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From: andy <>
To: "Robert Hancock" <>
Subject: Re: accessing file operations directly in the kernel
Date: Fri, 7 Nov 2008 14:46:51 +0000	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

I agree with you! But there are cases where standards
are followed from certain developers. I have to deal with a
very "peculiar" arrangement of a set of requirements to access
a serial device driver. The type of code below gives me what I need, I think.

filp = filp_open("/dev/device1", O_WRONLY, 0);

if (filp->f_op->ioctl(filp->f_dentry->d_inode, filp,
							(unsigned long) &args) != 0) {
        		goto failed;


On 11/7/08, Robert Hancock <> wrote:
> andy wrote:
> > Hi,
> >
> > I am dealing with an interesting situation, which I have to access a
> > serial device driver
> > from the kernel space. I tried to use sys_open, sys_ioctl ... but
> > there is a problem
> > with the file descriptors.  Now, I started using direct calls to the
> > drivers functions
> > driver_open, driver_ioctl... passing the *inode from user_path_walk(),
> > but it doesn't
> > seem that works right. This serial device is going to be used only
> > from the other
> > module that runs in the kernel.
> >
>  For some reason this kind of question (using file operations inside the
> kernel) gets asked a lot. The short answer is that if you're asking it, you
> likely have a wrong design. It's just not the right thing to do. For one
> thing, file descriptors belong to a process, so just stealing the FD space
> from some random process is unlikely to do the right thing.
>  If you really need to do this, adding hooks to the serial device driver
> would seem a more logical thing to do.. but even that seems a suspicious
> design. It would be best if you explained what it is you're actually trying
> to accomplish.

  reply	other threads:[~2008-11-07 14:47 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <fa.8yqIDPH3sfvHfyr9YeQyeb9HG/>
2008-11-07  1:20 ` Robert Hancock
2008-11-07 14:46   ` andy [this message]
2008-11-06 22:39 andy

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