Re: [Qemu-devel] [PATCH] qapi: fix input visitor bugs

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Jun 18, 2014 at 09:41:56AM -0600, Eric Blake wrote:
> On 06/18/2014 09:36 AM, Michael S. Tsirkin wrote:
> > Remove dead code.  Reset errno to 0 before each strtoull call, as the
> > man page requires.
> > 
> > Reported-by: Eric Blake <eblake@redhat.com>
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> >  qapi/string-input-visitor.c | 9 ++++-----
> >  1 file changed, 4 insertions(+), 5 deletions(-)
> > 
> > diff --git a/qapi/string-input-visitor.c b/qapi/string-input-visitor.c
> > index 72722e6..d8a8db0 100644
> > --- a/qapi/string-input-visitor.c
> > +++ b/qapi/string-input-visitor.c
> > @@ -48,11 +48,10 @@ static void parse_str(StringInputVisitor *siv, Error **errp)
> >          return;
> >      }
> >  
> > -    errno = 0;
> >      do {
> > +        errno = 0;
> >          start = strtoll(str, &endptr, 0);
> > -        if (errno == 0 && endptr > str && INT64_MIN <= start &&
> > -            start <= INT64_MAX) {
> > +        if (errno == 0 && endptr > str) {
> 
> Based on this conditional...
> 
> >              if (*endptr == '\0') {
> >                  cur = g_malloc0(sizeof(*cur));
> >                  cur->begin = start;
> > @@ -63,9 +62,9 @@ static void parse_str(StringInputVisitor *siv, Error **errp)
> >                  str = NULL;
> >              } else if (*endptr == '-') {
> >                  str = endptr + 1;
> > +                errno = 0;
> 
> ...this assignment to errno is dead code (we already know it is 0).  But
> I'd rather leave it in for robustness sake (any change to intermediate
> code may change the situation where we are no longer assured of the
> current value of errno at this point).

Exactly, that's why I put it here.

> Reviewed-by: Eric Blake <eblake@redhat.com>


Thanks!

> -- 
> Eric Blake   eblake redhat com    +1-919-301-3266
> Libvirt virtualization library http://libvirt.org
>