Subject: Re: qtopia
To: None <>
From: Christos Zoulas <>
List: tech-kern
Date: 06/06/2006 19:55:47
In article <>,
Jason Thorpe  <> wrote:
>On Jun 6, 2006, at 10:29 AM, Garrett D'Amore wrote:
>> That's not a bad idea.  Is there an example for passing properties in
>> ioctls, or is there another way to exchange this data?
>proplib is new enough that it's not being used for this purpose yet.   
>However, it's perfect for the "capabilities supported" / "options  
>enabled" kind of thing, where the list might grow in the future  
>(beyond 32-bits worth of features, perhaps).
>As for how to pass it back and forth, prop_dictionary_externalize()  
>before sending it across the boundary, prop_dictionary_internalize()  
>when receiving it from across the boundary.  Maybe we should even  
>make a generic ioctl argument:
>struct plistref {
>	const char *plist_ptr;
>	size_t plist_len;
>Then your hypothetical "get capabilities" ioctl could be:
>#define	FOOGETCAPS	_IOWR('f', 0, struct plistref)
>and your "get properties" / "set properties" could be:
>#define	FOOSETPROPS	_IOW('f', 1, struct plistref)
>#define	FOOGETPROPS	_IOWR('f', 2, struct plistref)
>We could probably even have a generic helper function in the kernel,  
>and a corresponding one in userspace, that took care of the temporary  
>buffer allocation, etc.

shouldn't the pointer be const void *?