【Linux设备驱动程序（第三版）】----ioctl

【Linux设备驱动程序（第三版）】----ioctl

scull.c

#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/fs.h>//file_operations, file
#include <linux/cdev.h>//cdev
#include <asm/uaccess.h>//copy_to_user & copy_from_user
#include <linux/proc_fs.h>//proc
#include <linux/ioctl.h>//ioctl

MODULE_LICENSE("Dual BSD/GPL");

#define SCULL_QUANTUM 4000
#define SCULL_QSET 1000

#define SCULL_IOC_MAGIC 'k'
#define SCULL_IOC_MAXNR 14
#define SCULL_IOCRESET		_IO(SCULL_IOC_MAGIC, 0)
#define SCULL_IOCSQUANTUM	_IOW(SCULL_IOC_MAGIC, 1, int)
#define SCULL_IOCSQSET		_IOW(SCULL_IOC_MAGIC, 2, int)
#define SCULL_IOCTQUANTUM	_IO(SCULL_IOC_MAGIC, 3)
#define SCULL_IOCTQSET		_IO(SCULL_IOC_MAGIC, 4)
#define SCULL_IOCGQUANTUM	_IOR(SCULL_IOC_MAGIC, 5, int)
#define SCULL_IOCGQSET		_IOR(SCULL_IOC_MAGIC, 6, int)
#define SCULL_IOCQQUANTUM	_IO(SCULL_IOC_MAGIC, 7)
#define SCULL_IOCQQSET		_IO(SCULL_IOC_MAGIC, 8)
#define SCULL_IOCXQUANTUM	_IOWR(SCULL_IOC_MAGIC, 9, int)
#define SCULL_IOCXQSET		_IOWR(SCULL_IOC_MAGIC, 10, int)
#define SCULL_QUANTUM		_IO(SCULL_IOC_MAGIC, 11)
#define SCULL_IOCHQSET 		_IO(SCULL_IOC_MAGIC, 12)

int scull_major = 250;
int scull_minor = 0;
int scull_nr_devs = 4;
int scull_quantum = 4000;
int scull_qset = 1000;

module_param(scull_major, int, S_IRUGO);
module_param(scull_minor, int, S_IRUGO);
module_param(scull_nr_devs, int, S_IRUGO);
module_param(scull_quantum, int, S_IRUGO);
module_param(scull_qset, int, S_IRUGO);

struct scull_qset {
void **data;
struct scull_qset *next;
};

struct scull_dev{
struct scull_qset *data;
int quantum;
int qset;
unsigned long size;
unsigned int access_key;
struct semaphore sem;
struct cdev cdev;
};

struct scull_dev *scull_devices;

int scull_read_procmem(char *buf, char **start, off_t offset, int count, int *eof, void *data)
{
int len = 0;
len += sprintf(buf + len, "Proc Test!\n");
eof = -1;
return len;
}

static void scull_create_proc(void)
{
create_proc_read_entry("scullmem", 0, NULL, scull_read_procmem, NULL);
}

static void scull_remove_proc(void)
{
remove_proc_entry("scullmem", NULL);
}

int scull_trim(struct scull_dev *dev)
{
struct scull_qset *next, *dptr;
int qset = dev->qset;
int i;

for(dptr = dev->data; dptr; dptr = next){
if(dptr->data){
for(i = 0; i < qset; i++)
kfree(dptr->data[i]);
kfree(dptr->data);
dptr->data = NULL;
}
next = dptr->next;
kfree(dptr);
}

dev->size = 0;
dev->quantum = scull_quantum;
dev->qset = scull_qset;
dev->data = NULL;
return 0;
}

int scull_open(struct inode *inode, struct file *filp)
{
struct scull_dev *dev;

dev = container_of(inode->i_cdev, struct scull_dev, cdev);
filp->private_data = dev;

