access to getdents

[gmorer]

Following the use-case and the failure of #1552 , it would be nice for rustix to export in some way a more direct access to getdents. I am just unsure how this would look like.

I see 2 easy possible options:

• make getdents_uninit public.
• RawDir could export the value of initialized so RawDir::new(...).next() could be used to fill the buffer once and, with the value of initialized the parsing of the buffer could be delayed for later. But this rely on the first call to next() to always call the syscall and fill the buffer which is an underlying behavior of the library and not really future proof.

With the Unsized nature of linux_dirent64 I cannot think of any safe implementation, maybe a new getdents method that takes in the rustix' Buffer trait (but then nothing about alignment there).

I can implement any of the above approaches.

[sunfishcode]

I unfortunately don't have the bandwidth to read up on linux_dirent64 and provide any guidance here. If a safe API is indeed not feasible, an unsafe API is an option.

One thing to keep in mind is that rustix aims to support the same API with both the linux_raw and libc backends. Since getdents64 is not provided in libc, this will require using libc::syscall.