diff options
Diffstat (limited to 'sys/kern/tty.c')
| -rw-r--r-- | sys/kern/tty.c | 140 |
1 files changed, 80 insertions, 60 deletions
diff --git a/sys/kern/tty.c b/sys/kern/tty.c index 66947ae..940a75b 100644 --- a/sys/kern/tty.c +++ b/sys/kern/tty.c @@ -36,7 +36,7 @@ * SUCH DAMAGE. * * @(#)tty.c 8.8 (Berkeley) 1/21/94 - * $Id: tty.c,v 1.59 1995/07/30 12:39:16 bde Exp $ + * $Id: tty.c,v 1.60 1995/07/30 13:52:56 bde Exp $ */ /*- @@ -95,9 +95,9 @@ static int proc_compare __P((struct proc *p1, struct proc *p2)); static int ttnread __P((struct tty *)); -static void ttyblock __P((struct tty *tp)); static void ttyecho __P((int, struct tty *tp)); static void ttyrubo __P((struct tty *, int)); +static void ttyunblock __P((struct tty *tp)); /* * Table with character classes and parity. The 8th bit indicates parity, @@ -177,6 +177,14 @@ char const char_type[] = { #define CLR(t, f) (t) &= ~(f) #define ISSET(t, f) ((t) & (f)) +/* + * Input control starts when we would not be able to fit the maximum + * contents of the ping-pong buffers and finishes when we would be able + * to fit that much plus 1/8 more. + */ +#define I_HIGH_WATER (TTYHOG - 2 * 256) /* XXX */ +#define I_LOW_WATER ((TTYHOG - 2 * 256) * 7 / 8) /* XXX */ + #undef MAX_INPUT /* XXX wrong in <sys/syslimits.h> */ #define MAX_INPUT TTYHOG @@ -285,9 +293,21 @@ ttyinput(c, tp) } ++tk_nin; + /* + * Block further input iff: + * current input > threshold AND input is available to user program + * AND input flow control is enabled and not yet invoked. + * The 3 is slop for PARMRK. + */ + iflag = tp->t_iflag; + if (tp->t_rawq.c_cc + tp->t_canq.c_cc > I_HIGH_WATER - 3 && + (!ISSET(lflag, ICANON) || tp->t_canq.c_cc != 0) && + (ISSET(tp->t_cflag, CRTS_IFLOW) || ISSET(iflag, IXOFF)) && + !ISSET(tp->t_state, TS_TBLOCK)) + ttyblock(tp); + /* Handle exceptional conditions (break, parity, framing). */ cc = tp->t_cc; - iflag = tp->t_iflag; err = (ISSET(c, TTY_ERRORMASK)); if (err) { CLR(c, TTY_ERRORMASK); @@ -317,11 +337,7 @@ parmrk: c = 0; } } - /* - * In tandem mode, check high water mark. - */ - if (ISSET(iflag, IXOFF) || ISSET(tp->t_cflag, CRTS_IFLOW)) - ttyblock(tp); + if (!ISSET(tp->t_state, TS_TYPEN) && ISSET(iflag, ISTRIP)) CLR(c, 0x80); if (!ISSET(lflag, EXTPROC)) { @@ -1109,6 +1125,7 @@ ttyflush(tp, rw) register int s; s = spltty(); +again: if (rw & FWRITE) CLR(tp->t_state, TS_TTSTOP); #ifdef sun4c /* XXX */ @@ -1123,25 +1140,33 @@ ttyflush(tp, rw) tp->t_rocol = 0; CLR(tp->t_state, TS_LOCAL); ttwakeup(tp); + if (ISSET(tp->t_state, TS_TBLOCK)) { + ttyunblock(tp); + if (ISSET(tp->t_iflag, IXOFF)) { + /* + * XXX wait a bit in the hope that the stop + * character (if any) will go out. Waiting + * isn't good since it allows races. This + * will be fixed when the stop character is + * put in a special queue. Don't bother with + * the checks in ttywait() since the timeout + * will save us. + */ + SET(tp->t_state, TS_SO_OCOMPLETE); + ttysleep(tp, TSA_OCOMPLETE(tp), TTOPRI, + "ttyfls", hz / 10); + /* + * Don't