[LTP] [PATCH v5 1/3] lib: Add support option for .needs_cmds

[Wei Gao]

On Fri, Dec 12, 2025 at 12:16:18PM +0100, Petr Vorel wrote:
> > Hi!
> > > diff --git a/lib/tst_test.c b/lib/tst_test.c
> > > index da5314c50..67553f65d 100644
> > > --- a/lib/tst_test.c
> > > +++ b/lib/tst_test.c
> > > @@ -1365,6 +1365,19 @@ static const char *default_fs_type(void)
> > >  	return tst_dev_fs_type();
> > >  }
> 
> > > +bool tst_cmd_present(const char *cmd)
> > > +{
> > > +	struct tst_cmd *pcmd = tst_test->needs_cmds;
> > > +
> > > +	while (pcmd->cmd) {
> > > +		if (!strcmp(pcmd->cmd, cmd))
> > > +			return pcmd->present;
> > > +
> > > +		pcmd++;
> > > +	}
> > > +	return false;
> 
> > Once again, we should tst_brk(TBROK, "Unexpected command '%s'", cmd) here since we asked for
> > something that we haven't checked for!
> 
> Good point. I'm sorry to overlook this in my review.
> 
> Also, strictly speaking tst_cmd_present() is only defined, not used. The commit
> is about changing .needs_cmds from char array (string) to struct tst_cmd.
> Therefore it could be in a separate commit. We don't have to be too strict, but
> given how many tests needed to be adapted adding tst_cmd_present() is somehow
> buried with other changes.

Thanks all for detail feedback. Let's me give some explaination why skip
tst_brk in above function:
tst_cmd_present will be used in latest ioctl_loop01.c and it should not
use tst_brk otherwise we will brk out of test in setup() too early.
The new support needs_cmds.optional in current patch is used for support 
tst_cmd_present scenario in ioctl_loop01.c.
Correct me if any mistake.

ioctl_loop01.c code:
static void setup(void)
{
        parted_sup = tst_cmd_present("parted");  <=====

.....
        if (parted_sup)
                SAFE_CMD(cmd_parted, NULL, NULL);  <===

        sprintf(partscan_path, "/sys/block/loop%d/loop/partscan", dev_num);
}

> 
> Kind regards,
> Petr