add spawn_pg

1 files changed, 24 insertions, 0 deletions

diff --git a/src/command.rs b/src/command.rs
index cd1c8a3..c6dac9d 100644
--- a/src/command.rs
+++ b/src/command.rs
@@ -128,6 +128,30 @@ impl Command {
         Ok(self.inner.spawn()?)
     }
 
+    pub fn spawn_pg(
+        &mut self,
+        pg: Option<u32>,
+    ) -> crate::Result<async_process::Child> {
+        let mut set_process_group = crate::sys::set_process_group_child(pg);
+        // Safety: setpgid() is an async-signal-safe function and ioctl() is a
+        // raw syscall (which is inherently async-signal-safe).
+        if let Some(mut custom) = self.pre_exec.take() {
+            unsafe {
+                self.inner.pre_exec(move || {
+                    set_process_group()?;
+                    custom()?;
+                    Ok(())
+                })
+            };
+        } else {
+            unsafe { self.inner.pre_exec(set_process_group) };
+        }
+
+        let child = self.inner.spawn()?;
+        crate::sys::set_process_group_parent(child.id(), pg)?;
+        Ok(child)
+    }
+
     pub fn uid(&mut self, id: u32) -> &mut Self {
         self.inner.uid(id);
         self