Re: [PATCH] block/curl: use strlen instead of strchr

[Vladimir Sementsov-Ogievskiy]

On 29.06.24 09:20, Michael Tokarev wrote:
> On 6/28/24 08:49, Vladimir Sementsov-Ogievskiy wrote:
> > We already know where colon is, so no reason to search for it. Also,
> > avoid a code, which looks like we forget to check return value of
> > strchr() to NULL.
> >
> > Suggested-by: Kevin Wolf <kwolf@redhat.com>
> > Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
> > ---
> >
> > This replaces my patch
> >    [PATCH] block/curl: explicitly assert that strchr returns non-NULL value
> > Supersedes: <20240627153059.589070-1-vsementsov@yandex-team.ru>
> >
> >   block/curl.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/block/curl.c b/block/curl.c
> > index 419f7c89ef..d03bfe4817 100644
> > --- a/block/curl.c
> > +++ b/block/curl.c
> > @@ -219,7 +219,7 @@ static size_t curl_header_cb(void *ptr, size_t size, size_t 
> > nmemb, void *opaque)
> >           && g_ascii_strncasecmp(header, accept_ranges,
> >                                  strlen(accept_ranges)) == 0) {
> > -        char *p = strchr(header, ':') + 1;
> > +        char *p = header + strlen(accept_ranges);
> >           /* Skip whitespace between the header name and value. */
> >           while (p < end && *p && g_ascii_isspace(*p)) {
>
> Heck.  All these strlen()s look ugly, especially in the
> loop iterations..

I expect that strlen of string constant is calculated in compilation time.

My aim was to fix Coverity complain (I don't see this complain in public qemu 
coverity project, that's why I don't specify CID in commit message), not to 
rewrite the whole function. So I'd prefer Kevein's suggesting which is both 
minimal and makes the code obviously correct.. The only simpler thing is to 
mark the problem false-positive in Coverity.

--
Best regards,
Vladimir