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

[Xiang W]

在 2023-06-09星期五的 08:04 +0100，Jessica Clarke写道：
> 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");?
sbi_panic cannot be called directly here, it will cause a deadlock. Also such an
error message is not convenient for error location. Maybe we can drop this patch.

Xiang
> 
> > 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
> > > > 
> > 
> 
>