if(filp->f_flags & O_ACCMODE == O_WRONLY){
scull_trim(dev);
}
return 0;
}

int scull_release(struct inode *inode, struct file *filp)
{
return 0;
}

struct scull_qset *scull_follow(struct scull_dev *dev, int n)
{
struct scull_qset *qs = dev->data;

if(!qs){
qs = dev->data = kmalloc(sizeof(struct scull_qset), GFP_KERNEL);
if(qs == NULL)
return NULL;
memset(qs, 0, sizeof(struct scull_qset));
}

while(n--){
if(!qs->next){
qs->next = kmalloc(sizeof(struct scull_qset), GFP_KERNEL);
if(qs->next == NULL)
return NULL;
memset(qs->next, 0, sizeof(struct scull_qset));
}
qs = qs->next;
continue;
}
return qs;
}

ssize_t scull_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
{
printk(KERN_NOTICE "Enter scull_read\n");
struct scull_dev *dev = filp->private_data;
struct scull_qset *dptr;
int quantum = dev->quantum;
int qset = dev->qset;
int itemsize = quantum * qset;
int item, s_pos, q_pos, rest;
ssize_t retval = 0;

if(down_interruptible(&dev->sem))
return -ERESTARTSYS;

if(*f_pos >= dev->size)
goto out;

if(*f_pos + count > dev->size)
count = dev->size - *f_pos;

item = (long)*f_pos / itemsize;
rest = (long)*f_pos % itemsize;

s_pos = rest / quantum;
q_pos = rest % quantum;

dptr = scull_follow(dev, item);

if(dptr == NULL || !dptr->data || !dptr->data[s_pos])
goto out;

if(count > quantum - q_pos)
count = quantum - q_pos;

if(copy_to_user(buf, dptr->data[s_pos] + q_pos, count)){
retval = -EFAULT;
goto out;
}

*f_pos += count;
retval = count;
out:
up(&dev->sem);
return retval;
}

ssize_t scull_write(struct file *filp, char __user *buf, size_t count, loff_t *f_pos)
{
printk(KERN_NOTICE "Enter scull_write\n");
struct scull_dev *dev = filp->private_data;
struct scull_qset *dptr;
int quantum = dev->quantum;
int qset = dev->qset;
int itemsize = quantum * qset;
int item, s_pos, q_pos, rest;
ssize_t retval = -ENOMEM;

if(down_interruptible(&dev->sem))
return -ERESTARTSYS;

item = (long)*f_pos / itemsize;
rest = (long)*f_pos % itemsize;

s_pos = rest / quantum;
q_pos = rest % quantum;

dptr = scull_follow(dev, item);
if(dptr == NULL)
goto out;

if(!dptr->data){
dptr->data = kmalloc(qset * sizeof(char *), GFP_KERNEL);
if(!dptr->data)
goto out;
memset(dptr->data, 0, qset * sizeof(char *));
}
if(!dptr->data[s_pos]){
dptr->data[s_pos] = kmalloc(quantum, GFP_KERNEL);
if(!dptr->data[s_pos])
goto out;
}

if(count > quantum - q_pos)
count = quantum - q_pos;

if(copy_from_user(dptr->data[s_pos] + q_pos, buf,  count)){
retval = -EFAULT;
goto out;
}

*f_pos += count;
retval = count;

if(dev->size < *f_pos)
dev->size = *f_pos;
out:
up(&dev->sem);
return retval;
}

int scull_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg)
{
int err = 0, tmp;
int retval = 0;

if(_IOC_TYPE(cmd) != SCULL_IOC_MAGIC)
return -ENOTTY;
if(_IOC_NR(cmd) > SCULL_IOC_MAXNR)
return -ENOTTY;

if(_IOC_DIR(cmd) & _IOC_READ)
err = !access_ok(VERIFY_WRITE, (void __user *)arg, _IOC_SIZE(cmd));
else if(_IOC_DIR(cmd) & _IOC_WRITE)
err = !access_ok(VERIFY_READ, (void __user *)arg, _IOC_SIZE(cmd));
if(err)
return -EFAULT;

