1 files changed, 433 insertions, 0 deletions

diff --git a/contrib/ivshmem-client/ivshmem-client.c b/contrib/ivshmem-client/ivshmem-client.c
new file mode 100644
index 0000000..fcc0930
--- /dev/null
+++ b/contrib/ivshmem-client/ivshmem-client.c
@@ -0,0 +1,433 @@
+/*
+ * 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 <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+#include "qemu-common.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, long *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 < 0) {
+        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;
+    }
+
+    *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;
+    long 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 %ld\n", peer_id);
+            return -1;
+        }
+
+        IVSHMEM_CLIENT_DEBUG(client, "delete peer id = %ld\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 = %ld\n", peer_id);
+    }
+
+    /* new vector */
+    IVSHMEM_CLIENT_DEBUG(client, "  new vector %d (fd=%d) for peer id %ld\n",
+                         peer->vectors_count, fd, peer->id);
+    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;
+    long 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 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\n");
+        goto err_close;
+    }
+    IVSHMEM_CLIENT_DEBUG(client, "our_id=%ld\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 (2)\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 %ld\n",
+                             vector, peer->id);
+        return -1;
+    }
+    fd = peer->vectors[vector];
+    IVSHMEM_CLIENT_DEBUG(client, "notify peer %ld 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, long 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 = %ld\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 = %ld\n", peer->id);
+
+        for (vector = 0; vector < peer->vectors_count; vector++) {
+            printf("  vector %d is enabled (fd=%d)\n", vector,
+                   peer->vectors[vector]);
+        }
+    }
+}