qemu-e2k/contrib/ivshmem-client/ivshmem-client.c

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/*
* 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 <sys/socket.h>
#include <sys/un.h>
#include "qemu/queue.h"
#include "ivshmem-client.h"
/* log a message on stdout if verbose=1 */
#define IVSHMEM_CLIENT_DEBUG(client, fmt, ...) do { \
if ((client)->verbose) { \
printf(fmt, ## __VA_ARGS__); \
} \
} while (0)
/* read message from the unix socket */
static int
ivshmem_client_read_one_msg(IvshmemClient *client, int64_t *index, 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;
iov[0].iov_base = index;
iov[0].iov_len = sizeof(*index);
memset(&msg, 0, sizeof(msg));
msg.msg_iov = iov;
msg.msg_iovlen = 1;
msg.msg_control = &msg_control;
msg.msg_controllen = sizeof(msg_control);
ret = recvmsg(client->sock_fd, &msg, 0);
if (ret < sizeof(*index)) {
IVSHMEM_CLIENT_DEBUG(client, "cannot read message: %s\n",
strerror(errno));
return -1;
}
if (ret == 0) {
IVSHMEM_CLIENT_DEBUG(client, "lost connection to server\n");
return -1;
}
*index = GINT64_FROM_LE(*index);
*fd = -1;
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)) ||
cmsg->cmsg_level != SOL_SOCKET ||
cmsg->cmsg_type != SCM_RIGHTS) {
continue;
}
memcpy(fd, CMSG_DATA(cmsg), sizeof(*fd));
}
return 0;
}
/* free a peer when the server advertises a disconnection or when the
* client is freed */
static void
ivshmem_client_free_peer(IvshmemClient *client, IvshmemClientPeer *peer)
{
unsigned vector;
QTAILQ_REMOVE(&client->peer_list, peer, next);
for (vector = 0; vector < peer->vectors_count; vector++) {
close(peer->vectors[vector]);
}
g_free(peer);
}
/* handle message coming from server (new peer, new vectors) */
static int
ivshmem_client_handle_server_msg(IvshmemClient *client)
{
IvshmemClientPeer *peer;
int64_t peer_id;
int ret, fd;
ret = ivshmem_client_read_one_msg(client, &peer_id, &fd);
if (ret < 0) {
return -1;
}
/* can return a peer or the local client */
peer = ivshmem_client_search_peer(client, peer_id);
/* delete peer */
if (fd == -1) {
if (peer == NULL || peer == &client->local) {
IVSHMEM_CLIENT_DEBUG(client, "receive delete for invalid "
"peer %" PRId64 "\n", peer_id);
return -1;
}
IVSHMEM_CLIENT_DEBUG(client, "delete peer id = %" PRId64 "\n", peer_id);
ivshmem_client_free_peer(client, peer);
return 0;
}
/* new peer */
if (peer == NULL) {
peer = g_malloc0(sizeof(*peer));
peer->id = peer_id;
peer->vectors_count = 0;
QTAILQ_INSERT_TAIL(&client->peer_list, peer, next);
IVSHMEM_CLIENT_DEBUG(client, "new peer id = %" PRId64 "\n", peer_id);
}
/* new vector */
IVSHMEM_CLIENT_DEBUG(client, " new vector %d (fd=%d) for peer id %"
PRId64 "\n", peer->vectors_count, fd, peer->id);
if (peer->vectors_count >= G_N_ELEMENTS(peer->vectors)) {
IVSHMEM_CLIENT_DEBUG(client, "Too many vectors received, failing");
return -1;
}
peer->vectors[peer->vectors_count] = fd;
peer->vectors_count++;
return 0;
}
/* init a new ivshmem client */
int
ivshmem_client_init(IvshmemClient *client, const char *unix_sock_path,
IvshmemClientNotifCb notif_cb, void *notif_arg,
bool verbose)
{
int ret;
unsigned i;
memset(client, 0, sizeof(*client));
ret = snprintf(client->unix_sock_path, sizeof(client->unix_sock_path),
"%s", unix_sock_path);
