Thank you a lot. But now,I have new problem in load

modules's link time.

#gcc -I/usr/src/linux/include -D__KERNEL__ -DMODULE\

-D__KERNEL_SYSCALLS__ hello.c -c -o hello.o

#insmod ./hello.o

./hello.o: unresolved symbol errno



It is a quite obvious messages that the variable 'errno' is

unresolved.

Can anybody told me how to...
BTW,To open a file in kernel module mode just for my interest.

#define MODULE
#define __KERNEL__
#define __KERNEL_SYSCALLS__
#include &ltlinux/module.h&gt
#include &ltlinux/version.h&gt
#include &ltlinux/kernel.h&gt
#include &ltlinux/fs.h&gt
#include &ltlinux/mm.h&gt
#include &ltlinux/slab.h&gt
#include &ltlinux/unistd.h&gt

int init_module(void){
    int fn=0;
                                                                                
    printk("<1>Hello, world\n");
    fn = open("/etc/inittab", 0, 0);
    if (fn == -1)
    {
        printk(KERN_INFO "Unable to load '%s'.\n", fn);
        return 0;
    }
    printk(KERN_INFO "LOAD File success!");
    close(fn);
    return 0;
}
void cleanup_module(void)  { printk("<1>Goodbye cruel world\n"); }