[git pull 08/14] Uinput: convert to dynalloc allocation

From: Dmitry Torokhov
Date: Sun Nov 20 2005 - 01:49:16 EST


Input: uinput - convert to dynalloc allocation

Also introduce proper locking when creating/deleting device.

Signed-off-by: Dmitry Torokhov <dtor@xxxxxxx>
---

drivers/input/misc/uinput.c | 308 +++++++++++++++++++++++---------------------
include/linux/uinput.h | 12 -
2 files changed, 168 insertions(+), 152 deletions(-)

Index: work/drivers/input/misc/uinput.c
===================================================================
--- work.orig/drivers/input/misc/uinput.c
+++ work/drivers/input/misc/uinput.c
@@ -152,67 +152,62 @@ static int uinput_dev_erase_effect(struc
return retval;
}

-static int uinput_create_device(struct uinput_device *udev)
+static void uinput_destroy_device(struct uinput_device *udev)
{
- if (!udev->dev->name) {
- printk(KERN_DEBUG "%s: write device info first\n", UINPUT_NAME);
- return -EINVAL;
- }
+ const char *name, *phys;

- udev->dev->event = uinput_dev_event;
- udev->dev->upload_effect = uinput_dev_upload_effect;
- udev->dev->erase_effect = uinput_dev_erase_effect;
- udev->dev->private = udev;
-
- init_waitqueue_head(&udev->waitq);
-
- input_register_device(udev->dev);
-
- set_bit(UIST_CREATED, &udev->state);
+ if (udev->dev) {
+ name = udev->dev->name;
+ phys = udev->dev->phys;
+ if (udev->state == UIST_CREATED)
+ input_unregister_device(udev->dev);
+ else
+ input_free_device(udev->dev);
+ kfree(name);
+ kfree(phys);
+ udev->dev = NULL;
+ }

- return 0;
+ udev->state = UIST_NEW_DEVICE;
}

-static int uinput_destroy_device(struct uinput_device *udev)
+static int uinput_create_device(struct uinput_device *udev)
{
- if (!test_bit(UIST_CREATED, &udev->state)) {
- printk(KERN_WARNING "%s: create the device first\n", UINPUT_NAME);
+ int error;
+
+ if (udev->state != UIST_SETUP_COMPLETE) {
+ printk(KERN_DEBUG "%s: write device info first\n", UINPUT_NAME);
return -EINVAL;
}

- input_unregister_device(udev->dev);
+ error = input_register_device(udev->dev);
+ if (error) {
+ uinput_destroy_device(udev);
+ return error;
+ }

- clear_bit(UIST_CREATED, &udev->state);
+ udev->state = UIST_CREATED;

return 0;
}

static int uinput_open(struct inode *inode, struct file *file)
{
- struct uinput_device *newdev;
- struct input_dev *newinput;
+ struct uinput_device *newdev;

- newdev = kmalloc(sizeof(struct uinput_device), GFP_KERNEL);
+ newdev = kzalloc(sizeof(struct uinput_device), GFP_KERNEL);
if (!newdev)
- goto error;
- memset(newdev, 0, sizeof(struct uinput_device));
+ return -ENOMEM;
+
+ init_MUTEX(&newdev->sem);
spin_lock_init(&newdev->requests_lock);
init_waitqueue_head(&newdev->requests_waitq);
-
- newinput = kmalloc(sizeof(struct input_dev), GFP_KERNEL);
- if (!newinput)
- goto cleanup;
- memset(newinput, 0, sizeof(struct input_dev));
-
- newdev->dev = newinput;
+ init_waitqueue_head(&newdev->waitq);
+ newdev->state = UIST_NEW_DEVICE;

file->private_data = newdev;

return 0;
-cleanup:
- kfree(newdev);
-error:
- return -ENOMEM;
}

static int uinput_validate_absbits(struct input_dev *dev)
@@ -246,34 +241,55 @@ static int uinput_validate_absbits(struc
return retval;
}

