I'm very interested in a little bit kernel hacking, so I bought
myself the book 'Linux device drivers' (O'Reilly) and started
to code a simple 'Hello world' module
Part 1:
-------
#define __NO_VERSION__
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/version.h>
char kernel_version[] = UTS_RELEASE;
int init_module(void)
{
printk("<1>Here we are :-)\n");
return 0;
}
Part 2:
-------
#define __NO_VERSION__
#include <linux/kernel.h>
#include <linux/module.h>
void cleanup_module(void)
{
printk("<1>Now we're gone :-(");
}
Compiling works just fine,
root@weyoun:/home/twesthei/C/kernel > make
gcc -D__KERNEL__ -I/usr/src/linux/include -O2 -Wall -Wstrict-prototypes
-fomit-frame-pointer -pipe -fno-strength-reduce -m486 -malign-loops=2
-malign-jumps=2 -malign-functions=2 -DCPU=586 -DMODULE -DEXPORT_SYMTAB
-c skull_init.c -o skull_init.o
gcc -D__KERNEL__ -I/usr/src/linux/include -O2 -Wall -Wstrict-prototypes
-fomit-frame-pointer -pipe -fno-strength-reduce -m486 -malign-loops=2
-malign-jumps=2 -malign-functions=2 -DCPU=586 -DMODULE -DEXPORT_SYMTAB
-c skull_clean.c -o skull_clean.o
ld -r skull_init.o skull_clean.o -o skull.o
but I can't insmod that piece of code because of
root@weyoun:/home/twesthei/C/kernel > insmod skull
./skull.o: unresolved symbol printk
What??? Any help appreciated ;-)
cu
Thorsten
===========================================================
Thorsten Westheider / / (_)__ __ ____ __
Im Schlingen 15 / /__/ / _ \/ // /\ \/ /
32120 Hiddenhausen -- Germany /____/_/_//_/\_,_/ /_/\_\
2.2.1
http://www.physik.uni-bielefeld.de/~twesthei
mailto:twesthei@phya1.physik.uni-bielefeld.de
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