mirror of
https://github.com/xemu-project/xemu.git
synced 2024-11-24 12:09:58 +00:00
d0cc2fbfa6
This takes the eventfd emulation code from the main loop. When the EventNotifier is used for the main loop too, we need this compatibility code. Without CONFIG_EVENTFD, event_notifier_get_fd is only usable for the "read" side of the notifier, for example to set a select() handler. The return value of event_notifier_set changes to the cleaner 0/-errno. No caller is actually checking the return value. Reviewed-by: Anthony Liguori <anthony@codemonkey.ws> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
121 lines
2.4 KiB
C
121 lines
2.4 KiB
C
/*
|
|
* event notifier support
|
|
*
|
|
* Copyright Red Hat, Inc. 2010
|
|
*
|
|
* Authors:
|
|
* Michael S. Tsirkin <mst@redhat.com>
|
|
*
|
|
* This work is licensed under the terms of the GNU GPL, version 2 or later.
|
|
* See the COPYING file in the top-level directory.
|
|
*/
|
|
|
|
#include "qemu-common.h"
|
|
#include "event_notifier.h"
|
|
#include "qemu-char.h"
|
|
|
|
#ifdef CONFIG_EVENTFD
|
|
#include <sys/eventfd.h>
|
|
#endif
|
|
|
|
void event_notifier_init_fd(EventNotifier *e, int fd)
|
|
{
|
|
e->rfd = fd;
|
|
e->wfd = fd;
|
|
}
|
|
|
|
int event_notifier_init(EventNotifier *e, int active)
|
|
{
|
|
int fds[2];
|
|
int ret;
|
|
|
|
#ifdef CONFIG_EVENTFD
|
|
ret = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
|
|
#else
|
|
ret = -1;
|
|
errno = ENOSYS;
|
|
#endif
|
|
if (ret >= 0) {
|
|
e->rfd = e->wfd = ret;
|
|
} else {
|
|
if (errno != ENOSYS) {
|
|
return -errno;
|
|
}
|
|
if (qemu_pipe(fds) < 0) {
|
|
return -errno;
|
|
}
|
|
ret = fcntl_setfl(fds[0], O_NONBLOCK);
|
|
if (ret < 0) {
|
|
ret = -errno;
|
|
goto fail;
|
|
}
|
|
ret = fcntl_setfl(fds[1], O_NONBLOCK);
|
|
if (ret < 0) {
|
|
ret = -errno;
|
|
goto fail;
|
|
}
|
|
e->rfd = fds[0];
|
|
e->wfd = fds[1];
|
|
}
|
|
if (active) {
|
|
event_notifier_set(e);
|
|
}
|
|
return 0;
|
|
|
|
fail:
|
|
close(fds[0]);
|
|
close(fds[1]);
|
|
return ret;
|
|
}
|
|
|
|
void event_notifier_cleanup(EventNotifier *e)
|
|
{
|
|
if (e->rfd != e->wfd) {
|
|
close(e->rfd);
|
|
}
|
|
close(e->wfd);
|
|
}
|
|
|
|
int event_notifier_get_fd(EventNotifier *e)
|
|
{
|
|
return e->rfd;
|
|
}
|
|
|
|
int event_notifier_set_handler(EventNotifier *e,
|
|
EventNotifierHandler *handler)
|
|
{
|
|
return qemu_set_fd_handler(e->rfd, (IOHandler *)handler, NULL, e);
|
|
}
|
|
|
|
int event_notifier_set(EventNotifier *e)
|
|
{
|
|
static const uint64_t value = 1;
|
|
ssize_t ret;
|
|
|
|
do {
|
|
ret = write(e->wfd, &value, sizeof(value));
|
|
} while (ret < 0 && errno == EINTR);
|
|
|
|
/* EAGAIN is fine, a read must be pending. */
|
|
if (ret < 0 && errno != EAGAIN) {
|
|
return -errno;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int event_notifier_test_and_clear(EventNotifier *e)
|
|
{
|
|
int value;
|
|
ssize_t len;
|
|
char buffer[512];
|
|
|
|
/* Drain the notify pipe. For eventfd, only 8 bytes will be read. */
|
|
value = 0;
|
|
do {
|
|
len = read(e->rfd, buffer, sizeof(buffer));
|
|
value |= (len > 0);
|
|
} while ((len == -1 && errno == EINTR) || len == sizeof(buffer));
|
|
|
|
return value;
|
|
}
|