Re: [PATCH] macfb: fix a memory leak (CID 1465231)

[Laurent Vivier <laurent@vivier.eu>]

Le 05/11/2021 à 18:01, Peter Maydell a écrit :
> On Fri, 5 Nov 2021 at 16:52, Laurent Vivier <laurent@vivier.eu> wrote:
>>
>> Rewrite the function using g_string_append_printf() rather than
>> g_strdup_printf()/g_strconcat().
>>
>> Fixes: df8abbbadf74 ("macfb: add common monitor modes supported by the MacOS toolbox ROM")
>> Cc: mark.cave-ayland@ilande.co.uk
>> Reported-by: Peter Maydell <peter.maydell@linaro.org>
>> Suggested-by: Peter Maydell <peter.maydell@linaro.org>
>> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
>> ---
>>   hw/display/macfb.c | 11 ++++-------
>>   1 file changed, 4 insertions(+), 7 deletions(-)
>>
>> diff --git a/hw/display/macfb.c b/hw/display/macfb.c
>> index 4b352eb89c3f..277d3e663331 100644
>> --- a/hw/display/macfb.c
>> +++ b/hw/display/macfb.c
>> @@ -440,21 +440,18 @@ static MacFbMode *macfb_find_mode(MacfbDisplayType display_type,
>>
>>   static gchar *macfb_mode_list(void)
>>   {
>> -    gchar *list = NULL;
>> -    gchar *mode;
>> +    GString *list = g_string_new("");
>>       MacFbMode *macfb_mode;
>>       int i;
>>
>>       for (i = 0; i < ARRAY_SIZE(macfb_mode_table); i++) {
>>           macfb_mode = &macfb_mode_table[i];
>>
>> -        mode = g_strdup_printf("    %dx%dx%d\n", macfb_mode->width,
>> +        g_string_append_printf(list, "    %dx%dx%d\n", macfb_mode->width,
>>                                  macfb_mode->height, macfb_mode->depth);
>> -        list = g_strconcat(mode, list, NULL);
>> -        g_free(mode);
>>       }
>>
>> -    return list;
>> +    return g_string_free(list, FALSE);
> 
> This reverses the order compared to the old code (which prepends
> 'mode' to the 'list' string it is building up). Does that matter ?
> 

Not at all. Perhaps it's even better like that as we have lower resolutions first.

It was done like that to be able to pass list set to NULL (first parameter must not be NULL).

Thanks,
Laurent