if (ret < 0 || ret >= sizeof(client->unix_sock_path)) {
IVSHMEM_CLIENT_DEBUG(client, "could not copy unix socket path\n");
return -1;
}
for (i = 0; i < IVSHMEM_CLIENT_MAX_VECTORS; i++) {
client->local.vectors[i] = -1;
}
QTAILQ_INIT(&client->peer_list);
client->local.id = -1;
client->notif_cb = notif_cb;
client->notif_arg = notif_arg;
client->verbose = verbose;
client->shm_fd = -1;
client->sock_fd = -1;
return 0;
}
/* create and connect to the unix socket */
int
ivshmem_client_connect(IvshmemClient *client)
{
struct sockaddr_un s_un;
int fd, ret;
int64_t tmp;
IVSHMEM_CLIENT_DEBUG(client, "connect to client %s\n",
client->unix_sock_path);
client->sock_fd = socket(AF_UNIX, SOCK_STREAM, 0);
if (client->sock_fd < 0) {
IVSHMEM_CLIENT_DEBUG(client, "cannot create socket: %s\n",
strerror(errno));
return -1;
}
s_un.sun_family = AF_UNIX;
ret = snprintf(s_un.sun_path, sizeof(s_un.sun_path), "%s",
client->unix_sock_path);
if (ret < 0 || ret >= sizeof(s_un.sun_path)) {
IVSHMEM_CLIENT_DEBUG(client, "could not copy unix socket path\n");
goto err_close;
}
if (connect(client->sock_fd, (struct sockaddr *)&s_un, sizeof(s_un)) < 0) {
IVSHMEM_CLIENT_DEBUG(client, "cannot connect to %s: %s\n", s_un.sun_path,
strerror(errno));
goto err_close;
}
/* first, we expect a protocol version */
if (ivshmem_client_read_one_msg(client, &tmp, &fd) < 0 ||
(tmp != IVSHMEM_PROTOCOL_VERSION) || fd != -1) {
IVSHMEM_CLIENT_DEBUG(client, "cannot read from server\n");
goto err_close;
}
/* then, we expect our index + a fd == -1 */
if (ivshmem_client_read_one_msg(client, &client->local.id, &fd) < 0 ||
client->local.id < 0 || fd != -1) {
IVSHMEM_CLIENT_DEBUG(client, "cannot read from server (2)\n");
goto err_close;
}
IVSHMEM_CLIENT_DEBUG(client, "our_id=%" PRId64 "\n", client->local.id);
/* now, we expect shared mem fd + a -1 index, note that shm fd
* is not used */
if (ivshmem_client_read_one_msg(client, &tmp, &fd) < 0 ||
tmp != -1 || fd < 0) {
if (fd >= 0) {
close(fd);
}
IVSHMEM_CLIENT_DEBUG(client, "cannot read from server (3)\n");
goto err_close;
}
client->shm_fd = fd;
IVSHMEM_CLIENT_DEBUG(client, "shm_fd=%d\n", fd);
return 0;
err_close:
close(client->sock_fd);
client->sock_fd = -1;
return -1;
}
/* close connection to the server, and free all peer structures */
void
ivshmem_client_close(IvshmemClient *client)
{
IvshmemClientPeer *peer;
unsigned i;
IVSHMEM_CLIENT_DEBUG(client, "close client\n");
while ((peer = QTAILQ_FIRST(&client->peer_list)) != NULL) {
ivshmem_client_free_peer(client, peer);
}
close(client->shm_fd);
client->shm_fd = -1;
close(client->sock_fd);
client->sock_fd = -1;
client->local.id = -1;
for (i = 0; i < IVSHMEM_CLIENT_MAX_VECTORS; i++) {
close(client->local.vectors[i]);
client->local.vectors[i] = -1;
}
client->local.vectors_count = 0;
}
/* get the fd_set according to the unix socket and peer list */
void
ivshmem_client_get_fds(const IvshmemClient *client, fd_set *fds, int *maxfd)
{
int fd;
unsigned vector;
FD_SET(client->sock_fd, fds);
if (client->sock_fd >= *maxfd) {
*maxfd = client->sock_fd + 1;
}
for (vector = 0; vector < client->local.vectors_count; vector++) {
fd = client->local.vectors[vector];
FD_SET(fd, fds);
if (fd >= *maxfd) {
*maxfd = fd + 1;
}
}
}
/* handle events from eventfd: just print a message on notification */
