Merge remote-tracking branch 'remotes/riku/tags/pull-linux-user-20141111' into staging
[qemu.git] / qemu-coroutine-io.c
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-common.h"
26 #include "qemu/sockets.h"
27 #include "block/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 int err;
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 err = socket_error();
45 if (err == EAGAIN || err == EWOULDBLOCK) {
46 qemu_coroutine_yield();
47 } else if (done == 0) {
48 return -1;
49 } else {
50 break;
51 }
52 } else if (ret == 0 && !do_send) {
53 /* write (send) should never return 0.
54 * read (recv) returns 0 for end-of-file (-data).
55 * In both cases there's little point retrying,
56 * but we do for write anyway, just in case */
57 break;
58 }
59 }
60 return done;
61 }
62
63 ssize_t coroutine_fn
64 qemu_co_send_recv(int sockfd, void *buf, size_t bytes, bool do_send)
65 {
66 struct iovec iov = { .iov_base = buf, .iov_len = bytes };
67 return qemu_co_sendv_recvv(sockfd, &iov, 1, 0, bytes, do_send);
68 }
69
70 typedef struct {
71 Coroutine *co;
72 int fd;
73 } FDYieldUntilData;
74
75 static void fd_coroutine_enter(void *opaque)
76 {
77 FDYieldUntilData *data = opaque;
78 qemu_set_fd_handler(data->fd, NULL, NULL, NULL);
79 qemu_coroutine_enter(data->co, NULL);
80 }
81
82 void coroutine_fn yield_until_fd_readable(int fd)
83 {
84 FDYieldUntilData data;
85
86 assert(qemu_in_coroutine());
87 data.co = qemu_coroutine_self();
88 data.fd = fd;
89 qemu_set_fd_handler(fd, fd_coroutine_enter, NULL, &data);
90 qemu_coroutine_yield();
91 }