Messages in this thread | | | Date | Mon, 11 Nov 2002 17:59:42 -0500 | From | Ben Collins <> | Subject | Re: how to access user space memory from kernel. |
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On Mon, Nov 11, 2002 at 11:40:19PM +0100, David San?n Baena wrote: > Hi. I need to access to user space memory from a kernel module. This module > is not a driver, so I would like how can i write and read from/to a variable > in a user application from my kernel module? > At first I thought I could do that with shared memory (shmget, shmat...), > but in that is not possible in a kernel module. So I have thought to do it > with copy_from_user and copy_to_user, but i don't know how to do it exactly, > basically how to know where to write or read in the user var... > Any suggestion??? > Thanks in advance
The user space application will have to make a call to the driver somehow. Usually this is in the way of an ioctl() on a device that the driver has made available to use space. The arguments passed across the ioctl are known to your kernel module and userspace app. You could pass a pointer to the kernel module which would be userspace memory that the driver could copy_to_user some data to.
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