Am 15.11.2025 um 19:05 schrieb Aurélien Couderc via Cygwin:
On Sat, Nov 15, 2025 at 3:43 PM Thomas Wolff via Cygwin
<[email protected]> wrote:
Am 15.11.2025 um 13:58 schrieb Aurélien Couderc via Cygwin:
Does Cygwin have an API to atomically create a new file with an ACL?
Aurélien
I don't think there's such an API in POSIX. Instead it's the purpose of
the directory default ACL entries to support this.
While the manual pages of setfacl/getfacl are lousy, a fairly lucid
description is in 7.6. POSIX Access Control Lists | Administration Guide
| Red Hat Gluster Storage | 3 | Red Hat Documentation
<https://docs.redhat.com/en/documentation/red_hat_gluster_storage/3/html/administration_guide/sect-posix_access_control_lists>.
That does not help. There are valid use cases, where this becomes
security relevant due race conditions between file creation and
setting of the ACLs.
That's why all mainframe operating systems (and Windows WinNT as VMS
descendant) which support ACLs also support file creation with ACLs as
an argument.
Aurélien
The directory default ACL is like an implicit argument. I do not see a
race condition as my assumption is that the new file is equipped with
the inherited ACL in an atomic creation instance, although I do not find
this specified. Maybe someone has a more specific clue.
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