Newbie questions on the kernel programming

Newbie questions on the kernel programming

[leo.liang.chen]

Hi all,

I am learning linux kernel programming starting from  "The Linux Kernel
Module Programming Guide"(http://www.faqs.org/docs/kernel/) .   I have
background in Windows DDK, but I am confused on the following topics.
Can anyone here give me some hints.

1) MODULE_PARM() macro (http://www.faqs.org/docs/kernel/x350.html)
static short int myshort = 1;
static int myint = 420;
static long int mylong = 9999;
static char *mystring = "blah";

MODULE_PARM (myshort, "h");
MODULE_PARM (myint, "i");
MODULE_PARM (mylong, "l");
MODULE_PARM (mystring, "s");

In the sample code, it is said the MODULE_PARM macro can allow
arguments to be passed to the driver module.  But how?

2) Character Device Drivers(http://www.faqs.org/docs/kernel/x571.html)
I can not catch the key points in this section.  What should I learn
from the "chardev.c" sample?  How can I install the module as a device?
 How can I call the functions in the driver?

3)  The /proc File System(http://www.faqs.org/docs/kernel/x716.html)
What's the main points in the section.  How does the /proc file system
matter linux kernel programming?
 
 
Many thanks!
 
Liang Chen

Re: Newbie questions on the kernel programming

[Erik Mouw]

On Mon, Jun 19, 2006 at 09:30:12AM -0000, leo.liang.chen@gmail.com wrote:
> I am learning linux kernel programming starting from  "The Linux Kernel
> Module Programming Guide"(http://www.faqs.org/docs/kernel/) .   I have
> background in Windows DDK, but I am confused on the following topics.
> Can anyone here give me some hints.
> 
> 1) MODULE_PARM() macro (http://www.faqs.org/docs/kernel/x350.html)
> static short int myshort = 1;
> static int myint = 420;
> static long int mylong = 9999;
> static char *mystring = "blah";
> 
> MODULE_PARM (myshort, "h");
> MODULE_PARM (myint, "i");
> MODULE_PARM (mylong, "l");
> MODULE_PARM (mystring, "s");

Note that this is an obsolete syntax, it changed in 2.6 like this:

  module_param(myint, int, 0);

> In the sample code, it is said the MODULE_PARM macro can allow
> arguments to be passed to the driver module.  But how?

  modprobe mydriver myshort=42

> 2) Character Device Drivers(http://www.faqs.org/docs/kernel/x571.html)
> I can not catch the key points in this section.  What should I learn
> from the "chardev.c" sample?  How can I install the module as a device?
>  How can I call the functions in the driver?
> 
> 3)  The /proc File System(http://www.faqs.org/docs/kernel/x716.html)
> What's the main points in the section.  How does the /proc file system
> matter linux kernel programming?

Hardly at all anymore.

See http://lwn.net/Kernel/LDD3/ for a book that describes the current
2.6 kernel.


Erik

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