can python do some kernel stuff?

[Jimmy]

Hi to all

python now has grown to a versatile language that can
accomplish tasks for many different purposes. However,
AFAIK, little is known about its ability of kernel coding.

So I am wondering if python can do some kernel coding that
used to be the private garden of C/C++. For example, can python
intercept the input of keyboard on a system level? someone told me
it's a kernel thing, isn't it?

[Andrew Lee]

Re: can python do some kernel stuff?

Jimmy wrote:

Hi to all
>
python now has grown to a versatile language that can
accomplish tasks for many different purposes. However,
AFAIK, little is known about its ability of kernel coding.
>
So I am wondering if python can do some kernel coding that
used to be the private garden of C/C++. For example, can python
intercept the input of keyboard on a system level? someone told me
it's a kernel thing, isn't it?

http://wiki.python.org/moin/elmer

[Jimmy]

Re: can python do some kernel stuff?

On May 23, 3:05 pm, Andrew Lee <fiacre.patr... @gmail.comwrote :

Jimmy wrote:

Hi to all

>

python now has grown to a versatile language that can
accomplish tasks for many different purposes. However,
AFAIK, little is known about its ability of kernel coding.

>

So I am wondering if python can do some kernel coding that
used to be the private garden of C/C++. For example, can python
intercept the input of keyboard on a system level? someone told me
it's a kernel thing, isn't it?

>
http://wiki.python.org/moin/elmer

well, straightly speaking, how can I know a key is pressed on a system-
level if
using python?

[Diez B. Roggisch]

Re: can python do some kernel stuff?

Jimmy schrieb:

On May 23, 3:05 pm, Andrew Lee <fiacre.patr... @gmail.comwrote :

>Jimmy wrote:

>>Hi to all
>>python now has grown to a versatile language that can
>>accomplish tasks for many different purposes. However,
>>AFAIK, little is known about its ability of kernel coding.
>>So I am wondering if python can do some kernel coding that
>>used to be the private garden of C/C++. For example, can python
>>intercept the input of keyboard on a system level? someone told me
>>it's a kernel thing, isn't it?

>http://wiki.python.org/moin/elmer

>
well, straightly speaking, how can I know a key is pressed on a system-
level if
using python?

What has that todo with kernel programming? You can use e.g. pygame to
get keystrokes. Or under linux, read (if you are root) the keyboard
input file - I've done that to support several keyboards attached to a
machine.

And the original question: no, python can't be used as kernel
programming language. Amongst other reasons, performance & the GIL
prevent that.

Diez

[Andrew Lee]

Re: can python do some kernel stuff?

Jimmy wrote:

On May 23, 3:05 pm, Andrew Lee <fiacre.patr... @gmail.comwrote :

>Jimmy wrote:

>>Hi to all
>>python now has grown to a versatile language that can
>>accomplish tasks for many different purposes. However,
>>AFAIK, little is known about its ability of kernel coding.
>>So I am wondering if python can do some kernel coding that
>>used to be the private garden of C/C++. For example, can python
>>intercept the input of keyboard on a system level? someone told me
>>it's a kernel thing, isn't it?

>http://wiki.python.org/moin/elmer

>
well, straightly speaking, how can I know a key is pressed on a system-
level if
using python?

http://docs.python.org/lib/module-curses.html

Unless you are using an ancient piece of hardware -- a terminal is a
pseudo terminal and a key stroke isn't a kernel event at all.

If you were looking for examples of kernel level functions you might
want to consider driver interfaces -- how to program device interfaces
-- that, too, can be done in Python -- but, again, you are always
calling some underlying C function exposed via SWIG or another cross
compilation tool. Python doesn't reinvent system calls! :-)

[Andrew Lee]

Re: can python do some kernel stuff?

Diez B. Roggisch wrote:

Jimmy schrieb:

>On May 23, 3:05 pm, Andrew Lee <fiacre.patr... @gmail.comwrote :

>>Jimmy wrote:
>>>Hi to all
>>>python now has grown to a versatile language that can
>>>accomplish tasks for many different purposes. However,
>>>AFAIK, little is known about its ability of kernel coding.
>>>So I am wondering if python can do some kernel coding that
>>>used to be the private garden of C/C++. For example, can python
>>>intercept the input of keyboard on a system level? someone told me
>>>it's a kernel thing, isn't it?
>>http://wiki.python.org/moin/elmer

>>
>well, straightly speaking, how can I know a key is pressed on a system-
>level if
>using python?

