On Tue, May 5, 2009 at 1:16 PM, Pavel Machek <pavel@xxxxxx> wrote:
> On Tue 2009-05-05 21:18:42, Arve Hj??nnev??g wrote:
>> Add a misc device, "suspend_blocker", that allows user-space processes
>> to block auto suspend. The device has ioctls to create a suspend_blocker,
>> and to block and unblock suspend. To delete the suspend_blocker, close
>> the device.
>>
>
>> +static int create_user_suspend_blocker(struct file *file, void __user *name,
>> + size_t name_len)
>> +{
>> + struct user_suspend_blocker *bl;
>> + if (file->private_data)
>> + return -EBUSY;
>> + bl = kzalloc(sizeof(*bl) + name_len + 1, GFP_KERNEL);
> ...
>> +static long user_suspend_blocker_ioctl(struct file *file, unsigned int cmd,
>> + unsigned long _arg)
>> +{
>> + void __user *arg = (void __user *)_arg;
>> + struct user_suspend_blocker *bl;
>> + long ret;
>> +
>> + mutex_lock(&ioctl_lock);
>> + if ((cmd & ~IOCSIZE_MASK) == SUSPEND_BLOCKER_IOCTL_INIT(0)) {
>> + ret = create_user_suspend_blocker(file, arg, _IOC_SIZE(cmd));
>> + goto done;
>> + }
>
> Wait a moment, wtf is this? Not one ioctl but one ioctl per length of
> string?!
This is not uncommon. _IOC encodes the size of the argument, and if
this is not a fixed size, then the raw ioctl number change based on
the size passed in. Look at input.h is you want other examples of
this.
--
Arve Hjønnevåg
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