runtime-rs: Move KATA_PATH creation from sb_storage_path() to MgmtServer

sb_storage_path() is a path accessor shared by both server (shim) and
client (kata-ctl). Having it call create_dir_all(KATA_PATH) on every
invocation is incorrect: the client side should never create directories
— if /run/kata/ does not exist, no shim is running.

Move the directory creation to MgmtServer::new(), which is the server-
side component that manages the shim management socket under KATA_PATH.
Make sb_storage_path() a pure accessor returning &'static str directly.

Signed-off-by: Alex Lyn <alex.lyn@antgroup.com>

src/libs/shim-interface/src/lib.rs

@@ -73,11 +73,8 @@ fn get_uds_with_sid(short_id: &str, path: &str) -> Result<String> {
 }
 
 // return sandbox's storage path
-pub fn sb_storage_path() -> Result<&'static str> {
-    //make sure the path existed
-    std::fs::create_dir_all(KATA_PATH).context(format!("failed to create dir: {KATA_PATH}"))?;
-
-    Ok(KATA_PATH)
+pub fn sb_storage_path() -> &'static str {
+    KATA_PATH
 }
 
 // returns the address of the unix domain socket(UDS) for communication with shim
@@ -90,7 +87,7 @@ pub fn mgmt_socket_addr(sid: &str) -> Result<String> {
         ));
     }
 
-    get_uds_with_sid(sid, sb_storage_path()?)
+    get_uds_with_sid(sid, sb_storage_path())
 }
 
 #[cfg(test)]

src/runtime-rs/crates/runtimes/src/shim_mgmt/server.rs

@@ -16,7 +16,7 @@ use std::{fs, path::Path, sync::Arc};
 use anyhow::{Context, Result};
 use common::Sandbox;
 use hyper::{server::conn::Http, service::service_fn};
-use shim_interface::{mgmt_socket_addr, shim_mgmt::ERR_NO_SHIM_SERVER};
+use shim_interface::{sb_storage_path, SHIM_MGMT_SOCK_NAME};
 use tokio::net::UnixListener;
 
 use super::handlers::handler_mux;
@@ -33,10 +33,14 @@ pub struct MgmtServer {
 impl MgmtServer {
     /// construct a new management server
     pub fn new(sid: &str, sandbox: Arc<dyn Sandbox>) -> Result<Self> {
-        Ok(Self {
-            s_addr: mgmt_socket_addr(sid).context(ERR_NO_SHIM_SERVER)?,
-            sandbox,
-        })
+        // make sure the storage path exists, and the socket file will be created in that path
+        let kata_path = sb_storage_path();
+        fs::create_dir_all(kata_path)
+            .context(format!("failed to create kata path directory {kata_path}"))?;
+
+        let s_addr = format!("unix://{kata_path}/{sid}/{SHIM_MGMT_SOCK_NAME}");
+
+        Ok(Self { s_addr, sandbox })
     }
 
     // TODO(when metrics is supported): write metric addresses to fs