On Thu, Jul 11, 2024 at 01:08:39PM +0200, Martin Wilck wrote:
> On Wed, 2024-07-10 at 18:54 -0400, Benjamin Marzinski wrote:
> > On Tue, Jul 09, 2024 at 11:39:12PM +0200, Martin Wilck wrote:
> > > Use sscanf to make the parsing of the UUID more robust.
> > >
> > > Signed-off-by: Martin Wilck <mwilck@xxxxxxxx>
> > > ---
> > > libmultipath/devmapper.c | 17 +++++++----------
> > > 1 file changed, 7 insertions(+), 10 deletions(-)
> > >
> > > diff --git a/libmultipath/devmapper.c b/libmultipath/devmapper.c
> > > index 56157af..d62a7dd 100644
> > > --- a/libmultipath/devmapper.c
> > > +++ b/libmultipath/devmapper.c
> > > @@ -846,23 +846,20 @@ int dm_get_uuid(const char *name, char *uuid,
> > > int uuid_len)
> > >
> > > static int is_mpath_part(const char *part_name, const char
> > > *map_name)
> > > {
> > > - char *p;
> > > - char part_uuid[DM_UUID_LEN], map_uuid[DM_UUID_LEN];
> > > + char part_uuid[DM_UUID_LEN], map_uuid[DM_UUID_LEN], c;
> > > + int np, nc;
> > >
> > > if (dm_get_dm_uuid(part_name, part_uuid) != DMP_OK)
> > > return 0;
> > >
> > > + if (2 != sscanf(part_uuid, "part%d-%n" UUID_PREFIX "%c",
> > > &np, &nc, &c)
> >
> > we should probably use "part%u-%n" so we can't match a "-" before the
> > number.
>
> That doesn't work, %u accepts negative numbers, too
> (https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf)
> That's why I use int and check whether the result is positive.
Huh? I learned something new. I actually find that kind of annoying,
since you could get the same result by just using %d and casting a
unsigned int to a signed one for the assignment, and it seems like
people would often not want to match a dash at the start.
At any rate, you're correct.
Reviewed-by: Benjamin Marzinski <bmarzins@xxxxxxxxxx>
>
> Martin
