linux/init.h: No such file or directory

Question

I'm trying to build a kernel module for my class, and I'm getting a massive wall of errors, but at the top of said wall is the infamous 'No such file or directory' error. It seems to be the root of the problem. This not only seems to affect init.h, but also module.h and kernel.h. The first three lines of the program go as follows:

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

I've looked around and tried other paths for where these files ought to be when browsing similar issues, but nothing has worked thus far. The strangest part is that I used this module already; I was provided starter code that had this at the top (I didn't change anything) and it didn't give me that error. Although, obviously the code after is different, but this seems to be the biggest problem at the moment.

The full code is as follows:

#include </usr/include/linux/init.h>
#include </usr/include/linux/module.h>
#include </usr/include/linux/kernel.h>

/* This function is called when the module is loaded. */
int simple_init(void)
{
    printk(KERN_INFO "Loading Module\n");
    static LIST_HEAD(birthday_list)
    struct birthday{
        int day;
        int month;
        int year;
        struct list_head list;
    };
    struct birthday *ptr, *next;
    struct birthday *bob;
    struct birthday *judy;
    struct birthday *josh;
    struct birthday *lana;
    struct birthday *jan;

    bob = kmalloc(sizeof(*bob), GFP_KERNEL);
    bob -> day = 17;
    bob -> month = 1;
    bob -> year = 1990;
    INIT_LIST_HEAD(&bob -> list);

    ...

    list_add_tail(bob -> list, &birthday_list);
    list_add_tail(judy -> list, &birthday_list);
    list_add_tail(josh -> list, &birthday_list);
    list_add_tail(lana -> list, &birthday_list);
    list_add_tail(jan -> list, &birthday_list);

    struct birthday *ptr;

    list_for_each_entry(ptr, &birthday_list, list){

        kprintf('%d/%d/%d \n', ptr -> month, ptr -> day,  ptr -> year);
    }

    list_for_each_entry_safe(ptr, &birthday_list, list){

        list_del(&ptr->list);
        kfree(ptr);
    }

       return 0;
}

/* This function is called when the module is removed. */
void simple_exit(void) {
    printk(KERN_INFO "Removing Module\n");
}

/* Macros for registering module entry and exit points. */
module_init( simple_init );
module_exit( simple_exit );

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Simple Module");
MODULE_AUTHOR("SGG");

Answer 1

I think you must first install something like linux-headers-[kernel version] by apt-get then you must create Makefile as following :

ifneq ($(KERNELRELEASE),)
    # call from kernel build system
    lifo-objs := main.o
    obj-m   := lifo.o
else
   KERNELDIR ?= /lib/modules/$(shell uname -r)/build
   PWD       := $(shell pwd)
modules:
    echo $(MAKE) -C $(KERNELDIR) M=$(PWD) LDDINC=$(PWD)/../include modules
    $(MAKE) -C $(KERNELDIR) M=$(PWD) LDDINC=$(PWD)/../include modules
endif

clean:  
    rm -rf *.o *~ core .depend *.mod.o .*.cmd *.ko *.mod.c \
    .tmp_versions *.markers *.symvers modules.order

depend .depend dep:
    $(CC) $(CFLAGS) -M *.c > .depend

ifeq (.depend,$(wildcard .depend))
    include .depend
endif

set KERNELDIR variable in above Makefile to your appropriate kernel version, by default it use your running kernel. If you use this Makefile you need to change your include to following format:

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

I think for kernel module developing use standard kernel from Linus Torvalds git is better. For some simple kernel module see this.