-static int uinput_alloc_device(struct file *file, const char __user *buffer, size_t count)
+static int uinput_allocate_device(struct uinput_device *udev)
+{
+ udev->dev = input_allocate_device();
+ if (!udev->dev)
+ return -ENOMEM;
+
+ udev->dev->event = uinput_dev_event;
+ udev->dev->upload_effect = uinput_dev_upload_effect;
+ udev->dev->erase_effect = uinput_dev_erase_effect;
+ udev->dev->private = udev;
+
+ return 0;
+}
+
+static int uinput_setup_device(struct uinput_device *udev, const char __user *buffer, size_t count)
{
struct uinput_user_dev *user_dev;
struct input_dev *dev;
- struct uinput_device *udev;
char *name;
int size;
int retval;

- retval = count;
+ if (count != sizeof(struct uinput_user_dev))
+ return -EINVAL;
+
+ if (!udev->dev) {
+ retval = uinput_allocate_device(udev);
+ if (retval)
+ return retval;
+ }

- udev = file->private_data;
dev = udev->dev;

user_dev = kmalloc(sizeof(struct uinput_user_dev), GFP_KERNEL);
- if (!user_dev) {
- retval = -ENOMEM;
- goto exit;
- }
+ if (!user_dev)
+ return -ENOMEM;

if (copy_from_user(user_dev, buffer, sizeof(struct uinput_user_dev))) {
retval = -EFAULT;
goto exit;
}

- kfree(dev->name);
-
size = strnlen(user_dev->name, UINPUT_MAX_NAME_SIZE) + 1;
+ if (!size) {
+ retval = -EINVAL;
+ goto exit;
+ }
+
+ kfree(dev->name);
dev->name = name = kmalloc(size, GFP_KERNEL);
if (!name) {
retval = -ENOMEM;
@@ -296,32 +312,50 @@ static int uinput_alloc_device(struct fi
/* check if absmin/absmax/absfuzz/absflat are filled as
* told in Documentation/input/input-programming.txt */
if (test_bit(EV_ABS, dev->evbit)) {
- int err = uinput_validate_absbits(dev);
- if (err < 0) {
- retval = err;
- kfree(dev->name);
- }
+ retval = uinput_validate_absbits(dev);
+ if (retval < 0)
+ goto exit;
}

-exit:
+ udev->state = UIST_SETUP_COMPLETE;
+ retval = count;
+
+ exit:
kfree(user_dev);
return retval;
}

+static inline ssize_t uinput_inject_event(struct uinput_device *udev, const char __user *buffer, size_t count)
+{
+ struct input_event ev;
+
+ if (count != sizeof(struct input_event))
+ return -EINVAL;
+
+ if (copy_from_user(&ev, buffer, sizeof(struct input_event)))
+ return -EFAULT;
+
+ input_event(udev->dev, ev.type, ev.code, ev.value);
+
+ return sizeof(struct input_event);
+}
+
static ssize_t uinput_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
struct uinput_device *udev = file->private_data;
+ int retval;

- if (test_bit(UIST_CREATED, &udev->state)) {
- struct input_event ev;
+ retval = down_interruptible(&udev->sem);
+ if (retval)
+ return retval;

- if (copy_from_user(&ev, buffer, sizeof(struct input_event)))
- return -EFAULT;
- input_event(udev->dev, ev.type, ev.code, ev.value);
- } else
- count = uinput_alloc_device(file, buffer, count);
+ retval = udev->state == UIST_CREATED ?
+ uinput_inject_event(udev, buffer, count) :
+ uinput_setup_device(udev, buffer, count);

- return count;
+ up(&udev->sem);
+
+ return retval;
}

static ssize_t uinput_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
@@ -329,28 +363,38 @@ static ssize_t uinput_read(struct file *
struct uinput_device *udev = file->private_data;
int retval = 0;