>
What has that todo with kernel programming? You can use e.g. pygame to
get keystrokes. Or under linux, read (if you are root) the keyboard
input file - I've done that to support several keyboards attached to a
machine.
>
And the original question: no, python can't be used as kernel
programming language. Amongst other reasons, performance & the GIL
prevent that.
>
Diez

http://www.kernel-panic.it/programming/py-pf/

Of course you can code kernel routines in Python -- you are just calling
the underlying C interface. The GIL means you have to manage
threadsafety on your own -- it doesn't imply kernel programming can not
be done.

I'm not talking about writing an OS in Python (though a simple DOS-like
OS is very possible). Nor would I suggest writing device drivers in
Python -- but of course you can call kernel routines and manage some
kernel resources effectively. Python's IPC libraries expose kernel
functionality.

[Diez B. Roggisch]

Re: can python do some kernel stuff?

Andrew Lee schrieb:

Diez B. Roggisch wrote:

>Jimmy schrieb:

>>On May 23, 3:05 pm, Andrew Lee <fiacre.patr... @gmail.comwrote :
>>>Jimmy wrote:
>>>>Hi to all
>>>>python now has grown to a versatile language that can
>>>>accomplis h tasks for many different purposes. However,
>>>>AFAIK, little is known about its ability of kernel coding.
>>>>So I am wondering if python can do some kernel coding that
>>>>used to be the private garden of C/C++. For example, can python
>>>>intercept the input of keyboard on a system level? someone told me
>>>>it's a kernel thing, isn't it?
>>>http://wiki.python.org/moin/elmer
>>>
>>well, straightly speaking, how can I know a key is pressed on a system-
>>level if
>>using python?

>>
>What has that todo with kernel programming? You can use e.g. pygame to
>get keystrokes. Or under linux, read (if you are root) the keyboard
>input file - I've done that to support several keyboards attached to a
>machine.
>>
>And the original question: no, python can't be used as kernel
>programming language. Amongst other reasons, performance & the GIL
>prevent that.
>>
>Diez

>

http://www.kernel-panic.it/programming/py-pf/

>
Of course you can code kernel routines in Python -- you are just calling
the underlying C interface. The GIL means you have to manage
threadsafety on your own -- it doesn't imply kernel programming can not
be done.

I understood the OP's question as "can one program kernelspace routines
in python". Which I don't think is possible. And I don't see how py-pf
does that either.

Diez

[Andrew Lee]

Re: can python do some kernel stuff?

Diez B. Roggisch wrote:

Andrew Lee schrieb:

>Diez B. Roggisch wrote:

>>Jimmy schrieb:
>>>On May 23, 3:05 pm, Andrew Lee <fiacre.patr... @gmail.comwrote :
>>>>Jimmy wrote:
>>>>>Hi to all
>>>>>python now has grown to a versatile language that can
>>>>>accompli sh tasks for many different purposes. However,
>>>>>AFAIK, little is known about its ability of kernel coding.
>>>>>So I am wondering if python can do some kernel coding that
>>>>>used to be the private garden of C/C++. For example, can python
>>>>>intercep t the input of keyboard on a system level? someone told me
>>>>>it's a kernel thing, isn't it?
>>>>http://wiki.python.org/moin/elmer
>>>>
>>>well, straightly speaking, how can I know a key is pressed on a system-
>>>level if
>>>using python?
>>>
>>What has that todo with kernel programming? You can use e.g. pygame
>>to get keystrokes. Or under linux, read (if you are root) the
>>keyboard input file - I've done that to support several keyboards
>>attached to a machine.
>>>
>>And the original question: no, python can't be used as kernel
>>programming language. Amongst other reasons, performance & the GIL
>>prevent that.
>>>
>>Diez

>>
>http://www.kernel-panic.it/programming/py-pf/
>>
>Of course you can code kernel routines in Python -- you are just
>calling the underlying C interface. The GIL means you have to manage
>threadsafety on your own -- it doesn't imply kernel programming can
>not be done.

