grep: avoid leak of chartables in PCRE2

94da919 ("grep: add support for PCRE v2", 2017-06-01) introduced
a small memory leak visible with valgrind in t7813.

Complete the creation of a PCRE2 specific variable that was missing from
the original change and free the generated table just like it is done
for PCRE1.

The table cleanup use free as there is no global context defined when
it was created (pcre2_maketables is passed a NULL pointer) but if that
gets ever changed will need to be updated in tandem.

Signed-off-by: Carlo Marcelo Arenas Belón <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: carenas

grep.c

@@ -488,7 +488,6 @@ static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt
 	PCRE2_UCHAR errbuf[256];
 	PCRE2_SIZE erroffset;
 	int options = PCRE2_MULTILINE;
-	const uint8_t *character_tables = NULL;
 	int jitret;
 	int patinforet;
 	size_t jitsizearg;
@@ -499,9 +498,10 @@ static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt
 
 	if (opt->ignore_case) {
 		if (has_non_ascii(p->pattern)) {
-			character_tables = pcre2_maketables(NULL);
+			p->pcre2_tables = pcre2_maketables(NULL);
 			p->pcre2_compile_context = pcre2_compile_context_create(NULL);
-			pcre2_set_character_tables(p->pcre2_compile_context, character_tables);
+			pcre2_set_character_tables(p->pcre2_compile_context,
+							p->pcre2_tables);
 		}
 		options |= PCRE2_CASELESS;
 	}
@@ -605,6 +605,7 @@ static void free_pcre2_pattern(struct grep_pat *p)
 	pcre2_match_data_free(p->pcre2_match_data);
 	pcre2_jit_stack_free(p->pcre2_jit_stack);
 	pcre2_match_context_free(p->pcre2_match_context);
+	free((void *)p->pcre2_tables);
 }
 #else /* !USE_LIBPCRE2 */
 static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt)

grep.h

@@ -96,6 +96,7 @@ struct grep_pat {
 	pcre2_compile_context *pcre2_compile_context;
 	pcre2_match_context *pcre2_match_context;
 	pcre2_jit_stack *pcre2_jit_stack;
+	const uint8_t *pcre2_tables;
 	uint32_t pcre2_jit_on;
 	kwset_t kws;
 	unsigned fixed:1;