It looks like Vinay didn't get a response when posting in 2013. A couple
things to keep in mind though:
- protobufs are raw binary data, and they can contain NULL bytes. In
Vinay's message above, GDB is probably treating the serialized protos as
text strings, and so will stop printing at the first NULL byte. You need to
get GDB to print the entire binary proto, which will probably require
having an explicit length for the string and passing that to GDB's printing
routine somehow.
- protoc --decode_raw expects its input in binary format. So passing it
input like 0?)\224\002\177 won't do the right thing -- that is a text
rendering of binary data. You could use printf to convert this to real
binary data:
$ printf "0?)\224\002\177" > binary_data
But that proto still fails to parse with --decode_raw, probably because it
is incomplete due to a NULL byte in the middle of the proto.
Hope this helps,
Josh
On Wednesday, February 3, 2016 at 1:37:40 PM UTC-8, tarun sharma wrote:
>
> Hi Vinay
>
> I am facing the same problem, I am reading protobuf data from a coredump
> and I need to decode it to see what values it has, and I am getting the
> same error ("Failed to parse input."). Did you find out a way out?
>
> Thanks!
> Tarun
>
> On Wednesday, 7 August 2013 16:22:58 UTC-7, Vinay Wagh wrote:
>>
>> Hi,
>>
>> I am debugging a core file in gdb and I have the raw encoded data of a
>> message. I want to decode this message to see the values. I tried using
>> --decode_raw with no success. Here is what I am doing
>>
>> (gdb) p $12->send_ctx_.parts[0]
>> $23 = {_ = "0?)\224\002\177", '\000' <repeats 25 times>, "\200"}
>> (gdb) p $12->send_ctx_.parts[1]
>> $24 = {_ = "\000M0\224\002\177", '\000' <repeats 25 times>, "\200"}
>>
>> parts is an array of serialized messages. Now I try
>>
>> vagrant@dev-01:~$ protoc --decode_raw
>> 0?)\224\002\177
>> Failed to parse input.
>>
>> I tried adding that data in a file and tried giving that as input
>>
>> protoc --decode_raw < ~/data.txt
>> Failed to parse input.
>>
>> I thought maybe I need to \000 repeated 25 times followed by a \200 so I
>> tried with that as well and still no luck. I then tried to use the decode
>> instead of decode_raw option by specifying the proto path and the proto
>> file and the message name but it still did not work.
>>
>> I then tried to encode some data and decode it back to see if it works. I
>> entered the values in text form in a file
>> error:OUT_OF_MEMORY,object_id:123,size:4096
>>
>> these are all valid values. I then ran the --encode option specifying the
>> proto path and file
>>
>> protoc --proto_path=/path_to_proto_dir
>> /path_to_proto_dir/proto_file.proto --encode=MessageName < ~/proto.txt
>> ?{?
>>
>> I copied the text as is in to a file and rand --decode on it and it fails
>> with 'Failed to parse input". What am I missing ? How do I use the
>> decode_raw or decode option ? Is there a format the data has to be in for
>> it to be decoded ?
>>
>> Thanks,
>> Vinay
>>
>>
--
You received this message because you are subscribed to the Google Groups
"Protocol Buffers" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to protobuf+unsubscr...@googlegroups.com.
To post to this group, send email to protobuf@googlegroups.com.
Visit this group at https://groups.google.com/group/protobuf.
For more options, visit https://groups.google.com/d/optout.
