all: split reusable components into workspace crates

utils/src/pidfd_send_signal.rs

@@ -0,0 +1,23 @@
+use {
+    crate::oserror::{OsError, OsErrorExt},
+    c::{c_int, syscall},
+    std::{ptr, rc::Rc},
+    uapi::{
+        OwnedFd,
+        c::{self, SYS_pidfd_send_signal, siginfo_t},
+        map_err,
+    },
+};
+
+pub fn pidfd_send_signal(pidfd: &Rc<OwnedFd>, signal: c_int) -> Result<(), OsError> {
+    let res = unsafe {
+        syscall(
+            SYS_pidfd_send_signal,
+            pidfd.raw(),
+            signal,
+            ptr::null_mut::<siginfo_t>(),
+            0,
+        )
+    };
+    map_err!(res).map(drop).to_os_error()
+}