[Agent] Fix the issue of getting the hostname to fail in low-version …

…kernels

agent/src/utils/command/linux.rs

@@ -179,14 +179,23 @@ fn set_utsns(fp: &File) -> Result<()> {
 }
 
 pub fn get_hostname() -> Result<String> {
-    let origin_fp = File::open(Path::new(ORIGIN_UTS_PATH))?;
-    let root_fp = File::open(Path::new(ROOT_UTS_PATH))?;
+    fn hostname() -> Result<String> {
+        hostname::get()?
+            .into_string()
+            .map_err(|_| Error::new(ErrorKind::Other, "get hostname failed"))
+    }
+    // If the ORIGIN_UTS_PATH or ROOT_UTS_PATH does not exist, it may be due to a kernel version that is too low
+    // to support UTS namespaces, therefore, do not switch UTS namespaces and directly return the hostname.
+    let Ok(origin_fp) = File::open(Path::new(ORIGIN_UTS_PATH)) else {
+        return hostname();
+    };
+    let Ok(root_fp) = File::open(Path::new(ROOT_UTS_PATH)) else {
+        return hostname();
+    };
     if let Err(e) = set_utsns(&root_fp) {
         return Err(Error::new(ErrorKind::Other, e));
     }
-    let name = hostname::get()?
-        .into_string()
-        .map_err(|_| Error::new(ErrorKind::Other, "get hostname failed"));
+    let name = hostname();
     if let Err(e) = set_utsns(&origin_fp) {
         return Err(Error::new(ErrorKind::Other, e));
     }