From: Denys Vlasenko <vda.linux@googlemail.com>
Subject: [PATCH 4/5] keyboard input: treat only ESC<char><end> or <ESC><char><ESC> as valid
Date: Mon, 22 Oct 2012 16:49:44 +0200
This change prevents misinterpreting an unknown ESC sequence's
tail as a garbage input. To reproduce, run "sleep 3" and
hold down Down_Arrow key until sleep runs.
With debugging log enabled, the following can be seen:
entered get_key_code(no_delay:0)
c=tty_lowlevel_getch()=27
push_char(27) !0
c=xgetch_second()=91
push_char(91) !0
2 c=tty_lowlevel_getch()=66
push_char(66)
seq_buffer[0]:27 <---- the saved Down Arrow sequence "ESC [ B"
seq_buffer[1]:91
seq_buffer[2]:66
seq_buffer[3]:0
pending_keys!=NULL. m=-1
d=*pending_keys++=27
d=ALT(*pending_keys++)=ALT(91)=8283
^^^^^^^^^^^^^^^^^^^^^^^ we misinterpret "ESC [ B" as "ESC ["
return correct_key_code(8283)
entered get_key_code(no_delay:0)
pending_keys!=NULL. m=-1
d=*pending_keys++=66
^^^^^^^^^^^^ we think user pressed "B"
return correct_key_code(66)
With this patch, no bogus "input" is generated.
Longer unknown sequences need an additional fix, coming next.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
---
lib/tty/key.c | 11 +++++++++--
1 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/lib/tty/key.c b/lib/tty/key.c
index 77185ce..9b97aa8 100644
|
a
|
b
|
get_key_code (int no_delay) |
| 1874 | 1874 | { |
| 1875 | 1875 | int d = *pending_keys++; |
| 1876 | 1876 | keylog (" d=*pending_keys++=%d\n", d); |
| 1877 | | check_pend: |
| 1878 | 1877 | if (*pending_keys == 0) |
| 1879 | 1878 | { |
| 1880 | 1879 | pending_keys = NULL; |
| … |
… |
get_key_code (int no_delay) |
| 1882 | 1881 | } |
| 1883 | 1882 | else if (d == ESC_CHAR) |
| 1884 | 1883 | { |
| | 1884 | int bad_seq; |
| 1885 | 1885 | d = ALT (*pending_keys++); |
| 1886 | 1886 | keylog (" d=ALT(*pending_keys++)=ALT(%d)=%d\n", pending_keys[-1], d); |
| 1887 | | goto check_pend; |
| | 1887 | bad_seq = (*pending_keys != ESC_CHAR && *pending_keys != 0); |
| | 1888 | if (*pending_keys == 0 || bad_seq) |
| | 1889 | { |
| | 1890 | pending_keys = NULL; |
| | 1891 | seq_append = NULL; |
| | 1892 | } |
| | 1893 | if (bad_seq) |
| | 1894 | goto nodelay_try_again; |
| 1888 | 1895 | } |
| 1889 | 1896 | if ((d > 127 && d < 256) && use_8th_bit_as_meta) |
| 1890 | 1897 | { |
