vmlogrdr.c

linux-2.6.15.6

			 * We need to return the total length of the record
                         * + size of FENCE in the first 4 bytes of the buffer.
		         */
			iucv_data_count =
				priv->local_interrupt_buffer.ln1msg2.ipbfln1f;
			user_data_count = sizeof(int);
			temp = (int*)priv->buffer;
			*temp= iucv_data_count + sizeof(FENCE);
			buffer = priv->buffer + sizeof(int);
		}
		/*
		 * If the record is bigger then our buffer, we receive only
		 * a part of it. We can get the rest later.
		 */
		if (iucv_data_count > NET_BUFFER_SIZE)
			iucv_data_count = NET_BUFFER_SIZE;
		rc = iucv_receive(priv->pathid,
				  priv->local_interrupt_buffer.ipmsgid,
				  priv->local_interrupt_buffer.iptrgcls,
				  buffer,
				  iucv_data_count,
				  NULL,
				  NULL,
				  &priv->residual_length);
		spin_unlock_bh(&priv->priv_lock);
		/* An rc of 5 indicates that the record was bigger then
		 * the buffer, which is OK for us. A 9 indicates that the
		 * record was purged befor we could receive it.
		 */
		if (rc == 5)
			rc = 0;
		if (rc == 9)
			atomic_set(&priv->receive_ready, 0);
	} else {
		rc = 1;
	}
	if (!rc) {
		priv->buffer_free = 0;
 		user_data_count += iucv_data_count;
		priv->current_position = priv->buffer;
		if (priv->residual_length == 0){
			/* the whole record has been captured,
			 * now add the fence */
			atomic_dec(&priv->receive_ready);
			buffer = priv->buffer + user_data_count;
			memcpy(buffer, FENCE, sizeof(FENCE));
			user_data_count += sizeof(FENCE);
		}
		priv->remaining = user_data_count;
	}

	return rc;
}


static ssize_t
vmlogrdr_read (struct file *filp, char *data, size_t count, loff_t * ppos)
{
	int rc;
	struct vmlogrdr_priv_t * priv = filp->private_data;

	while (priv->buffer_free) {
		rc = vmlogrdr_receive_data(priv);
		if (rc) {
			rc = wait_event_interruptible(read_wait_queue,
					atomic_read(&priv->receive_ready));
			if (rc)
				return rc;
		}
	}
	/* copy only up to end of record */
	if (count > priv->remaining)
		count = priv->remaining;

	if (copy_to_user(data, priv->current_position, count))
		return -EFAULT;

	*ppos += count;
	priv->current_position += count;
	priv->remaining -= count;

	/* if all data has been transferred, set buffer free */
	if (priv->remaining == 0)
		priv->buffer_free = 1;

	return count;
}

static ssize_t
vmlogrdr_autopurge_store(struct device * dev, struct device_attribute *attr, const char * buf, size_t count) {
	struct vmlogrdr_priv_t *priv = dev->driver_data;
	ssize_t ret = count;

	switch (buf[0]) {
	case '0':
		priv->autopurge=0;
		break;
	case '1':
		priv->autopurge=1;
		break;
	default:
		ret = -EINVAL;
	}
	return ret;
}


static ssize_t
vmlogrdr_autopurge_show(struct device *dev, struct device_attribute *attr, char *buf) {
	struct vmlogrdr_priv_t *priv = dev->driver_data;
	return sprintf(buf, "%u\n", priv->autopurge);
}


static DEVICE_ATTR(autopurge, 0644, vmlogrdr_autopurge_show,
		   vmlogrdr_autopurge_store);


static ssize_t
vmlogrdr_purge_store(struct device * dev, struct device_attribute *attr, const char * buf, size_t count) {

	char cp_command[80];
	char cp_response[80];
	struct vmlogrdr_priv_t *priv = dev->driver_data;

	if (buf[0] != '1')
		return -EINVAL;

	memset(cp_command, 0x00, sizeof(cp_command));
	memset(cp_response, 0x00, sizeof(cp_response));