switch(cmd){
case SCULL_IOCRESET:
scull_quantum = SCULL_QUANTUM;
scull_qset = SCULL_QSET;
break;

case SCULL_IOCSQUANTUM:
retval = __get_user(scull_quantum, (int __user *)arg);
break;

case SCULL_IOCTQUANTUM:
scull_quantum = arg;
break;

case SCULL_IOCGQUANTUM:
retval = __put_user(scull_quantum, (int __user *)arg);
break;

case SCULL_IOCQQUANTUM:
return scull_quantum;

case SCULL_IOCXQUANTUM:
tmp = scull_quantum;
retval = __get_user(scull_quantum, (int __user *)arg);
if(retval == 0)
retval = __put_user(tmp, (int __user *)arg);
break;
case SCULL_QUANTUM:
tmp = scull_quantum;
scull_quantum = arg;
return tmp;

case SCULL_IOCSQSET:
retval = __get_user(scull_qset, (int __user *)arg);
break;

case SCULL_IOCTQSET:
scull_qset = arg;
break;

case SCULL_IOCGQSET:
retval = __put_user(scull_qset, (int __user *)arg);
break;

case SCULL_IOCQQSET:
return scull_qset;

case SCULL_IOCXQSET:
tmp = scull_qset;
retval = __get_user(scull_qset, (int __user *)arg);
if(retval == 0)
retval = put_user(tmp, (int __user *)arg);
break;

case SCULL_IOCHQSET:
tmp = scull_qset;
scull_qset = arg;
return tmp;

}
}

struct file_operations scull_fops = {
.owner = THIS_MODULE,
.open = scull_open,
.release = scull_release,
.read = scull_read,
.write = scull_write,
	.ioctl = scull_ioctl,
};

static void scull_setup_cdev(struct scull_dev *dev, int index)
{
int err, devno = MKDEV(scull_major, scull_minor + index);

cdev_init(&dev->cdev, &scull_fops);
dev->cdev.owner = THIS_MODULE;
err = cdev_add(&dev->cdev, devno, 1);
if(err)
printk(KERN_NOTICE "Error %d adding scull%d", err, index);
}

static void scull_cleanup_module(void)
{
printk(KERN_ALERT "Goodbye,world!\n");
int i;
dev_t devno = MKDEV(scull_major, scull_minor);

if(scull_devices){
for(i = 0; i < scull_nr_devs; i++){
scull_trim(scull_devices + i);
cdev_del(&scull_devices[i].cdev);
}
kfree(scull_devices);
}

unregister_chrdev_region(devno, scull_nr_devs);

scull_remove_proc();
}

static int __init scull_init_module(void)
{
printk(KERN_ALERT "Hello, World!\n");
int result, i;
dev_t dev = 0;

if(scull_major){
dev = MKDEV(scull_major, scull_minor);
result = register_chrdev_region(dev, scull_nr_devs, "scull");
}else{
result = alloc_chrdev_region(&dev, scull_major, scull_nr_devs, "scull");
scull_major = MAJOR(dev);
}

if(result < 0){
printk(KERN_WARNING "scull:can't get major %d\n", scull_major);
return result;
}

scull_devices = kmalloc(scull_nr_devs * sizeof(struct scull_dev), GFP_KERNEL);
if(!scull_devices){
result = -ENOMEM;
goto fail;
}
memset(scull_devices, 0, scull_nr_devs * sizeof(struct scull_dev));

for(i = 0; i < scull_nr_devs; i++){
scull_devices[i].quantum = scull_quantum;
scull_devices[i].qset = scull_qset;
init_MUTEX(&scull_devices[i].sem);
scull_setup_cdev(&scull_devices[i], i);
}

scull_create_proc();

return 0;

fail:
scull_cleanup_module();
return result;
}

module_init(scull_init_module);
module_exit(scull_cleanup_module);