Re: [PATCH v3 08/15] ref-filter: introduce color_atom_parser()

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 5, 2016, 20:49 UTC
Message-ID: <xmqqwprniwfq.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <1451980994-26865-9-git-send-email-Karthik.188@gmail.com>

Karthik Nayak <karthik.188@gmail.com> writes:

Show 39 quoted lines

> Introduce color_atom_parser() which will parse a "color" atom and
> store its color in the "used_atom" structure for further usage in
> populate_value().
>
> Helped-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
> Helped-by: Eric Sunshine <sunshine@sunshineco.com>
> Signed-off-by: Karthik Nayak <Karthik.188@gmail.com>
> ---
>  ref-filter.c | 29 ++++++++++++++++++++---------
>  1 file changed, 20 insertions(+), 9 deletions(-)
>
> diff --git a/ref-filter.c b/ref-filter.c
> index b54c872..9708d67 100644
> --- a/ref-filter.c
> +++ b/ref-filter.c
> @@ -29,6 +29,9 @@ typedef enum { FIELD_STR, FIELD_ULONG, FIELD_TIME } cmp_type;
>  static struct used_atom {
>  	const char *name;
>  	cmp_type type;
> +	union {
> +		char *color;
> +	} u;
>  } *used_atom;
>  static int used_atom_cnt, need_tagged, need_symref;
>  static int need_color_reset_at_eol;
> @@ -53,6 +56,18 @@ static int match_atom_name(const char *name, const char *atom_name, const char *
>  	return 1;
>  }
>  
> +static void color_atom_parser(struct used_atom *atom)
> +{
> +	if (!match_atom_name(atom->name, "color", (const char **)&atom->u.color))
> +		die("BUG: parsing non-'color'");
> +	if (!atom->u.color)
> +		die(_("expected format: %%(color:<color>)"));
> +	/* atom->u.color points to part of atom->name */
> +	atom->u.color = xstrdup(atom->u.color);
> +	if (color_parse(atom->u.color, atom->u.color) < 0)
> +		die(_("invalid color value: %s"), atom->u.color);

Is this calling color_parse() from color.c?

The function wants the destination to be at least COLOR_MAXLEN, but I do not see where the piece memory pointed by atom->u.color is guaranteed to be that long in the new code. Looking at the code removed by this patch, it used to correctly use a buffer that is COLOR_MAXLEN bytes long. So...

	const char *color_value;

	if (!match_atom_name(atom->name, "color", color_value))
		die("BUG: parsing non-'color'");
	if (!color_value)
		die(_("expected format: %%(color:<color>)"));
	atom->u.color = xmalloc(COLOR_MAXLEN);
        if (color_parse(color_value, atom->u.color) < 0)
		die(_("invalid color value: %s"), color_value);

or even define it in the union, i.e.

	union {
        	char color[COLOR_MAXLEN];
	} u;

and then use atom->u.color[] in-place?