[U-Boot] [PATCH] gpt: support random UUIDs without setting environment variables

[Rob Herring]

On Wed, Feb 18, 2015 at 11:48 AM, Przemyslaw Marczak
<p.marczak at samsung.com> wrote:
> Hello Rob,
>
> Sorry for delay.
>
> On 01/26/2015 04:44 PM, Rob Herring wrote:
>>
>> Currently, an environment variable must be used to store the randomly
>> generated UUID for each partition. This is not necessary, so make storing
>> the UUID optional. Now passing uuid_disk and uuid are optional when random
>> UUIDs are enabled.
>>
>> Signed-off-by: Rob Herring <robh at kernel.org>
>> ---
>>   common/cmd_gpt.c | 48 ++++++++++++++++++++++++++++++------------------
>>   doc/README.gpt   |  8 +++++---
>>   2 files changed, 35 insertions(+), 21 deletions(-)
>>
>> diff --git a/common/cmd_gpt.c b/common/cmd_gpt.c
>> index 75df3fe..c56fe15 100644
>> --- a/common/cmd_gpt.c
>> +++ b/common/cmd_gpt.c
>> @@ -154,17 +154,24 @@ static int set_gpt_info(block_dev_desc_t *dev_desc,
>>
>>         /* extract disk guid */
>>         s = str;
>> -       tok = strsep(&s, ";");
>> -       val = extract_val(tok, "uuid_disk");
>> +       val = extract_val(str, "uuid_disk");
>>         if (!val) {
>
>
> The code below is not required, since the same thing is done inside the
> extract_env() function.

Okay.

>
>
>> +#ifdef CONFIG_RANDOM_UUID
>> +               *str_disk_guid = malloc(UUID_STR_LEN + 1);
>> +               gen_rand_uuid_str(*str_disk_guid, UUID_STR_FORMAT_STD);
>> +#else
>>                 free(str);
>>                 return -2;
>> +#endif
>> +       } else {
>> +               val = strsep(&val, ";");
>> +               if (extract_env(val, &p))
>> +                       p = val;
>> +               *str_disk_guid = strdup(p);
>> +               free(val);
>> +               /* Move s to first partition */
>> +               strsep(&s, ";");
>>         }
>> -       if (extract_env(val, &p))
>> -               p = val;
>> -       *str_disk_guid = strdup(p);
>> -       free(val);
>> -
>>         if (strlen(s) == 0)
>>                 return -3;
>>
>> @@ -192,20 +199,25 @@ static int set_gpt_info(block_dev_desc_t *dev_desc,
>>
>>                 /* uuid */
>>                 val = extract_val(tok, "uuid");
>> -               if (!val) { /* 'uuid' is mandatory */
>> -                       errno = -4;
>> -                       goto err;
>> -               }
>> -               if (extract_env(val, &p))
>> -                       p = val;
>> -               if (strlen(p) >= sizeof(parts[i].uuid)) {
>> -                       printf("Wrong uuid format for partition %d\n", i);
>> +               if (!val) {
>
>
> The same in this place - code duplication.
>
>
>> +                       /* 'uuid' is optional if random uuid's are enabled
>> */
>> +#ifdef CONFIG_RANDOM_UUID
>> +                       gen_rand_uuid_str(parts[i].uuid,
>> UUID_STR_FORMAT_STD);
>> +#else
>>                         errno = -4;
>>                         goto err;
>> +#endif
>> +               } else {
>> +                       if (extract_env(val, &p))
>> +                               p = val;
>> +                       if (strlen(p) >= sizeof(parts[i].uuid)) {
>> +                               printf("Wrong uuid format for partition
>> %d\n", i);
>> +                               errno = -4;
>> +                               goto err;
>> +                       }
>> +                       strcpy((char *)parts[i].uuid, p);
>> +                       free(val);
>>                 }
>> -               strcpy((char *)parts[i].uuid, p);
>> -               free(val);
>> -
>>                 /* name */
>>                 val = extract_val(tok, "name");
>>                 if (!val) { /* name is mandatory */
>> diff --git a/doc/README.gpt b/doc/README.gpt
>> index ec0156d..59fdeeb 100644
>> --- a/doc/README.gpt
>> +++ b/doc/README.gpt
>> @@ -157,11 +157,13 @@ To restore GUID partition table one needs to:
>>        "partitions=uuid_disk=${uuid_gpt_disk};name=${uboot_name},
>>         size=${uboot_size},uuid=${uboot_uuid};"
>>
>> -   Fields 'name', 'size' and 'uuid' are mandatory for every partition.
>> +   The fields 'name' and 'size' are mandatory for every partition.
>>      The field 'start' is optional.
>>
>> -   option: CONFIG_RANDOM_UUID
>> -   If any partition "UUID" no exists then it is randomly generated.
>> +   The fields 'uuid' and 'uuid_disk' are optional if CONFIG_RANDOM_UUID
>> is
>> +   enabled. A random uuid will be used if omitted or they point to an
>> empty/
>> +   non-existent environment variable. The environment variable will be
>> set to
>> +   the generated UUID.
>
>
> The things from the above comment are implemented at present in mainline.

Partially yes, but as presently worded it did not make sense to me. It
took me some time to figure out I had to define env variables for each
uuid. So I expanded the text so the next person is not scratching
their head to get this to work.

>
>>
>>   2. Define 'CONFIG_EFI_PARTITION' and 'CONFIG_CMD_GPT'
>>
>>
>
>
> If you want drop saving the uuid to env, then you can do it by modify the
> extract_env() function (diff):
>
> +#ifdef CONFIG_RANDOM_UUID_SKIP_SETENV
> +               e = strdup(uuid_str);
> +#else
>                 setenv(s, uuid_str);
> -
>                 e = getenv(s);
> +#endif
>
>
> I would prefer introduce the new config like *SKIP_SETENV*, rather than drop
> this feature at all, since somebody could use it.

I did not drop the feature as both saving to env or not are supported
and I see little reason to make it compile time, but I will look
whether I can move some of this to extract_env.

Rob