Hello world Module

[lucyd88]

Hi Everyone,

This is the hello world kernel module:
#include <linux/module.h>
#include <linux/kernel.h>
int init_module(void)
{
printk(KERN_INFO "Hello world.\n");
return 0;
}
void cleanup_module(void)
{
printk(KERN_INFO "Goodbye world\n");
}

and this is the make file

obj-m += hello.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

At the command prompt i type make and this is what I am getting:

make -C /lib/modues/2.6.24-16-generic/build M=/home/louisemodules
make[1]: Entering directory 'usr/src/linux-headers-2.6.24-16-generic
make: *** [all] Error 2
mkdir: cannot create directory home/louisemodules: permission denied
scripts /Makefile.build:41: home/louisemodules/Makefile: No such file or
directory
make[2]: *** No rule to make target /home/louisemodules/Makefile. Stop
make[1]:***[_module_/home/louisemodules] Error 2
make[1]: Leaving directory /usr/src/linux-headers-2.6.24-16-generic
make: *** [all] Error 2

Please help me,

Thanks

[gerard4143]

Did you install the kernel-header and kernel-devel files?

[lucyd88]

Hi there,

Thanks for getting back to me. I know that I have the header files, is there a command that I can type to check for deval files? Looking at the output when I run make, it seems to be opening the header files, but seems to have a problem making the directory for the module.

Thanks

[gerard4143]

Try logging in as root

[lucyd88]

Hi Gerard,

I tried that, but I am still getting the same error message. Have you any other suggestions?
Thanks

[gerard4143]

The only other thing I can think of...Is your Makefile formatted correctly

obj-m += hello.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

where each make line is <TAB> in

[bloggins666]

I tried your code on my machine here. I ran into an issue with where your make file is expecting to find your kernel source. This pointed out to me that we really need to know which distro you are compiling on. I use openSuSE which really used the /lib/module/`uname -r`/source directory rather than the /lib/module/`uname -r`/build directory. This is easily fixed with a symbolic link (which did exist but was pointing to the wrong place.. better go annoy the openSuSE people about that!).

So, which distro are you compiling on?

Cheers!!