On Fri, 6 Feb 2015 04:00:11 +0000
Al Viro <v...@zeniv.linux.org.uk> wrote:
> From: Al Viro <v...@zeniv.linux.org.uk>
>
> we know the lengths in advance...
>
> Signed-off-by: Al Viro <v...@zeniv.linux.org.uk>
> ---
> kernel/trace/trace_events_filter.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/trace/trace_events_filter.c
> b/kernel/trace/trace_events_filter.c
> index ced69da..6c4a96b 100644
> --- a/kernel/trace/trace_events_filter.c
> +++ b/kernel/trace/trace_events_filter.c
> @@ -271,21 +271,25 @@ static int filter_pred_none(struct filter_pred *pred,
> void *event)
>
> static int regex_match_full(char *str, struct regex *r, int len)
> {
> - if (strncmp(str, r->pattern, len) == 0)
> + if (len - 1 != r->len)
> + return 0;
> + if (memcmp(str, r->pattern, r->len) == 0)
> return 1;
> return 0;
> }
>
> static int regex_match_front(char *str, struct regex *r, int len)
> {
> - if (strncmp(str, r->pattern, r->len) == 0)
> + if (len - 1 < r->len)
> + return 0;
> + if (memcmp(str, r->pattern, r->len) == 0)
> return 1;
> return 0;
> }
>
> static int regex_match_middle(char *str, struct regex *r, int len)
> {
> - if (strnstr(str, r->pattern, len))
> + if (memmem(str, len, r->pattern, r->len))
Since len includes '\0', shouldn't this be:
if (memmem(str, len - 1, r->pattern, r->len);
It doesn't break the code either way, the algorithm still works, and
the original code did not pass in len-1 either. But if this is
optimizing the code, might as well eliminate one extra loop.
-- Steve
> return 1;
> return 0;
> }
--
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