The curious case of O_DIRECTORY|O

The curious case of O_DIRECTORY|O_CREAT

Posted Mar 28, 2023 8:40 UTC (Tue) by smcv (subscriber, #53363)
In reply to: The curious case of O_DIRECTORY|O_CREAT by josh
Parent article: The curious case of O_DIRECTORY|O_CREAT

Perhaps openat2() (which always rejected unknown flags) could interpret O_DIRECTORY|O_CREAT as "open a directory, creating it if it doesn't exist", even if plain open() and openat() don't? Or would it be more confusing for openat2() and openat() to differ on that?

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The curious case of O_DIRECTORY|O_CREAT

Posted Mar 28, 2023 9:36 UTC (Tue) by brauner (subscriber, #109349) [Link] (4 responses)

openat2() can very well differ from the other variants. But if we wanted it to be the only open* syscall to open and create a directory then we should add an openat2() specific flag instead of reusing O_DIRECTORY | O_CREAT. Otherwise userspace might rightly be confused why O_DIRECTORY|O_CREAT works on openat2() but not on other open() variants. Reusing O_DIRECTORY|O_CREAT really only makes sense when we provide consistent behavior for all open syscalls imho.

The curious case of O_DIRECTORY|O_CREAT

Posted Mar 28, 2023 9:49 UTC (Tue) by josh (subscriber, #17465) [Link] (3 responses)

Yeah, agreed; might as well make O_CREATE_DIR.

The curious case of O_DIRECTORY|O_CREAT

Posted Mar 28, 2023 11:58 UTC (Tue) by mathstuf (subscriber, #69389) [Link] (2 responses)

I like how you give "create" back its "E" but then steal "ectory" again.

The curious case of O_DIRECTORY|O_CREAT

Posted Mar 28, 2023 12:54 UTC (Tue) by brauner (subscriber, #109349) [Link] (1 responses)

The API giveth, and the API taketh away.

The curious case of O_DIRECTORY|O_CREAT

Posted Mar 28, 2023 20:44 UTC (Tue) by Villemoes (subscriber, #91911) [Link]

O_LORD_WONT_YOU_BUY_ME_PONIES