Linux Kernel and Device Drivers

[Srinivas Ganji]

Yes. As said by Anish, I generally practice through a dummy hello world
module. Suppose, if I want to print all the processes currently running, I
do like this.

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>

MODULE_LICENSE("Dual BSD/GPL");

static int hello_init(void)
{
struct task_struct *task;

printk("Hello World!\n");
 for_each_process(task) {
printk("%s %d\n", task->comm, task->pid);
}
 printk("\n\n\n");
 for(task = &init_task; ((task=next_task(task)) != &init_task) ; )
printk("%s %d\n", task->comm, task->pid);
 printk("\n\n\n");
 return 0;
}

static void hello_exit(void)
{
printk("Good bye!\n");
}

module_init(hello_init);
module_exit(hello_exit);

By the way, you can do as suggested by Valdis, too. I do search for a
particular code/strings using find, xargs, grep combination.

I hope this helps you.

Regards,
Srinivas



On Tue, Jul 16, 2013 at 12:42 PM, Satya Prakash Prasad <
unixkernel497 at gmail.com> wrote:

> Thanks .. I have another question. I was trying to practice some kernel
> process management APIs as in
> http://reiber.org/nxt/pub/Linux/LinuxKernelDevelopment/Linux.Kernel.Development.3rd.Edition.pdf<http://www.linkedin.com/redirect?url=http%3A%2F%2Freiber%2Eorg%2Fnxt%2Fpub%2FLinux%2FLinuxKernelDevelopment%2FLinux%2EKernel%2EDevelopment%2E3rd%2EEdition%2Epdf&urlhash=3MN8&_t=tracking_disc>(Linux Kernel Development by Robert Love, 3rd edition).
>
> I am not sure how to practice the code snippet given in the text book. I
> can understand the theory but do not find a way to practice. For example: I
> want to read a process 'struct task_struct' to find it parent's process
> identifier, how many tasks are in which state, creating kernel threads etc?
>
> Any idea?
>
>
> On Mon, Jul 15, 2013 at 2:32 PM, Srinivas Ganji <
> srinivasganji.kernel at gmail.com> wrote:
>
>> As per as I know, you can follow two text books.
>>
>> 1. Linux Kernel Development by Robert Love, 3rd edition.
>> 2. Linux Device Drivers by Alessandro Rubini, Jonathan Corbet, Greh
>> Kroah-Hartman. 3rd edition.
>>
>> At the same time, you can practice the exercises given in the text books
>> - practice makes a man perfect. The other thing is "Make your hands dirty
>> by digging the kernel code whenever you have a doubt".
>>
>> Regards,
>> Srinivas
>>
>>
>>
>>
>> On Mon, Jul 15, 2013 at 2:06 PM, Satya Prakash Prasad <
>> unixkernel497 at gmail.com> wrote:
>>
>>> Please let me know how to study and get hands on experience on Linux
>>> Kernel and Device Drivers?
>>>
>>> Regards,
>>> Prakash
>>>
>>> _______________________________________________
>>> Kernelnewbies mailing list
>>> Kernelnewbies at kernelnewbies.org
>>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>>>
>>>
>>
>
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