Re: Fwd: [PATCH] [-mm] ACPI: export ACPI events via netlink

Zhang Rui
2007-06-14T08:58:23Z

[-- Attachment #1: Type: text/plain, Size: 4950 bytes --]

Hi, Jamal,

Now the genl utility can find the acpi event genetlink family.
And a simple user space demo is finished for handling acpi event.
I really appreciate your help. :)

I think the patch which exposes ACPI events via netlink is ok.
But I still have some problems on
how to listen to specified genetlink family in user space?

I can get the dynamic id for "acpi_event" genl family.
But I don't know how to use this to receive messages from
specified genl family.
It seems that "#genl ctrl monitor" has something to do with this,
IMO, rtnl_open_byproto(&rth, nl_mgrp(GENL_ID_CTRL), NETLINK_GENERIC) is
used to receive messages from the nlctrl(controller) only, but
unfortunately it never works for me. :(

Any suggestions? What interfaces should I use? Or where can I find some
example code?

Attachment is the simple user space demo I made.
It receives all the broadcasted genetlink messages and only parses the
ones sent by "acpi_event" genl family.

Thanks,
Rui

On Sun, 2007-05-27 at 09:34 -0400, jamal wrote:
> On 5/27/07, Zhang Rui <rui.zhang@intel.com> wrote:
> >
> > I need to write a user application to test my patch.
> > Netlink messages can be sent/received using the standard socket API.
>
> sure.
>
> > But how to receive Genetlink messages from specified genetlink family?
> > There is no socket ACPI with such a parameter, right?
>
> Each module has a unique identifier that it receives dynamically on
> insertion at the kernel.
>
> > Do I have to receive all the genetlink messages first?
>
> No, just the ones for your dynamic id. Try what i described first for
> kernel side on the earlier email. I will repeat it here for clarity.
> Then look at genl code and if you have questions i can
> help.
> Note: You need to discover your dynamic id (the iproute2/genl code has a stub
> example code)
> As i told you in the earlier email, in your development:
> - start first by just writting your kernel side.
> - Then use the genl utility - which is part of iproute2 to see if the
> kernel side is "discoverable".
>
> E.g if i wanted to "discover" currently loaded modules on my laptop, i
> would do this:
>
> ---------------
> hadi@lilsol:~$ genl ctrl ls
>
> Name: nlctrl
> ID: 0x10 Version: 0x2 header size: 0 max attribs: 6
> commands supported:
> #1: ID-0x3 flags-0xe
>
>
> Name: nl80211
> ID: 0x11 Version: 0x1 header size: 0 max attribs: 22
> commands supported:
> #1: ID-0x1 flags-0xa
> #2: ID-0x6 flags-0xa
> #3: ID-0x8 flags-0xa
> #4: ID-0x3 flags-0xb
> #5: ID-0x4 flags-0xb
> #6: ID-0x5 flags-0xb
> #7: ID-0xa flags-0xb
> #8: ID-0xb flags-0xa
> #9: ID-0xf flags-0xb
> #10: ID-0x10 flags-0xa
> #11: ID-0x12 flags-0xb
> #12: ID-0x13 flags-0xa
> #13: ID-0x15 flags-0xa
> #14: ID-0x19 flags-0xb
> #15: ID-0x17 flags-0xb
> #16: ID-0x18 flags-0xb
> #17: ID-0x1a flags-0xb
> #18: ID-0x1b flags-0xa
> #19: ID-0xd flags-0xb
>
>
> Name: TASKSTATS
> ID: 0x12 Version: 0x1 header size: 0 max attribs: 4
> commands supported:
> #1: ID-0x1 flags-0xa
> ---------------------------
>
> As you can see, i can see from user space the name of the kernel end
> point, its numeric id, what version it is running (so i can make sure
> user space is compatible), what extra header it may have, what the
> maximum number of attributes it can take. The last thing that gets
> listed is the commands, and flags for those commands.
>
> Lets load tipc kernel module and repeat...
>
> -----------
>
> hadi@lilsol:~$ sudo modprobe tipc
> Name: nlctrl
> ID: 0x10 Version: 0x2 header size: 0 max attribs: 6
> commands supported:
> #1: ID-0x3 flags-0xe
>
> ....
> [same as before]
> ....
>
> Name: TIPC
> ID: 0x13 Version: 0x1 header size: 8 max attribs: 0
> commands supported:
> #1: ID-0x1 flags-0x2
>
> ===============
>
> > It would be great if there are any examples on user space communication.
>
>
>
> Bug Thomas - he has written some simple example. I also have some but i
> changed laptops and i have to go and dig it up for you.
> I do have plans for making this easier for people - but havent had time.
> If there is persistence - or someone out there wants to be a hero email
> me privately and i will explain it.
>
> > Or should I use libnl library instead?
>
> Why am i answering all these questions if you are fine with using libnl?
> Last time you said you couldnt use a library, no?
>
> cheers,
> jamal
>
>
> > Thanks,
> > Rui.
> >

[-- Attachment #2: acpi_genl.tgz --]
[-- Type: application/x-compressed-tar, Size: 8401 bytes --]