[CRIU] [PATCH 1/3]v3 libcriu: criu_dump_me() and library header

[Ruslan Kuprieiev]

On 08/29/2013 11:21 PM, Pavel Emelyanov wrote:
> On 08/29/2013 11:08 PM, Ruslan Kuprieiev wrote:
>> Hi!
>>
>> Patch 1\3 contains criu_dump_me() for library and library header.
>>          -- criu_dump_me() gets an argument of  type struct criu_dump_args
>> from user program,
>>            processes it and sends request to criu through unix domain
>> socket.
>>            Then, it gets flag from criu and returns it back to program.
>>          -- libcriu.h contains definitions of flags, struct
>> criu_dump_args etc.
>>             So, it is to be used in user program.
>>
>> Signed-off-by: Ruslan Kuprieiev <kupruser at gmail.com>
>>
>
>> +int criu_dump_me(struct criu_dump_args *arg)
>> +{
>> +	int socket_fd;
>> +	int ret, c;
>> +	struct sockaddr_un server_addr;
>> +	socklen_t server_addr_len;
> I'm trying to imagine how this all should work when a user that has some
> 3rd party app linked with v0.7's libcriu.so upgrades criu and has v0.8's
> one with criu_dump_args extended.
>
> In his software the new "tail" of this structure is not seen (as hi had it
> compiled against old headers with shorted struct). Thus we'd see uninitialized
> data here in the library and have no idea how to check this.
>
> I think we need the criu_alloc_args() call that will call malloc() with
> proper size and zeroify the whole structure.
>
Ok, i will fix it.
By the way, maybe i should add version check? (maybe, after i fix what i 
should fix, and first patch will be applied)
Correct me, if i'm mistaken.
I should add criu_check_version(), that must be called right after 
connect to socket.
It should send version of library and recv "true" if 
libversion<=criuversion or "false" if libversion>criuversion.
Also add some CRIU_OLD_VERSION macro to return for "false" case.