2022-04-05 01:19:53

by Tom Rix

[permalink] [raw]
Subject: Re: [PATCH v3 1/2] hwmon: introduce hwmon_sanitize_name()


On 4/4/22 11:43 AM, 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 <[email protected]>
> ---
> Documentation/hwmon/hwmon-kernel-api.rst | 16 ++++++++
> drivers/hwmon/hwmon.c | 50 ++++++++++++++++++++++++
> include/linux/hwmon.h | 3 ++
> 3 files changed, 69 insertions(+)
>
> diff --git a/Documentation/hwmon/hwmon-kernel-api.rst b/Documentation/hwmon/hwmon-kernel-api.rst
> index c41eb6108103..e2975d5caf34 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
> @@ -95,6 +99,18 @@ 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.
>
> +If the driver doesn't use a static device name (for example it uses
> +dev_name()), and therefore cannot make sure the name only contains valid
> +characters, hwmon_sanitize_name can be used. This convenience function
> +will duplicate the string and replace any invalid characters with an
> +underscore. It will allocate memory for the new string and it is the
> +responsibility of the caller to release the memory when the device is
> +removed.
> +
> +devm_hwmon_sanitize_name is the resource managed version of
> +hwmon_sanitize_name; the memory will be freed automatically on device
> +removal.
> +
> Using devm_hwmon_device_register_with_info()
> --------------------------------------------
>
> diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
> index 989e2c8496dd..cc4a16a466a0 100644
> --- a/drivers/hwmon/hwmon.c
> +++ b/drivers/hwmon/hwmon.c
> @@ -1057,6 +1057,56 @@ void devm_hwmon_device_unregister(struct device *dev)
> }
> EXPORT_SYMBOL_GPL(devm_hwmon_device_unregister);
>
> +static char *__hwmon_sanitize_name(struct device *dev, const char *old_name)
> +{
> + char *name, *p;
> +
> + if (dev)
> + name = devm_kstrdup(dev, old_name, GFP_KERNEL);
> + else
> + name = kstrdup(old_name, GFP_KERNEL);
> + if (!name)
> + return NULL;
should return ERR_PTR(-ENOMEM)
> +
> + for (p = name; *p; p++)
> + if (hwmon_is_bad_char(*p))
> + *p = '_';
> +
> + return name;
> +}
> +
> +/**
> + * hwmon_sanitize_name - Replaces invalid characters in a hwmon name
> + * @name: NUL-terminated name
> + *
> + * Allocates a new string where any invalid characters will be replaced
> + * by an underscore. It is the responsibility of the caller to release
> + * the memory.
> + *
> + * Returns newly allocated name or %NULL in case of error.
> + */
> +char *hwmon_sanitize_name(const char *name)
> +{
> + return __hwmon_sanitize_name(NULL, name);
> +}
> +EXPORT_SYMBOL_GPL(hwmon_sanitize_name);
> +
> +/**
> + * devm_hwmon_sanitize_name - resource managed hwmon_sanitize_name()
> + * @dev: device to allocate memory for
> + * @name: NUL-terminated name
> + *
> + * Allocates a new string where any invalid characters will be replaced
> + * by an underscore.
> + *
> + * Returns newly allocated name or %NULL in case of error.
> + */
> +char *devm_hwmon_sanitize_name(struct device *dev, const char *name)
> +{
> + return __hwmon_sanitize_name(dev, name);
Should have a (!dev) check.
> +}
> +EXPORT_SYMBOL_GPL(devm_hwmon_sanitize_name);
> +
> static void __init hwmon_pci_quirks(void)
> {
> #if defined CONFIG_X86 && defined CONFIG_PCI
> diff --git a/include/linux/hwmon.h b/include/linux/hwmon.h
> index eba380b76d15..4efaf06fd2b8 100644
> --- a/include/linux/hwmon.h
> +++ b/include/linux/hwmon.h
> @@ -461,6 +461,9 @@ void devm_hwmon_device_unregister(struct device *dev);
> int hwmon_notify_event(struct device *dev, enum hwmon_sensor_types type,
> u32 attr, int channel);
>
> +char *hwmon_sanitize_name(const char *name);
> +char *devm_hwmon_sanitize_name(struct device *dev, const char *name);
> +
> /**
> * hwmon_is_bad_char - Is the char invalid in a hwmon name

This still needed in *.h ?

