Re: [Xen-devel] [PATCH 3 of 5] blktap2: fix vhd compilation under uclibc

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Wed, 2011-12-21 at 10:15 +0000, Roger Pau Monnà wrote:
> 2011/12/21 Ian Campbell <Ian.Campbell@xxxxxxxxxx>:
> > On Tue, 2011-12-20 at 17:55 +0000, Roger Pau Monnà wrote:
> >> Hello,
> >>
> >> I've added -liconv to blktap2/vhd/lib, and succesfully compiled and
> >> linked the library. The output from ldd libvhd.so shows:
> >>
> >> checking sub-depends for '/lib/libuuid.so.1'
> >> checking sub-depends for '/usr/lib/libiconv.so.2'
> >> checking sub-depends for '/lib/libc.so.0.9.32'
> >> checking sub-depends for '/lib/ld64-uClibc.so.0.9.32'
> >>       libuuid.so.1 => /lib/libuuid.so.1 (0x00000000)
> >>       libiconv.so.2 => /usr/lib/libiconv.so.2 (0x00000000)
> >>       libc.so.0.9.32 => /lib/libc.so.0.9.32 (0x00000000)
> >>       ld64-uClibc.so.0.9.32 => /lib/ld64-uClibc.so.0.9.32 (0x00000000)
> >>       not a dynamic executable
> >>
> >> Then I've compiled and linked vhd tools (vhd-util and vhd-update)
> >> without -liconv, since vhd tools doesn't use any iconv functions. They
> >> compile fine, but when I try to execute them I get the following
> >> error:
> >>
> >> vhd-util: symbol 'libiconv_open': can't resolve symbol
> >>
> >> If I do a ldd of vhd-util:
> >>
> >>       libvhd.so.1.0 => /usr/lib/libvhd.so.1.0 (0x7699efaf4000)
> >>       libc.so.0.9.32 => /lib/libc.so.0.9.32 (0x7699ef88c000)
> >>       libuuid.so.1 => /lib/libuuid.so.1 (0x7699ef689000)
> >>       ld64-uClibc.so.0.9.32 => /lib/ld64-uClibc.so.0.9.32 (0x7699efd10000)
> >>
> >> How come libiconv is not linked to the application if libvhd is?
> >
> > Can you post the complete link line for each stage?
> >
> > Are you sure that /usr/lib/libvhd.so.1.0 is the same one you just built
> > and linked against? Is there a chance you have linked against something
> > in the build directory which did not get properly installed?
> 
> Sorry, I'm just stupid, today I've realized what the problem was. It
> was linked against and old /usr/lib/libvhd.so which was not compiled
> with -liconv.

Great.

> 
> > Running
> >        objdump -p <object> | egrep NEEDED\|SONAME
> > for the library (both build dir and installed copies) and binary would
> > be interesting.
> >
> > It seems like either this is a bug in uClibc's dynamic linker or my
> > expectation of how these sorts of transitive library dependencies work
> > has been set too high by glibc...
> >
> >>  And
> >> what's most strange, why is the link to libuuid keep, but not the one
> >> to libiconv?
> >
> > Yes, that is strange.
> 
> I still don't get the libuuid thing, but it works just fine now.

Presumably the old libvhd.so not compiled against -liconv _was_ compiled
with -luuid.

Ian.

> 
> > Ian.
> >



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