Re: [PATCH v2] grep: avoid leak of chartables in PCRE2

[Junio C Hamano <gitster@pobox.com>]

Carlo Marcelo Arenas Belón  <carenas@gmail.com> writes:

> 94da9193a6 ("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 <carenas@gmail.com>
> ---
> V2:
> * better document why free is used as suggested by René
> * avoid reusing PCRE1 variable for easy of maintenance (per Ævar)

Thanks; will queue.

>
>  grep.c | 7 ++++---
>  grep.h | 1 +
>  2 files changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/grep.c b/grep.c
> index f7c3a5803e..fbd3f3757c 100644
> --- a/grep.c
> +++ b/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)
> diff --git a/grep.h b/grep.h
> index 1875880f37..26d21a3433 100644
> --- a/grep.h
> +++ b/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;