126 lines
2.8 KiB
C
Executable File
126 lines
2.8 KiB
C
Executable File
/* Necessary includes for drivers */
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#include <linux/init.h>
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//#include <linux/config.h>
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#include <linux/module.h>
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#include <linux/kernel.h> /* printk() */
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#include <linux/slab.h> /* kmalloc() */
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#include <linux/fs.h> /* everything... */
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#include <linux/errno.h> /* error codes */
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#include <linux/types.h> /* size_t */
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#include <linux/proc_fs.h>
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#include <linux/fcntl.h> /* O_ACCMODE */
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#include <linux/ioport.h>
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#include <asm/system.h> /* cli(), *_flags */
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#include <asm/uaccess.h> /* copy_from/to_user */
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#include <asm/io.h> /* inb, outb */
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MODULE_LICENSE("GPL");
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/* Declaration of memory.c functions */
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int memory_open(struct inode *inode, struct file *filp);
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int memory_release(struct inode *inode, struct file *filp);
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ssize_t memory_read(struct file *filp, char *buf, size_t count, loff_t *f_pos);
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ssize_t memory_write(struct file *filp, char *buf, size_t count, loff_t *f_pos);
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void memory_exit(void);
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int memory_init(void);
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/* Structure that declares the usual file */
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/* access functions */
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struct file_operations memory_fops = {
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read: memory_read,
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write: memory_write,
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open: memory_open,
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release: memory_release
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};
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/* Declaration of the init and exit functions */
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module_init(memory_init);
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module_exit(memory_exit);
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/* Global variables of the driver */
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/* Major number */
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int memory_major = 60;
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/* Buffer to store data */
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char *memory_buffer;
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int memory_init(void) {
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int result;
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/* Registering device */
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result = register_chrdev(memory_major, "memory", &memory_fops);
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if (result < 0) {
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printk(
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"<1>memory: cannot obtain major number %d\n", memory_major);
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return result;
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}
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/* Allocating memory for the buffer */
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memory_buffer = kmalloc(1, GFP_KERNEL);
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if (!memory_buffer) {
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result = -ENOMEM;
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goto fail;
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}
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memset(memory_buffer, 0, 1);
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printk("<1>Inserting memory module\n");
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return 0;
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fail:
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memory_exit();
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return result;
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}
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void memory_exit(void) {
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/* Freeing the major number */
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unregister_chrdev(memory_major, "memory");
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/* Freeing buffer memory */
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if (memory_buffer) {
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kfree(memory_buffer);
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}
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printk("<1>Removing memory module\n");
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}
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int memory_open(struct inode *inode, struct file *filp) {
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/* Success */
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return 0;
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}
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int memory_release(struct inode *inode, struct file *filp) {
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/* Success */
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return 0;
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}
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ssize_t memory_read(struct file *filp, char *buf,
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size_t count, loff_t *f_pos) {
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/* Transfering data to user space */
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copy_to_user(buf,memory_buffer,1);
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/* Changing reading position as best suits */
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if (*f_pos == 0) {
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*f_pos+=1;
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return 1;
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} else {
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return 0;
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}
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}
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ssize_t memory_write( struct file *filp, char *buf,
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size_t count, loff_t *f_pos) {
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char *tmp;
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tmp=buf+count-1;
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copy_from_user(memory_buffer,tmp,1);
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return 1;
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}
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