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>
---
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>