447 lines
12 KiB
C
447 lines
12 KiB
C
/*
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* Copyright 6WIND S.A., 2014
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or
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* (at your option) any later version. See the COPYING file in the
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* top-level directory.
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*/
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/un.h>
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#include "qemu-common.h"
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#include "qemu/queue.h"
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#include "ivshmem-client.h"
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/* log a message on stdout if verbose=1 */
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#define IVSHMEM_CLIENT_DEBUG(client, fmt, ...) do { \
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if ((client)->verbose) { \
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printf(fmt, ## __VA_ARGS__); \
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} \
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} while (0)
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/* read message from the unix socket */
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static int
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ivshmem_client_read_one_msg(IvshmemClient *client, int64_t *index, int *fd)
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{
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int ret;
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struct msghdr msg;
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struct iovec iov[1];
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union {
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struct cmsghdr cmsg;
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char control[CMSG_SPACE(sizeof(int))];
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} msg_control;
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struct cmsghdr *cmsg;
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iov[0].iov_base = index;
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iov[0].iov_len = sizeof(*index);
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memset(&msg, 0, sizeof(msg));
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msg.msg_iov = iov;
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msg.msg_iovlen = 1;
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msg.msg_control = &msg_control;
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msg.msg_controllen = sizeof(msg_control);
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ret = recvmsg(client->sock_fd, &msg, 0);
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if (ret < sizeof(*index)) {
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IVSHMEM_CLIENT_DEBUG(client, "cannot read message: %s\n",
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strerror(errno));
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return -1;
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}
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if (ret == 0) {
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IVSHMEM_CLIENT_DEBUG(client, "lost connection to server\n");
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return -1;
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}
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*index = GINT64_FROM_LE(*index);
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*fd = -1;
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for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
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if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)) ||
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cmsg->cmsg_level != SOL_SOCKET ||
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cmsg->cmsg_type != SCM_RIGHTS) {
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continue;
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}
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memcpy(fd, CMSG_DATA(cmsg), sizeof(*fd));
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}
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return 0;
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}
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/* free a peer when the server advertises a disconnection or when the
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* client is freed */
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static void
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ivshmem_client_free_peer(IvshmemClient *client, IvshmemClientPeer *peer)
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{
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unsigned vector;
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QTAILQ_REMOVE(&client->peer_list, peer, next);
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for (vector = 0; vector < peer->vectors_count; vector++) {
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close(peer->vectors[vector]);
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}
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g_free(peer);
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}
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/* handle message coming from server (new peer, new vectors) */
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static int
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ivshmem_client_handle_server_msg(IvshmemClient *client)
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{
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IvshmemClientPeer *peer;
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int64_t peer_id;
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int ret, fd;
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ret = ivshmem_client_read_one_msg(client, &peer_id, &fd);
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if (ret < 0) {
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return -1;
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}
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/* can return a peer or the local client */
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peer = ivshmem_client_search_peer(client, peer_id);
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/* delete peer */
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if (fd == -1) {
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if (peer == NULL || peer == &client->local) {
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IVSHMEM_CLIENT_DEBUG(client, "receive delete for invalid "
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"peer %" PRId64 "\n", peer_id);
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return -1;
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}
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IVSHMEM_CLIENT_DEBUG(client, "delete peer id = %" PRId64 "\n", peer_id);
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ivshmem_client_free_peer(client, peer);
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return 0;
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}
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/* new peer */
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if (peer == NULL) {
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peer = g_malloc0(sizeof(*peer));
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peer->id = peer_id;
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peer->vectors_count = 0;
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QTAILQ_INSERT_TAIL(&client->peer_list, peer, next);
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IVSHMEM_CLIENT_DEBUG(client, "new peer id = %" PRId64 "\n", peer_id);
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}
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/* new vector */
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IVSHMEM_CLIENT_DEBUG(client, " new vector %d (fd=%d) for peer id %"
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PRId64 "\n", peer->vectors_count, fd, peer->id);
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if (peer->vectors_count >= G_N_ELEMENTS(peer->vectors)) {
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IVSHMEM_CLIENT_DEBUG(client, "Too many vectors received, failing");
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return -1;
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}
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peer->vectors[peer->vectors_count] = fd;
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peer->vectors_count++;
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return 0;
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}
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/* init a new ivshmem client */
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int
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ivshmem_client_init(IvshmemClient *client, const char *unix_sock_path,
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IvshmemClientNotifCb notif_cb, void *notif_arg,
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bool verbose)
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{
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int ret;
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unsigned i;
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memset(client, 0, sizeof(*client));
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ret = snprintf(client->unix_sock_path, sizeof(client->unix_sock_path),
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"%s", unix_sock_path);
