Messages in this thread | | | Date | Wed, 30 Mar 2022 08:13:14 -0700 | From | Guenter Roeck <> | Subject | Re: [PATCH v2 1/5] hwmon: introduce hwmon_sanitize_name() |
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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
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