printing number of processes in kernel module

Question

I'm very new to kernel programming and I have written a small kernel module which is like this,

mod.c

#include<linux/kernel.h>
#include<linux/module.h>
#include<sys/sysinfo.h>

int init_module(void)
{
    int k;
    struct sysinfo info;
    printk(KERN_INFO "hello\n");
    k = sysinfo(&info);
    printk(KERN_EMERG "procs = %d\n", info.procs)

    return 0;
}

void cleanup_module(void)
{

    printk(KERN_INFO "Goodbye\n");
}

and Makefile looks like this,

 obj-m +=mod.o

 all:
    make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules

 clean:
    make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean

if i issue make from terminal, it gives error
fatal error: sys/sysinfo.h: No such file or directory

could you tell me what's the problem here?

Answer 1

If anyone is still looking how to do this, I solved this sometime ago, Here is the solution. This works for debian Linux 3.16 version. If you want to take look at the code which is here.

https://github.com/st0rmi/rootkit_programming/blob/master/assignment01/assignment01_mod.c