Opening files from within geom filters

[Ali Mashtizadeh]

Hi Benjamin,

Thanks for the reference. I originally wanted to open an fd in
userspace as suggested, but the alq(9) API did not support that. I
guess I'll try adding a new alq creation function for this purpose.
Similarly, geom did not support that as well. I guess I'll spend
sometime on adding that infrastructure.

Thanks,
~ Ali

On Sun, Jun 5, 2011 at 12:01 AM, Benjamin Kaduk <kaduk at mit.edu> wrote:
> On Sat, 4 Jun 2011, Ali Mashtizadeh wrote:
>
>> Hi Folks,
>>
>> I'm working on a small geom filter where I need to open a file with
>> vn_open_cred, but this causes an assert because of a null pointer
>> because g_run_event proc structure has null pointer for the current
>> working directory.
>
> Hi Ali,
>
> In general, it is not recommended to open a file from within the kernel, due
> to a multitude of complications and difficulties.
> The old thread here:
> http://lists.freebsd.org/pipermail/freebsd-hackers/2007-May/020544.html
> may provide you with some other options to do what you're doing, and insight
> from a previous time when this sort of question came up.
>
> -Ben Kaduk
>