/* Simulated users input. */
 static struct parse_events_term test_terms[] = {
        {
-               .config    = (char *) "krava01",
+               .config    = "krava01",
                .val.num   = 15,
                .type_val  = PARSE_EVENTS__TERM_TYPE_NUM,
                .type_term = PARSE_EVENTS__TERM_TYPE_USER,
        },
        {
-               .config    = (char *) "krava02",
+               .config    = "krava02",
                .val.num   = 170,
                .type_val  = PARSE_EVENTS__TERM_TYPE_NUM,
                .type_term = PARSE_EVENTS__TERM_TYPE_USER,
        },
        {
-               .config    = (char *) "krava03",
+               .config    = "krava03",
                .val.num   = 1,
                .type_val  = PARSE_EVENTS__TERM_TYPE_NUM,
                .type_term = PARSE_EVENTS__TERM_TYPE_USER,
        },
        {
-               .config    = (char *) "krava11",
+               .config    = "krava11",
                .val.num   = 27,
                .type_val  = PARSE_EVENTS__TERM_TYPE_NUM,
                .type_term = PARSE_EVENTS__TERM_TYPE_USER,
        },
        {
-               .config    = (char *) "krava12",
+               .config    = "krava12",
                .val.num   = 1,
                .type_val  = PARSE_EVENTS__TERM_TYPE_NUM,
                .type_term = PARSE_EVENTS__TERM_TYPE_USER,
        },
        {
-               .config    = (char *) "krava13",
+               .config    = "krava13",
                .val.num   = 2,
                .type_val  = PARSE_EVENTS__TERM_TYPE_NUM,
                .type_term = PARSE_EVENTS__TERM_TYPE_USER,
        },
        {
-               .config    = (char *) "krava21",
+               .config    = "krava21",
                .val.num   = 119,
                .type_val  = PARSE_EVENTS__TERM_TYPE_NUM,
                .type_term = PARSE_EVENTS__TERM_TYPE_USER,
        },
        {
-               .config    = (char *) "krava22",
+               .config    = "krava22",
                .val.num   = 11,
                .type_val  = PARSE_EVENTS__TERM_TYPE_NUM,
                .type_term = PARSE_EVENTS__TERM_TYPE_USER,
        },
        {
-               .config    = (char *) "krava23",
+               .config    = "krava23",
                .val.num   = 2,
                .type_val  = PARSE_EVENTS__TERM_TYPE_NUM,
                .type_term = PARSE_EVENTS__TERM_TYPE_USER,
 
                        continue;
 
                if (perf_pmu__have_event(pmu, term->val.str)) {
-                       free(term->config);
+                       zfree(&term->config);
                        term->config = term->val.str;
                        term->type_val = PARSE_EVENTS__TERM_TYPE_NUM;
                        term->type_term = PARSE_EVENTS__TERM_TYPE_USER;
                        continue;
                }
 
-               free(term->config);
+               zfree(&term->config);
                term->config = strdup("config");
                errno = 0;
                num = strtoull(term->val.str + 1, NULL, 16);
        struct perf_pmu *pmu = NULL;
        YYLTYPE *loc = loc_;
        int ok = 0;
-       char *config;
+       const char *config;
 
        *listp = NULL;
 
                                   PARSE_EVENTS__TERM_TYPE_USER,
                                   config, 1, false, NULL,
                                        NULL) < 0) {
-               free(config);
+               zfree(&config);
                goto out_err;
        }
        list_add_tail(&term->list, head);
 }
 
 int parse_events_term__num(struct parse_events_term **term,
-                          int type_term, char *config, u64 num,
+                          int type_term, const char *config, u64 num,
                           bool no_value,
                           void *loc_term_, void *loc_val_)
 {
 
 };
 
 struct parse_events_term {
-       char *config;
+       const char *config;
        union {
                char *str;
                u64  num;
 void parse_events__shrink_config_terms(void);
 int parse_events__is_hardcoded_term(struct parse_events_term *term);
 int parse_events_term__num(struct parse_events_term **term,
-                          int type_term, char *config, u64 num,
+                          int type_term, const char *config, u64 num,
                           bool novalue,
                           void *loc_term, void *loc_val);
 int parse_events_term__str(struct parse_events_term **term,