From 30e1e3a13dc19c47afc517d1178e1dbf5b401596 Mon Sep 17 00:00:00 2001
From: syn <isaqtm@gmail.com>
Date: Sun, 9 Feb 2020 19:17:57 +0300
Subject: timeout'ed waiter for process

---
 src/wait/mod.rs | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 src/wait/mod.rs

(limited to 'src/wait/mod.rs')

diff --git a/src/wait/mod.rs b/src/wait/mod.rs
new file mode 100644
index 0000000..9761f08
--- /dev/null
+++ b/src/wait/mod.rs
@@ -0,0 +1,81 @@
+use nix::libc::{self, c_int};
+use nix::{
+    errno::Errno,
+    sys::wait::WaitStatus,
+    unistd::Pid
+};
+use std::time::{ Instant, Duration };
+use std::process::Child;
+use std::thread;
+use std::sync::mpsc;
+
+mod error;
+mod rusage_ffi;
+pub use rusage_ffi::Rusage;
+
+pub use error::WaitError;
+
+#[derive(Debug)]
+pub struct WaitInfo {
+    pub status: WaitStatus,
+    pub usage: Rusage,
+    pub wall_time: Duration
+}
+
+
+fn wait4_pid(
+    pid: Pid,
+    chan: mpsc::Sender<std::result::Result<WaitInfo, nix::Error>>,
+    timer: Instant
+) {
+    let mut status: c_int = 0;
+    let mut usg: libc::rusage;
+    let wait_ret;
+
+    unsafe {
+        usg = std::mem::zeroed();
+        wait_ret = libc::wait4(pid.as_raw(), &mut status, 0 as c_int, &mut usg);
+    }
+
+    #[allow(unused_must_use)] {
+        chan.send(match wait_ret {
+            -1 => Err(nix::Error::Sys(Errno::last())),
+            _ => WaitStatus::from_raw(pid, status).map(|nix_status| {
+                    WaitInfo {
+                        status: nix_status,
+                        usage: usg.into(),
+                        wall_time: timer.elapsed()
+                    }
+                }
+            )
+        });
+    };
+}
+
+
+pub fn wait_child(
+    mut child: Child,
+    timeout: Duration,
+    timer: Instant
+) -> Result<WaitInfo, WaitError> {
+    let pid = Pid::from_raw(child.id() as i32);
+    let (send, recv) = mpsc::channel();
+
+    let thr = thread::spawn(move || wait4_pid(pid, send, timer));
+
+    match recv.recv_timeout(timeout) {
+        Ok(Ok(usg)) => Ok(usg),
+        Ok(Err(err)) => Err(err.into()),
+        Err(mpsc::RecvTimeoutError::Timeout) => {
+            drop(recv);
+            drop(thr);
+
+            #[allow(unused_must_use)] {
+                child.kill();
+            }
+
+            Err(WaitError::TimedOut(timeout))
+        },
+        Err(mpsc::RecvTimeoutError::Disconnected) => unreachable!()
+    }
+}
-- 
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