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-common.h" 27 #include "qemu/sockets.h" 28 #include "qemu/coroutine.h" 29 #include "qemu/iov.h" 30 #include "qemu/main-loop.h" 31 32 ssize_t coroutine_fn 33 qemu_co_sendv_recvv(int sockfd, struct iovec *iov, unsigned iov_cnt, 34 size_t offset, size_t bytes, bool do_send) 35 { 36 size_t done = 0; 37 ssize_t ret; 38 while (done < bytes) { 39 ret = iov_send_recv(sockfd, iov, iov_cnt, 40 offset + done, bytes - done, do_send); 41 if (ret > 0) { 42 done += ret; 43 } else if (ret < 0) { 44 if (errno == EAGAIN || errno == EWOULDBLOCK) { 45 qemu_coroutine_yield(); 46 } else if (done == 0) { 47 return -errno; 48 } else { 49 break; 50 } 51 } else if (ret == 0 && !do_send) { 52 /* write (send) should never return 0. 53 * read (recv) returns 0 for end-of-file (-data). 54 * In both cases there's little point retrying, 55 * but we do for write anyway, just in case */ 56 break; 57 } 58 } 59 return done; 60 } 61 62 ssize_t coroutine_fn 63 qemu_co_send_recv(int sockfd, void *buf, size_t bytes, bool do_send) 64 { 65 struct iovec iov = { .iov_base = buf, .iov_len = bytes }; 66 return qemu_co_sendv_recvv(sockfd, &iov, 1, 0, bytes, do_send); 67 } 68 69 typedef struct { 70 Coroutine *co; 71 int fd; 72 } FDYieldUntilData; 73 74 static void fd_coroutine_enter(void *opaque) 75 { 76 FDYieldUntilData *data = opaque; 77 qemu_set_fd_handler(data->fd, NULL, NULL, NULL); 78 qemu_coroutine_enter(data->co); 79 } 80 81 void coroutine_fn yield_until_fd_readable(int fd) 82 { 83 FDYieldUntilData data; 84 85 assert(qemu_in_coroutine()); 86 data.co = qemu_coroutine_self(); 87 data.fd = fd; 88 qemu_set_fd_handler(fd, fd_coroutine_enter, NULL, &data); 89 qemu_coroutine_yield(); 90 } 91