root / event_notifier-posix.c @ 927d4878
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/*
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* event notifier support
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*
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* Copyright Red Hat, Inc. 2010
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*
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* Authors:
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* Michael S. Tsirkin <mst@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*/
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#include "qemu-common.h" |
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#include "qemu/event_notifier.h" |
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#include "char/char.h" |
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#include "qemu/main-loop.h" |
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#ifdef CONFIG_EVENTFD
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#include <sys/eventfd.h> |
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#endif
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void event_notifier_init_fd(EventNotifier *e, int fd) |
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{ |
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e->rfd = fd; |
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e->wfd = fd; |
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} |
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int event_notifier_init(EventNotifier *e, int active) |
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{ |
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int fds[2]; |
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int ret;
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#ifdef CONFIG_EVENTFD
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ret = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
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#else
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ret = -1;
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errno = ENOSYS; |
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#endif
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if (ret >= 0) { |
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e->rfd = e->wfd = ret; |
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} else {
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if (errno != ENOSYS) {
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return -errno;
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} |
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if (qemu_pipe(fds) < 0) { |
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return -errno;
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} |
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ret = fcntl_setfl(fds[0], O_NONBLOCK);
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if (ret < 0) { |
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ret = -errno; |
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goto fail;
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} |
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ret = fcntl_setfl(fds[1], O_NONBLOCK);
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if (ret < 0) { |
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ret = -errno; |
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goto fail;
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} |
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e->rfd = fds[0];
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e->wfd = fds[1];
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} |
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if (active) {
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event_notifier_set(e); |
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} |
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return 0; |
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fail:
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close(fds[0]);
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close(fds[1]);
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return ret;
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} |
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void event_notifier_cleanup(EventNotifier *e)
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{ |
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if (e->rfd != e->wfd) {
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close(e->rfd); |
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} |
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close(e->wfd); |
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} |
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int event_notifier_get_fd(EventNotifier *e)
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{ |
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return e->rfd;
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} |
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int event_notifier_set_handler(EventNotifier *e,
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EventNotifierHandler *handler) |
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{ |
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return qemu_set_fd_handler(e->rfd, (IOHandler *)handler, NULL, e); |
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} |
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int event_notifier_set(EventNotifier *e)
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{ |
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static const uint64_t value = 1; |
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ssize_t ret; |
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do {
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ret = write(e->wfd, &value, sizeof(value));
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} while (ret < 0 && errno == EINTR); |
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/* EAGAIN is fine, a read must be pending. */
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if (ret < 0 && errno != EAGAIN) { |
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return -errno;
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} |
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return 0; |
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} |
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int event_notifier_test_and_clear(EventNotifier *e)
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{ |
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int value;
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ssize_t len; |
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char buffer[512]; |
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/* Drain the notify pipe. For eventfd, only 8 bytes will be read. */
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value = 0;
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do {
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len = read(e->rfd, buffer, sizeof(buffer));
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value |= (len > 0);
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} while ((len == -1 && errno == EINTR) || len == sizeof(buffer)); |
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return value;
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} |