Re: [PATCH] ui/curses: Fix infinite loop on windows

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 8/4/25 16:08, Stefan Hajnoczi wrote:
> On Thu, Apr 03, 2025 at 01:07:56AM +0000, William Hu via wrote:
>> >From a42046272f0544dd18ed58661e53ea17d1584c2c Mon Sep 17 00:00:00 2001
>> From: William Hu <purplearmadillo77@proton.me>
>> Date: Wed, 2 Apr 2025 12:00:00 -0400
>> Subject: [PATCH] ui/curses: Fix infinite loop on windows
>>
>> Replace -1 comparisons for wint_t with WEOF to fix infinite loop caused by a
>> 65535 == -1 comparison.
>>
>> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2905
>> Signed-off-by: William Hu <purplearmadillo77@proton.me>
>> ---
>>   ui/curses.c | 10 ++++++++--
>>   1 file changed, 8 insertions(+), 2 deletions(-)
> 
> I have CCed Gerd Hoffmann (git-shortlog(1) shows he is the most frequent
> committer to this source file) and Marc-André Lureau (ui/ maintainer
> according to the ./MAINTAINERS file) so they can also review your patch.
> 
>>
>> diff --git a/ui/curses.c b/ui/curses.c
>> index a39aee8762..3f5c5adf78 100644
>> --- a/ui/curses.c
>> +++ b/ui/curses.c
>> @@ -265,7 +265,12 @@ static int curses2foo(const int _curses2foo[], const int _curseskey2foo[],
>>   
>>   static void curses_refresh(DisplayChangeListener *dcl)
>>   {
>> -    int chr, keysym, keycode, keycode_alt;
>> +    /*
>> +     * DO NOT MAKE chr AN INT:
>> +     * Causes silent conversion errors on Windows where wint_t is unsigned short.
>> +     */
>> +    wint_t chr = 0;
>> +    int keysym, keycode, keycode_alt;
>>       enum maybe_keycode maybe_keycode = CURSES_KEYCODE;
>>   
>>       curses_winch_check();
>> @@ -284,8 +289,9 @@ static void curses_refresh(DisplayChangeListener *dcl)
>>           /* while there are any pending key strokes to process */
>>           chr = console_getch(&maybe_keycode);
>>   
>> -        if (chr == -1)
>> +        if (chr == WEOF) {
>>               break;
>> +        }
> 
> Further below there appears to be another instance of the same bug:
> 
>    /* alt or esc key */
>    if (keycode == 1) {
>        enum maybe_keycode next_maybe_keycode = CURSES_KEYCODE;
>        int nextchr = console_getch(&next_maybe_keycode);
> 
>        if (nextchr != -1) {
>            ^^^^^^^^^^^^^

Indeed.

The changes comes from commit 459a707eccc ("curses: support wide input")
from 2019. This isn't a blocker for the next release IMHO.