Kernel: Implement Process::custody_for_dirfd

This allows deduplicating a bunch of code that has to work with POSIX' *at syscall semantics.
Author: https://github.com/sin-ack Commit: 5c1d5ed51d Pull-request: https://github.com/SerenityOS/serenity/pull/15428 Reviewed-by: https://github.com/ADKaster ✅ Reviewed-by: https://github.com/AtkinsSJ Reviewed-by: https://github.com/BertalanD Reviewed-by: https://github.com/linusg Reviewed-by: https://github.com/timschumi
2025-06-09 17:44:56 +09:00 · 2022-10-01 11:28:27 +00:00 · 2022-10-01 11:28:27 +00:00 · 5c1d5ed51d · 2024-07-17 03:24:13 +09:00
commit 5c1d5ed51d
parent 5b335e7fba
2 changed files with 13 additions and 0 deletions
--- a/Kernel/Process.cpp
+++ b/Kernel/Process.cpp
@ -1100,4 +1100,15 @@ RefPtr<Custody const> Process::executable() const
    return m_executable.with([](auto& executable) { return executable; });
 }

+ErrorOr<NonnullRefPtr<Custody>> Process::custody_for_dirfd(int dirfd)
+{
+    if (dirfd == AT_FDCWD)
+        return current_directory();
+
+    auto base_description = TRY(open_file_description(dirfd));
+    if (!base_description->custody())
+        return EINVAL;
+    return *base_description->custody();
+}
+
 }
--- a/Kernel/Process.h
+++ b/Kernel/Process.h
@ -844,6 +844,8 @@ public:
    }

 private:
+    ErrorOr<NonnullRefPtr<Custody>> custody_for_dirfd(int dirfd);
+
    SpinlockProtected<Thread::ListInProcess>& thread_list() { return m_thread_list; }
    SpinlockProtected<Thread::ListInProcess> const& thread_list() const { return m_thread_list; }