- if (!test_bit(UIST_CREATED, &udev->state))
+ if (udev->state != UIST_CREATED)
return -ENODEV;

if (udev->head == udev->tail && (file->f_flags & O_NONBLOCK))
return -EAGAIN;

retval = wait_event_interruptible(udev->waitq,
- udev->head != udev->tail || !test_bit(UIST_CREATED, &udev->state));
+ udev->head != udev->tail || udev->state != UIST_CREATED);
if (retval)
return retval;

- if (!test_bit(UIST_CREATED, &udev->state))
- return -ENODEV;
+ retval = down_interruptible(&udev->sem);
+ if (retval)
+ return retval;

- while ((udev->head != udev->tail) &&
- (retval + sizeof(struct input_event) <= count)) {
- if (copy_to_user(buffer + retval, &udev->buff[udev->tail], sizeof(struct input_event)))
- return -EFAULT;
+ if (udev->state != UIST_CREATED) {
+ retval = -ENODEV;
+ goto out;
+ }
+
+ while (udev->head != udev->tail && retval + sizeof(struct input_event) <= count) {
+ if (copy_to_user(buffer + retval, &udev->buff[udev->tail], sizeof(struct input_event))) {
+ retval = -EFAULT;
+ goto out;
+ }
udev->tail = (udev->tail + 1) % UINPUT_BUFFER_SIZE;
retval += sizeof(struct input_event);
}

+ out:
+ up(&udev->sem);
+
return retval;
}

@@ -366,28 +410,30 @@ static unsigned int uinput_poll(struct f
return 0;
}

-static int uinput_burn_device(struct uinput_device *udev)
+static int uinput_release(struct inode *inode, struct file *file)
{
- if (test_bit(UIST_CREATED, &udev->state))
- uinput_destroy_device(udev);
+ struct uinput_device *udev = file->private_data;

- kfree(udev->dev->name);
- kfree(udev->dev->phys);
- kfree(udev->dev);
+ uinput_destroy_device(udev);
kfree(udev);

return 0;
}

-static int uinput_close(struct inode *inode, struct file *file)
-{
- uinput_burn_device(file->private_data);
- return 0;
-}
+#define uinput_set_bit(_arg, _bit, _max) \
+({ \
+ int __ret = 0; \
+ if (udev->state == UIST_CREATED) \
+ __ret = -EINVAL; \
+ else if ((_arg) > (_max)) \
+ __ret = -EINVAL; \
+ else set_bit((_arg), udev->dev->_bit); \
+ __ret; \
+})

-static int uinput_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
+static long uinput_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
- int retval = 0;
+ int retval;
struct uinput_device *udev;
void __user *p = (void __user *)arg;
struct uinput_ff_upload ff_up;
@@ -398,19 +444,14 @@ static int uinput_ioctl(struct inode *in

udev = file->private_data;

- /* device attributes can not be changed after the device is created */
- switch (cmd) {
- case UI_SET_EVBIT:
- case UI_SET_KEYBIT:
- case UI_SET_RELBIT:
- case UI_SET_ABSBIT:
- case UI_SET_MSCBIT:
- case UI_SET_LEDBIT:
- case UI_SET_SNDBIT:
- case UI_SET_FFBIT:
- case UI_SET_PHYS:
- if (test_bit(UIST_CREATED, &udev->state))
- return -EINVAL;
+ retval = down_interruptible(&udev->sem);
+ if (retval)
+ return retval;
+
+ if (!udev->dev) {
+ retval = uinput_allocate_device(udev);
+ if (retval)
+ goto out;
}

switch (cmd) {
@@ -419,74 +460,46 @@ static int uinput_ioctl(struct inode *in
break;

case UI_DEV_DESTROY:
- retval = uinput_destroy_device(udev);
+ uinput_destroy_device(udev);
break;

case UI_SET_EVBIT:
- if (arg > EV_MAX) {
- retval = -EINVAL;
- break;
- }
- set_bit(arg, udev->dev->evbit);
+ retval = uinput_set_bit(arg, evbit, EV_MAX);
break;

case UI_SET_KEYBIT:
- if (arg > KEY_MAX) {
- retval = -EINVAL;
- break;
- }
- set_bit(arg, udev->dev->keybit);
+ retval = uinput_set_bit(arg, keybit, KEY_MAX);
break;

