runtime-rs: enable start container from bundle

enable start container from bundle in this way

$ ls ./bundle
config.json  rootfs
$ sudo ctr run -d --runtime io.containerd.kata.v2 --config bundle/config.json test_kata

Fixes:#5872
Signed-off-by: Zhongtao Hu <zhongtaohu.tim@linux.alibaba.com>

src/runtime-rs/crates/resource/src/manager.rs

@@ -68,11 +68,14 @@ impl ResourceManager {
     pub async fn handler_rootfs(
         &self,
         cid: &str,
+        root: &oci::Root,
         bundle_path: &str,
         rootfs_mounts: &[Mount],
     ) -> Result<Arc<dyn Rootfs>> {
         let inner = self.inner.read().await;
-        inner.handler_rootfs(cid, bundle_path, rootfs_mounts).await
+        inner
+            .handler_rootfs(cid, root, bundle_path, rootfs_mounts)
+            .await
     }
 
     pub async fn handler_volumes(

src/runtime-rs/crates/resource/src/manager_inner.rs

@@ -196,6 +196,7 @@ impl ResourceManagerInner {
     pub async fn handler_rootfs(
         &self,
         cid: &str,
+        root: &oci::Root,
         bundle_path: &str,
         rootfs_mounts: &[Mount],
     ) -> Result<Arc<dyn Rootfs>> {
@@ -205,6 +206,7 @@ impl ResourceManagerInner {
                 self.hypervisor.as_ref(),
                 &self.sid,
                 cid,
+                root,
                 bundle_path,
                 rootfs_mounts,
             )

src/runtime-rs/crates/resource/src/rootfs/mod.rs

@@ -51,16 +51,37 @@ impl RootFsResource {
         }
     }
 
+    #[allow(clippy::too_many_arguments)]
     pub async fn handler_rootfs(
         &self,
         share_fs: &Option<Arc<dyn ShareFs>>,
         hypervisor: &dyn Hypervisor,
         sid: &str,
         cid: &str,
+        root: &oci::Root,
         bundle_path: &str,
         rootfs_mounts: &[Mount],
     ) -> Result<Arc<dyn Rootfs>> {
         match rootfs_mounts {
+            // if rootfs_mounts is empty
+            mounts_vec if mounts_vec.is_empty() => {
+                if let Some(share_fs) = share_fs {
+                    let share_fs_mount = share_fs.get_share_fs_mount();
+                    // share fs rootfs
+                    Ok(Arc::new(
+                        share_fs_rootfs::ShareFsRootfs::new(
+                            &share_fs_mount,
+                            cid,
+                            root.path.as_str(),
+                            None,
+                        )
+                        .await
+                        .context("new share fs rootfs")?,
+                    ))
+                } else {
+                    return Err(anyhow!("share fs is unavailable"));
+                }
+            }
             mounts_vec if is_single_layer_rootfs(mounts_vec) => {
                 // Safe as single_layer_rootfs must have one layer
                 let layer = &mounts_vec[0];
@@ -86,7 +107,7 @@ impl RootFsResource {
                                 &share_fs_mount,
                                 cid,
                                 bundle_path,
-                                layer,
+                                Some(layer),
                             )
                             .await
                             .context("new share fs rootfs")?,

src/runtime-rs/crates/resource/src/rootfs/share_fs_rootfs.rs

@@ -23,14 +23,18 @@ impl ShareFsRootfs {
         share_fs_mount: &Arc<dyn ShareFsMount>,
         cid: &str,
         bundle_path: &str,
-        rootfs: &Mount,
+        rootfs: Option<&Mount>,
     ) -> Result<Self> {
+        let bundle_rootfs = if let Some(rootfs) = rootfs {
             let bundle_rootfs = format!("{}/{}", bundle_path, ROOTFS);
             rootfs.mount(&bundle_rootfs).context(format!(
                 "mount rootfs from {:?} to {}",
                 &rootfs, &bundle_rootfs
             ))?;
-
+            bundle_rootfs
+        } else {
+            bundle_path.to_string()
+        };
         let mount_result = share_fs_mount
             .share_rootfs(ShareFsRootfsConfig {
                 cid: cid.to_string(),

src/runtime-rs/crates/runtimes/virt_container/src/container_manager/container.rs

@@ -16,6 +16,7 @@ use common::{
     },
 };
 use kata_sys_util::k8s::update_ephemeral_storage_type;
+
 use oci::{LinuxResources, Process as OCIProcess};
 use resource::ResourceManager;
 use tokio::sync::RwLock;
@@ -84,23 +85,30 @@ impl Container {
         amend_spec(&mut spec, toml_config.runtime.disable_guest_seccomp).context("amend spec")?;
         let sandbox_pidns = is_pid_namespace_enabled(&spec);
 
+        // get mutable root from oci spec
+        let mut root = match spec.root.as_mut() {
+            Some(root) => root,
+            None => return Err(anyhow!("spec miss root field")),
+        };
+
         // handler rootfs
         let rootfs = self
             .resource_manager
-            .handler_rootfs(&config.container_id, &config.bundle, &config.rootfs_mounts)
+            .handler_rootfs(
+                &config.container_id,
+                root,
+                &config.bundle,
+                &config.rootfs_mounts,
+            )
             .await
             .context("handler rootfs")?;
 
         // update rootfs
-        match spec.root.as_mut() {
-            Some(root) => {
         root.path = rootfs
             .get_guest_rootfs_path()
             .await
-                    .context("get guest rootfs path")?
-            }
-            None => return Err(anyhow!("spec miss root field")),
-        };
+            .context("get guest rootfs path")?;
+
         let mut storages = vec![];
         if let Some(storage) = rootfs.get_storage().await {
             storages.push(storage);