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

[Xiang W]

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...") .

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