Re: [PATCH] target/ppc/kvm: Skip ".." directory in kvmppc_find_cpu_dt

[Daniel Henrique Barboza]

On 7/12/22 00:46, David Gibson wrote:
> On Mon, Jul 11, 2022 at 04:37:43PM -0300, Murilo Opsfelder Araujo wrote:
> > Some systems have /proc/device-tree/cpus/../clock-frequency. However,
> > this is not the expected path for a CPU device tree directory.
> >
> > Signed-off-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
> > Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
> > ---
> >   target/ppc/kvm.c | 6 ++++++
> >   1 file changed, 6 insertions(+)
> >
> > diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c
> > index 6eed466f80..c8485a5cc0 100644
> > --- a/target/ppc/kvm.c
> > +++ b/target/ppc/kvm.c
> > @@ -1877,6 +1877,12 @@ static int kvmppc_find_cpu_dt(char *buf, int buf_len)
> >       buf[0] = '\0';
> >       while ((dirp = readdir(dp)) != NULL) {
> >           FILE *f;
> > +
> > +        /* Don't accidentally read from the upper directory */
> > +        if (strcmp(dirp->d_name, "..") == 0) {
>
> It might not be causing problems now, but it would be technically more
> correct to also skip ".", wouldn't it?

Given that the use of this function is inside kvmppc_read_int_cpu_dt(), which
is used to read a property that belongs to a CPU node, I believe you're right.
It's better to avoid returning "PROC_DEVTREE_CPU" as well.

Murilo, can you please re-send it skipping both ".." and "." ? Better be
on the safe side.


Daniel


> > +            continue;
> > +        }
> > +
> >           snprintf(buf, buf_len, "%s%s/clock-frequency", PROC_DEVTREE_CPU,
> >                    dirp->d_name);
> >           f = fopen(buf, "r");