Add fts_openat() as a new entry point for fts(3).
When dirfd is AT_FDCWD the behaviour is identical to fts_open().
Passing a pre-opened directory fd allows fts traversal inside
Capsicum capability mode where path-based operations are not
permitted.
Capability mode users should use fts_parent->fts_dirfd + fts_name with
openat(2) to access files.
Reviewed by: asomers
Relnotes: yes
Sponsored by: Google LLC (GSoC 2026)
Pull Request: https://github.com/freebsd/freebsd-src/pull/2273
Jitendra Bhati
9aed7a7745