virtiofsd: Start wiring up vhost-user

Listen on our unix socket for the connection from QEMU, when we get it
initialise vhost-user and dive into our own loop variant (currently
dummy).

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

1 files changed, 86 insertions, 1 deletions

diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
index cbef6ffdda..2ae3c764dd 100644
--- a/tools/virtiofsd/fuse_virtio.c
+++ b/tools/virtiofsd/fuse_virtio.c
@@ -19,18 +19,78 @@
 
 #include <stdint.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <sys/socket.h>
 #include <sys/types.h>
 #include <sys/un.h>
 #include <unistd.h>
 
+#include "contrib/libvhost-user/libvhost-user.h"
+
+/*
+ * We pass the dev element into libvhost-user
+ * and then use it to get back to the outer
+ * container for other data.
+ */
+struct fv_VuDev {
+    VuDev dev;
+    struct fuse_session *se;
+};
+
 /* From spec */
 struct virtio_fs_config {
     char tag[36];
     uint32_t num_queues;
 };
 
+/*
+ * Callback from libvhost-user if there's a new fd we're supposed to listen
+ * to, typically a queue kick?
+ */
+static void fv_set_watch(VuDev *dev, int fd, int condition, vu_watch_cb cb,
+                         void *data)
+{
+    fuse_log(FUSE_LOG_WARNING, "%s: TODO! fd=%d\n", __func__, fd);
+}
+
+/*
+ * Callback from libvhost-user if we're no longer supposed to listen on an fd
+ */
+static void fv_remove_watch(VuDev *dev, int fd)
+{
+    fuse_log(FUSE_LOG_WARNING, "%s: TODO! fd=%d\n", __func__, fd);
+}
+
+/* Callback from libvhost-user to panic */
+static void fv_panic(VuDev *dev, const char *err)
+{
+    fuse_log(FUSE_LOG_ERR, "%s: libvhost-user: %s\n", __func__, err);
+    /* TODO: Allow reconnects?? */
+    exit(EXIT_FAILURE);
+}
+
+static bool fv_queue_order(VuDev *dev, int qidx)
+{
+    return false;
+}
+
+static const VuDevIface fv_iface = {
+    /* TODO: Add other callbacks */
+    .queue_is_processed_in_order = fv_queue_order,
+};
+
+int virtio_loop(struct fuse_session *se)
+{
+    fuse_log(FUSE_LOG_INFO, "%s: Entry\n", __func__);
+
+    while (1) {
+        /* TODO: Add stuffing */
+    }
+
+    fuse_log(FUSE_LOG_INFO, "%s: Exit\n", __func__);
+}
+
 int virtio_session_mount(struct fuse_session *se)
 {
     struct sockaddr_un un;
@@ -75,5 +135,30 @@ int virtio_session_mount(struct fuse_session *se)
         return -1;
     }
 
-    return -1;
+    fuse_log(FUSE_LOG_INFO, "%s: Waiting for vhost-user socket connection...\n",
+             __func__);
+    int data_sock = accept(listen_sock, NULL, NULL);
+    if (data_sock == -1) {
+        fuse_log(FUSE_LOG_ERR, "vhost socket accept: %m\n");
+        close(listen_sock);
+        return -1;
+    }
+    close(listen_sock);
+    fuse_log(FUSE_LOG_INFO, "%s: Received vhost-user socket connection\n",
+             __func__);
+
+    /* TODO: Some cleanup/deallocation! */
+    se->virtio_dev = calloc(sizeof(struct fv_VuDev), 1);
+    if (!se->virtio_dev) {
+        fuse_log(FUSE_LOG_ERR, "%s: virtio_dev calloc failed\n", __func__);
+        close(data_sock);
+        return -1;
+    }
+
+    se->vu_socketfd = data_sock;
+    se->virtio_dev->se = se;
+    vu_init(&se->virtio_dev->dev, 2, se->vu_socketfd, fv_panic, fv_set_watch,
+            fv_remove_watch, &fv_iface);
+
+    return 0;
 }