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Subject[PATCH] Resume TTY on SUSP and fix CRNL order in N_TTY line discipline
Here is a small patch to further refine behavior in n_tty.c.  It
addresses two fine points in how received characters are treated - one
to handle the signal chars in stopped TTYs more consistently, and the
other to make the order of cr/nl translations more logical and
consistent with other Unixes when unusual stty settings are used (e.g.
if someone were to set intr to ^J).

-Joe
Refine these behaviors in the N_TTY line discipline:

1) Handle the signal characters consistently when received in
a stopped TTY so that SUSP (typically ctrl-Z) behaves like
INTR and QUIT in resuming a stopped TTY.

2) Adjust the order in which the IGNCR/ICRNL/INLCR processing
is applied to be more logical and consistent with the behavior
of other Unix systems.

Signed-off-by: Joe Peterson <joe@skyrush.com>
---
diff -puN drivers/char/n_tty.c~resume-tty-on-susp-and-fix-crnl-order-in-n_tty-line-discipline drivers/char/n_tty.c
--- a/drivers/char/n_tty.c~resume-tty-on-susp-and-fix-crnl-order-in-n_tty-line-discipline 2008-02-24 08:36:24.000000000 -0700
+++ a/drivers/char/n_tty.c 2008-02-24 21:08:15.000000000 -0700
@@ -701,7 +701,7 @@ static inline void n_tty_receive_char(st

if (tty->stopped && !tty->flow_stopped && I_IXON(tty) &&
((I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty)) ||
- c == INTR_CHAR(tty) || c == QUIT_CHAR(tty)))
+ c == INTR_CHAR(tty) || c == QUIT_CHAR(tty) || c == SUSP_CHAR(tty)))
start_tty(tty);

if (tty->closing) {
@@ -739,13 +739,6 @@ static inline void n_tty_receive_char(st
return;
}

- if (c == '\r') {
- if (I_IGNCR(tty))
- return;
- if (I_ICRNL(tty))
- c = '\n';
- } else if (c == '\n' && I_INLCR(tty))
- c = '\r';
if (I_IXON(tty)) {
if (c == START_CHAR(tty)) {
start_tty(tty);
@@ -756,6 +749,7 @@ static inline void n_tty_receive_char(st
return;
}
}
+
if (L_ISIG(tty)) {
int signal;
signal = SIGINT;
@@ -785,6 +779,15 @@ send_signal:
return;
}
}
+
+ if (c == '\r') {
+ if (I_IGNCR(tty))
+ return;
+ if (I_ICRNL(tty))
+ c = '\n';
+ } else if (c == '\n' && I_INLCR(tty))
+ c = '\r';
+
if (tty->icanon) {
if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
(c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
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