new command import-layer-splitfdstream

Add a client library for communicating with the containers-storage
splitfdstream server.  This enables importing OCI container layers
via UNIX socket with file descriptor passing.

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

Author: giuseppe

Cargo.toml

@@ -20,6 +20,7 @@ composefs = { version = "0.3.0", path = "crates/composefs", default-features = f
 composefs-oci = { version = "0.3.0", path = "crates/composefs-oci", default-features = false }
 composefs-boot = { version = "0.3.0", path = "crates/composefs-boot", default-features = false }
 composefs-http = { version = "0.3.0", path = "crates/composefs-http", default-features = false }
+splitfdstream = { version = "0.3.0", path = "crates/splitfdstream", default-features = false }
 
 [profile.dev.package.sha2]
 # this is *really* slow otherwise

crates/cfsctl/Cargo.toml

@@ -13,7 +13,7 @@ version.workspace = true
 [features]
 default = ['pre-6.15', 'oci']
 http = ['composefs-http']
-oci = ['composefs-oci']
+oci = ['composefs-oci', 'splitfdstream']
 rhel9 = ['composefs/rhel9']
 'pre-6.15' = ['composefs/pre-6.15']
 
@@ -25,6 +25,7 @@ composefs = { workspace = true }
 composefs-boot = { workspace = true }
 composefs-oci = { workspace = true, optional = true }
 composefs-http = { workspace = true, optional = true }
+splitfdstream = { workspace = true, optional = true }
 env_logger = { version = "0.11.0", default-features = false }
 hex = { version = "0.4.0", default-features = false }
 rustix = { version = "1.0.0", default-features = false, features = ["fs", "process"] }

crates/cfsctl/src/main.rs

@@ -84,6 +84,21 @@ enum OciCommand {
         digest: String,
         name: Option<String>,
     },
+    /// Imports a layer from a splitfdstream server into the repository.
+    ImportLayerSplitfdstream {
+        /// Path to the splitfdstream server socket
+        socket: PathBuf,
+        /// The layer digest (e.g., sha256:abc123...)
+        digest: String,
+        /// Optional reference name for the layer
+        name: Option<String>,
+        /// Layer ID to request from splitfdstream server (defaults to digest)
+        #[clap(long)]
+        layer_id: Option<String>,
+        /// Parent layer ID for delta computation
+        #[clap(long)]
+        parent_id: Option<String>,
+    },
     /// Lists the contents of a tar stream
     LsLayer {
         /// the name of the stream to list, either a stream ID in format oci-config-<hash_type>:<hash_digest> or a reference in 'ref/'
@@ -295,6 +310,23 @@ where
                 )?;
                 println!("{}", object_id.to_id());
             }
+            OciCommand::ImportLayerSplitfdstream {
+                socket,
+                digest,
+                name,
+                layer_id,
+                parent_id,
+            } => {
+                let object_id = composefs_oci::import_from_splitfdstream(
+                    &Arc::new(repo),
+                    &socket,
+                    &digest,
+                    layer_id.as_deref(),
+                    parent_id.as_deref(),
+                    name.as_deref(),
+                )?;
+                println!("{}", object_id.to_id());
+            }
             OciCommand::LsLayer { name } => {
                 composefs_oci::ls_layer(&repo, &name)?;
             }