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nh2today at 10:29 AM2 repliesview on HN

But those are all unsafe, taking raw strings.

Why can I easily use "*at" functions from Python's stdlib, but not Rust's?

They are much safer against path traversal and symlink attacks.

Working safely with files should not require *const c_char.

This should be fixed .


Replies

kibwentoday at 11:23 AM

> But those are all unsafe, taking raw strings.

The parent was asking for access to the C syscall, and C syscalls are unsafe, including in C. You can wrap that syscall in a safe interface if you like, and many have. And to reiterate, I'm all for supporting this pattern in Rust's stdlib itself. But openat itself is a questionable API (I have not yet seen anyone mention that openat2 exists), and if Rust wanted to provide this, it would want to design something distinct.

> Why can I easily use "*at" functions from Python's stdlib, but not Rust's?

I'm not sure you can. The supported pattern appears to involve passing the optional `opener` parameter to `os.open`, but while the example of this shown in the official documentation works on Linux, I just tried it on Windows and it throws a PermissionError exception because AFAIK you can't open directories on Windows.

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yx827hatoday at 1:29 PM

The nix crate provides the safe wrappers. https://docs.rs/nix/latest/nix/fcntl/fn.openat2.html