Function sys_fcntl 

pub fn sys_fcntl(fd: u64, cmd: u64, arg: u64) -> Result<u64, SyscallError>

SYS_FCNTL (313): manipulate file descriptor.

Supported commands:

• F_GETFD (1): Get file descriptor flags
• F_SETFD (2): Set file descriptor flags (FD_CLOEXEC)