Return PID from waitpid (#996)

Signed-off-by: Alex Saveau <[email protected]>

Author: SUPERCILEX

src/process/wait.rs

@@ -306,8 +306,8 @@ pub enum WaitId<'a> {
 /// [Linux]: https://man7.org/linux/man-pages/man2/waitpid.2.html
 #[cfg(not(target_os = "wasi"))]
 #[inline]
-pub fn waitpid(pid: Option<Pid>, waitopts: WaitOptions) -> io::Result<Option<WaitStatus>> {
-    Ok(backend::process::syscalls::waitpid(pid, waitopts)?.map(|(_, status)| status))
+pub fn waitpid(pid: Option<Pid>, waitopts: WaitOptions) -> io::Result<Option<(Pid, WaitStatus)>> {
+    backend::process::syscalls::waitpid(pid, waitopts)
 }
 
 /// `waitpid(-pgid, waitopts)`—Wait for a process in a specific process group
@@ -328,8 +328,8 @@ pub fn waitpid(pid: Option<Pid>, waitopts: WaitOptions) -> io::Result<Option<Wai
 /// [Linux]: https://man7.org/linux/man-pages/man2/waitpid.2.html
 #[cfg(not(target_os = "wasi"))]
 #[inline]
-pub fn waitpgid(pgid: Pid, waitopts: WaitOptions) -> io::Result<Option<WaitStatus>> {
-    Ok(backend::process::syscalls::waitpgid(pgid, waitopts)?.map(|(_, status)| status))
+pub fn waitpgid(pgid: Pid, waitopts: WaitOptions) -> io::Result<Option<(Pid, WaitStatus)>> {
+    backend::process::syscalls::waitpgid(pgid, waitopts)
 }
 
 /// `wait(waitopts)`—Wait for any of the children of calling process to

tests/process/wait.rs

@@ -18,9 +18,10 @@ fn test_waitpid_none() {
         .expect("failed to execute child");
     unsafe { kill(child.id() as _, SIGSTOP) };
 
-    let status = process::waitpid(None, process::WaitOptions::UNTRACED)
+    let (pid, status) = process::waitpid(None, process::WaitOptions::UNTRACED)
         .expect("failed to wait")
         .unwrap();
+    assert_eq!(pid, process::Pid::from_child(&child));
     assert!(status.stopped());
 }
 
@@ -35,9 +36,10 @@ fn test_waitpid_some() {
     unsafe { kill(child.id() as _, SIGSTOP) };
 
     let pid = process::Pid::from_child(&child);
-    let status = process::waitpid(Some(pid), process::WaitOptions::UNTRACED)
+    let (rpid, status) = process::waitpid(Some(pid), process::WaitOptions::UNTRACED)
         .expect("failed to wait")
         .unwrap();
+    assert_eq!(rpid, pid);
     assert!(status.stopped());
 }
 
@@ -52,9 +54,10 @@ fn test_waitpgid() {
     unsafe { kill(child.id() as _, SIGSTOP) };
 
     let pgid = process::getpgrp();
-    let status = process::waitpgid(pgid, process::WaitOptions::UNTRACED)
+    let (pid, status) = process::waitpgid(pgid, process::WaitOptions::UNTRACED)
         .expect("failed to wait")
         .unwrap();
+    assert_eq!(pid, process::Pid::from_child(&child));
     assert!(status.stopped());
 }