fileStatPosix

fn fileStatPosix(userdata: ?*anyopaque, file: File) File.StatError!File.Stat {
    const t: *Threaded = @ptrCast(@alignCast(userdata));
    _ = t;

    if (posix.Stat == void) return error.Streaming;

    const syscall: Syscall = try .start();
    while (true) {
        var stat = std.mem.zeroes(posix.Stat);
        switch (posix.errno(fstat_sym(file.handle, &stat))) {
            .SUCCESS => {
                syscall.finish();
                return statFromPosix(&stat);
            },
            .INTR => {
                try syscall.checkCancel();
                continue;
            },
            else => |e| {
                syscall.finish();
                switch (e) {
                    .INVAL => |err| return errnoBug(err),
                    .BADF => |err| return errnoBug(err), // File descriptor used after closed.
                    .NOMEM => return error.SystemResources,
                    .ACCES => return error.AccessDenied,
                    else => |err| return posix.unexpectedErrno(err),
                }
            },
        }
    }
}