Re: [PATCH] led: try to get LED's label from the 'label' property

[Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>]

On 07/28/2014 08:22 AM, Antony Pavlov wrote:
> On Mon, 28 Jul 2014 07:49:17 +0200
> Sascha Hauer <s.hauer@pengutronix.de> wrote:
> 
>> On Sun, Jul 27, 2014 at 12:35:52PM +0400, Antony Pavlov wrote:
>>> Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
>>> ---
>>>  drivers/led/led-gpio.c | 4 +++-
>>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/led/led-gpio.c b/drivers/led/led-gpio.c
>>> index 7bb3b49..cddac08 100644
>>> --- a/drivers/led/led-gpio.c
>>> +++ b/drivers/led/led-gpio.c
>>> @@ -212,7 +212,9 @@ static int led_gpio_of_probe(struct device_d *dev)
>>>  			continue;
>>>  
>>>  		gled = xzalloc(sizeof(*gled));
>>> -		gled->led.name = xstrdup(child->name);
>>> +		gled->led.name = xstrdup(of_get_property(child, "label", NULL));
>>
>> When the property doesn't exist you pass NULL to xstrdup. This will
>> crash.
> 
> My bad. I have seen barebox strdup() realization but missed xstrdup() realization.
> 
> Barebox' strdup() can handle NULL argument:
> 
> char * strdup(const char *s)
> {
>         char *new;
> 
>         if ((s == NULL) ||
>             ((new = malloc (strlen(s) + 1)) == NULL) ) {                         
>                 return NULL;                                                     
>         }
> 
>         strcpy (new, s);
>         return new;
> }
> 
> But xstrdup() can't do so:
> 
> char *xstrdup(const char *s)
> {
>         char *p = strdup(s);
> 
>         if (!p)
>                 panic("ERROR: out of memory\n");
>         return p;
> }               
> 
> Can I just change first xstrdup() to strdup() in my patch?
> 
> E.g.
> 
> -               gled->led.name = xstrdup(of_get_property(child, "label", NULL));
> +               gled->led.name = strdup(of_get_property(child, "label", NULL));
>                 if (!gled->led.name)
>                         gled->led.name = xstrdup(child->name);
> 
>> You'll have to add a check or make xstrdup tolerate NULL
>> pointers.
>>

Correct code sequence would probably be:

const char *label;

if (of_property_read_string(child, "label", &label))
	gled->led.name = xstrdup(label);
else
	gled->led.name = xstrdup(child->name);

or

const char *label = child->name;

of_property_read_string(child, "label", &label);
gled->led.name = xstrdup(label);

Sebastian

>>> +		if (!gled->led.name)
>>> +			gled->led.name = xstrdup(child->name);
>>>  		gled->gpio = gpio;
>>>  		gled->active_low = (flags & OF_GPIO_ACTIVE_LOW) ? 1 : 0;
>>>  
>>> -- 
>>> 2.0.1
>>>
>>>
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>>
>> -- 
>> Pengutronix e.K.                           |                             |
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> 
> 


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