Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging
[qemu/ar7.git] / util / event_notifier-posix.c
blobed4ca2b01e8fc6fb76cbcb30b87a856e6c997d02
1 /*
2 * event notifier support
4 * Copyright Red Hat, Inc. 2010
6 * Authors:
7 * Michael S. Tsirkin <mst@redhat.com>
9 * This work is licensed under the terms of the GNU GPL, version 2 or later.
10 * See the COPYING file in the top-level directory.
13 #include "qemu-common.h"
14 #include "qemu/event_notifier.h"
15 #include "sysemu/char.h"
16 #include "qemu/main-loop.h"
18 #ifdef CONFIG_EVENTFD
19 #include <sys/eventfd.h>
20 #endif
22 void event_notifier_init_fd(EventNotifier *e, int fd)
24 e->rfd = fd;
25 e->wfd = fd;
28 int event_notifier_init(EventNotifier *e, int active)
30 int fds[2];
31 int ret;
33 #ifdef CONFIG_EVENTFD
34 ret = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
35 #else
36 ret = -1;
37 errno = ENOSYS;
38 #endif
39 if (ret >= 0) {
40 e->rfd = e->wfd = ret;
41 } else {
42 if (errno != ENOSYS) {
43 return -errno;
45 if (qemu_pipe(fds) < 0) {
46 return -errno;
48 ret = fcntl_setfl(fds[0], O_NONBLOCK);
49 if (ret < 0) {
50 ret = -errno;
51 goto fail;
53 ret = fcntl_setfl(fds[1], O_NONBLOCK);
54 if (ret < 0) {
55 ret = -errno;
56 goto fail;
58 e->rfd = fds[0];
59 e->wfd = fds[1];
61 if (active) {
62 event_notifier_set(e);
64 return 0;
66 fail:
67 close(fds[0]);
68 close(fds[1]);
69 return ret;
72 void event_notifier_cleanup(EventNotifier *e)
74 if (e->rfd != e->wfd) {
75 close(e->rfd);
77 close(e->wfd);
80 int event_notifier_get_fd(EventNotifier *e)
82 return e->rfd;
85 int event_notifier_set_handler(EventNotifier *e,
86 EventNotifierHandler *handler)
88 qemu_set_fd_handler(e->rfd, (IOHandler *)handler, NULL, e);
89 return 0;
92 int event_notifier_set(EventNotifier *e)
94 static const uint64_t value = 1;
95 ssize_t ret;
97 do {
98 ret = write(e->wfd, &value, sizeof(value));
99 } while (ret < 0 && errno == EINTR);
101 /* EAGAIN is fine, a read must be pending. */
102 if (ret < 0 && errno != EAGAIN) {
103 return -errno;
105 return 0;
108 int event_notifier_test_and_clear(EventNotifier *e)
110 int value;
111 ssize_t len;
112 char buffer[512];
114 /* Drain the notify pipe. For eventfd, only 8 bytes will be read. */
115 value = 0;
116 do {
117 len = read(e->rfd, buffer, sizeof(buffer));
118 value |= (len > 0);
119 } while ((len == -1 && errno == EINTR) || len == sizeof(buffer));
121 return value;