[libvirt] [PATCH v2] log: actually do substring matches with fnmatch

[Erik Skultety]

On Wed, May 16, 2018 at 12:17:16PM +0100, Daniel P. Berrangé wrote:
> Historically we matched log filters with strstr(), and when switching to
> fnmatch in cbb0fd3cfdc287f6f4653ef1f04a7cfb2ea51b27, it was stated that
> we would continue to match substrings, with "foo" being equivalent to
> "*foo*". Unfortuntely I forget to provide the code to actually make that
> happen. This fixes it to prepend and append "*". We don't bother to
> check if the pattern already has a leading/trailing '*', because
> "**foo**" will match the same as "*foo*".
>
> Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>
> ---
>
> Changed in v2:
>
>  - Simplify to always append/prepend '*'
>  - Other fixes from Erik
>
>  src/util/virlog.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/src/util/virlog.c b/src/util/virlog.c
> index be9fc0cf78..9b63b8e7cd 100644
> --- a/src/util/virlog.c
> +++ b/src/util/virlog.c
> @@ -1409,6 +1409,7 @@ virLogFilterNew(const char *match,
>  {
>      virLogFilterPtr ret = NULL;
>      char *mdup = NULL;
> +    size_t mlen = strlen(match);
>
>      virCheckFlags(VIR_LOG_STACK_TRACE, NULL);
>
> @@ -1418,9 +1419,16 @@ virLogFilterNew(const char *match,
>          return NULL;
>      }
>
> -    if (VIR_STRDUP_QUIET(mdup, match) < 0)
> +    /* We must treat 'foo' as equiv to '*foo*' for fnmatch
> +     * todo substring matches, so add 2 extra bytes */

An extra comment block closing sequence at the ^end of the line, or one extra
below, I don't care as long as one is dropped to pass compilation...

> +     */
> +    if (VIR_ALLOC_N_QUIET(mdup, mlen + 3) < 0)
>          return NULL;
>
> +    mdup[0] = '*';
> +    memcpy(mdup + 1, match, mlen);
> +    mdup[mlen + 1] = '*';
> +

Oh, nice simplification indeed.

Reviewed-by: Erik Skultety <eskultet at redhat.com>