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if (ret < 0 || ret >= sizeof(client->unix_sock_path)) {
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IVSHMEM_CLIENT_DEBUG(client, "could not copy unix socket path\n");
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return -1;
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}
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for (i = 0; i < IVSHMEM_CLIENT_MAX_VECTORS; i++) {
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client->local.vectors[i] = -1;
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}
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QTAILQ_INIT(&client->peer_list);
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client->local.id = -1;
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client->notif_cb = notif_cb;
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client->notif_arg = notif_arg;
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client->verbose = verbose;
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client->shm_fd = -1;
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client->sock_fd = -1;
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return 0;
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}
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/* create and connect to the unix socket */
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int
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ivshmem_client_connect(IvshmemClient *client)
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{
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struct sockaddr_un sun;
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int fd, ret;
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int64_t tmp;
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IVSHMEM_CLIENT_DEBUG(client, "connect to client %s\n",
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client->unix_sock_path);
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client->sock_fd = socket(AF_UNIX, SOCK_STREAM, 0);
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if (client->sock_fd < 0) {
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IVSHMEM_CLIENT_DEBUG(client, "cannot create socket: %s\n",
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strerror(errno));
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return -1;
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}
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sun.sun_family = AF_UNIX;
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ret = snprintf(sun.sun_path, sizeof(sun.sun_path), "%s",
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client->unix_sock_path);
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if (ret < 0 || ret >= sizeof(sun.sun_path)) {
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IVSHMEM_CLIENT_DEBUG(client, "could not copy unix socket path\n");
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goto err_close;
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}
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if (connect(client->sock_fd, (struct sockaddr *)&sun, sizeof(sun)) < 0) {
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IVSHMEM_CLIENT_DEBUG(client, "cannot connect to %s: %s\n", sun.sun_path,
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strerror(errno));
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goto err_close;
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}
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/* first, we expect a protocol version */
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if (ivshmem_client_read_one_msg(client, &tmp, &fd) < 0 ||
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(tmp != IVSHMEM_PROTOCOL_VERSION) || fd != -1) {
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IVSHMEM_CLIENT_DEBUG(client, "cannot read from server\n");
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goto err_close;
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}
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/* then, we expect our index + a fd == -1 */
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if (ivshmem_client_read_one_msg(client, &client->local.id, &fd) < 0 ||
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client->local.id < 0 || fd != -1) {
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IVSHMEM_CLIENT_DEBUG(client, "cannot read from server (2)\n");
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goto err_close;
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}
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IVSHMEM_CLIENT_DEBUG(client, "our_id=%" PRId64 "\n", client->local.id);
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/* now, we expect shared mem fd + a -1 index, note that shm fd
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* is not used */
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if (ivshmem_client_read_one_msg(client, &tmp, &fd) < 0 ||
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tmp != -1 || fd < 0) {
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if (fd >= 0) {
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close(fd);
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}
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IVSHMEM_CLIENT_DEBUG(client, "cannot read from server (3)\n");
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goto err_close;
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}
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client->shm_fd = fd;
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IVSHMEM_CLIENT_DEBUG(client, "shm_fd=%d\n", fd);
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return 0;
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err_close:
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close(client->sock_fd);
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client->sock_fd = -1;
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return -1;
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}
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/* close connection to the server, and free all peer structures */
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void
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ivshmem_client_close(IvshmemClient *client)
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{
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IvshmemClientPeer *peer;
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unsigned i;
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IVSHMEM_CLIENT_DEBUG(client, "close client\n");
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while ((peer = QTAILQ_FIRST(&client->peer_list)) != NULL) {
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ivshmem_client_free_peer(client, peer);
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}
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close(client->shm_fd);
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client->shm_fd = -1;
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close(client->sock_fd);
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client->sock_fd = -1;
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client->local.id = -1;
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for (i = 0; i < IVSHMEM_CLIENT_MAX_VECTORS; i++) {
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close(client->local.vectors[i]);
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client->local.vectors[i] = -1;
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}
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client->local.vectors_count = 0;
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}
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/* get the fd_set according to the unix socket and peer list */
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void
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ivshmem_client_get_fds(const IvshmemClient *client, fd_set *fds, int *maxfd)
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{
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int fd;
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unsigned vector;
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FD_SET(client->sock_fd, fds);
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if (client->sock_fd >= *maxfd) {
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*maxfd = client->sock_fd + 1;
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}
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for (vector = 0; vector < client->local.vectors_count; vector++) {
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fd = client->local.vectors[vector];
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FD_SET(fd, fds);
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if (fd >= *maxfd) {
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*maxfd = fd + 1;
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}
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}
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}
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/* handle events from eventfd: just print a message on notification */
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static int
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ivshmem_client_handle_event(IvshmemClient *client, const fd_set *cur, int maxfd)
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{
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IvshmemClientPeer *peer;
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uint64_t kick;
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unsigned i;
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int ret;
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peer = &client->local;
