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authorPaolo Bonzini <pbonzini@redhat.com>2010-05-24 17:17:04 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2012-10-30 09:30:52 +0100
commitd0cc2fbfa607678866475383c508be84818ceb64 (patch)
treee062dcd177512bc99491396c207a5eea3ac7326c
parentfc97a652de3e54394ca4d0e5e5d689fd8aba8b6f (diff)
downloadqemu-d0cc2fbfa607678866475383c508be84818ceb64.tar.gz
event_notifier: enable it to use pipes
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>
-rw-r--r--event_notifier-posix.c85
-rw-r--r--event_notifier.h3
2 files changed, 71 insertions, 17 deletions
diff --git a/event_notifier-posix.c b/event_notifier-posix.c
index 2c207e1399..6f3239a3fc 100644
--- a/event_notifier-posix.c
+++ b/event_notifier-posix.c
@@ -20,48 +20,101 @@
void event_notifier_init_fd(EventNotifier *e, int fd)
{
- e->fd = fd;
+ e->rfd = fd;
+ e->wfd = fd;
}
int event_notifier_init(EventNotifier *e, int active)
{
+ int fds[2];
+ int ret;
+
#ifdef CONFIG_EVENTFD
- int fd = eventfd(!!active, EFD_NONBLOCK | EFD_CLOEXEC);
- if (fd < 0)
- return -errno;
- e->fd = fd;
- return 0;
+ ret = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
#else
- return -ENOSYS;
+ 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)
{
- close(e->fd);
+ if (e->rfd != e->wfd) {
+ close(e->rfd);
+ }
+ close(e->wfd);
}
int event_notifier_get_fd(EventNotifier *e)
{
- return e->fd;
+ return e->rfd;
}
int event_notifier_set_handler(EventNotifier *e,
EventNotifierHandler *handler)
{
- return qemu_set_fd_handler(e->fd, (IOHandler *)handler, NULL, e);
+ return qemu_set_fd_handler(e->rfd, (IOHandler *)handler, NULL, e);
}
int event_notifier_set(EventNotifier *e)
{
- uint64_t value = 1;
- int r = write(e->fd, &value, sizeof(value));
- return r == sizeof(value);
+ 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)
{
- uint64_t value;
- int r = read(e->fd, &value, sizeof(value));
- return r == sizeof(value);
+ 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;
}
diff --git a/event_notifier.h b/event_notifier.h
index b283a497ce..88b57af7ce 100644
--- a/event_notifier.h
+++ b/event_notifier.h
@@ -23,7 +23,8 @@ struct EventNotifier {
#ifdef _WIN32
HANDLE event;
#else
- int fd;
+ int rfd;
+ int wfd;
#endif
};