svn commit: r364855 - head/sys/kern
Warner Losh
imp at FreeBSD.org
Thu Aug 27 05:11:16 UTC 2020
Author: imp
Date: Thu Aug 27 05:11:15 2020
New Revision: 364855
URL: https://svnweb.freebsd.org/changeset/base/364855
Log:
Implement FLUSHO
Turn FLUSHO on/off with ^O (or whatever VDISCARD is). Honor that to
throw away output quickly. This tries to remain true to 4.4BSD
behavior (since that was the origin of this feature), with any
corrections NetBSD has done. Since the implemenations are a little
different, though, some edge conditions may be handled differently.
Reviewed by: kib, kevans
Differential Review: https://reviews.freebsd.org/D26148
Modified:
head/sys/kern/tty.c
head/sys/kern/tty_ttydisc.c
Modified: head/sys/kern/tty.c
==============================================================================
--- head/sys/kern/tty.c Thu Aug 27 03:50:34 2020 (r364854)
+++ head/sys/kern/tty.c Thu Aug 27 05:11:15 2020 (r364855)
@@ -1467,6 +1467,7 @@ tty_signal_sessleader(struct tty *tp, int sig)
/* Make signals start output again. */
tp->t_flags &= ~TF_STOPPED;
+ tp->t_termios.c_lflag &= ~FLUSHO;
if (tp->t_session != NULL && tp->t_session->s_leader != NULL) {
p = tp->t_session->s_leader;
@@ -1486,6 +1487,7 @@ tty_signal_pgrp(struct tty *tp, int sig)
/* Make signals start output again. */
tp->t_flags &= ~TF_STOPPED;
+ tp->t_termios.c_lflag &= ~FLUSHO;
if (sig == SIGINFO && !(tp->t_termios.c_lflag & NOKERNINFO))
tty_info(tp);
@@ -1930,6 +1932,7 @@ tty_generic_ioctl(struct tty *tp, u_long cmd, void *da
return (0);
case TIOCSTART:
tp->t_flags &= ~TF_STOPPED;
+ tp->t_termios.c_lflag &= ~FLUSHO;
ttydevsw_outwakeup(tp);
ttydevsw_pktnotify(tp, TIOCPKT_START);
return (0);
Modified: head/sys/kern/tty_ttydisc.c
==============================================================================
--- head/sys/kern/tty_ttydisc.c Thu Aug 27 03:50:34 2020 (r364854)
+++ head/sys/kern/tty_ttydisc.c Thu Aug 27 05:11:15 2020 (r364855)
@@ -95,6 +95,7 @@ ttydisc_close(struct tty *tp)
/* Clean up our flags when leaving the discipline. */
tp->t_flags &= ~(TF_STOPPED|TF_HIWAT|TF_ZOMBIE);
+ tp->t_termios.c_lflag &= ~FLUSHO;
/*
* POSIX states that we must drain output and flush input on
@@ -474,6 +475,12 @@ ttydisc_write(struct tty *tp, struct uio *uio, int iof
MPASS(oblen == 0);
+ if (CMP_FLAG(l, FLUSHO)) {
+ uio->uio_offset += uio->uio_resid;
+ uio->uio_resid = 0;
+ return (0);
+ }
+
/* Step 1: read data. */
obstart = ob;
nlen = MIN(uio->uio_resid, sizeof ob);
@@ -495,6 +502,12 @@ ttydisc_write(struct tty *tp, struct uio *uio, int iof
do {
unsigned int plen, wlen;
+ if (CMP_FLAG(l, FLUSHO)) {
+ uio->uio_offset += uio->uio_resid;
+ uio->uio_resid = 0;
+ return (0);
+ }
+
/* Search for special characters for post processing. */
if (CMP_FLAG(o, OPOST)) {
plen = ttydisc_findchar(obstart, oblen);
@@ -629,6 +642,9 @@ static int
ttydisc_echo_force(struct tty *tp, char c, int quote)
{
+ if (CMP_FLAG(l, FLUSHO))
+ return 0;
+
if (CMP_FLAG(o, OPOST) && CTL_ECHO(c, quote)) {
/*
* Only perform postprocessing when OPOST is turned on
@@ -879,8 +895,10 @@ ttydisc_rint(struct tty *tp, char c, int flags)
}
/* Allow any character to perform a wakeup. */
- if (CMP_FLAG(i, IXANY))
+ if (CMP_FLAG(i, IXANY)) {
tp->t_flags &= ~TF_STOPPED;
+ tp->t_termios.c_lflag &= ~FLUSHO;
+ }
/* Remove the top bit. */
if (CMP_FLAG(i, ISTRIP))
@@ -905,6 +923,18 @@ ttydisc_rint(struct tty *tp, char c, int flags)
}
tp->t_flags |= TF_LITERAL;
return (0);
+ }
+ /* Discard processing */
+ if (CMP_CC(VDISCARD, c)) {
+ if (CMP_FLAG(l, FLUSHO)) {
+ tp->t_termios.c_lflag &= ~FLUSHO;
+ } else {
+ tty_flush(tp, FWRITE);
+ ttydisc_echo(tp, c, 0);
+ if (tp->t_inq.ti_end > 0)
+ ttydisc_reprint(tp);
+ tp->t_termios.c_lflag |= FLUSHO;
+ }
}
}
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