From aa4dcca0b21af01008bca943d1498fa75fdc0f1f Mon Sep 17 00:00:00 2001
From: rmg-x <git@rmgx.io>
Date: Wed, 27 Nov 2024 15:43:12 -0600
Subject: [PATCH] LibCore/Process: Add `DupFd` file action

This commit provides a new file action allowing callers to provide a
`write_fd` that Process will "redirect" the child's stdin/stdout to.
---
 Libraries/LibCore/Process.cpp | 4 ++++
 Libraries/LibCore/Process.h   | 8 +++++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/Libraries/LibCore/Process.cpp b/Libraries/LibCore/Process.cpp
index 4305a97cfac..588515f53dd 100644
--- a/Libraries/LibCore/Process.cpp
+++ b/Libraries/LibCore/Process.cpp
@@ -121,6 +121,10 @@ ErrorOr<Process> Process::spawn(ProcessSpawnOptions const& options)
             [&](FileAction::CloseFile const& action) -> ErrorOr<void> {
                 CHECK(posix_spawn_file_actions_addclose(&spawn_actions, action.fd));
                 return {};
+            },
+            [&](FileAction::DupFd const& action) -> ErrorOr<void> {
+                CHECK(posix_spawn_file_actions_adddup2(&spawn_actions, action.write_fd, action.fd));
+                return {};
             }));
     }
 
diff --git a/Libraries/LibCore/Process.h b/Libraries/LibCore/Process.h
index 24145022b23..7ae9b571801 100644
--- a/Libraries/LibCore/Process.h
+++ b/Libraries/LibCore/Process.h
@@ -11,7 +11,6 @@
 
 #include <AK/ByteString.h>
 #include <AK/Forward.h>
-#include <AK/Span.h>
 #include <LibCore/File.h>
 
 namespace Core {
@@ -29,7 +28,10 @@ struct CloseFile {
     int fd { -1 };
 };
 
-// FIXME: Implement other file actions
+struct DupFd {
+    int write_fd { -1 };
+    int fd { -1 };
+};
 
 }
 
@@ -40,7 +42,7 @@ struct ProcessSpawnOptions {
     Vector<ByteString> const& arguments {};
     Optional<ByteString> working_directory {};
 
-    using FileActionType = Variant<FileAction::OpenFile, FileAction::CloseFile>;
+    using FileActionType = Variant<FileAction::OpenFile, FileAction::CloseFile, FileAction::DupFd>;
     Vector<FileActionType> file_actions {};
 };