/* * 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 sun; 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; } sun.sun_family = AF_UNIX; ret = snprintf(sun.sun_path, sizeof(sun.sun_path), "%s", client->unix_sock_path); if (ret < 0 || ret >= sizeof(sun.sun_path)) { IVSHMEM_CLIENT_DEBUG(client, "could not copy unix socket path\n"); goto err_close; } if (connect(client->sock_fd, (struct sockaddr *)&sun, sizeof(sun)) < 0) { IVSHMEM_CLIENT_DEBUG(client, "cannot connect to %s: %s\n", sun.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]); } } }