/*
* Copyright 6WIND S.A., 2014
*
* This work is licensed under the terms of the GNU GPL, version 2 or
* (at your option) any later version. See the COPYING file in the
* top-level directory.
*/
#include "qemu/osdep.h"
#include "qemu-common.h"
#include "qemu/host-utils.h"
#include "qemu/sockets.h"
#include <sys/socket.h>
#include <sys/un.h>
#include "ivshmem-server.h"
/* log a message on stdout if verbose=1 */
#define IVSHMEM_SERVER_DEBUG(server, fmt, ...) do { \
if ((server)->verbose) { \
printf(fmt, ## __VA_ARGS__); \
} \
} while (0)
/** maximum size of a huge page, used by ivshmem_server_ftruncate() */
#define IVSHMEM_SERVER_MAX_HUGEPAGE_SIZE (1024 * 1024 * 1024)
/** default listen backlog (number of sockets not accepted) */
#define IVSHMEM_SERVER_LISTEN_BACKLOG 10
/* send message to a client unix socket */
static int
ivshmem_server_send_one_msg(int sock_fd, int64_t peer_id, int fd)
{
int ret;
struct msghdr msg;
struct iovec iov[1];
union {
struct cmsghdr cmsg;
char control[CMSG_SPACE(sizeof(int))];
} msg_control;
struct cmsghdr *cmsg;
peer_id = GINT64_TO_LE(peer_id);
iov[0].iov_base = &peer_id;
iov[0].iov_len = sizeof(peer_id);
memset(&msg, 0, sizeof(msg));
msg.msg_iov = iov;
msg.msg_iovlen = 1;
/* if fd is specified, add it in a cmsg */
if (fd >= 0) {
memset(&msg_control, 0, sizeof(msg_control));
msg.msg_control = &msg_control;
msg.msg_controllen = sizeof(msg_control);
cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
cmsg->cmsg_len = CMSG_LEN(sizeof(int));
memcpy(CMSG_DATA(cmsg), &fd, sizeof(fd));
}
ret = sendmsg(sock_fd, &msg, 0);
if (ret <= 0) {
return -1;
}
return 0;
}
/* free a peer when the server advertises a disconnection or when the
* server is freed */
static void
ivshmem_server_free_peer(IvshmemServer *server, IvshmemServerPeer *peer)
{
unsigned vector;
IvshmemServerPeer *other_peer;
IVSHMEM_SERVER_DEBUG(server, "free peer %" PRId64 "\n", peer->id);
close(peer->sock_fd);
QTAILQ_REMOVE(&server->peer_list, peer, next);
/* advertise the deletion to other peers */
QTAILQ_FOREACH(other_peer, &server->peer_list, next) {
ivshmem_server_send_one_msg(other_peer->sock_fd, peer->id, -1);
}
for (vector = 0; vector < peer->vectors_count; vector++) {
event_notifier_cleanup(&peer->vectors[vector]);
}
g_free(peer);
}
/* send the peer id and the shm_fd just after a new client connection */
static int
ivshmem_server_send_initial_info(IvshmemServer *server, IvshmemServerPeer *peer)
{
int ret;
/* send our protocol version first */
ret = ivshmem_server_send_one_msg(peer->sock_fd, IVSHMEM_PROTOCOL_VERSION,
-1);
if (ret < 0) {
IVSHMEM_SERVER_DEBUG(server, "cannot send version: %s\n",
strerror(errno));
return -1;
}
/* send the peer id to the client */
ret = ivshmem_server_send_one_msg(peer->sock_fd, peer->id, -1);
if (ret < 0) {
IVSHMEM_SERVER_DEBUG(server, "cannot send peer id: %s\n",
strerror(errno));
return -1;
}
/* send the shm_fd */
ret = ivshmem_server_send_one_msg(peer->sock_fd, -1, server->shm_fd);
if (ret < 0) {
IVSHMEM_SERVER_DEBUG(server, "cannot send shm fd: %s\n",
strerror(errno));
return -1;
}
return 0;
}
/* handle message on listening unix socket (new client connection) */
static int
ivshmem_server_handle_new_conn(IvshmemServer *server)
{
IvshmemServerPeer *peer, *other_peer;
struct sockaddr_un unaddr;
socklen_t unaddr_len;
int newfd;
unsigned i;
/* accept the incoming connection */
unaddr_len = sizeof(unaddr);
newfd = qemu_accept(server->sock_fd,
(struct sockaddr *)&unaddr, &unaddr_len);
if (newfd < 0) {
IVSHMEM_SERVER_DEBUG(server, "cannot accept() %s\n", strerror(errno));
return -1;
}
qemu_set_nonblock(newfd);
IVSHMEM_SERVER_DEBUG(server, "accept()=%d\n", newfd);
/* allocate new structure for this peer */
