[patch 1/1] hvc_console: escape magic sysrq key

From: Hendrik Brueckner
Date: Tue Dec 16 2008 - 04:24:26 EST


From: Hendrik Brueckner <brueckner@xxxxxxxxxxxxxxxxxx>

The ctrl-o (^O) is a common control key used by several applications like vim.

To allow users to send ^O to the terminal, this patch introduces a check
if ^O is pressed again if the sysrq_pressed variable is already set.
In this case, clear sysrq_pressed state and flip the ^O character to the tty.
(The old behavior has always set "sysrq_pressed" if ^0 has been entered, and it
has not flipped the ^O character to the tty.)

Signed-off-by: Hendrik Brueckner <brueckner@xxxxxxxxxxxxxxxxxx>
---
drivers/char/hvc_console.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

--- a/drivers/char/hvc_console.c
+++ b/drivers/char/hvc_console.c
@@ -642,8 +642,11 @@ int hvc_poll(struct hvc_struct *hp)
/* Handle the SysRq Hack */
/* XXX should support a sequence */
if (buf[i] == '\x0f') { /* ^O */
- sysrq_pressed = 1;
- continue;
+ /* if ^0 is pressed again, reset
+ * sysrq_pressed and flip ^0 char */
+ sysrq_pressed = (sysrq_pressed) ? 0 : 1;
+ if (sysrq_pressed)
+ continue;
} else if (sysrq_pressed) {
handle_sysrq(buf[i], tty);
sysrq_pressed = 0;

--
Hendrik Brueckner
D/3303 Linux on System z Development
eMail: brueckner@xxxxxxxxxxxxxxxxxx
IBM Deutschland Research & Development GmbH, Schoenaicher Str. 220, 71032 Boeblingen

IBM Deutschland Research & Development GmbH
Vorsitzender des Aufsichtsrats: Martin Jetter
Geschaeftsfuehrung: Erich Baier
Sitz der Gesellschaft: Boeblingen
Registergericht: Amtsgericht Stuttgart, HRB 243294

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