        /*
	 * The recording command needs to be called with option QID
	 * for guests that have previlege classes A or B.
	 * Other guests will not recognize the command and we have to
	 * issue the same command without the QID parameter.
	 */

	if (recording_class_AB)
		snprintf(cp_command, sizeof(cp_command),
			 "RECORDING %s PURGE QID * ",
			 priv->recording_name);
	else
		snprintf(cp_command, sizeof(cp_command),
			 "RECORDING %s PURGE ",
			 priv->recording_name);

	printk (KERN_DEBUG "vmlogrdr: recording command: %s\n", cp_command);
	cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
	printk (KERN_DEBUG "vmlogrdr: recording response: %s",
		cp_response);

	return count;
}


static DEVICE_ATTR(purge, 0200, NULL, vmlogrdr_purge_store);


static ssize_t
vmlogrdr_autorecording_store(struct device *dev, struct device_attribute *attr, const char *buf,
			     size_t count) {
	struct vmlogrdr_priv_t *priv = dev->driver_data;
	ssize_t ret = count;

	switch (buf[0]) {
	case '0':
		priv->autorecording=0;
		break;
	case '1':
		priv->autorecording=1;
		break;
	default:
		ret = -EINVAL;
	}
	return ret;
}


static ssize_t
vmlogrdr_autorecording_show(struct device *dev, struct device_attribute *attr, char *buf) {
	struct vmlogrdr_priv_t *priv = dev->driver_data;
	return sprintf(buf, "%u\n", priv->autorecording);
}


static DEVICE_ATTR(autorecording, 0644, vmlogrdr_autorecording_show,
		   vmlogrdr_autorecording_store);


static ssize_t
vmlogrdr_recording_store(struct device * dev, struct device_attribute *attr, const char * buf, size_t count) {

	struct vmlogrdr_priv_t *priv = dev->driver_data;
	ssize_t ret;

	switch (buf[0]) {
	case '0':
		ret = vmlogrdr_recording(priv,0,0);
		break;
	case '1':
		ret = vmlogrdr_recording(priv,1,0);
		break;
	default:
		ret = -EINVAL;
	}
	if (ret)
		return ret;
	else
		return count;

}


static DEVICE_ATTR(recording, 0200, NULL, vmlogrdr_recording_store);


static ssize_t
vmlogrdr_recording_status_show(struct device_driver *driver, char *buf) {

	char cp_command[] = "QUERY RECORDING ";
	int len;

	cpcmd(cp_command, buf, 4096, NULL);
	len = strlen(buf);
	return len;
}


static DRIVER_ATTR(recording_status, 0444, vmlogrdr_recording_status_show,
		   NULL);

static struct attribute *vmlogrdr_attrs[] = {
	&dev_attr_autopurge.attr,
	&dev_attr_purge.attr,
	&dev_attr_autorecording.attr,
	&dev_attr_recording.attr,
	NULL,
};

static struct attribute_group vmlogrdr_attr_group = {
	.attrs = vmlogrdr_attrs,
};

static struct class *vmlogrdr_class;
static struct device_driver vmlogrdr_driver = {
	.name = "vmlogrdr",
	.bus  = &iucv_bus,
};


static int
vmlogrdr_register_driver(void) {
	int ret;

	ret = driver_register(&vmlogrdr_driver);
	if (ret) {
		printk(KERN_ERR "vmlogrdr: failed to register driver.\n");
		return ret;
	}

	ret = driver_create_file(&vmlogrdr_driver,
				 &driver_attr_recording_status);
	if (ret) {
		printk(KERN_ERR "vmlogrdr: failed to add driver attribute.\n");
		goto unregdriver;
	}

	vmlogrdr_class = class_create(THIS_MODULE, "vmlogrdr");
	if (IS_ERR(vmlogrdr_class)) {
		printk(KERN_ERR "vmlogrdr: failed to create class.\n");
		ret=PTR_ERR(vmlogrdr_class);
		vmlogrdr_class=NULL;
		goto unregattr;
	}
	return 0;

unregattr:
	driver_remove_file(&vmlogrdr_driver, &driver_attr_recording_status);
unregdriver:
	driver_unregister(&vmlogrdr_driver);
	return ret;
}


static void
vmlogrdr_unregister_driver(void) {
	class_destroy(vmlogrdr_class);
	vmlogrdr_class = NULL;
	driver_remove_file(&vmlogrdr_driver, &driver_attr_recording_status);
	driver_unregister(&vmlogrdr_driver);
	return;
}


static int
vmlogrdr_register_device(struct vmlogrdr_priv_t *priv) {
	struct device *dev;
	int ret;

	dev = kmalloc(sizeof(struct device), GFP_KERNEL);
	if (dev) {
		memset(dev, 0, sizeof(struct device));
		snprintf(dev->bus_id, BUS_ID_SIZE, "%s",
			 priv->internal_name);
		dev->bus = &iucv_bus;
		dev->parent = iucv_root;
		dev->driver = &vmlogrdr_driver;
		/*
		 * The release function could be called after the
		 * module has been unloaded. It's _only_ task is to
		 * free the struct. Therefore, we specify kfree()
		 * directly here. (Probably a little bit obfuscating
		 * but legitime ...).
		 */
		dev->release = (void (*)(struct device *))kfree;
	} else
		return -ENOMEM;
	ret = device_register(dev);
	if (ret)
		return ret;

