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@xxxxxxxx> > > --- > > 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. 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. Oh yes, it has my 'favourite construct': if (!strlen(name)) ... (well str[strlen(str)] = 0 also happens!) David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
