> On Jul 16, 2018, at 7:51 AM, Daniel Kiper <daniel.ki...@oracle.com> wrote:
>
> Sorry for late reply but I was busy with other stuff.
>
> On Thu, Jun 21, 2018 at 01:46:46PM -0600, Eric Snowberg wrote:
>>> On Jun 21, 2018, at 10:58 AM, Daniel Kiper <daniel.ki...@oracle.com> wrote:
>>> On Fri, Jun 15, 2018 at 09:58:56AM -0600, Eric Snowberg wrote:
>>>>> On Jun 15, 2018, at 6:02 AM, Daniel Kiper <daniel.ki...@oracle.com> wrote:
>>>>> On Wed, May 30, 2018 at 04:55:22PM -0700, Eric Snowberg wrote:
>
> [...]
>
>>>>>> +static char *
>>>>>> +replace_escaped_commas (char *src)
>>>>>> +{
>>>>>> + char *iptr;
>>>>>> +
>>>>>> + if (src == NULL)
>>>>>> + return NULL;
>>>>>> + for (iptr = src; *iptr; )
>>>>>> + {
>>>>>> + if ((*iptr == '\\') && (*(iptr + 1) == ','))
>>>>>> + {
>>>>>> + *iptr++ = '_';
>>>>>> + *iptr++ = '_';
>>>>>> + }
>>>>>> + iptr++;
>>>>>> + }
>>>>>> +
>>>>>> + return src;
>>>>>> +}
>>>>>> +
>>>>>> +static int
>>>>>> +count_commas (const char *src)
>>>>>> +{
>>>>>> + int count = 0;
>>>>>> +
>>>>>> + for ( ; *src; src++)
>>>>>> + if (*src == ',')
>>>>>> + count++;
>>>>>> +
>>>>>> + return count;
>>>>>> +}
>>>>>> +
>>>>>> +static void
>>>>>> +escape_commas (const char *src, char *dest)
>>>>>
>>>>> I am confused by this play with commas. Could explain somewhere
>>>>> where this commas are needed unescaped, escaped, replaced, etc.
>>>>> Could not we simplify this somehow?
>>>>
>>>> I’m open for recommendations.
>>>
>>> Great! However, I need more info which layer need what WRT ",”,
>>
>> AFAIK all layers above expect it:
>> https://www.gnu.org/software/grub/manual/grub/grub.html#Device-syntax
>>
>> Everything above this driver expects it to be escaped. Obviously when
>
> Do you mean from the command line?
This goes much further than the command line. For example, it is built right
into the disk driver. Look at grub-core/kern/disk.c: 544
/* Return the location of the first ',', if any, which is not
escaped by a '\'. */
static const char *
find_part_sep (const char *name)
{
const char *p = name;
char c;
while ((c = *p++) != '\0')
{
if (c == '\\' && *p == ',')
p++;
else if (c == ',')
return p - 1;
}
return NULL;
}
When the obdisk driver discovers a disk, it must put the disk name in the
proper format. Otherwise when grub_disk_open takes place later on, the wrong
disk name will eventually get sent back to the obdisk driver.
> If yes could you give an example with
> proper escaping?
>
>> the driver talks to the actual hardware these devices can not have the
>> escaped names.
>
> OK but this is not clear. So, please add a comment explaining it in
> the code somewhere.
Ok
>
>>> how often this conversions must be done, why you have chosen that
>>> solution, etc. Then I will try to optimize solution a bit.
>>
>> Under normal circumstances it only takes place once per disk as they
>> are enumerated. All disks are cached within this driver so it should
>> not happen often. That is why I store both versions so I don’t have
>> to go back and forth. Look at the current driver ofdisk. It has a
>> function called compute_dev_path which does this conversion on every
>> single open (grub_ofdisk_open). That does not happen with this new
>> driver. IMHO this is a much more optimized solution than the current
>> driver.
>
> Then OK. However, this have to be explained somewhere in the code.
> Additionally, I think that proper variable naming would help too,
> e.g. name and name_esc. And I would do this:
> - s/decode_grub_devname/unescape_grub_devnam/,
> - s/encode_grub_devname/escape_grub_devname/,
> - extract unscaping code to the unescape_commas() function;
> even if it is called once; just for the completeness.
Ok
>
> What is replace_escaped_commas()? Why do we need that function?
It is a convenience function for the end-user, so they can access a disk
without having to understand all this escaping when they want to use one thru
the shell.
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