state machine defect in drivers/tty/vt/vt.c?

state machine defect in drivers/tty/vt/vt.c?

[Joe Perches]

vc->vc_state is sequentially set to different values.

Looks like there's either a return or a break
missing at the end of case ESgetpars:

Anyone know the right fix here?

/* console_lock is held */
static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
{
[...]
	switch(vc->vc_state) {
[...]
	case ESgetpars:
		if (c == ';' && vc->vc_npar < NPAR - 1) {
			vc->vc_npar++;
			return;
		} else if (c>='0' && c<='9') {
			vc->vc_par[vc->vc_npar] *= 10;
			vc->vc_par[vc->vc_npar] += c - '0';
			return;
		} else
			vc->vc_state = ESgotpars;
	case ESgotpars:
		vc->vc_state = ESnormal;

Re: state machine defect in drivers/tty/vt/vt.c?

[Andreas Schwab]

Joe Perches <joe@perches.com> writes:

> vc->vc_state is sequentially set to different values.
>
> Looks like there's either a return or a break
> missing at the end of case ESgetpars:
>
> Anyone know the right fix here?

The first assignment can be removed.

> 	case ESgetpars:
> 		if (c == ';' && vc->vc_npar < NPAR - 1) {
> 			vc->vc_npar++;
> 			return;
> 		} else if (c>='0' && c<='9') {
> 			vc->vc_par[vc->vc_npar] *= 10;
> 			vc->vc_par[vc->vc_npar] += c - '0';
> 			return;
> 		} else
> 			vc->vc_state = ESgotpars;
> 	case ESgotpars:
> 		vc->vc_state = ESnormal;

That handles cases like '\033[m' where '\033[' enters state ESgetpars,
but 'm' is handled by ESgotpars.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
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