Re: question on ebl openbackend dlopen()

[Tony Jones <tonyj at suse dot de>]

On 12/14/2011 01:21 PM, Roland McGrath wrote:
> Probably nobody has really used static linking for libdw before.
> We wouldn't recommend it.

Indeed.   The usage in question comes from the makedumpfile package
(http://sourceforge.net/projects/makedumpfile).  They actually link 
everything using --static .... "$(CC) $(CFLAGS) $(LDFLAGS) $(OBJ_PART) 
$(OBJ_ARCH) -o $@ $< -static -ldw -lbz2 -lebl -ldl -lelf -lz"

I guess someone at our end (in an attempt to reduce the size of the 
kdump initrd) modified this to a combination of -Wl,-Bstatic for the 
elfutils stuff and -Wl,-Bdynamic for the remaining libs.

> Since the library has no way to know where you're installing a program you
> link it into, the $ORIGIN methods are not really viable.  Resorting to an
> absolute file name in the library would be dismal.

Agreed.

Tangentally: The whole dlopen() - to load the backend - seems fairly 
non-static friendly, i.e no way to statically incorporate these 
elements. No argument, I just wanted to verify I wasn't missing something.

> The library tries the unadorned DSO name if the $ORIGIN name fails.
> So you can just build your program with an appropriate DT_RUNPATH,
> as we do for libdw.so itself (see libdw/Makefile.am).

Thanks Roland, I'll try this.   Appreciate the reply.

Tony