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Re: [Bug-readline] heap-buffer-overflow in update_line
From: |
Chet Ramey |
Subject: |
Re: [Bug-readline] heap-buffer-overflow in update_line |
Date: |
Fri, 17 May 2019 11:34:32 -0400 |
User-agent: |
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 |
On 5/17/19 10:59 AM, Tom de Vries wrote:
>
> I've tried this:
> ...
> diff --git a/gdb/utils.c b/gdb/utils.c
> index 9686927473..2bfa22055e 100644
> --- a/gdb/utils.c
> +++ b/gdb/utils.c
> @@ -1371,7 +1371,7 @@ set_screen_size (void)
>
> if (cols <= 0 || cols > sqrt_int_max)
> {
> - cols = sqrt_int_max;
> + cols = -1;
> chars_per_line = UINT_MAX;
> }
It's not apparent from this patch whether or not gdb uses `cols' for
anything besides passing to readline.
> ...
> but ran into this test failure in gdb.ada/pp-rec-component.exp:
> ...
> (gdb) source
> /data/gdb_versions/devel/build/gdb/testsuite/outputs/gdb.ada/pp^M<sions/devel/build/gdb/testsuite/outputs/gdb.ada/pp-
>
> ^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^Hrec-component/pp-rec-com
> ^M<tsuite/outputs/gdb.ada/pp-rec-component/pp-rec-comp
> ^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^Honent.py^M
> (gdb) FAIL: gdb.ada/pp-rec-component.exp: source pp-rec-component.py
> ...
> which is readline doing it's horizontal scrolling mode, which AFAIU is
> triggered by this condition in rl_redisplay failing:
> ...
> if (_rl_horizontal_scroll_mode == 0 && _rl_term_up && *_rl_term_up)
> ...
> not because _rl_horizontal_scroll_mode is 1, but because _rl_term_up is
> NULL (because of TERM=dumb).
Correct. If the terminal type is unknown or tgetent returns a set of
capabilities that doesn't include "up", you're going to get horizontal
scrolling.
>
> Note btw that ^H is used here by readline despite the fact that
> TERM=dumb does not support backspace. I'm not sure if this is a bug, or
> intentional behaviour.
Readline uses what tgetent returns for "le" or defaults to "\b" if tgetent
fails. Most dumb terminals support ^H to move the cursor left one position.
>
> Either way, I'm open for suggestions that make gdb call
> rl_set_screen_size with legal parameters, and disable features like
> horizontal scrolling to get unformatted output for the testsuite run.
You can't specify a dumb terminal and expect to have line wrapping.
Chet
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU address@hidden http://tiswww.cwru.edu/~chet/
- [Bug-readline] heap-buffer-overflow in update_line, Tom de Vries, 2019/05/08
- Re: [Bug-readline] heap-buffer-overflow in update_line, Chet Ramey, 2019/05/16
- Re: [Bug-readline] heap-buffer-overflow in update_line, Tom de Vries, 2019/05/17
- Re: [Bug-readline] heap-buffer-overflow in update_line,
Chet Ramey <=
- Re: [Bug-readline] heap-buffer-overflow in update_line, Chet Ramey, 2019/05/20
- Re: [Bug-readline] heap-buffer-overflow in update_line, Tom de Vries, 2019/05/23
- Re: [Bug-readline] heap-buffer-overflow in update_line, Chet Ramey, 2019/05/23
- Re: [Bug-readline] heap-buffer-overflow in update_line, Tom de Vries, 2019/05/23
- Re: [Bug-readline] heap-buffer-overflow in update_line, Chet Ramey, 2019/05/24