static int
ivshmem_client_handle_event(IvshmemClient *client, const fd_set *cur, int maxfd)
{
IvshmemClientPeer *peer;
uint64_t kick;
unsigned i;
int ret;
peer = &client->local;
for (i = 0; i < peer->vectors_count; i++) {
if (peer->vectors[i] >= maxfd || !FD_ISSET(peer->vectors[i], cur)) {
continue;
}
ret = read(peer->vectors[i], &kick, sizeof(kick));
if (ret < 0) {
return ret;
}
if (ret != sizeof(kick)) {
IVSHMEM_CLIENT_DEBUG(client, "invalid read size = %d\n", ret);
errno = EINVAL;
return -1;
}
IVSHMEM_CLIENT_DEBUG(client, "received event on fd %d vector %d: %"
PRIu64 "\n", peer->vectors[i], i, kick);
if (client->notif_cb != NULL) {
client->notif_cb(client, peer, i, client->notif_arg);
}
}
return 0;
}
/* read and handle new messages on the given fd_set */
int
ivshmem_client_handle_fds(IvshmemClient *client, fd_set *fds, int maxfd)
{
if (client->sock_fd < maxfd && FD_ISSET(client->sock_fd, fds) &&
ivshmem_client_handle_server_msg(client) < 0 && errno != EINTR) {
IVSHMEM_CLIENT_DEBUG(client, "ivshmem_client_handle_server_msg() "
"failed\n");
return -1;
} else if (ivshmem_client_handle_event(client, fds, maxfd) < 0 &&
errno != EINTR) {
IVSHMEM_CLIENT_DEBUG(client, "ivshmem_client_handle_event() failed\n");
return -1;
}
return 0;
}
/* send a notification on a vector of a peer */
int
ivshmem_client_notify(const IvshmemClient *client,
const IvshmemClientPeer *peer, unsigned vector)
{
uint64_t kick;
int fd;
if (vector >= peer->vectors_count) {
IVSHMEM_CLIENT_DEBUG(client, "invalid vector %u on peer %" PRId64 "\n",
vector, peer->id);
return -1;
}
fd = peer->vectors[vector];
IVSHMEM_CLIENT_DEBUG(client, "notify peer %" PRId64
" on vector %d, fd %d\n", peer->id, vector, fd);
kick = 1;
if (write(fd, &kick, sizeof(kick)) != sizeof(kick)) {
fprintf(stderr, "could not write to %d: %s\n", peer->vectors[vector],
strerror(errno));
return -1;
}
return 0;
}
/* send a notification to all vectors of a peer */
int
ivshmem_client_notify_all_vects(const IvshmemClient *client,
const IvshmemClientPeer *peer)
{
unsigned vector;
int ret = 0;
for (vector = 0; vector < peer->vectors_count; vector++) {
if (ivshmem_client_notify(client, peer, vector) < 0) {
ret = -1;
}
}
return ret;
}
/* send a notification to all peers */
int
ivshmem_client_notify_broadcast(const IvshmemClient *client)
{
IvshmemClientPeer *peer;
int ret = 0;
QTAILQ_FOREACH(peer, &client->peer_list, next) {
if (ivshmem_client_notify_all_vects(client, peer) < 0) {
ret = -1;
}
}
return ret;
}
/* lookup peer from its id */
IvshmemClientPeer *
ivshmem_client_search_peer(IvshmemClient *client, int64_t peer_id)
{
IvshmemClientPeer *peer;
if (peer_id == client->local.id) {
return &client->local;
}
QTAILQ_FOREACH(peer, &client->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_client_dump(const IvshmemClient *client)
{
const IvshmemClientPeer *peer;
unsigned vector;
/* dump local infos */
peer = &client->local;
printf("our_id = %" PRId64 "\n", peer->id);
for (vector = 0; vector < peer->vectors_count; vector++) {
printf(" vector %d is enabled (fd=%d)\n", vector,
peer->vectors[vector]);
}
/* dump peers */
QTAILQ_FOREACH(peer, &client->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,
peer->vectors[vector]);
}
}
}