov, 1, 0, bytes, do_send);
     66 }
     67 
     68 typedef struct {
     69     AioContext *ctx;
     70     Coroutine *co;
     71     int fd;
     72 } FDYieldUntilData;
     73 
     74 static void fd_coroutine_enter(void *opaque)
     75 {
     76     FDYieldUntilData *data = opaque;
     77     aio_set_fd_handler(data->ctx, data->fd, false,
     78                        NULL, NULL, NULL, NULL, NULL);
     79     qemu_coroutine_enter(data->co);
     80 }
     81 
     82 void coroutine_fn yield_until_fd_readable(int fd)
     83 {
     84     FDYieldUntilData data;
     85 
     86     assert(qemu_in_coroutine());
     87     data.ctx = qemu_get_current_aio_context();
     88     data.co = qemu_coroutine_self();
     89     data.fd = fd;
     90     aio_set_fd_handler(
     91         data.ctx, fd, false, fd_coroutine_enter, NULL, NULL, NULL, &data);
     92     qemu_coroutine_yield();
     93 }