>
I understood the OP's question as "can one program kernelspace routines
in python". Which I don't think is possible. And I don't see how py-pf
does that either.
>
Diez

OP: "I am wondering if python can do some kernel coding that
used to be the private garden of C/C++."

The answer is yes. IPC and py-pf are examples. If you don't think of
packet filtering as kernel coding, I can understand. But clearly the
Python interfaces to fork(), waitpid(), signal(), alarm() and so forth
are forays into the once private garden of C.

[Diez B. Roggisch]

Re: can python do some kernel stuff?

>

OP: "I am wondering if python can do some kernel coding that
used to be the private garden of C/C++."

"kernel coding" is pretty clear I'd say - coding a or in the kernel. Not
coding that runs on an OS that happens to have a kernel.

The answer is yes. IPC and py-pf are examples. If you don't think of
packet filtering as kernel coding, I can understand. But clearly the
Python interfaces to fork(), waitpid(), signal(), alarm() and so forth
are forays into the once private garden of C.

Also not "kernel coding" in my book. system-near coding - yes. But not
coding a kernel...

Diez

[Jimmy]

Re: can python do some kernel stuff?

On May 23, 5:53 pm, "Diez B. Roggisch" <de...@nospam.w eb.dewrote:

Jimmy schrieb:
>

On May 23, 3:05 pm, Andrew Lee <fiacre.patr... @gmail.comwrote :

Jimmy wrote:
>Hi to all
>python now has grown to a versatile language that can
>accomplish tasks for many different purposes. However,
>AFAIK, little is known about its ability of kernel coding.
>So I am wondering if python can do some kernel coding that
>used to be the private garden of C/C++. For example, can python
>intercept the input of keyboard on a system level? someone told me
>it's a kernel thing, isn't it?
>http://wiki.python.org/moin/elmer

>

well, straightly speaking, how can I know a key is pressed on a system-
level if
using python?

>
What has that todo with kernel programming? You can use e.g. pygame to
get keystrokes. Or under linux, read (if you are root) the keyboard
input file - I've done that to support several keyboards attached to a
machine.
>
And the original question: no, python can't be used as kernel
programming language. Amongst other reasons, performance & the GIL
prevent that.
>
Diez

sorry, my aim is not limited to one particular program. Yes, many
library can
permit you to respond to keyboard event, however, what I want is a
universal
function. as long as a key is pressed, no matter where, my program can
repond.

I am quite strange with this topic. But according to my understanding,
any event, keyboard event
for example, once triggered, will be dilivered by keyboard driver to X
system, and then
any running program can either choose to respond or ignore. So my
question can be translated to:
how to make my program respond ?

[Jimmy]

Re: can python do some kernel stuff?

On May 23, 11:14 pm, Jimmy <mcknight0...@g mail.comwrote:

On May 23, 5:53 pm, "Diez B. Roggisch" <de...@nospam.w eb.dewrote:
>
>
>

Jimmy schrieb:

>

On May 23, 3:05 pm, Andrew Lee <fiacre.patr... @gmail.comwrote :
>Jimmy wrote:
>>Hi to all
>>python now has grown to a versatile language that can
>>accomplish tasks for many different purposes. However,
>>AFAIK, little is known about its ability of kernel coding.
>>So I am wondering if python can do some kernel coding that
>>used to be the private garden of C/C++. For example, can python
>>intercept the input of keyboard on a system level? someone told me
>>it's a kernel thing, isn't it?
>>http://wiki.python.org/moin/elmer

>

well, straightly speaking, how can I know a key is pressed on a system-
level if
using python?

>

What has that todo with kernel programming? You can use e.g. pygame to
get keystrokes. Or under linux, read (if you are root) the keyboard
input file - I've done that to support several keyboards attached to a
machine.

>

And the original question: no, python can't be used as kernel
programming language. Amongst other reasons, performance & the GIL
prevent that.