try sending the stop character again. + */ + CLR(tp->t_state, TS_TBLOCK); + goto again; + } + } } if (rw & FWRITE) { FLUSHQ(&tp->t_outq); ttwwakeup(tp); } - if ((rw & FREAD) && - ISSET(tp->t_state, TS_TBLOCK) && tp->t_rawq.c_cc < TTYHOG/5) { - int queue_full = 0; - - if (ISSET(tp->t_iflag, IXOFF) && - tp->t_cc[VSTART] != _POSIX_VDISABLE && - (queue_full = putc(tp->t_cc[VSTART], &tp->t_outq)) == 0 || - ISSET(tp->t_cflag, CRTS_IFLOW)) { - CLR(tp->t_state, TS_TBLOCK); - ttstart(tp); - if (queue_full) /* try again */ - SET(tp->t_state, TS_TBLOCK); - } - } splx(s); } @@ -1168,34 +1193,37 @@ ttychars(tp) } /* - * Send stop character on input overflow. + * Handle input high water. Send stop character for the IXOFF case. Turn + * on our input flow control bit and propagate the changes to the driver. + * XXX the stop character should be put in a special high priority queue. */ -static void +void ttyblock(tp) - register struct tty *tp; + struct tty *tp; { - register int total; - total = tp->t_rawq.c_cc + tp->t_canq.c_cc; - /* - * Block further input iff: current input > threshold - * AND input is available to user program. - */ - if (total >= TTYHOG / 2 && - !ISSET(tp->t_state, TS_TBLOCK) && - (!ISSET(tp->t_lflag, ICANON) || tp->t_canq.c_cc > 0)) { - int queue_full = 0; - - if (ISSET(tp->t_iflag, IXOFF) && - tp->t_cc[VSTOP] != _POSIX_VDISABLE && - (queue_full = putc(tp->t_cc[VSTOP], &tp->t_outq)) == 0 || - ISSET(tp->t_cflag, CRTS_IFLOW)) { - SET(tp->t_state, TS_TBLOCK); - ttstart(tp); - if (queue_full) /* try again */ - CLR(tp->t_state, TS_TBLOCK); - } - } + SET(tp->t_state, TS_TBLOCK); + if (ISSET(tp->t_iflag, IXOFF) && tp->t_cc[VSTOP] != _POSIX_VDISABLE && + putc(tp->t_cc[VSTOP], &tp->t_outq) != 0) + CLR(tp->t_state, TS_TBLOCK); /* try again later */ + ttstart(tp); +} + +/* + * Handle input low water. Send start character for the IXOFF case. Turn + * off our input flow control bit and propagate the changes to the driver. + * XXX the start character should be put in a special high priority queue. + */ +static void +ttyunblock(tp) + struct tty *tp; +{ + + CLR(tp->t_state, TS_TBLOCK); + if (ISSET(tp->t_iflag, IXOFF) && tp->t_cc[VSTART] != _POSIX_VDISABLE && + putc(tp->t_cc[VSTART], &tp->t_outq) != 0) + SET(tp->t_state, TS_TBLOCK); /* try again later */ + ttstart(tp); } void @@ -1590,26 +1618,18 @@ slowcase: break; first = 0; } + +out: /* * Look to unblock input now that (presumably) * the input queue has gone down. */ -out: s = spltty(); - if (ISSET(tp->t_state, TS_TBLOCK) && tp->t_rawq.c_cc < TTYHOG/5) { - int queue_full = 0; - - if (ISSET(tp->t_iflag, IXOFF) && - cc[VSTART] != _POSIX_VDISABLE && - (queue_full = putc(cc[VSTART], &tp->t_outq)) == 0 || - ISSET(tp->t_cflag, CRTS_IFLOW)) { - CLR(tp->t_state, TS_TBLOCK); - ttstart(tp); - if (queue_full) /* try again */ - SET(tp->t_state, TS_TBLOCK); - } - } + if (ISSET(tp->t_state, TS_TBLOCK) && + tp->t_rawq.c_cc + tp->t_canq.c_cc <= I_LOW_WATER) + ttyunblock(tp); splx(s); + return (error); } |
