lkml.org 
[lkml]   [2022]   [Mar]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2 1/5] hwmon: introduce hwmon_sanitize_name()
On 3/30/22 07:50, David Laight wrote:
> From: Guenter Roeck
>> Sent: 30 March 2022 15:23
>> On 3/29/22 09:07, Michael Walle wrote:
>>> More and more drivers will check for bad characters in the hwmon name
>>> and all are using the same code snippet. Consolidate that code by adding
>>> a new hwmon_sanitize_name() function.
>>>
>>> Signed-off-by: Michael Walle <michael@walle.cc>
>>> ---
>>> Documentation/hwmon/hwmon-kernel-api.rst | 9 ++++-
>>> drivers/hwmon/hwmon.c | 49 ++++++++++++++++++++++++
>>> include/linux/hwmon.h | 3 ++
>>> 3 files changed, 60 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/Documentation/hwmon/hwmon-kernel-api.rst b/Documentation/hwmon/hwmon-kernel-api.rst
>>> index c41eb6108103..12f4a9bcef04 100644
>>> --- a/Documentation/hwmon/hwmon-kernel-api.rst
>>> +++ b/Documentation/hwmon/hwmon-kernel-api.rst
>>> @@ -50,6 +50,10 @@ register/unregister functions::
>>>
>>> void devm_hwmon_device_unregister(struct device *dev);
>>>
>>> + char *hwmon_sanitize_name(const char *name);
>>> +
>>> + char *devm_hwmon_sanitize_name(struct device *dev, const char *name);
>>> +
>>> hwmon_device_register_with_groups registers a hardware monitoring device.
>>> The first parameter of this function is a pointer to the parent device.
>>> The name parameter is a pointer to the hwmon device name. The registration
>>> @@ -93,7 +97,10 @@ removal would be too late.
>>>
>>> All supported hwmon device registration functions only accept valid device
>>> names. Device names including invalid characters (whitespace, '*', or '-')
>>> -will be rejected. The 'name' parameter is mandatory.
>>> +will be rejected. The 'name' parameter is mandatory. Before calling a
>>> +register function you should either use hwmon_sanitize_name or
>>> +devm_hwmon_sanitize_name to replace any invalid characters with an
>>> +underscore.
>>
>> That needs more details and deserves its own paragraph. Calling one of
>> the functions is only necessary if the original name does or can include
>> unsupported characters; an unconditional "should" is therefore a bit
>> strong. Also, it is important to mention that the function duplicates
>> the name, and that it is the responsibility of the caller to release
>> the name if hwmon_sanitize_name() was called and the device is removed.
>
> More worrying, and not documented, is that the buffer 'name' points
> to must persist.
>

You mean the name argument passed to the hwmon registration functions ?
That has been the case forever, and I don't recall a single problem
with it. If it disturbs you, please feel free to submit a patch adding
more details to the documentation.

I would not want to change the code and always copy the name because in
almost all cases it _is_ a fixed string, and duplicating it would have
no value.

> ISTM that the kmalloc() in __hwmon_device_register() should include
> space for a copy of the name.
> It can then do what it will with whatever is passed in.
>

Whatever is passed in is what the user wants. Registration functions
don't change the name. Providing a valid name is the responsibility
of the caller.

> Oh yes, it has my 'favourite construct': if (!strlen(name)) ...
> (well str[strlen(str)] = 0 also happens!)
>

Sorry, I don't understand what the problem is here.

Thanks,
Guenter

\
 
 \ /
  Last update: 2022-03-30 17:14    [W:0.290 / U:0.044 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site