shim: refine set subreaper

Signed-off-by: Zhang Tianyang <burning9699@gmail.com>

crates/shim/Cargo.toml

@@ -24,6 +24,7 @@ serde = "1.0.136"
 uuid = { version = "0.8.2", features = ["v4"] }
 signal-hook = "0.3.13"
 oci-spec = "0.5.4"
+prctl = "1.0.0"
 
 containerd-shim-protos = { path = "../shim-protos", version = "0.1.2" }
 

crates/shim/src/lib.rs

@@ -207,7 +207,7 @@ where
     let signals = setup_signals(&config);
 
     if !config.no_sub_reaper {
-        reap::set_subreaper().map_err(io_error!(e, "set subreaper"))?;
+        reap::set_subreaper()?;
     }
 
     let mut shim = T::new(

crates/shim/src/reap.rs

@@ -14,7 +14,7 @@
    limitations under the License.
 */
 
-use std::io::Result;
+use crate::error::Result;
 
 #[cfg(target_os = "linux")]
 /// Set current process as subreaper for child processes.
@@ -26,21 +26,23 @@ use std::io::Result;
 /// it is the subreaper process that will receive a SIGCHLD signal and will be able to `wait()`
 /// on the process to discover its termination status.
 pub fn set_subreaper() -> Result<()> {
-    use libc::PR_SET_CHILD_SUBREAPER;
-    use std::io::Error;
-
-    // Set current process as `subreaper` for child processes if the second parameter is non-zero,
-    // otherwise unset the attribute.
-    // Safe because we trust the kernel and have checked the result.
-    let code = unsafe { libc::prctl(PR_SET_CHILD_SUBREAPER, 1, 0, 0) };
-    if code != 0 {
-        Err(Error::from_raw_os_error(code))
-    } else {
-        Ok(())
-    }
+    use crate::error::Error;
+    prctl::set_child_subreaper(true).map_err(other_error!(code, "linux prctl returned"))
 }
 
 #[cfg(not(target_os = "linux"))]
 pub fn set_subreaper() -> Result<()> {
     Ok(())
 }
+
+#[cfg(test)]
+#[cfg(target_os = "linux")]
+mod tests {
+    use crate::reap::set_subreaper;
+
+    #[test]
+    fn test_set_subreaper() {
+        set_subreaper().unwrap();
+        assert!(prctl::get_child_subreaper().unwrap());
+    }
+}