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

On Mon, May 14, 2018 at 02:53:49PM +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 "*" if not already present in > the user's pattern. > > Signed-off-by: Daniel P. Berrangé <berrange(a)redhat.com&gt; > --- > src/util/virlog.c | 14 +++++++++++++- > 1 file changed, 13 insertions(+), 1 deletion(-) > > diff --git a/src/util/virlog.c b/src/util/virlog.c > index be9fc0cf78..d548010b10 100644 > --- a/src/util/virlog.c > +++ b/src/util/virlog.c > @@ -1409,6 +1409,8 @@ virLogFilterNew(const char *match, > { > virLogFilterPtr ret = NULL; > char *mdup = NULL; > + size_t mlen = strlen(match); > + size_t off = 0; > > virCheckFlags(VIR_LOG_STACK_TRACE, NULL); > > @@ -1418,9 +1420,19 @@ virLogFilterNew(const char *match, > return NULL; > } > > - if (VIR_STRDUP_QUIET(mdup, match) < 0) > + if (VIR_ALLOC_N_QUIET(mdup, mlen + 3) < 0) > return NULL; > At first glance it's not very clear why we need the hunk below, so I'd add a comment stating that we treat a match 'foo' to be equal to '*foo*' for the purposes of fnmatch() use. Also, now that I see commit 8ccee910f5, I know we say we treat the match always as substring, but I'd go even further and enhance the sentence in that config (could be a separate patch) that not just 'foo', but also '*foo' and 'foo*' are in fact equal to '*foo*' for that matter. But this config change is not a deal-breaker to me. > + if (match[0] != '*') { > + mdup[off++] = '*'; > + } ^Braces around a single line body... > + memcpy(mdup + off, match, mlen + 1); Why do you copy the null byte too? 'mlen' should suffice.

> + off += mlen; > + if (match[mlen - 1] != '*') { > + mdup[off++] = '*'; > + mdup[off++] = '\0'; You won't need ^this extra null byte assignment, because we always use calloc to allocate a block.

> + } > + > if (VIR_ALLOC_QUIET(ret) < 0) { > VIR_FREE(mdup); > return NULL; With the nit-picks fixed and a commentary added right before the hunk this patch adds: Reviewed-by: Erik Skultety <eskultet(a)redhat.com&gt;