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 | |