message: Remove F_SETFD command
diff: @@ -108,7 +108,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
  &mut self,
  fd_op: OpTy<'tcx, Tag>,
  cmd_op: OpTy<'tcx, Tag>,
  - arg_op: Option<OpTy<'tcx, Tag>>,
  + _arg_op: Option<OpTy<'tcx, Tag>>,
  ) -> InterpResult<'tcx, i32> {
  let this = self.eval_context_mut();
  @@ -118,29 +118,11 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
  let fd = this.read_scalar(fd_op)?.to_i32()?;
  let cmd = this.read_scalar(cmd_op)?.to_i32()?;
  -
  - if cmd == this.eval_libc_i32("F_SETFD")? {
  - // This does not affect the file itself. Certain flags might require changing the file
  - // or the way it is accessed somehow.
  - let flag = this.read_scalar(arg_op.unwrap())?.to_i32()?;
  - // The only usage of this in stdlib at the moment is to enable the `FD_CLOEXEC` flag.
  - let fd_cloexec = this.eval_libc_i32("FD_CLOEXEC")?;
  - if let Some(FileHandle { flag: old_flag, .. }) =
  - this.machine.file_handler.handles.get_mut(&fd)
  - {
  - // Check that the only difference between the old flag and the current flag is
  - // exactly the `FD_CLOEXEC` value.
  - if flag ^ *old_flag == fd_cloexec {
  - *old_flag = flag;
  - } else {
  - throw_unsup_format!("Unsupported arg {:#x} for `F_SETFD`", flag);
  - }
  - }
  - Ok(0)
  - } else if cmd == this.eval_libc_i32("F_GETFD")? {
  + // We only support getting the flags for a descriptor
  + if cmd == this.eval_libc_i32("F_GETFD")? {
  this.get_handle_and(fd, |handle| Ok(handle.flag))
  } else {
  - throw_unsup_format!("Unsupported command {:#x}", cmd);
  + throw_unsup_format!("The {:#x} command is not supported for `fcntl`)", cmd);
  }
  }
  