Intercept System call using Kernel module is 2.6 kernel

[Jeff.Fellin at rflelect.com]

                      "Meswani, Mitesh" <mmeswani at utep.edu>                                                                          
                      Sent by:                                             To:       <linuxppc-dev at ozlabs.org>                       
                      linuxppc-dev-bounces+jeff.fellin=rflelect.com        cc:                                                       
                      @ozlabs.org                                          Subject:  Intercept System call using Kernel  module is   
                                                                            2.6 kernel                                               
                                                                                                                                     
                      06/06/2006 12:25                                                                                               
                                                                                                                                     
                                                                                                                                     










>Hello


>I am attempting to run some user code with kernel space permission. I am
using the ppc64 kernel version >2.6.16-rc4-3-ppc64 for IBM Power5
processors.
>In this kernel module I am trying to implement a function that can be
called from user space.
>
>I have found through various posts that using unused system calls and
replacing them temporarily can acheive this >objective.
>
>This is what I am doing, but its not working, please bear with the
slightly long code that follows:
>
>1) since the 2.6 kernel does not export sys_call_table, I grep it from the
boot image
First sign what you are doing is not a good idea. There are better methods
of this
1) device driver interface with read/write/ioctl interface
2) procfs files from a module/driver
3) sysfs files from a module/driver

SNIP
>
>The problem is that when I execute my user app I expect to see two things:
 >a) I should see a message in the log "Executing mitesh_func..." and
> b) A return value of 2
>However I get an error value -1 returned.
An indication of thinking of system calls vs other methods is wrong!.

>Any help and ideas are highly appreciated.
Don't add your own or hijack system calls

Thank you in advance,
Mitesh
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