[LTP] [PATCH v5 1/4] lib/tst_kconfig.c: add any kconfig with or without expected value function

[Pengfei Xu]

Hi Cyril,
  Thanks for advice!
  I only support the CONFIG_A|CONFIG_B=X function, and there is only 1 '='
  contained in 1 line kconfig check.
  Could we add the function first, only support CONFIG_A|CONFIG_B=X function?

  Next to consider the function for CONFIG_A=X|CONFIG_B=Y.
  And I tried to add the function you mentioned in tst_kconfig.c,
  found CONFIG_A=X|CONFIG_B=Y, if kconfig set as CONFIG_A=Y, it will meet
  judge correctly issue, there is no kconfig item string in tst_kconfig_res.
struct tst_kconfig_res {
	char match;  // match char like y|m|v
	char *value; // *value like 4|44
};

  Or shall we need change the kconfig verify way?

  Thanks!
  BR.

On 2020-01-29 at 17:19:57 +0100, Cyril Hrubis wrote:
> Hi!
> >  	for (i = 0; i < cnt; i++) {
> >  		const char *val = strchr(kconfigs[i], '=');
> > @@ -176,12 +177,9 @@ void tst_kconfig_read(const char *const *kconfigs,
> >  			tst_brk(TBROK, "Invalid config string '%s'", kconfigs[i]);
> >  
> >  		matches[i].match = 0;
> > -		matches[i].len = strlen(kconfigs[i]);
> >  
> > -		if (val) {
> > +		if (val)
> >  			matches[i].val = val + 1;
> > -			matches[i].len -= strlen(val);
> > -		}
> >  
> >  		results[i].match = 0;
> >  		results[i].value = NULL;
> > @@ -193,17 +191,29 @@ void tst_kconfig_read(const char *const *kconfigs,
> >  
> >  	while (fgets(buf, sizeof(buf), fp)) {
> >  		for (i = 0; i < cnt; i++) {
> > -			if (match(&matches[i], kconfigs[i], &results[i], buf)) {
> > -				for (j = 0; j < cnt; j++) {
> > -					if (matches[j].match)
> > -						break;
> > +			memset(kconfig_multi, 0, sizeof(kconfig_multi));
> > +			/* strtok_r will split kconfigs[i] to multi string, so copy it */
> > +			memcpy(kconfig_multi, kconfigs[i], strlen(kconfigs[i]));
> > +			kconfig_token = strtok_r(kconfig_multi, "|=", &p_left);
> > +
> > +			while (kconfig_token != NULL) {
> > +				if (strncmp("CONFIG_", kconfig_token, 7))
> > +					tst_brk(TBROK, "Invalid config string '%s'", kconfig_token);
> > +				matches[i].len = strlen(kconfig_token);
> > +				if (match(&matches[i], kconfig_token, &results[i], buf)) {
> > +					for (j = 0; j < cnt; j++) {
> > +						if (matches[j].match)
> > +							break;
> > +					}
> > +					if (j == cnt)
> > +						goto exit;
> 
> I do not think that this actually works correctly. One of the problems I
> see is that we do match only the CONFIG_FOO part in the
> tst_kconfig_read() and the result value is evaluated later on. This
> means that if we had something as "CONFIG_FOO=5|CONFIG_FOO=4" the code
> will pick up only the first occurence of the = and we would end up doing
> strcmp("4", "5|CONFIG_FOO=4") which would fail as well.
> 
> If we wanted to have proper solution for logic statements inside of the
> kconfig parser we would have to isolate the CONFIG_FOO names first, pass
> them to the tst_kconfig_read() function, that would get us values for
> all config variables we need, then we could split the configs strings
> greadily on | and evaluate them one after another.
> 
> So the first function would have to be able to get arrays of strings and
> return another array of strings isolating the CONFIG_FOO variables. That
> would be passed to tst_kconfig_read() that would yield results[] array,
> for all interesting variables. From that point we can split the kconfig
> strings by | and evaluate one after another until we get match or end of
> the string.
> 
> -- 
> Cyril Hrubis
> chrubis@suse.cz