Messages in this thread Patch in this message | | | Date | Mon, 30 Aug 2021 11:17:29 +0200 | Subject | Re: [PATCH] console: consume APC, DM, DCS | From | Jiri Slaby <> |
| |
On 30. 08. 21, 10:56, nick black wrote: > console: consume APC, DM, DCS > > The Linux console's VT102 implementation already > consumes OSC ("Operating System Command") sequences, > probably because that's how palette changes are > transmitted. In addition to OSC, there are three other > major clases of ANSI control strings: APC ("Application > Program Command"), PM ("Privacy Message", and DCS > ("Device Control String"). They are handled similarly > to OSC in terms of termination. > > Source: vt100.net > > Add three new enumerated states, one for each of these > types. All three are handled the same way right now--they > simply consume input until terminated. I hope to expand > upon this firmament in the future. Add new predicate > ansi_control_string(), returning true for any of these > states. Replace explicit checks against ESosc with calls > to this function. Transition to these states appropriately > from the escape initiation (ESesc) state. > > This was motivated by the following Notcurses bugs: > > https://github.com/dankamongmen/notcurses/issues/2050 > https://github.com/dankamongmen/notcurses/issues/1828 > https://github.com/dankamongmen/notcurses/issues/2069 > > where standard VT sequences are not consumed by the > Linux console. It's not necessary that the Linux console > *support* these sequences, but it ought *consume* these > well-specified classes of sequences. > > Tested by sending a variety of escape sequences to the > console, and verifying that they still worked, or were > now properly consumed. Verified that the escapes were > properly terminated at a generic level. Verified that > the Notcurses tools continued to show expected output on > the Linux console, except now without escape bleedthrough. > > Signed-off-by: nick black <dankamongmen@gmail.com> > --- > diff --git drivers/tty/vt/vt.c drivers/tty/vt/vt.c > index ef981d3b7bb4..62b77ee3f8d1 100644 > --- a/drivers/tty/vt/vt.c > +++ b/drivers/tty/vt/vt.c > @@ -2059,7 +2059,7 @@ static void restore_cur(struct vc_data *vc) > > enum { ESnormal, ESesc, ESsquare, ESgetpars, ESfunckey, > EShash, ESsetG0, ESsetG1, ESpercent, EScsiignore, ESnonstd, > - ESpalette, ESosc }; > + ESpalette, ESosc, ESapc, ESpm, ESdcs }; > > /* console_lock is held (except via vc_init()) */ > static void reset_terminal(struct vc_data *vc, int do_clear) > @@ -2133,20 +2133,28 @@ static void vc_setGx(struct vc_data *vc, unsigned int which, int c) > vc->vc_translate = set_translate(*charset, vc); > } > > +/* is this state an ANSI control string? */ > +static bool ansi_control_string(unsigned int state) > +{ > + if (state == ESosc || state == ESapc || state == ESpm || state == ESdcs) > + return true; > + return false;
So simply: return state == ESosc || state == ESapc || state == ESpm || state == ESdcs;
I wonder if we can simply hide them all behind single ESignore?
> +} > + > /* console_lock is held */ > static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c) > { > /* > * Control characters can be used in the _middle_ > - * of an escape sequence. > + * of an escape sequence, aside from ANSI control strings. > */ > - if (vc->vc_state == ESosc && c>=8 && c<=13) /* ... except for OSC */ > + if (ansi_control_string(vc->vc_state) && c >= 8 && c <= 13) > return; > switch (c) { > case 0: > return; > case 7: > - if (vc->vc_state == ESosc) > + if (ansi_control_string(vc->vc_state)) > vc->vc_state = ESnormal; > else if (vc->vc_bell_duration) > kd_mksound(vc->vc_bell_pitch, vc->vc_bell_duration); > @@ -2207,6 +2215,12 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c) > case ']': > vc->vc_state = ESnonstd; > return; > + case '_': > + vc->vc_state = ESapc; > + return; > + case '^': > + vc->vc_state = ESpm; > + return; > case '%': > vc->vc_state = ESpercent; > return; > @@ -2224,6 +2238,9 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c) > if (vc->state.x < VC_TABSTOPS_COUNT) > set_bit(vc->state.x, vc->vc_tab_stop); > return; > + case 'P': > + vc->vc_state = ESdcs; > + return; > case 'Z': > respond_ID(tty); > return; > @@ -2520,8 +2537,14 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c) > vc_setGx(vc, 1, c); > vc->vc_state = ESnormal; > return; > + case ESapc: > + return; > case ESosc: > return; > + case ESpm: > + return; > + case ESdcs: > + return; > default: > vc->vc_state = ESnormal; > } >
-- js suse labs
| |