Hi Jonathan,
On Sun, Jan 07, 2024 at 03:53:33PM +0000, Jonathan Cameron wrote:
> On Thu, 4 Jan 2024 12:12:45 +0200
> Petre Rodan <petre.rodan@xxxxxxxxxxxxxxx> wrote:
>
> > Fix code flow problem and floating point exception caused by improper
> > directory stream positioning.
> >
> > Fixes: <e58537ccce733> ("staging: iio: update example application.")
> > Signed-off-by: Petre Rodan <petre.rodan@xxxxxxxxxxxxxxx>
> Hi Petre,
>
> This doesn't really explain 'why' seeekdir(dp, 0) is wrong.
> My assumption is that telldir() would not have returned 0 on this particular
> system? Could you confirm that and update the message to explain why
> seekdir(dp, 0) is not equivalent to rewinddir(dp).
it looks like there is a 32-bit specific bug in one of the glibc patches that
the stable Gentoo Linux is using [1]. telldir returns (u32)(-1) if seekdir is
used which ends up in a floating point exception.
it so happens that the rewinddir() function (which is equivalent) works
correctly. so it is a fix for Gentoo users and should not impact anyone else.
[1] https://sourceware.org/bugzilla/show_bug.cgi?id=31212
my very best regards,
peter
> Thanks,
>
> Jonathan
>
> > ---
> > tools/iio/iio_utils.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/tools/iio/iio_utils.c b/tools/iio/iio_utils.c
> > index 6a00a6eecaef..c5c5082cb24e 100644
> > --- a/tools/iio/iio_utils.c
> > +++ b/tools/iio/iio_utils.c
> > @@ -376,7 +376,7 @@ int build_channel_array(const char *device_dir, int buffer_idx,
> > goto error_close_dir;
> > }
> >
> > - seekdir(dp, 0);
> > + rewinddir(dp);
> > while (ent = readdir(dp), ent) {
> > if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
> > "_en") == 0) {
> > --
> > 2.41.0
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