peer = g_malloc0(sizeof(*peer));
peer->sock_fd = newfd;
/* get an unused peer id */
/* XXX: this could use id allocation such as Linux IDA, or simply
* a free-list */
for (i = 0; i < G_MAXUINT16; i++) {
if (ivshmem_server_search_peer(server, server->cur_id) == NULL) {
break;
}
server->cur_id++;
}
if (i == G_MAXUINT16) {
IVSHMEM_SERVER_DEBUG(server, "cannot allocate new client id\n");
close(newfd);
g_free(peer);
return -1;
}
peer->id = server->cur_id++;
/* create eventfd, one per vector */
peer->vectors_count = server->n_vectors;
for (i = 0; i < peer->vectors_count; i++) {
if (event_notifier_init(&peer->vectors[i], FALSE) < 0) {
IVSHMEM_SERVER_DEBUG(server, "cannot create eventfd\n");
goto fail;
}
}
/* send peer id and shm fd */
if (ivshmem_server_send_initial_info(server, peer) < 0) {
IVSHMEM_SERVER_DEBUG(server, "cannot send initial info\n");
goto fail;
}
/* advertise the new peer to others */
QTAILQ_FOREACH(other_peer, &server->peer_list, next) {
for (i = 0; i < peer->vectors_count; i++) {
ivshmem_server_send_one_msg(other_peer->sock_fd, peer->id,
peer->vectors[i].wfd);
}
}
/* advertise the other peers to the new one */
QTAILQ_FOREACH(other_peer, &server->peer_list, next) {
for (i = 0; i < peer->vectors_count; i++) {
ivshmem_server_send_one_msg(peer->sock_fd, other_peer->id,
other_peer->vectors[i].wfd);
}
}
/* advertise the new peer to itself */
for (i = 0; i < peer->vectors_count; i++) {
ivshmem_server_send_one_msg(peer->sock_fd, peer->id,
event_notifier_get_fd(&peer->vectors[i]));
}
QTAILQ_INSERT_TAIL(&server->peer_list, peer, next);
IVSHMEM_SERVER_DEBUG(server, "new peer id = %" PRId64 "\n",
peer->id);
return 0;
fail:
while (i--) {
event_notifier_cleanup(&peer->vectors[i]);
}
close(newfd);
g_free(peer);
return -1;
}
/* Try to ftruncate a file to next power of 2 of shmsize.
* If it fails; all power of 2 above shmsize are tested until
* we reach the maximum huge page size. This is useful
* if the shm file is in a hugetlbfs that cannot be truncated to the
* shm_size value. */
static int
ivshmem_server_ftruncate(int fd, unsigned shmsize)
{
int ret;
struct stat mapstat;
/* align shmsize to next power of 2 */
shmsize = pow2ceil(shmsize);
if (fstat(fd, &mapstat) != -1 && mapstat.st_size == shmsize) {
return 0;
}
while (shmsize <= IVSHMEM_SERVER_MAX_HUGEPAGE_SIZE) {
ret = ftruncate(fd, shmsize);
if (ret == 0) {
return ret;
}
shmsize *= 2;
}
return -1;
}
/* Init a new ivshmem server */
int
ivshmem_server_init(IvshmemServer *server, const char *unix_sock_path,
const char *shm_path, bool use_shm_open,
size_t shm_size, unsigned n_vectors,
bool verbose)
{
int ret;
memset(server, 0, sizeof(*server));
server->verbose = verbose;
ret = snprintf(server->unix_sock_path, sizeof(server->unix_sock_path),
"%s", unix_sock_path);
if (ret < 0 || ret >= sizeof(server->unix_sock_path)) {
IVSHMEM_SERVER_DEBUG(server, "could not copy unix socket path\n");
return -1;
}
ret = snprintf(server->shm_path, sizeof(server->shm_path),
"%s", shm_path);
if (ret < 0 || ret >= sizeof(server->shm_path)) {
IVSHMEM_SERVER_DEBUG(server, "could not copy shm path\n");
return -1;
}
server->use_shm_open = use_shm_open;
server->shm_size = shm_size;
server->n_vectors = n_vectors;
QTAILQ_INIT(&server->peer_list);
return 0;
}
/* open shm, create and bind to the unix socket */
int
ivshmem_server_start(IvshmemServer *server)
{
struct sockaddr_un sun;
int shm_fd, sock_fd, ret;
/* open shm file */
if (server->use_shm_open) {
IVSHMEM_SERVER_DEBUG(server, "Using POSIX shared memory: %s\n",
server->shm_path);
shm_fd = shm_open(server->shm_path, O_CREAT | O_RDWR, S_IRWXU);
} else {
gchar *filename = g_strdup_printf("%s/ivshmem.XXXXXX", server->shm_path);
