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/*
* virtio-fs glue for FUSE
* Copyright (C) 2018 Red Hat, Inc. and/or its affiliates
*
* Authors:
* Dave Gilbert <dgilbert@redhat.com>
*
* Implements the glue between libfuse and libvhost-user
*
* This program can be distributed under the terms of the GNU LGPLv2.
* See the file COPYING.LIB
*/
#include "fuse_virtio.h"
#include "fuse_i.h"
#include "standard-headers/linux/fuse.h"
#include "fuse_misc.h"
#include "fuse_opt.h"
#include <assert.h>
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>
#include <unistd.h>
#include "contrib/libvhost-user/libvhost-user.h"
/*
* We pass the dev element into libvhost-user
* and then use it to get back to the outer
* container for other data.
*/
struct fv_VuDev {
VuDev dev;
struct fuse_session *se;
};
/* From spec */
struct virtio_fs_config {
char tag[36];
uint32_t num_queues;
};
/* Callback from libvhost-user */
static uint64_t fv_get_features(VuDev *dev)
{
return 1ULL << VIRTIO_F_VERSION_1;
}
/* Callback from libvhost-user */
static void fv_set_features(VuDev *dev, uint64_t features)
{
}
/*
* Callback from libvhost-user if there's a new fd we're supposed to listen
* to, typically a queue kick?
*/
static void fv_set_watch(VuDev *dev, int fd, int condition, vu_watch_cb cb,
void *data)
{
fuse_log(FUSE_LOG_WARNING, "%s: TODO! fd=%d\n", __func__, fd);
}
/*
* Callback from libvhost-user if we're no longer supposed to listen on an fd
*/
static void fv_remove_watch(VuDev *dev, int fd)
{
fuse_log(FUSE_LOG_WARNING, "%s: TODO! fd=%d\n", __func__, fd);
}
/* Callback from libvhost-user to panic */
static void fv_panic(VuDev *dev, const char *err)
{
fuse_log(FUSE_LOG_ERR, "%s: libvhost-user: %s\n", __func__, err);
/* TODO: Allow reconnects?? */
exit(EXIT_FAILURE);
}
static bool fv_queue_order(VuDev *dev, int qidx)
{
return false;
}
static const VuDevIface fv_iface = {
.get_features = fv_get_features,
.set_features = fv_set_features,
.queue_is_processed_in_order = fv_queue_order,
};
/*
* Main loop; this mostly deals with events on the vhost-user
* socket itself, and not actual fuse data.
*/
int virtio_loop(struct fuse_session *se)
{
fuse_log(FUSE_LOG_INFO, "%s: Entry\n", __func__);
while (!fuse_session_exited(se)) {
struct pollfd pf[1];
pf[0].fd = se->vu_socketfd;
pf[0].events = POLLIN;
pf[0].revents = 0;
fuse_log(FUSE_LOG_DEBUG, "%s: Waiting for VU event\n", __func__);
int poll_res = ppoll(pf, 1, NULL, NULL);
if (poll_res == -1) {
if (errno == EINTR) {
fuse_log(FUSE_LOG_INFO, "%s: ppoll interrupted, going around\n",
__func__);
continue;
}
fuse_log(FUSE_LOG_ERR, "virtio_loop ppoll: %m\n");
break;
}
assert(poll_res == 1);
if (pf[0].revents & (POLLERR | POLLHUP | POLLNVAL)) {
fuse_log(FUSE_LOG_ERR, "%s: Unexpected poll revents %x\n", __func__,
pf[0].revents);
break;
}
assert(pf[0].revents & POLLIN);
fuse_log(FUSE_LOG_DEBUG, "%s: Got VU event\n", __func__);
if (!vu_dispatch(&se->virtio_dev->dev)) {
fuse_log(FUSE_LOG_ERR, "%s: vu_dispatch failed\n", __func__);
break;
}
}
fuse_log(FUSE_LOG_INFO, "%s: Exit\n", __func__);
return 0;
}
int virtio_session_mount(struct fuse_session *se)
{
struct sockaddr_un un;
mode_t old_umask;
if (strlen(se->vu_socket_path) >= sizeof(un.sun_path)) {
fuse_log(FUSE_LOG_ERR, "Socket path too long\n");
return -1;
}
se->fd = -1;
/*
* Create the Unix socket to communicate with qemu
* based on QEMU's vhost-user-bridge
*/
unlink(se->vu_socket_path);
strcpy(un.sun_path, se->vu_socket_path);
size_t addr_len = sizeof(un);
int listen_sock = socket(AF_UNIX, SOCK_STREAM, 0);
if (listen_sock == -1) {
fuse_log(FUSE_LOG_ERR, "vhost socket creation: %m\n");
return -1;
}
un.sun_family = AF_UNIX;
/*
* Unfortunately bind doesn't let you set the mask on the socket,
* so set umask to 077 and restore it later.
*/
old_umask = umask(0077);
if (bind(listen_sock, (struct sockaddr *)&un, addr_len) == -1) {
fuse_log(FUSE_LOG_ERR, "vhost socket bind: %m\n");
umask(old_umask);
return -1;
}
umask(old_umask);
if (listen(listen_sock, 1) == -1) {
fuse_log(FUSE_LOG_ERR, "vhost socket listen: %m\n");
return -1;
}
fuse_log(FUSE_LOG_INFO, "%s: Waiting for vhost-user socket connection...\n",
__func__);
int data_sock = accept(listen_sock, NULL, NULL);
if (data_sock == -1) {
fuse_log(FUSE_LOG_ERR, "vhost socket accept: %m\n");
close(listen_sock);
return -1;
}
close(listen_sock);
fuse_log(FUSE_LOG_INFO, "%s: Received vhost-user socket connection\n",
__func__);
/* TODO: Some cleanup/deallocation! */
se->virtio_dev = calloc(sizeof(struct fv_VuDev), 1);
if (!se->virtio_dev) {
fuse_log(FUSE_LOG_ERR, "%s: virtio_dev calloc failed\n", __func__);
close(data_sock);
return -1;
}
se->vu_socketfd = data_sock;
se->virtio_dev->se = se;
vu_init(&se->virtio_dev->dev, 2, se->vu_socketfd, fv_panic, fv_set_watch,
fv_remove_watch, &fv_iface);
return 0;
}
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