[Crash-utility] [RFC] makedumpfile, crash: LZO compression support

[HATAYAMA Daisuke]

Hello Dave,

From: Dave Anderson <anderson at redhat.com>
Subject: Re: [Crash-utility] [RFC] makedumpfile, crash: LZO compression support
Date: Fri, 18 Nov 2011 10:20:26 -0500 (EST)

> 
> 
> ----- Original Message -----
> 
>> > This could involve configure.c, but conceivably it could all be
>> > done within the Makefile itself.  For example, by entering something
>> > like "make compress=lzo2", and then adding this to the Makefile:
>> > 
>> > ifneq ($(compress),)
>> > ifeq ($(compress), lzo2)
>> >   LZOFLAG=-DLZO
>> >   LZOLIB=-llzo2
>> > endif
>> > endif
>> > 
>> > And then the diskdump.c compile line could use ${LZOFLAG}, and the
>> > gdb_merge stanza could include ${LZOLIB}.
>> > 
>> 
>> Thanks for accepting the request and for detailed instructions.
>> 
>> I'll reflect these configuration logic in the next patch.
> 
> Actually, thinking more about it, I prefer the second solution:
> 
>> On the other hand, the capability of dynamically adding an optional
>> library could be a useful feature in general -- not only for LZO 
>> compression support, but for other things in the future.
>>
>> I'm thinking that we could allow the user create an "extralibs" file
>> in the top-level directory, and then build_configure() in configure.c
>> could read it and dynamically create the LDFLAGS= line in the Makefile.
>> Currently LDFLAGS can only be modified manually, but the -static example 
>> hasn't worked for a long time, and should be removed.
> 
> Then the only issue would be the extra -DLZO to be passed to diskdump.c.
> Since any additional library would pretty much always require a conditional
> function call or other library-specific reference, a general purpose
> "extracflags" file could also be created and read by build_configure(),
> and its contents appended to the Makefile's TARGET_CFLAGS line.  
> 
> With "extralibs" and "extracfiles", we would have a general-purpose 
> solution for adding optional libraries for use by both the top-level
> crash sources as well as by extension modules that are built within 
> the extensions sub-directory.  It would also negate the need to always
> have to enter special "make ..." command every time -- instead just
> create the "extralibs" and "extracflags" files, and it gets done 
> automatically.
> 

Should I post the patch after this mechanism is prepared?

And anyway I'm going to post the patch after makedumpfile accepts the
corresponding patch.

Thanks.
HATAYAMA, Daisuke