Dmitry Adamushko wrote:
On 10/10/05, Philippe Gerum <[EMAIL PROTECTED]> wrote:
Dmitry Adamushko wrote:
As you noticed below, the point is that this feature should be active for
kernel-based code only; for user-space, we're toast: typical chicken-and-egg
problem since we need the registry to cross the space boundaries but the
registry requires a name to index the object first. So yes, we need to check for
anonymous calls in every service taking a symbolic name in native/syscalls.c,
and return -EINVAL when applicable.
I thought that "libnative" would be a better place since this way we
would avoid the user mode -> kernel mode switch.
...Or, we might auto-generate some dummy name in native/syscalls.c we would pass
to the registry when this situation arises, so that anonymous creation and use
from user-space would still be possible.
Yep, in this case a name would be a string == object's address, thus
Ok, I'd probably vote for the 2-nd approach.
Definitely better since this keeps the semantics consistent across execution
Then we still have a difference in behaviour of the objectes depending
on where they are craeted. I mean, the NULL-named user-space objects
will be displayed under some, well, not-that-informative names (e.g.
0xc3264780) while the kernel-based ones will not have an entry in the
registry (they are really NULL-named).
1) don't display such names in /proc;
2) make a common mechanism for both spaces.
rt_mutex_create() // for other objects as well
snprintf(dst, XNOBJECT_NAME_LEN, "%p", object);
// the slightly ugly thing is that we need to be sure that dst is
always object->name so it's really of XNOBJECT_NAME_LEN size.
We should pass the size along with the copy buffer, mainly for readability, and
also as a safety belt.
Then we don't need "*name = '\n';" in syscall.c:__rt_object_create().
But this bit should be removed in any case.
What do you think?
Frankly, I like this approach better. All objects get some name if
they are NULL-named by a user and the code changes are a bit more
graceful. To show them in /proc or not is still another question.
I'd like we don't generalize an exception case here. The fact that for some
internal reason we need to put a dummy name on anon objects created from
user-space should not make all anon objects from kernel space have a registry
slot too, this would just be overkill (registry slots don't come for free actually).
That said, the remaining point basically is: how do we avoid anon objects with
auto-generated names from appearing under /proc? I'm not a fan of "magic values"
which would distinguish a real name from a dummy one, so I'd rather use the
existing possibility of passing a NULL pnode pointer to rt_registry_enter(),
which would still index an object without actually exporting it to the /proc
interface. The question is: how could we make the *_create() calls invoking
rt_registry_enter() with a NULL pnode when applicable, without changing the
kernel-based interface of the API.