Implement waitid.

Fixes #75.

c-scape/src/process/wait.rs

@@ -1,6 +1,8 @@
+use core::mem::zeroed;
 use errno::{set_errno, Errno};
-use libc::{c_int, pid_t};
-use rustix::process::{Pid, WaitOptions};
+use libc::{c_int, id_t, idtype_t, pid_t, siginfo_t};
+use rustix::fd::BorrowedFd;
+use rustix::process::{Pid, WaitId, WaitOptions, WaitidOptions};
 
 use crate::convert_res;
 
@@ -62,3 +64,45 @@ unsafe extern "C" fn wait(status: *mut c_int) -> pid_t {
     libc!(libc::wait(status));
     waitpid(-1, status, 0)
 }
+
+#[no_mangle]
+unsafe extern "C" fn waitid(
+    idtype: idtype_t,
+    id: id_t,
+    infop: *mut siginfo_t,
+    options: c_int,
+) -> c_int {
+    libc!(libc::waitid(idtype, id, infop, options));
+
+    let id = match idtype {
+        libc::P_PID => {
+            if let Some(pid) = Pid::from_raw(id as _) {
+                WaitId::Pid(pid)
+            } else {
+                set_errno(Errno(libc::EINVAL));
+                return -1;
+            }
+        }
+        libc::P_PIDFD => WaitId::PidFd(BorrowedFd::borrow_raw(id as _)),
+        libc::P_PGID => WaitId::Pgid(Pid::from_raw(id as _)),
+        libc::P_ALL => WaitId::All,
+        _ => {
+            set_errno(Errno(libc::EINVAL));
+            return -1;
+        }
+    };
+
+    let options = WaitidOptions::from_bits(options as _).unwrap();
+
+    match convert_res(rustix::process::waitid(id, options)) {
+        Some(Some(new_info)) => {
+            *infop = zeroed();
+            (*infop).si_signo = new_info.as_raw().__bindgen_anon_1.__bindgen_anon_1.si_signo;
+            (*infop).si_errno = new_info.as_raw().__bindgen_anon_1.__bindgen_anon_1.si_errno;
+            (*infop).si_code = new_info.as_raw().__bindgen_anon_1.__bindgen_anon_1.si_code;
+            0
+        }
+        Some(None) => 0,
+        None => -1,
+    }
+}

c-scape/src/todo.rs

@@ -46,10 +46,6 @@ unsafe extern "C" fn process_vm_readv() {
     todo!("process_vm_readv")
 }
 #[no_mangle]
-unsafe extern "C" fn waitid() {
-    todo!("waitid")
-}
-#[no_mangle]
 unsafe extern "C" fn signalfd() {
     todo!("signalfd")
 }