Tom

> * @ch: the char to be considered


2022-04-05 03:33:37

by Guenter Roeck

[permalink] [raw]
Subject: Re: [PATCH v3 1/2] hwmon: introduce hwmon_sanitize_name()

On 4/4/22 16:14, Tom Rix wrote:
>
> On 4/4/22 11:43 AM, 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 <[email protected]>
>> ---
>>   Documentation/hwmon/hwmon-kernel-api.rst | 16 ++++++++
>>   drivers/hwmon/hwmon.c                    | 50 ++++++++++++++++++++++++
>>   include/linux/hwmon.h                    |  3 ++
>>   3 files changed, 69 insertions(+)
>>
>> diff --git a/Documentation/hwmon/hwmon-kernel-api.rst b/Documentation/hwmon/hwmon-kernel-api.rst
>> index c41eb6108103..e2975d5caf34 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
>> @@ -95,6 +99,18 @@ 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.
>> +If the driver doesn't use a static device name (for example it uses
>> +dev_name()), and therefore cannot make sure the name only contains valid
>> +characters, hwmon_sanitize_name can be used. This convenience function
>> +will duplicate the string and replace any invalid characters with an
>> +underscore. It will allocate memory for the new string and it is the
>> +responsibility of the caller to release the memory when the device is
>> +removed.
>> +
>> +devm_hwmon_sanitize_name is the resource managed version of
>> +hwmon_sanitize_name; the memory will be freed automatically on device
>> +removal.
>> +
>>   Using devm_hwmon_device_register_with_info()
>>   --------------------------------------------
>> diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
>> index 989e2c8496dd..cc4a16a466a0 100644
>> --- a/drivers/hwmon/hwmon.c
>> +++ b/drivers/hwmon/hwmon.c
>> @@ -1057,6 +1057,56 @@ void devm_hwmon_device_unregister(struct device *dev)
>>   }
>>   EXPORT_SYMBOL_GPL(devm_hwmon_device_unregister);
>> +static char *__hwmon_sanitize_name(struct device *dev, const char *old_name)
>> +{
>> +    char *name, *p;
>> +
>> +    if (dev)
>> +        name = devm_kstrdup(dev, old_name, GFP_KERNEL);
>> +    else
>> +        name = kstrdup(old_name, GFP_KERNEL);
>> +    if (!name)
>> +        return NULL;
> should return ERR_PTR(-ENOMEM)

In general this is a matter of opinion, but other hwmon functions
return ERR_PTR(-ENOMEM), so I agree here.

>> +
>> +    for (p = name; *p; p++)
>> +        if (hwmon_is_bad_char(*p))
>> +            *p = '_';
>> +
>> +    return name;
>> +}
>> +
>> +/**
>> + * hwmon_sanitize_name - Replaces invalid characters in a hwmon name
>> + * @name: NUL-terminated name
>> + *
>> + * Allocates a new string where any invalid characters will be replaced
>> + * by an underscore. It is the responsibility of the caller to release
>> + * the memory.
>> + *
>> + * Returns newly allocated name or %NULL in case of error.
>> + */
>> +char *hwmon_sanitize_name(const char *name)
>> +{
>> +    return __hwmon_sanitize_name(NULL, name);
>> +}
>> +EXPORT_SYMBOL_GPL(hwmon_sanitize_name);
>> +
>> +/**
>> + * devm_hwmon_sanitize_name - resource managed hwmon_sanitize_name()
>> + * @dev: device to allocate memory for
>> + * @name: NUL-terminated name
>> + *
>> + * Allocates a new string where any invalid characters will be replaced
>> + * by an underscore.
>> + *
>> + * Returns newly allocated name or %NULL in case of error.
>> + */
>> +char *devm_hwmon_sanitize_name(struct device *dev, const char *name)
>> +{
>> +    return __hwmon_sanitize_name(dev, name);
> Should have a (!dev) check.

... and return ERR_PTR(-EINVAL) if it is NULL, to match
hwmon registration functions.

>> +}
>> +EXPORT_SYMBOL_GPL(devm_hwmon_sanitize_name);
>> +
>>   static void __init hwmon_pci_quirks(void)
>>   {
>>   #if defined CONFIG_X86 && defined CONFIG_PCI
>> diff --git a/include/linux/hwmon.h b/include/linux/hwmon.h
>> index eba380b76d15..4efaf06fd2b8 100644
>> --- a/include/linux/hwmon.h
>> +++ b/include/linux/hwmon.h
>> @@ -461,6 +461,9 @@ void devm_hwmon_device_unregister(struct device *dev);
>>   int hwmon_notify_event(struct device *dev, enum hwmon_sensor_types type,
>>                  u32 attr, int channel);
>> +char *hwmon_sanitize_name(const char *name);
>> +char *devm_hwmon_sanitize_name(struct device *dev, const char *name);
>> +
>>   /**
>>    * hwmon_is_bad_char - Is the char invalid in a hwmon name
>
> This still needed in *.h ?
>

Yes, because it is used by out-of-tree drivers. We can only move
that into hwmon.c after all users are gone.

Guenter

2022-04-05 22:43:51

by David Laight

[permalink] [raw]
Subject: RE: [PATCH v3 1/2] hwmon: introduce hwmon_sanitize_name()

From: Guenter Roeck
> Sent: 05 April 2022 00:31
...
> >>   /**
> >>    * hwmon_is_bad_char - Is the char invalid in a hwmon name
> >
> > This still needed in *.h ?
> >
>
> Yes, because it is used by out-of-tree drivers. We can only move
> that into hwmon.c after all users are gone.

And drivers might want to 'sanitize' a copy of the name without
reallocating it.

David

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