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Linux, .
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P.S
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1 , .
2 open, read, write trim.
3 Makefile .
, , , .
, .
(Char driver) , , / .
scull_dev, cdev .
struct scull_dev {
struct scull_qset *data; /* */
int quantum; /* */
int qset; /* */
unsigned long size; /* */
struct semaphore sem; /* */
struct cdev cdev; /* , */
};
struct scull_dev *scull_device;
, scull_qset.
struct scull_qset {
void **data;
struct scull_qset *next;
};
.
, , :
MAJOR ( ).
MINOR ( ).
, , , .
, . file_operations.
struct file_operations scull_fops = {
.owner = THIS_MODULE,
.read = scull_read,
.write = scull_write,
.open = scull_open,
.release = scull_release,
};
module_init/module_exit, / . / .
module_init(scull_init_module);
module_exit(scull_cleanup_module);
.
int scull_major = 0; /* MAJOR */
int scull_minor = 0; /* MINOR */
int scull_nr_devs = 1; /* */
int scull_quantum = 4000; /* */
int scull_qset = 1000; /* */
.
, , :
lxr
#include module.h> /* */
#include init.h> /* */
#include fs.h> /* */
#include cdev.h> /* */
#include slab.h> /* */
#include uaccess.h> /* */
.
static int scull_init_module(void)
{
int rv, i;
dev_t dev;
rv = alloc_chrdev_region(&dev, scull_minor, scull_nr_devs, "scull");
scull_major = MAJOR(dev);
if (rv) {
printk(KERN_WARNING "scull: can't get major %d\n", scull_major);
return rv;
}
scull_device = kmalloc(scull_nr_devs * sizeof(struct scull_dev), GFP_KERNEL);
if (!scull_device) {
rv = -ENOMEM;
goto fail;
}
memset(scull_device, 0, scull_nr_devs * sizeof(struct scull_dev));
for (i = 0; i < scull_nr_devs; i++) {
scull_device[i].quantum = scull_quantum;
scull_device[i].qset = scull_qset;
sema_init(&scull_device[i].sem, 1);
scull_setup_cdev(&scull_device[i], i);
}
dev = MKDEV(scull_major, scull_minor + scull_nr_devs);
return 0;
fail:
scull_cleanup_module();
return rv;
}
, alloc_chrdev_region . MAJOR(dev) .
, , . , , (NULL?).
rv = alloc_chrdev_region(&dev, scull_minor, scull_nr_devs, "scull");
scull_major = MAJOR(dev);
if (rv) {
printk(KERN_WARNING "scull: can't get major %d\n", scull_major);
return rv;
}
.
, kmalloc NULL.
scull_device = kmalloc(scull_nr_devs * sizeof(struct scull_dev), GFP_KERNEL);
if (!scull_device) {
rv = -ENOMEM;
goto fail;
}
memset(scull_device, 0, scull_nr_devs * sizeof(struct scull_dev));
. scull_setup_cdev, . MKDEV .
for (i = 0; i < scull_nr_devs; i++) {
scull_device[i].quantum = scull_quantum;
scull_device[i].qset = scull_qset;
sema_init(&scull_device[i].sem, 1);
scull_setup_cdev(&scull_device[i], i);
}
dev = MKDEV(scull_major, scull_minor + scull_nr_devs);
.
return 0;
fail:
scull_cleanup_module();
return rv;
}
scull_dev cdev, . scull_setup_cdev .
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;
dev->cdev.ops = &scull_fops;
err = cdev_add(&dev->cdev, devno, 1);
if (err)
printk(KERN_NOTICE "Error %d adding scull %d", err, index);
}
scull_cleanup_module .
, , .
void scull_cleanup_module(void)
{
int i;
dev_t devno = MKDEV(scull_major, scull_minor);
if (scull_device) {
for (i = 0; i < scull_nr_devs; i++) {
scull_trim(scull_device + i);
cdev_del(&scull_device[i].cdev);
}
kfree(scull_device);
}
unregister_chrdev_region(devno, scull_nr_devs);
}
#include module.h>
#include init.h>
#include fs.h>
#include cdev.h>
#include slab.h>
#include uaccess.h>
int scull_major = 0;
int scull_minor = 0;
int scull_nr_devs = 1;
int scull_quantum = 4000;
int scull_qset = 1000;
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_device;
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;
}
struct file_operations scull_fops = {
.owner = THIS_MODULE,
//.read = scull_read,
//.write = scull_write,
//.open = scull_open,
//.release = scull_release,
};
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;
dev->cdev.ops = &scull_fops;
err = cdev_add(&dev->cdev, devno, 1);
if (err)
printk(KERN_NOTICE "Error %d adding scull %d", err, index);
}
void scull_cleanup_module(void)
{
int i;
dev_t devno = MKDEV(scull_major, scull_minor);
if (scull_device) {
for (i = 0; i < scull_nr_devs; i++) {
scull_trim(scull_device + i);
cdev_del(&scull_device[i].cdev);
}
kfree(scull_device);
}
unregister_chrdev_region(devno, scull_nr_devs);
}
static int scull_init_module(void)
{
int rv, i;
dev_t dev;
rv = alloc_chrdev_region(&dev, scull_minor, scull_nr_devs, "scull");
scull_major = MAJOR(dev);
if (rv) {
printk(KERN_WARNING "scull: can't get major %d\n", scull_major);
return rv;
}
scull_device = kmalloc(scull_nr_devs * sizeof(struct scull_dev), GFP_KERNEL);
if (!scull_device) {
rv = -ENOMEM;
goto fail;
}
memset(scull_device, 0, scull_nr_devs * sizeof(struct scull_dev));
for (i = 0; i < scull_nr_devs; i++) {
scull_device[i].quantum = scull_quantum;
scull_device[i].qset = scull_qset;
sema_init(&scull_device[i].sem, 1);
scull_setup_cdev(&scull_device[i], i);
}
dev = MKDEV(scull_major, scull_minor + scull_nr_devs);
printk(KERN_INFO "scull: major = %d minor = %d\n", scull_major, scull_minor);
return 0;
fail:
scull_cleanup_module();
return rv;
}
MODULE_AUTHOR("Your name");
MODULE_LICENSE("GPL");
module_init(scull_init_module);
module_exit(scull_cleanup_module);
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