You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: uname.rs
    path of file: ./repos/kerla/kernel/syscalls
    
    the code of the file until where you have to start completion: use crate::result::Result;
use crate::syscalls::SyscallHandler;
use kerla_runtime::address::UserVAddr;

use crate::user_buffer::UserBufWriter;

    
    pub fn sys_uname(&mut self, buf: UserVAddr) -> Result<isize> {
        let mut writer = UserBufWriter::from_uaddr(buf, 6 * UTS_FIELD_LEN);
        // sysname
        writer.write_bytes_or_zeroes(b"Linux", UTS_FIELD_LEN)?;
        // nodename
        writer.write_bytes_or_zeroes(b"", UTS_FIELD_LEN)?;
        // release
        // We use a hard-coded release number instead of using our own version
        // because glibc checks the kernel version to determine supported
        // Linux's kernel features.
        writer.write_bytes_or_zeroes(b"4.0.0", UTS_FIELD_LEN)?;
        // version
        writer.write_bytes_or_zeroes(b"Kerla", UTS_FIELD_LEN)?;
        // machine
        writer.write_bytes_or_zeroes(b"", UTS_FIELD_LEN)?;
        // domainname
        writer.write_bytes_or_zeroes(b"", UTS_FIELD_LEN)?;
        Ok(0)
    }