Run world service policy in WASI init with pollable process observation

userland/spawn/src/lib.rs

@@ -7,7 +7,10 @@ mod bindings {
 }
 use bindings::sausage::process::host;
 pub use bindings::wasi::io::streams::{InputStream, OutputStream};
-pub use host::Stdio;
+pub use host::{Stdio, Watcher, Change, ChangeKind};
+pub use bindings::wasi::io::poll::{Pollable, poll};
+/// Hard-stop a process group by a live process ID.
+pub fn kill(pid: u32) -> io::Result<()> { host::kill(pid).map_err(io::Error::other) }
 
 /// A prepared child process.
 pub struct Command {
@@ -63,6 +66,7 @@ pub struct Child {
 }
 impl Child {
     pub fn id(&self) -> u32 { self.child.pid() }
+    pub fn subscribe(&self) -> Pollable { self.child.subscribe() }
     pub fn try_wait(&self) -> Option<i32> { self.child.status() }
     pub fn wait(&self) -> i32 { self.child.wait() }
     /// Stop every process in this child's group.