[CRIU] [PATCH 2/4] tools: add criu2text

[Pavel Emelyanov]

On 09/30/2014 02:27 PM, Ruslan Kuprieiev wrote:
> On 30.09.2014 12:54, Pavel Emelyanov wrote:
>> On 09/30/2014 01:47 PM, Ruslan Kuprieiev wrote:
>>> On 30.09.2014 12:14, Pavel Emelyanov wrote:
>>>> On 09/30/2014 01:08 PM, Ruslan Kuprieiev wrote:
>>>>> On 30.09.2014 11:12, Pavel Emelyanov wrote:
>>>>>> On 09/19/2014 05:53 PM, Ruslan Kuprieiev wrote:
>>>>>>> criu2text.py handles cmdline opts, opens files and reads\writes them
>>>>>>> properly. images.py has a dict with MAGIC:pb_entry_type to specify what
>>>>>>> type of pb entry we should read from image with magic MAGIC.
>>>>>>> magic-gen.py parses include/magic.h to get all MAGIC values except
>>>>>>> RAW and V1, because criu2text can't handle them for now.
>>>>>> OK, I like the code, but let's rework the way tool works a little bit.
>>>>>>
>>>>>> 1. Right now, AFAIK, the tool turns one .img file into a set of .txt
>>>>>> ones. Let's make tool convert _one_ file to _one_ file, e.g. core.img
>>>>>> into core.txt. And the syntax should look like this:
>>>>>>
>>>>>> criu2text -i|--in <filename> -o|--out <filename>
>>>>>>
>>>>>> If <filename> == "-", then stdin/stdout is used.
>>>>>>
>>>>>> The conversion from .img to .txt would work automatically, the conversion
>>>>>> back would have to know what kind of image we're working on. For this
>>>>>> the tool can write the magic value as the first line (in a form of a
>>>>>> comment if it makes sense).
>>>>> In early criu2json it worked just as you described =).
>>>>> In json it was easy to create a new message, but in pbtext it is a bit less
>>>>> smooth. Well, we can separate msgs in txt file by special comments, e.g:
>>>>> #0x12345                  magic
>>>>> #0                              №
>>>>> MSG0                          pb entry
>>>>> #1                              №
>>>>> MSG1                          pb entry
>>>>> #2
>>>>> MSG2
>>>>> ........
>>>>>
>>>>> Does it look good to you?
>>>>> Or maybe we should drop № and just leave # as a separator, e.g.:
>>>>> #0x12345
>>>>> MSG0
>>>>> #
>>>>> MSG1
>>>>> #
>>>>> MSG2
>>>>>
>>>>> ?
>>>> Plz, show how the fdinfo-$pid.img would look like in this format.
>>> #0x56213732
>>> #0
>>> id: 1
>>> flags: 0
>>> type: REG
>>> fd: 0
>>> #1
>>> id: 2
>>> flags: 0
>>> type: REG
>>> fd: 1
>>> #2
>>> id: 2
>>> flags: 0
>>> type: REG
>>> fd: 2
>>> #3
>>> id: 3
>>> flags: 1
>>> type: REG
>>> fd: 255
>>>
>>> Well, yeah, doesn't look great.
>> But ready for scripted modification :)
>>
>>> But, if i'll figure out how to add some indent:
>>> #0x56213732
>>> #0
>>>       id: 1
>>>       flags: 0
>>>       type: REG
>>>       fd: 0
>>> #1
>>>       id: 2
>>>       flags: 0
>>>       type: REG
>>>       fd: 1
>>> #2
>>>       id: 2
>>>       flags: 0
>>>       type: REG
>>>       fd: 2
>>> #3
>>>       id: 3
>>>       flags: 1
>>>       type: REG
>>>       fd: 255
>> This is more human-readable. Can we make both outputs be available?
> 
> Sure. Maybe make raw format to look like:
> #magic
> 0x12345
> #0
> MSG
> #1
> MSG
> .....
> ?

Either

#$magic 

or

magic: $magic

No need in two lines for this. The 1st one looks better.


>> If stdio is a terminal, then use the 2nd, if not -- the 1st. And
>> add the --format option with two (for now) meanings "raw" and "nice"
>> (or how is this text called? pbtext?) that forcibly switches between
>> them. In the future we'll be able to extend it to "--format json" :)
> 
> Well, adding --format json doesn't look hard. Btw, json is not that good for
> scripted modification, right? Well, "#magic ... #0 ..." is better, right?

JSON is not for scripting, yes.

>> BTW, in the "nice" version of the output it would be nice to replace
>> the magic with some name, e.g. the criu proto file one.
> 
> Not sure about .proto files. Especially, because we need that magic to 
> identify
> pb entry, not just proto file where it is described. And because we need 
> to write that
> magic back when converting from text to img.
> We might just add pb_entry name, e.g.
> 
> #magic
> 0x12345
> #0 pagemap_head
> MSG
> #1 pagemap_entry
> MSG
> #2
> MSG
> #3
> MSG
> 
> What do you think?


Name of an object is cool in "nice" mode :) But I'd still replace
magic with some name which 1:1 maps to magic.

>>> But I still like better the current "name.img into set of files
>>> name.img.magic name.img.0...":
>>>
>>> $cat fdinfo-2.img.magic
>>> 0x56213732
>>> $cat fdinfo-2.img.0
>>> id: 1
>>> flags: 0
>>> type: REG
>>> fd: 0
>>>
>>> because it looks easier to modify and manage.
>> If a format is non-suitable for shell piplining, it's not easy
>> from my POV :)
> 
> Ok, I see.
> 
>>
>> Thanks,
>> Pavel
>>
>>
> 
> .
>