LinuxQuestions.org - kernel function to print uptime in seconds?

Hi there,

I'm trying to compile a kernel module which will print the uptime since booting in seconds.
This is what I have so far:

Code:

#include <linux/module.h>  /* Needed by all modules */

#include <linux/kernel.h>  /* Needed for KERN_ALERT */

#include <linux/sysinfo.h>



int init_module(void)

{

  printk("Uptime: ", sysinfo.uptime, "\n");



  // A non 0 return means init_module failed; module can't be loaded.

  return 0;

}





void cleanup_module(void)

{

  printk(KERN_ALERT "Goodbye world 1.\n");

}





MODULE_LICENSE("GPL");

However compiling it will error out with:

make[1]: Map '/usr/src/kernels/4.0.6-300.fc22.x86_64' wordt binnengegaan
CC [M] /home/mastag/time.o
/home/mastag/time.c: In functie ‘init_module’:
/home/mastag/time.c:14:23: fout: ‘sysinfo’ undeclared (first use in this function)
printk("Uptime: ", sysinfo.uptime, "\n");
^
/home/mastag/time.c:14:23: note: each undeclared identifier is reported only once for each function it appears in
scripts/Makefile.build:264: recept voor doel '/home/mastag/time.o' is mislukt
make[2]: *** [/home/mastag/time.o] Fout 1

Why is it undeclared?
I've included sysinfo.h which has the sysinfo struct right?

linux/sysinfo.h contains:

Code:

struct sysinfo {

        __kernel_long_t uptime;        /* Seconds since boot */

        __kernel_ulong_t loads[3];      /* 1, 5, and 15 minute load averages */

        __kernel_ulong_t totalram;      /* Total usable main memory size */

        __kernel_ulong_t freeram;      /* Available memory size */

        __kernel_ulong_t sharedram;    /* Amount of shared memory */

        __kernel_ulong_t bufferram;    /* Memory used by buffers */

        __kernel_ulong_t totalswap;    /* Total swap space size */

        __kernel_ulong_t freeswap;      /* swap space still available */

        __u16 procs;                    /* Number of current processes */

        __u16 pad;                      /* Explicit padding for m68k */

        __kernel_ulong_t totalhigh;    /* Total high memory size */

        __kernel_ulong_t freehigh;      /* Available high memory size */

        __u32 mem_unit;                /* Memory unit size in bytes */

        char _f[20-2*sizeof(__kernel_ulong_t)-sizeof(__u32)];  /* Padding: libc5 uses this.. */

};