Rollup merge of #93858 - krallin:process-process_group, r=dtolnay

Add a `process_group` method to UNIX `CommandExt`

- Tracking issue: #93857
- RFC: https://github.com/rust-lang/rfcs/pull/3228

Add a `process_group` method to `std::os::unix::process::CommandExt` that
allows setting the process group id (i.e. calling `setpgid`) in the child, thus
enabling users to set process groups while leveraging the `posix_spawn` fast
path.

1 files changed, 14 insertions, 1 deletions

diff --git a/library/std/src/sys/unix/process/process_unix.rs b/library/std/src/sys/unix/process/process_unix.rs
index 2a97a802a20..3d305cd7310 100644
--- a/library/std/src/sys/unix/process/process_unix.rs
+++ b/library/std/src/sys/unix/process/process_unix.rs
@@ -320,6 +320,10 @@ impl Command {
             cvt(libc::chdir(cwd.as_ptr()))?;
         }
 
+        if let Some(pgroup) = self.get_pgroup() {
+            cvt(libc::setpgid(0, pgroup))?;
+        }
+
         // emscripten has no signal support.
         #[cfg(not(target_os = "emscripten"))]
         {
@@ -459,6 +463,8 @@ impl Command {
             None => None,
         };
 
+        let pgroup = self.get_pgroup();
+
         // Safety: -1 indicates we don't have a pidfd.
         let mut p = unsafe { Process::new(0, -1) };
 
@@ -487,6 +493,8 @@ impl Command {
             cvt_nz(libc::posix_spawnattr_init(attrs.as_mut_ptr()))?;
             let attrs = PosixSpawnattr(&mut attrs);
 
+            let mut flags = 0;
+
             let mut file_actions = MaybeUninit::uninit();
             cvt_nz(libc::posix_spawn_file_actions_init(file_actions.as_mut_ptr()))?;
             let file_actions = PosixSpawnFileActions(&mut file_actions);
@@ -516,13 +524,18 @@ impl Command {
                 cvt_nz(f(file_actions.0.as_mut_ptr(), cwd.as_ptr()))?;
             }
 
+            if let Some(pgroup) = pgroup {
+                flags |= libc::POSIX_SPAWN_SETPGROUP;
+                cvt_nz(libc::posix_spawnattr_setpgroup(attrs.0.as_mut_ptr(), pgroup))?;
+            }
+
             let mut set = MaybeUninit::<libc::sigset_t>::uninit();
             cvt(sigemptyset(set.as_mut_ptr()))?;
             cvt_nz(libc::posix_spawnattr_setsigmask(attrs.0.as_mut_ptr(), set.as_ptr()))?;
             cvt(sigaddset(set.as_mut_ptr(), libc::SIGPIPE))?;
             cvt_nz(libc::posix_spawnattr_setsigdefault(attrs.0.as_mut_ptr(), set.as_ptr()))?;
 
-            let flags = libc::POSIX_SPAWN_SETSIGDEF | libc::POSIX_SPAWN_SETSIGMASK;
+            flags |= libc::POSIX_SPAWN_SETSIGDEF | libc::POSIX_SPAWN_SETSIGMASK;
             cvt_nz(libc::posix_spawnattr_setflags(attrs.0.as_mut_ptr(), flags as _))?;
 
             // Make sure we synchronize access to the global `environ` resource