Re: [PATCH v1] core: Relax gpiod_chip_open() for symbolic links

[Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>]

czw., 6 lut 2020 o 19:14 Andy Shevchenko
<andriy.shevchenko@xxxxxxxxxxxxxxx> napisał(a):
>
> User may ask device helper tool, for example, udev, to create a specific
> symbolic link to a device node. GPIO chip character device node is not
> exceptional. However, libgpiod in the commit d9b1c1f14c6b
> ("core: harden gpiod_chip_open()") went way too far in the hardening device
> node check.
>
> Relax that hardening for symbolic link to fix the regression.
>
> Reproducer:
>
>   % gpioinfo /dev/gpiochip5
>   gpiochip5 - 16 lines:
>       line   0:  "MUX33_DIR" "uart1-rx-oe" output active-high [used]
>       ...
>
>   % ln -sf /dev/gpiochip5 /dev/MyGPIO_5
>
>   % gpioinfo /dev/MyGPIO_5
>   gpioinfo: looking up chip /dev/MyGPIO_5: Inappropriate ioctl for device
>
> Link: https://stackoverflow.com/questions/60057494/gpio-issue-with-sym-link
> Fixes: d9b1c1f14c6b ("core: harden gpiod_chip_open()")
> Cc: Bartosz Golaszewski <bartekgola@xxxxxxxxx>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>

Patch applied and backported to v1.4.x and v1.5.x stable branches.

Thanks!
Bartosz