diff options
Diffstat (limited to 'qemu/contrib/ivshmem-server/ivshmem-server.c')
| -rw-r--r-- | qemu/contrib/ivshmem-server/ivshmem-server.c | 457 |
1 files changed, 457 insertions, 0 deletions
diff --git a/qemu/contrib/ivshmem-server/ivshmem-server.c b/qemu/contrib/ivshmem-server/ivshmem-server.c new file mode 100644 index 000000000..172db78b3 --- /dev/null +++ b/qemu/contrib/ivshmem-server/ivshmem-server.c @@ -0,0 +1,457 @@ +/* + * 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/sockets.h" + +#include <sys/mman.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])); + } + } +} |