On 11/06/16(Sat) 16:44, Marcus Glocker wrote:
> Currently one can open multiple instances of /dev/ttyU* since ucom(4)
> just checks 'TS_ISOPEN' against /dev/cuaU* access. There are quiet a
> lot of flags in ucom.c so it's a bit difficult to understand what the
> initial idea was. But moving the 'TS_ISOPEN' check before the UCOMCUA
> branch makes /dev/ttyU* access also return EBUSY if already opened.
>
> Ok? Or better ideas to fix this?
No idea how this is supposed to work but com(4) contains the exact same
code, so if this is a bug it should probably fixed there too.
> Index: ucom.c
> ===================================================================
> RCS file: /cvs/src/sys/dev/usb/ucom.c,v
> retrieving revision 1.65
> diff -u -p -u -p -r1.65 ucom.c
> --- ucom.c 14 Mar 2015 03:38:49 -0000 1.65
> +++ ucom.c 11 Jun 2016 12:08:20 -0000
> @@ -474,12 +474,13 @@ ucom_do_open(dev_t dev, int flag, int mo
> else
> s = spltty();
>
> + if (ISSET(tp->t_state, TS_ISOPEN)) {
> + /* Someone is already dialed in */
> + splx(s);
> + return (EBUSY);
> + }
> +
> if (UCOMCUA(dev)) {
> - if (ISSET(tp->t_state, TS_ISOPEN)) {
> - /* Someone is already dialed in */
> - splx(s);
> - return (EBUSY);
> - }
> sc->sc_cua = 1;
> } else {
> /* tty (not cua) device, wait for carrier */
>