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for (i = 0; i < peer->vectors_count; i++) {
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if (peer->vectors[i] >= maxfd || !FD_ISSET(peer->vectors[i], cur)) {
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continue;
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}
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ret = read(peer->vectors[i], &kick, sizeof(kick));
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if (ret < 0) {
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return ret;
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}
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if (ret != sizeof(kick)) {
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IVSHMEM_CLIENT_DEBUG(client, "invalid read size = %d\n", ret);
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errno = EINVAL;
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return -1;
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}
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IVSHMEM_CLIENT_DEBUG(client, "received event on fd %d vector %d: %"
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PRIu64 "\n", peer->vectors[i], i, kick);
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if (client->notif_cb != NULL) {
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client->notif_cb(client, peer, i, client->notif_arg);
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}
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}
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return 0;
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}
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/* read and handle new messages on the given fd_set */
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int
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ivshmem_client_handle_fds(IvshmemClient *client, fd_set *fds, int maxfd)
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{
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if (client->sock_fd < maxfd && FD_ISSET(client->sock_fd, fds) &&
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ivshmem_client_handle_server_msg(client) < 0 && errno != EINTR) {
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IVSHMEM_CLIENT_DEBUG(client, "ivshmem_client_handle_server_msg() "
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"failed\n");
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return -1;
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} else if (ivshmem_client_handle_event(client, fds, maxfd) < 0 &&
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errno != EINTR) {
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IVSHMEM_CLIENT_DEBUG(client, "ivshmem_client_handle_event() failed\n");
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return -1;
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}
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return 0;
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}
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/* send a notification on a vector of a peer */
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int
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ivshmem_client_notify(const IvshmemClient *client,
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const IvshmemClientPeer *peer, unsigned vector)
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{
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uint64_t kick;
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int fd;
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if (vector >= peer->vectors_count) {
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IVSHMEM_CLIENT_DEBUG(client, "invalid vector %u on peer %" PRId64 "\n",
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vector, peer->id);
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return -1;
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}
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fd = peer->vectors[vector];
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IVSHMEM_CLIENT_DEBUG(client, "notify peer %" PRId64
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" on vector %d, fd %d\n", peer->id, vector, fd);
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kick = 1;
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if (write(fd, &kick, sizeof(kick)) != sizeof(kick)) {
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fprintf(stderr, "could not write to %d: %s\n", peer->vectors[vector],
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strerror(errno));
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return -1;
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}
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return 0;
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}
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/* send a notification to all vectors of a peer */
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int
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ivshmem_client_notify_all_vects(const IvshmemClient *client,
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const IvshmemClientPeer *peer)
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{
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unsigned vector;
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int ret = 0;
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for (vector = 0; vector < peer->vectors_count; vector++) {
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if (ivshmem_client_notify(client, peer, vector) < 0) {
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ret = -1;
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}
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}
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return ret;
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}
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/* send a notification to all peers */
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int
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ivshmem_client_notify_broadcast(const IvshmemClient *client)
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{
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IvshmemClientPeer *peer;
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int ret = 0;
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QTAILQ_FOREACH(peer, &client->peer_list, next) {
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if (ivshmem_client_notify_all_vects(client, peer) < 0) {
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ret = -1;
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}
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}
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return ret;
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}
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/* lookup peer from its id */
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IvshmemClientPeer *
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ivshmem_client_search_peer(IvshmemClient *client, int64_t peer_id)
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{
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IvshmemClientPeer *peer;
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if (peer_id == client->local.id) {
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return &client->local;
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}
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QTAILQ_FOREACH(peer, &client->peer_list, next) {
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if (peer->id == peer_id) {
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return peer;
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}
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}
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return NULL;
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}
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/* dump our info, the list of peers their vectors on stdout */
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void
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ivshmem_client_dump(const IvshmemClient *client)
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{
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const IvshmemClientPeer *peer;
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unsigned vector;
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/* dump local infos */
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peer = &client->local;
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printf("our_id = %" PRId64 "\n", peer->id);
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for (vector = 0; vector < peer->vectors_count; vector++) {
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printf(" vector %d is enabled (fd=%d)\n", vector,
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peer->vectors[vector]);
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}
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/* dump peers */
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QTAILQ_FOREACH(peer, &client->peer_list, next) {
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printf("peer_id = %" PRId64 "\n", peer->id);
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for (vector = 0; vector < peer->vectors_count; vector++) {
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printf(" vector %d is enabled (fd=%d)\n", vector,
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peer->vectors[vector]);
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}
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}
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}
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