Subject: Re: uprintf() limitations?
To: None <tech-kern@netbsd.org>
From: Nick Gimbrone <Nicholas.Gimbrone@Comcast.Net>
List: tech-kern
Date: 03/13/2002 02:06:58
Thanks, that's what I figured was likely occuring (the last operating system I
was working on would add buffer space for this type case, but this smelled like
a full buffer issue ;-). In this particular case I can easilly pass the raw data
up to userland for formatting, and figured that is what I'd have to do (unless
someone had a simpler "turn this knob" solution for the short term ;-).

This leads me to the next question, my first thought was to use copyout() to
pass the raw data up from the ioctl() routine for a pseudo-device to userland
for formatting... but attempts to make that work failed (likely due to my not
completely understanding the interface for passing the buffer address between
layers). Can someone point me to a good example of passing data between userland
& kernel space in an ioctl() function for a pseudo-device driver? (I keep
getting EFAULT errors out of the copyout() call, clearly I don't understand the
data address that my ioctl() was passed. Something I'm sure a good example will
solve. ;-)

Peace -njg