linux-kernel - Re: new file in kernel.

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Date:	Sat, 19 Jan 2008 15:30:24 +0100 (CET)
From:	Jan Engelhardt <jengelh@...putergmbh.de>
To:	Rafael Sisto <rafael.sisto@...il.com>
cc:	Linux kernel <linux-kernel@...r.kernel.org>
Subject: Re: new file in kernel.


On Jan 19 2008 11:08, Rafael Sisto wrote:
>
>I had already read that webpage, but I dont need to change the data on
>that file. I just want to create a new file and then close it, so I
>can use it later in another system call, to mmap it to a user space.
>Is it clearer now?
>Can you please give me some code snippet?

I don't get what your indirection is supposed to do.

 userspace -> sys_open -> kernel space -> create file
           -> sys_close -> kernel space -> close it

vs

 userspace -> sys_mycall -> kernelspace -> sys_open -> create_file
                                        -> sys_close -> create_file

As for code snippets:

asmlinkage logn sys_mycall(const char __user *filename,
    unsigned int flags, unsigned int mode)
{
	long ret;

	ret = sys_open(filename, flags, mode);
	if (ret < 0)
		return ret;

	return sys_close(fd);
}

You see, this is currently just too trivial to make sense, but if
it helps you, no problem.

>Sorry for the last mail, I answered to your personal mail only)

Here, we use Reply-to-all.

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