Re: [PATCH 03/34] brcmfmac: firmware: Support having multiple alt paths

[Hector Martin]

On 2022/01/02 15:45, Dmitry Osipenko wrote:
> 26.12.2021 18:35, Hector Martin пишет:
>> -static char *brcm_alt_fw_path(const char *path, const char *board_type)
>> +static const char **brcm_alt_fw_paths(const char *path, const char *board_type)
>>  {
>>  	char alt_path[BRCMF_FW_NAME_LEN];
>> +	char **alt_paths;
>>  	char suffix[5];
>>  
>>  	strscpy(alt_path, path, BRCMF_FW_NAME_LEN);
>> @@ -609,27 +612,46 @@ static char *brcm_alt_fw_path(const char *path, const char *board_type)
>>  	strlcat(alt_path, board_type, BRCMF_FW_NAME_LEN);
>>  	strlcat(alt_path, suffix, BRCMF_FW_NAME_LEN);
>>  
>> -	return kstrdup(alt_path, GFP_KERNEL);
>> +	alt_paths = kzalloc(sizeof(char *) * 2, GFP_KERNEL);
> 
> array_size()?

Of what array?

> 
>> +	alt_paths[0] = kstrdup(alt_path, GFP_KERNEL);
>> +
>> +	return (const char **)alt_paths;
> 
> Why this casting is needed?

Because implicit conversion from char ** to const char ** is not legal
in C, as that could cause const unsoundness if you do this:

char *foo[1];
const char **bar = foo;

bar[0] = "constant string";
foo[0][0] = '!'; // clobbers constant string

But it's fine in this case since the non-const pointer disappears so
nothing can ever write through it again.

-- 
Hector Martin (marcan@xxxxxxxxx)
Public Key: https://mrcn.st/pub