mikros: Add process wait support

library/std/src/sys/pal/mikros/process.rs

@@ -144,7 +144,7 @@ pub fn spawn(
             res?;
         };
         syscalls::wake_new(pid).unwrap();
-        Ok((Process { dummy: () }, StdioPipes { stdin: None, stdout: None, stderr: None }))
+        Ok((Process { pid }, StdioPipes { stdin: None, stdout: None, stderr: None }))
     }
 
     pub fn output(&mut self) -> io::Result<(ExitStatus, Vec<u8>, Vec<u8>)> {
@@ -242,15 +242,19 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 
 #[derive(PartialEq, Eq, Clone, Copy, Debug, Default)]
 #[non_exhaustive]
-pub struct ExitStatus();
+pub struct ExitStatus(u8);
 
 impl ExitStatus {
     pub fn exit_ok(&self) -> Result<(), ExitStatusError> {
+        if self.0 == 0 {
             Ok(())
+        } else {
+            Err(ExitStatusError(self.0))
+        }
     }
 
     pub fn code(&self) -> Option<i32> {
-        Some(0)
+        Some(self.0 as i32)
     }
 }
 
@@ -260,39 +264,18 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     }
 }
 
-pub struct ExitStatusError(!);
-
-impl Clone for ExitStatusError {
-    fn clone(&self) -> ExitStatusError {
-        self.0
-    }
-}
-
-impl Copy for ExitStatusError {}
-
-impl PartialEq for ExitStatusError {
-    fn eq(&self, _other: &ExitStatusError) -> bool {
-        self.0
-    }
-}
-
-impl Eq for ExitStatusError {}
-
-impl fmt::Debug for ExitStatusError {
-    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        self.0
-    }
-}
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+pub struct ExitStatusError(u8);
 
 impl Into<ExitStatus> for ExitStatusError {
     fn into(self) -> ExitStatus {
-        self.0
+        ExitStatus(self.0)
     }
 }
 
 impl ExitStatusError {
     pub fn code(self) -> Option<NonZero<i32>> {
-        self.0
+        Some(NonZero::new(self.0 as i32).unwrap())
     }
 }
 
@@ -318,24 +301,44 @@ fn from(code: u8) -> Self {
 }
 
 pub struct Process {
-    dummy: (),
+    pid: u64,
 }
 
 impl Process {
     pub fn id(&self) -> u32 {
-        todo!()
+        self.pid.try_into().unwrap()
     }
 
     pub fn kill(&mut self) -> io::Result<()> {
-        todo!()
+        unsupported()
     }
 
     pub fn wait(&mut self) -> io::Result<ExitStatus> {
-        todo!()
+        let Some(proc_man_pid) = syscalls::try_get_registered(3) else {
+            return unsupported();
+        };
+        let wait_res: Result<(u64, u8), Errno> = postcard::from_bytes(
+            &rpc::send_call(proc_man_pid, 8, 5, &postcard::to_allocvec(&(self.pid, true)).unwrap()).get_return(),
+        )
+        .unwrap();
+        let (_wait_pid, code) = wait_res?;
+        Ok(ExitStatus(code))
     }
 
     pub fn try_wait(&mut self) -> io::Result<Option<ExitStatus>> {
-        todo!()
+        let Some(proc_man_pid) = syscalls::try_get_registered(3) else {
+            return unsupported();
+        };
+        let wait_res: Result<(u64, u8), Errno> = postcard::from_bytes(
+            &rpc::send_call(proc_man_pid, 8, 5, &postcard::to_allocvec(&(self.pid, true)).unwrap()).get_return(),
+        )
+        .unwrap();
+        let (_wait_pid, code) = match wait_res {
+            Ok(val) => val,
+            Err(Errno::EAGAIN) => return Ok(None),
+            Err(e) => return Err(e.into()),
+        };
+        Ok(Some(ExitStatus(code)))
     }
 }