[PATCH v5 14/14] lib: sbi: Fix invalid directive print

[Jessica Clarke]

On 9 Jun 2023, at 07:37, Xiang W <wxjstz at 126.com> wrote:
> 
> 在 2023-06-09星期五的 05:15 +0100，Jessica Clarke写道：
>> On 9 Jun 2023, at 04:36, Xiang W <wxjstz at 126.com> wrote:
>>> 
>>> before fix:
>>>> printf("%1234"); /* print noting */
>>> after fix:
>>>> printf("%1234"); /* print %1234 */
>>> 
>>> Signed-off-by: Xiang W <wxjstz at 126.com>
>> 
>> Who cares what it does? It’s UB. Going out of your way to make it do a
>> specific thing with extra code is a waste of time and obfuscation.
>> 
>> Turn on -Wformat -Werror=format and get rid of broken code.
> Yes the compiler's error detection does catch problems early. But our sbi_printf
> implementation is not complete. For example, in the following case:
> sbi_printf("... %f...") .

case ‘f': panic("f not implemented");?

> And this patch has very little impact on the code size

I wasn’t talking about the compiled code, I meant the source.

Jess

> befor
> size build/lib/sbi/sbi_console.o
>   text   data    bss    dec    hex filename
>   3203      0    272   3475    d93 build/lib/sbi/sbi_console.o
> 
> after
> size build/lib/sbi/sbi_console.o
>   text   data    bss    dec    hex filename
>   3205      0    272   3477    d95 build/lib/sbi/sbi_console.o
> 
> Xiang
>> 
>> Jess
>> 
>>> ---
>>> lib/sbi/sbi_console.c | 10 +++++++---
>>> 1 file changed, 7 insertions(+), 3 deletions(-)
>>> 
>>> diff --git a/lib/sbi/sbi_console.c b/lib/sbi/sbi_console.c
>>> index f7fd761..a4ee1e5 100644
>>> --- a/lib/sbi/sbi_console.c
>>> +++ b/lib/sbi/sbi_console.c
>>> @@ -266,6 +266,7 @@ static void print(struct print_info *info, const char *format, va_list args)
>>> {
>>> bool flags_done;
>>> char scr[2];
>>> + const char *format_bak;
>>> bool use_tbuf = (!info->out) ? true : false;
>>> info->pos = 0;
>>> info->pc = 0;
>>> @@ -285,6 +286,8 @@ static void print(struct print_info *info, const char *format, va_list args)
>>> if (use_tbuf)
>>> info->flags |= USED_TBUF;
>>> if (*format == '%') {
>>> + /* need restore when the directive is invalid */
>>> + format_bak = format;
>>> ++format;
>>> if (*format == '\0')
>>> break;
>>> @@ -377,10 +380,11 @@ static void print(struct print_info *info, const char *format, va_list args)
>>> prints(info, scr);
>>> continue;
>>> }
>>> - } else {
>>> -literal:
>>> - printc(info, *format);
>>> + /* invalid directive */
>>> + format = format_bak;
>>> }
>>> +literal:
>>> + printc(info, *format);
>>> }
>>> 
>>> if (use_tbuf && info->pos > 0)
>>> -- 
>>> 2.39.2
>>> 
>