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/*
* Based on:
* 1) file-posix.c of QEMU Project
*
* Copyright (c) 2006 Fabrice Bellard
*
* 2) event_notifier-posix.c of QEMU Project
*
* Copyright Red Hat, Inc. 2010
*
* Authors:
* Michael S. Tsirkin <mst@redhat.com>
*
* 3) os-posix-lib.c of QEMU project
*
* Copyright (c) 2003-2008 Fabrice Bellard
* Copyright (c) 2010 Red Hat, Inc.
*
* Copyright 2023 Virtual Open Systems SAS.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <sys/eventfd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <pthread.h>
#include <stdbool.h>
#include <sys/param.h>
#include <assert.h>
/* For socket */
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
/* Project header files */
#include "vhost_user_loopback.h"
/* Sets a specific flag */
int fcntl_setfl(int fd, int flag)
{
int flags;
flags = fcntl(fd, F_GETFL);
if (flags == -1) {
return -errno;
}
if (fcntl(fd, F_SETFL, flags | flag) == -1) {
return -errno;
}
return 0;
}
void qemu_set_cloexec(int fd)
{
int f;
f = fcntl(fd, F_GETFD);
f = fcntl(fd, F_SETFD, f | FD_CLOEXEC);
}
/*
* Creates a pipe with FD_CLOEXEC set on both file descriptors
*/
int qemu_pipe(int pipefd[2])
{
int ret;
#ifdef CONFIG_PIPE2
ret = pipe2(pipefd, O_CLOEXEC);
if (ret != -1 || errno != ENOSYS) {
return ret;
}
#endif
ret = pipe(pipefd);
if (ret == 0) {
qemu_set_cloexec(pipefd[0]);
qemu_set_cloexec(pipefd[1]);
}
return ret;
}
int event_notifier_get_fd(const EventNotifier *e)
{
return e->rfd;
}
int event_notifier_get_wfd(const EventNotifier *e)
{
return e->wfd;
}
int event_notifier_set(EventNotifier *e)
{
static const uint64_t value = 1;
ssize_t ret;
if (!e->initialized) {
return -1;
}
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_init(EventNotifier *e, int active)
{
int fds[2];
int ret;
ret = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
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];
}
e->initialized = true;
if (active) {
event_notifier_set(e);
}
return 0;
fail:
close(fds[0]);
close(fds[1]);
return ret;
}
bool ioeventfd_enabled(void)
{
/*
* TODO: Delete if not needed:
* return !kvm_enabled() || kvm_eventfds_enabled();
*/
return 1;
}
int event_notifier_test_and_clear(EventNotifier *e)
{
int value;
ssize_t len;
char buffer[512];
if (!e->initialized) {
return 0;
}
/* 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;
}
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