Function link

crates/vm/src/stdlib/os.rs:1647–1706

(args: LinkArgs, vm: &VirtualMachine)

    #[pyfunction]
    fn link(args: LinkArgs, vm: &VirtualMachine) -> PyResult<()> {
        let LinkArgs {
            src,
            dst,
            follow_symlinks,
        } = args;

        #[cfg(unix)]
        {
            use std::os::unix::ffi::OsStrExt;
            let src_cstr = alloc::ffi::CString::new(src.path.as_os_str().as_bytes())
                .map_err(|_| vm.new_value_error("embedded null byte"))?;
            let dst_cstr = alloc::ffi::CString::new(dst.path.as_os_str().as_bytes())
                .map_err(|_| vm.new_value_error("embedded null byte"))?;

            let follow = follow_symlinks.into_option().unwrap_or(true);
            let flags = if follow { libc::AT_SYMLINK_FOLLOW } else { 0 };

            let ret = unsafe {
                libc::linkat(
                    libc::AT_FDCWD,
                    src_cstr.as_ptr(),
                    libc::AT_FDCWD,
                    dst_cstr.as_ptr(),
                    flags,
                )
            };

            if ret != 0 {
                let err = std::io::Error::last_os_error();
                let builder = err.to_os_error_builder(vm);
                let builder = builder.filename(src.filename(vm));
                let builder = builder.filename2(dst.filename(vm));
                return Err(builder.build(vm).upcast());
            }

            Ok(())
        }

        #[cfg(not(unix))]
        {
            let src_path = match follow_symlinks.into_option() {
                Some(true) => {
                    // Explicit follow_symlinks=True: resolve symlinks
                    fs::canonicalize(&src.path).unwrap_or_else(|_| PathBuf::from(src.path.clone()))
                }
                Some(false) | None => {
                    // Default or explicit no-follow: native hard_link behavior
                    PathBuf::from(src.path.clone())
                }
            };

            fs::hard_link(&src_path, &dst.path).map_err(|err| {
                let builder = err.to_os_error_builder(vm);
                let builder = builder.filename(src.filename(vm));
                let builder = builder.filename2(dst.filename(vm));
                builder.build(vm).upcast()
            })