Procfs demo

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

#include <linux/proc_fs.h>
#include <asm/uaccess.h>

static ssize_t my_read(struct file *instance, char __user *buffer, size_t max_bytes_to_write, loff_t *offset)
{
    char kernel_buffer[10];
    size_t to_copy, not_copied;

    if (*offset > 5)
        return 0;

    strncpy(kernel_buffer, "benis\n", sizeof(kernel_buffer));
    to_copy = min(strlen(kernel_buffer), max_bytes_to_write);
    not_copied = copy_to_user(buffer, kernel_buffer, to_copy);
    *offset += to_copy - not_copied;
    return to_copy - not_copied;
}

static const struct file_operations proc_fops =
{
    .owner = THIS_MODULE, // Fürs handling intern, u.a. für die erkennung ob strukturen leaken
    .read  = my_read,
};

static struct proc_dir_entry *my_proc_file;
#define PROC_FILE_NAME "myFile"

static int __init blah_init(void)
{
    my_proc_file = proc_create(PROC_FILE_NAME, 0666, NULL, &proc_fops);
    if (my_proc_file == NULL)
        return 1;

    return 0;
}

static void __exit blah_exit(void)
{
    remove_proc_entry(PROC_FILE_NAME, NULL);
}

module_init(blah_init);
module_exit(blah_exit);