IVSHMEM_SERVER_DEBUG(server, "Using file-backed shared memory: %s\n",
server->shm_path);
shm_fd = mkstemp(filename);
unlink(filename);
g_free(filename);
}
if (shm_fd < 0) {
fprintf(stderr, "cannot open shm file %s: %s\n", server->shm_path,
strerror(errno));
return -1;
}
if (ivshmem_server_ftruncate(shm_fd, server->shm_size) < 0) {
fprintf(stderr, "ftruncate(%s) failed: %s\n", server->shm_path,
strerror(errno));
goto err_close_shm;
}
IVSHMEM_SERVER_DEBUG(server, "create & bind socket %s\n",
server->unix_sock_path);
/* create the unix listening socket */
sock_fd = socket(AF_UNIX, SOCK_STREAM, 0);
if (sock_fd < 0) {
IVSHMEM_SERVER_DEBUG(server, "cannot create socket: %s\n",
strerror(errno));
goto err_close_shm;
}
sun.sun_family = AF_UNIX;
ret = snprintf(sun.sun_path, sizeof(sun.sun_path), "%s",
server->unix_sock_path);
if (ret < 0 || ret >= sizeof(sun.sun_path)) {
IVSHMEM_SERVER_DEBUG(server, "could not copy unix socket path\n");
goto err_close_sock;
}
if (bind(sock_fd, (struct sockaddr *)&sun, sizeof(sun)) < 0) {
IVSHMEM_SERVER_DEBUG(server, "cannot connect to %s: %s\n", sun.sun_path,
strerror(errno));
goto err_close_sock;
}
if (listen(sock_fd, IVSHMEM_SERVER_LISTEN_BACKLOG) < 0) {
IVSHMEM_SERVER_DEBUG(server, "listen() failed: %s\n", strerror(errno));
goto err_close_sock;
}
server->sock_fd = sock_fd;
server->shm_fd = shm_fd;
return 0;
err_close_sock:
close(sock_fd);
err_close_shm:
close(shm_fd);
return -1;
}
/* close connections to clients, the unix socket and the shm fd */
void
ivshmem_server_close(IvshmemServer *server)
{
IvshmemServerPeer *peer, *npeer;
IVSHMEM_SERVER_DEBUG(server, "close server\n");
QTAILQ_FOREACH_SAFE(peer, &server->peer_list, next, npeer) {
ivshmem_server_free_peer(server, peer);
}
unlink(server->unix_sock_path);
close(server->sock_fd);
close(server->shm_fd);
server->sock_fd = -1;
server->shm_fd = -1;
}
/* get the fd_set according to the unix socket and the peer list */
void
ivshmem_server_get_fds(const IvshmemServer *server, fd_set *fds, int *maxfd)
{
IvshmemServerPeer *peer;
if (server->sock_fd == -1) {
return;
}
FD_SET(server->sock_fd, fds);
if (server->sock_fd >= *maxfd) {
*maxfd = server->sock_fd + 1;
}
QTAILQ_FOREACH(peer, &server->peer_list, next) {
FD_SET(peer->sock_fd, fds);
if (peer->sock_fd >= *maxfd) {
*maxfd = peer->sock_fd + 1;
}
}
}
/* process incoming messages on the sockets in fd_set */
int
ivshmem_server_handle_fds(IvshmemServer *server, fd_set *fds, int maxfd)
{
IvshmemServerPeer *peer, *peer_next;
if (server->sock_fd < maxfd && FD_ISSET(server->sock_fd, fds) &&
ivshmem_server_handle_new_conn(server) < 0 && errno != EINTR) {
IVSHMEM_SERVER_DEBUG(server, "ivshmem_server_handle_new_conn() "
"failed\n");
return -1;
}
QTAILQ_FOREACH_SAFE(peer, &server->peer_list, next, peer_next) {
/* any message from a peer socket result in a close() */
IVSHMEM_SERVER_DEBUG(server, "peer->sock_fd=%d\n", peer->sock_fd);
if (peer->sock_fd < maxfd && FD_ISSET(peer->sock_fd, fds)) {
ivshmem_server_free_peer(server, peer);
}
}
return 0;
}
/* lookup peer from its id */
IvshmemServerPeer *
ivshmem_server_search_peer(IvshmemServer *server, int64_t peer_id)
{
IvshmemServerPeer *peer;
QTAILQ_FOREACH(peer, &server->peer_list, next) {
if (peer->id == peer_id) {
return peer;
}
}
return NULL;
}
/* dump our info, the list of peers their vectors on stdout */
void
ivshmem_server_dump(const IvshmemServer *server)
{
const IvshmemServerPeer *peer;
unsigned vector;
/* dump peers */
QTAILQ_FOREACH(peer, &server->peer_list, next) {
printf("peer_id = %" PRId64 "\n", peer->id);
for (vector = 0; vector < peer->vectors_count; vector++) {
printf(" vector %d is enabled (fd=%d)\n", vector,
event_notifier_get_fd(&peer->vectors[vector]));
}
}
}
