Re: see if a mutex lock is taken?
Re: see if a mutex lock is taken?
- Subject: Re: see if a mutex lock is taken?
- From: "mm w" <email@hidden>
- Date: Mon, 11 Feb 2008 19:26:35 -0800
Hi Greg,
as far I understand you want to use
/System/Library/Frameworks/Kernel.framework/Headers/kern/locks.h
there is a private method: extern boolean_t lck_mtx_try_lock(lck_mtx_t *lck);
but as I tried to explain you this API does the job for you, it is
lock system/api for a mutex_t
nm /mach_kernel | grep lck_mtx_try_lock
0019aa30 T _lck_mtx_try_lock
004d1b03 D _lck_mtx_try_lock_lockstat_patch_point
0019a930 T _lck_mtx_try_lock_spin
004d1aff D _lck_mtx_try_lock_spin_lockstat_patch_point
if you absolutely want to use it just declare it as extern in your header
extern boolean_t lck_mtx_try_lock(lck_mtx_t *lck);
further information: take a look here xnu/osfmk/i386/i386_lock.s
or here
xnu/osfmk/ppc/hw_lock.s
and sure the IOKit interface
http://developer.apple.com/documentation/Darwin/Reference/KernelIOKitFramework/IOLocks/CompositePage.html
call me mousse,\\ enjoy
-mmw
On Feb 11, 2008 6:54 PM, Greg <email@hidden> wrote:
>
> On Feb 11, 2008, at 3:42 PM, mm w wrote:
>
> > hi Greg, yep these mechanisms exist, this is the first things that you
> > implement when you write a lock system no matter on what: islockable
> > and islocked
> >
> > try to understand, what you do (if you use a lck object (locked))
> > if your lock object has been created, a lock has been aquired
> > when you create a lock object, the lock system test it for you
> >
> > -mmw
>
>
> Hi mmw, thanks for your reply. I was specifically wondering how I
> could do this from a kernel extension? I don't see a header in
> Kernel.framework that contains any try_lock functions for lck_mtx_t.
>
> Thanks!
>
> - Greg
>
>
>
> >>
> >> Hmm... I've found this in the sources to xnu, but I can't find this
> >> in
> >> the Kernel.framework. Perhaps I should have mentioned that I'm
> >> writing a kernel extension. Does this exist for kernel extensions,
> >> and if so how do I access it? Right now I'm just linking against
> >> Kernel.framework, which doesn't seem to have this header.
> >>
> >> Thanks!
> >>
> >> - Greg
> >>
>
>
--
-mmw
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