main.c


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#include <linux/module.h>
#include <linux/version.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/string.h>
/* used for kmalloc */
#include <linux/slab.h>

#include <debug.h>

char *debugmsg = "Tesla coil is a hi freq transformer";
struct dentry *debug_dir = NULL;
struct dentry *debug_file = NULL;

/* __init is a hint that the func is only used at initialization time, then module
 * loader drops the function after module is loaded making its memory available for other uses
 */
static int __init hello_init(void)
{
    int err = 0;
    char *msg = (char *) kmalloc_array(128, sizeof(char), GFP_KERNEL /* kernel ram */);

    printk("module named hello inserted\n");
    strcpy(msg, "photon is the energy carrier particle for EM waves within light spectrum");
    printk("%s\n", msg);
    kfree(msg);

    /* modifies passed in ptrs */
    err = debug_init(&debug_dir, &debug_file);
    if (err)
        printk("debugfs might not have been mounted\n");

    return 0;
}
 
static void __exit hello_exit(void)
{
    debug_destroy(debug_dir, debug_file);
    printk("module named hello removed\n");
}

module_init(hello_init);
module_exit(hello_exit);

MODULE_LICENSE("GPL");