	ret = sysfs_create_group(&dev->kobj, &vmlogrdr_attr_group);
	if (ret) {
		device_unregister(dev);
		return ret;
	}
	priv->class_device = class_device_create(
				vmlogrdr_class,
				NULL,
				MKDEV(vmlogrdr_major, priv->minor_num),
				dev,
				"%s", dev->bus_id );
	if (IS_ERR(priv->class_device)) {
		ret = PTR_ERR(priv->class_device);
		priv->class_device=NULL;
		sysfs_remove_group(&dev->kobj, &vmlogrdr_attr_group);
		device_unregister(dev);
		return ret;
	}
	dev->driver_data = priv;
	priv->device = dev;
	return 0;
}


static int
vmlogrdr_unregister_device(struct vmlogrdr_priv_t *priv ) {
	class_device_destroy(vmlogrdr_class, MKDEV(vmlogrdr_major, priv->minor_num));
	if (priv->device != NULL) {
		sysfs_remove_group(&priv->device->kobj, &vmlogrdr_attr_group);
		device_unregister(priv->device);
		priv->device=NULL;
	}
	return 0;
}


static int
vmlogrdr_register_cdev(dev_t dev) {
	int rc = 0;
	vmlogrdr_cdev = cdev_alloc();
	if (!vmlogrdr_cdev) {
		return -ENOMEM;
	}
	vmlogrdr_cdev->owner = THIS_MODULE;
	vmlogrdr_cdev->ops = &vmlogrdr_fops;
	vmlogrdr_cdev->dev = dev;
	rc = cdev_add(vmlogrdr_cdev, vmlogrdr_cdev->dev, MAXMINOR);
	if (!rc)
		return 0;

	// cleanup: cdev is not fully registered, no cdev_del here!
	kobject_put(&vmlogrdr_cdev->kobj);
	vmlogrdr_cdev=NULL;
	return rc;
}


static void
vmlogrdr_cleanup(void) {
        int i;
	if (vmlogrdr_cdev) {
		cdev_del(vmlogrdr_cdev);
		vmlogrdr_cdev=NULL;
	}
	for (i=0; i < MAXMINOR; ++i ) {
		vmlogrdr_unregister_device(&sys_ser[i]);
		free_page((unsigned long)sys_ser[i].buffer);
	}
	vmlogrdr_unregister_driver();
	if (vmlogrdr_major) {
		unregister_chrdev_region(MKDEV(vmlogrdr_major, 0), MAXMINOR);
		vmlogrdr_major=0;
	}
}


static int
vmlogrdr_init(void)
{
	int rc;
	int i;
	dev_t dev;

	if (! MACHINE_IS_VM) {
		printk (KERN_ERR "vmlogrdr: not running under VM, "
				"driver not loaded.\n");
		return -ENODEV;
	}

        recording_class_AB = vmlogrdr_get_recording_class_AB();

	rc = alloc_chrdev_region(&dev, 0, MAXMINOR, "vmlogrdr");
	if (rc)
		return rc;
	vmlogrdr_major = MAJOR(dev);

	rc=vmlogrdr_register_driver();
	if (rc)
		goto cleanup;

	for (i=0; i < MAXMINOR; ++i ) {
		sys_ser[i].buffer = (char *) get_zeroed_page(GFP_KERNEL);
		if (!sys_ser[i].buffer) {
			rc = ENOMEM;
			break;
		}
		sys_ser[i].current_position = sys_ser[i].buffer;
		rc=vmlogrdr_register_device(&sys_ser[i]);
		if (rc)
			break;
	}
	if (rc)
		goto cleanup;

	rc = vmlogrdr_register_cdev(dev);
	if (rc)
		goto cleanup;
	printk (KERN_INFO "vmlogrdr: driver loaded\n");
	return 0;

cleanup:
	vmlogrdr_cleanup();
	printk (KERN_ERR "vmlogrdr: driver not loaded.\n");
	return rc;
}


static void
vmlogrdr_exit(void)
{
	vmlogrdr_cleanup();
	printk (KERN_INFO "vmlogrdr: driver unloaded\n");
	return;
}


module_init(vmlogrdr_init);
module_exit(vmlogrdr_exit);