case UI_SET_RELBIT:
- if (arg > REL_MAX) {
- retval = -EINVAL;
- break;
- }
- set_bit(arg, udev->dev->relbit);
+ retval = uinput_set_bit(arg, relbit, REL_MAX);
break;

case UI_SET_ABSBIT:
- if (arg > ABS_MAX) {
- retval = -EINVAL;
- break;
- }
- set_bit(arg, udev->dev->absbit);
+ retval = uinput_set_bit(arg, absbit, ABS_MAX);
break;

case UI_SET_MSCBIT:
- if (arg > MSC_MAX) {
- retval = -EINVAL;
- break;
- }
- set_bit(arg, udev->dev->mscbit);
+ retval = uinput_set_bit(arg, mscbit, MSC_MAX);
break;

case UI_SET_LEDBIT:
- if (arg > LED_MAX) {
- retval = -EINVAL;
- break;
- }
- set_bit(arg, udev->dev->ledbit);
+ retval = uinput_set_bit(arg, ledbit, LED_MAX);
break;

case UI_SET_SNDBIT:
- if (arg > SND_MAX) {
- retval = -EINVAL;
- break;
- }
- set_bit(arg, udev->dev->sndbit);
+ retval = uinput_set_bit(arg, sndbit, SND_MAX);
break;

case UI_SET_FFBIT:
- if (arg > FF_MAX) {
- retval = -EINVAL;
- break;
- }
- set_bit(arg, udev->dev->ffbit);
+ retval = uinput_set_bit(arg, ffbit, FF_MAX);
break;

case UI_SET_PHYS:
+ if (udev->state == UIST_CREATED) {
+ retval = -EINVAL;
+ goto out;
+ }
length = strnlen_user(p, 1024);
if (length <= 0) {
retval = -EFAULT;
@@ -575,23 +588,26 @@ static int uinput_ioctl(struct inode *in
default:
retval = -EINVAL;
}
+
+ out:
+ up(&udev->sem);
return retval;
}

static struct file_operations uinput_fops = {
- .owner = THIS_MODULE,
- .open = uinput_open,
- .release = uinput_close,
- .read = uinput_read,
- .write = uinput_write,
- .poll = uinput_poll,
- .ioctl = uinput_ioctl,
+ .owner = THIS_MODULE,
+ .open = uinput_open,
+ .release = uinput_release,
+ .read = uinput_read,
+ .write = uinput_write,
+ .poll = uinput_poll,
+ .unlocked_ioctl = uinput_ioctl,
};

static struct miscdevice uinput_misc = {
- .fops = &uinput_fops,
- .minor = UINPUT_MINOR,
- .name = UINPUT_NAME,
+ .fops = &uinput_fops,
+ .minor = UINPUT_MINOR,
+ .name = UINPUT_NAME,
};

static int __init uinput_init(void)
Index: work/include/linux/uinput.h
===================================================================
--- work.orig/include/linux/uinput.h
+++ work/include/linux/uinput.h
@@ -34,8 +34,7 @@
#define UINPUT_BUFFER_SIZE 16
#define UINPUT_NUM_REQUESTS 16

-/* state flags => bit index for {set|clear|test}_bit ops */
-#define UIST_CREATED 0
+enum uinput_state { UIST_NEW_DEVICE, UIST_SETUP_COMPLETE, UIST_CREATED };

struct uinput_request {
int id;
@@ -52,11 +51,12 @@ struct uinput_request {

struct uinput_device {
struct input_dev *dev;
- unsigned long state;
+ struct semaphore sem;
+ enum uinput_state state;
wait_queue_head_t waitq;
- unsigned char ready,
- head,
- tail;
+ unsigned char ready;
+ unsigned char head;
+ unsigned char tail;
struct input_event buff[UINPUT_BUFFER_SIZE];

struct uinput_request *requests[UINPUT_NUM_REQUESTS];

-
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