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 } 94