[PATCH 1/1] tools: iio: replace seekdir() in iio_generic_buffer

[PATCH 1/1] tools: iio: replace seekdir() in iio_generic_buffer

[Petre Rodan]

Replace seekdir() with rewinddir() in order to fix a localized glibc bug.

One of the glibc patches that stable Gentoo is using causes an improper
directory stream positioning bug on 32bit arm. That in turn ends up as a
floating point exception in iio_generic_buffer.

The attached patch provides a fix by using an equivalent function which
should not cause trouble for other distros.

https://sourceware.org/bugzilla/show_bug.cgi?id=31212

Signed-off-by: Petre Rodan <petre.rodan@subdimension.ro>
---
 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

Re: [PATCH 1/1] tools: iio: replace seekdir() in iio_generic_buffer

[Jonathan Cameron]

On Mon,  8 Jan 2024 12:32:20 +0200
Petre Rodan <petre.rodan@subdimension.ro> wrote:

> Replace seekdir() with rewinddir() in order to fix a localized glibc bug.
> 
> One of the glibc patches that stable Gentoo is using causes an improper
> directory stream positioning bug on 32bit arm. That in turn ends up as a
> floating point exception in iio_generic_buffer.
> 
> The attached patch provides a fix by using an equivalent function which
> should not cause trouble for other distros.
> 
> https://sourceware.org/bugzilla/show_bug.cgi?id=31212
> 
> Signed-off-by: Petre Rodan <petre.rodan@subdimension.ro>
I tweaked the description a tiny bit to say it's also easier to reason about
in general.

Applied to the togreg branch of iio.git and pushed out as tesing for 0-day
to probably ignore it.

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
>