changed fallbackexitval

Author: rahulrangers

io/native/src/main/scala/fs2/io/process/ProcessesPlatform.scala

@@ -37,6 +37,8 @@ import java.io.IOException
 import cats.effect.LiftIO
 import cats.effect.IO
 import org.typelevel.scalaccompat.annotation._
+import scala.concurrent.duration.*
+import cats.effect.implicits.*
 
 @extern
 @nowarn212("cat=unused")
@@ -247,13 +249,30 @@ private[process] trait ProcessesCompanionPlatform extends Processesjvmnative {
           }
         }
 
-        private def fallbackExitValue(pid: pid_t): F[Int] =
-          F.blocking {
-            val status = stackalloc[CInt]()
-            val result = waitpid(pid, status, 0)
-            if (result == pid) WEXITSTATUS(!status)
-            else throw new IOException(s"waitpid failed with errno: ${errno.errno}")
+        private def fallbackExitValue(pid: pid_t): F[Int] = {
+          def loop: F[Int] =
+            F.blocking {
+              Zone { _ =>
+                val status = stackalloc[CInt]()
+                val result = waitpid(pid, status, WNOHANG)
+
+                if (result == pid) {
+                  Some(WEXITSTATUS(!status))
+                } else if (result == 0) None
+                else throw new IOException(s"waitpid failed with errno: ${errno.errno}")
+              }
+            }.flatMap {
+              case Some(code) => F.pure(code)
+              case None       => F.sleep(10.millis) >> loop
+            }
+
+          loop.onCancel {
+            F.blocking {
+              kill(pid, SIGKILL)
+              ()
+            }
           }
+        }
       }
     } else super.forAsync[F]
 }