>

Diez

>
sorry, my aim is not limited to one particular program. Yes, many
library can
permit you to respond to keyboard event, however, what I want is a
universal
function. as long as a key is pressed, no matter where, my program can
repond.
>
I am quite strange with this topic. But according to my understanding,
any event, keyboard event
for example, once triggered, will be dilivered by keyboard driver to X
system, and then
any running program can either choose to respond or ignore. So my
question can be translated to:
how to make my program respond ?

maybe I'd better elaborate on my question. Back to my original
question:
intercept keyboard event on a system level. If you are writing program
in
emacs, of course, the keyboard inputs are meant for emacs only. What
I
want is no matter what program you're running, keyboard events can be
anyway caught by my program.

Am I clear with myself? :)

[Diez B. Roggisch]

Re: can python do some kernel stuff?

Jimmy schrieb:

On May 23, 11:14 pm, Jimmy <mcknight0...@g mail.comwrote:

>On May 23, 5:53 pm, "Diez B. Roggisch" <de...@nospam.w eb.dewrote:
>>
>>
>>

>>Jimmy schrieb:
>>>On May 23, 3:05 pm, Andrew Lee <fiacre.patr... @gmail.comwrote :
>>>>Jimmy wrote:
>>>>>Hi to all
>>>>>python now has grown to a versatile language that can
>>>>>accompli sh tasks for many different purposes. However,
>>>>>AFAIK, little is known about its ability of kernel coding.
>>>>>So I am wondering if python can do some kernel coding that
>>>>>used to be the private garden of C/C++. For example, can python
>>>>>intercep t the input of keyboard on a system level? someone told me
>>>>>it's a kernel thing, isn't it?
>>>>http://wiki.python.org/moin/elmer
>>>well, straightly speaking, how can I know a key is pressed on a system-
>>>level if
>>>using python?
>>What has that todo with kernel programming? You can use e.g. pygame to
>>get keystrokes. Or under linux, read (if you are root) the keyboard
>>input file - I've done that to support several keyboards attached to a
>>machine.
>>And the original question: no, python can't be used as kernel
>>programming language. Amongst other reasons, performance & the GIL
>>prevent that.
>>Diez

>sorry, my aim is not limited to one particular program. Yes, many
>library can
>permit you to respond to keyboard event, however, what I want is a
>universal
>function. as long as a key is pressed, no matter where, my program can
>repond.
>>
>I am quite strange with this topic. But according to my understanding,
>any event, keyboard event
>for example, once triggered, will be dilivered by keyboard driver to X
>system, and then
>any running program can either choose to respond or ignore. So my
>question can be translated to:
>how to make my program respond ?

>
maybe I'd better elaborate on my question. Back to my original
question:
intercept keyboard event on a system level. If you are writing program
in
emacs, of course, the keyboard inputs are meant for emacs only. What
I
want is no matter what program you're running, keyboard events can be
anyway caught by my program.
>
Am I clear with myself? :)

Do you want to intercept the call (prevent that it is passed through to
e.g. emacs), or are you merely interested in getting it? If the latter,
you can (as root) access the /dev/input keyboard device and get the
scan-codes.

The former is more complicated - without research I don't know out of my
head how to accomplish that. But it must be possible, as e.g. KDE
observes global key-shortcuts. Most probably a X-server thing.



Diez

[Jimmy]

Re: can python do some kernel stuff?

On May 24, 12:34 am, "Diez B. Roggisch" <de...@nospam.w eb.dewrote:

Jimmy schrieb:
>
>
>

On May 23, 11:14 pm, Jimmy <mcknight0...@g mail.comwrote:

On May 23, 5:53 pm, "Diez B. Roggisch" <de...@nospam.w eb.dewrote:

>

>Jimmy schrieb:
>>On May 23, 3:05 pm, Andrew Lee <fiacre.patr... @gmail.comwrote :
>>>Jimmy wrote:
>>>>Hi to all
>>>>python now has grown to a versatile language that can
>>>>accomplis h tasks for many different purposes. However,
>>>>AFAIK, little is known about its ability of kernel coding.
>>>>So I am wondering if python can do some kernel coding that
>>>>used to be the private garden of C/C++. For example, can python
>>>>intercept the input of keyboard on a system level? someone told me
>>>>it's a kernel thing, isn't it?
>>>>http://wiki.python.org/moin/elmer
>>well, straightly speaking, how can I know a key is pressed on a system-
>>level if
>>using python?
>What has that todo with kernel programming? You can use e.g. pygame to
>get keystrokes. Or under linux, read (if you are root) the keyboard
>input file - I've done that to support several keyboards attached to a
>machine.
>And the original question: no, python can't be used as kernel
>programming language. Amongst other reasons, performance & the GIL
>prevent that.
>Diez
sorry, my aim is not limited to one particular program. Yes, many
library can
permit you to respond to keyboard event, however, what I want is a
universal
function. as long as a key is pressed, no matter where, my program can
repond.

>

I am quite strange with this topic. But according to my understanding,
any event, keyboard event
for example, once triggered, will be dilivered by keyboard driver to X
system, and then
any running program can either choose to respond or ignore. So my
question can be translated to:
how to make my program respond ?

>

maybe I'd better elaborate on my question. Back to my original
question:
intercept keyboard event on a system level. If you are writing program
in
emacs, of course, the keyboard inputs are meant for emacs only. What
I
want is no matter what program you're running, keyboard events can be
anyway caught by my program.

>

Am I clear with myself? :)

>
Do you want to intercept the call (prevent that it is passed through to
e.g. emacs), or are you merely interested in getting it? If the latter,
you can (as root) access the /dev/input keyboard device and get the
scan-codes.
>
The former is more complicated - without research I don't know out of my
head how to accomplish that. But it must be possible, as e.g. KDE
observes global key-shortcuts. Most probably a X-server thing.
>
Diez

thanks, right now I am content with just knowing a key is pressed.
as you said, I checked /etc/input/event1 which seems the input of
keyboard. Then I got some extremely strange code. however, how can
I just simply know a key is pressed?

[Ivan Illarionov]

Re: can python do some kernel stuff?

On 23 ÍÁÊ, 22:32, Jimmy <mcknight0...@g mail.comwrote:
[...]

however, how can I just simply know a key is pressed?

If you are on Linux, use XLib

http://python-xlib.sourceforge.net/

You need to catch the KeyPress or KeyRelease X events.
while 1:
ev = display.next_ev ent()
if ev.type == X.KeyPress:
key_code = ev.detail
....
....

Ivan

[Ethan Furman]

Re: can python do some kernel stuff?

Andrew Lee wrote:

Diez B. Roggisch wrote:
>

>Andrew Lee schrieb:
>>

>>Diez B. Roggisch wrote:
>>>
>>>What has that todo with kernel programming? You can use e.g. pygame
>>>to get keystrokes. Or under linux, read (if you are root) the
>>>keyboard input file - I've done that to support several keyboards
>>>attached to a machine.
>>>>
>>>And the original question: no, python can't be used as kernel
>>>programmin g language. Amongst other reasons, performance & the GIL
>>>prevent that.
>>>>
>>>Diez
>>>
>>>
>>http://www.kernel-panic.it/programming/py-pf/
>>>
>>Of course you can code kernel routines in Python -- you are just
>>calling the underlying C interface. The GIL means you have to
>>manage threadsafety on your own -- it doesn't imply kernel
>>programming can not be done.

>>
>>
>I understood the OP's question as "can one program kernelspace
>routines in python". Which I don't think is possible. And I don't see
>how py-pf does that either.
>>
>Diez

>
>
>
OP: "I am wondering if python can do some kernel coding that
used to be the private garden of C/C++."
>
The answer is yes. IPC and py-pf are examples. If you don't think of
packet filtering as kernel coding, I can understand. But clearly the
Python interfaces to fork(), waitpid(), signal(), alarm() and so forth
are forays into the once private garden of C.

Being able to call routines in the kernel is *not* the same as kernel
coding. Calling C routines is *not* the same as kernel coding.
Actually writing the routines that are to be called, and that constitute
the kernel itself, *is* kernel coding. And as wonderful as Python is,
it is *not* for kernel coding.

Having just looked at Py-PF, it is *managing* the firewall, not
implementing it. Again, not kernel coding.
--
Ethan