Messages in this thread | | | Date | Sat, 7 Jun 2003 14:32:19 +0200 | From | Ingo Oeser <> | Subject | Re: __user annotations |
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Hi Linus,
On Fri, Jun 06, 2003 at 10:28:22AM -0700, Linus Torvalds wrote: > HOWEVER, usually it's very obvious to fix the whole chain, unless some > type is sometimes used for kernel addresses and sometimes for user > addresses (which networking does with iovec's, for example).
Then it's not very useful for me. I usally define the ABI between user space and kernel space trough IOCTL like that:
/* These structures are usally bigger and nested deeper */ struct in_foo_ioctl_name { int bla; }
struct out_foo_ioctl_name { char blubb; }
union foo_ioctl_name { struct in_foo_ioctl_name in; struct out_foo_ioctl_name out; }
#define SUBSYS_IOCTL 0xee
#define SUBSYS_FOO _IOWR(SUBSYS_IOCTL, 0x1, union foo_ioctl_name)
Now I do in principle
union foo_ioctl_name k, *u = (union foo_ioctl_name *)arg;
if (copy_from_user(&k.in, &u, sizeof(k.in)) return -EFAULT; if (handle_foo(&k)) return -EINVAL; if (copy_to_user(&u, &k.out, sizeof(k.out)) return -EFAULT; which I consider very clean (our project provides both: The only ABI provider and the only ABI user) and works from 2.0 trough 2.5 so far.
This will NOT work anymore with __user annotations, right?
That's a big pity. How do I workaround this? I would like to help resolving this issues, if you are interested.
Regards
Ingo Oeser - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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