[lttng-dev] Odd dependency for lttng-ust - resolved

[Thibault, Daniel]

-----Message d'origine-----
Date: Mon, 21 Jan 2013 14:34:29 -0500
Subject: Re: [lttng-dev] Odd dependency for lttng-ust
-----Message d'origine (intérieur)-----
De?: Mathieu Desnoyers [mailto:mathieu.desnoyers at efficios.com] 
Envoy??: 21 janvier 2013 13:39

As the error messages suggests, please try:
LDFLAGS=-L/usr/local/lib ./configure
instead of "./configure"

Mathieu
-----Fin du message d'origine (intérieur)-----
   Interesting, that prefix does allow configure to complete successfully.  lttng-tools runs into the same problem as lttng-ust, and requires the same LDFLAGS prefix for its configure.  No other problems arise.

   So how do we fix userspace-rcu so the bootstrap -configure - make - install sequence doesn't run into this problem?  I'm presuming here that userspace-rcu's install needs to be touched up.  Or maybe lttng-ust's (and lttng-tools's) bootstrap.

   (It's a problem because the ReadMe for the lttng-ust and lttng-tools packages stipulate a plain ./configure invocation: as they currently stand, the instructions fail)
-----Fin du message d'origine-----

   I've finally stumbled onto what was causing ./configure to fail for lttng-ust and lttng-tools.

   According to the ld-linux man pages, the Linux default library/header paths are just /lib and /usr/lib: they do not include /usr/local/lib.  However, /etc/ld.so.conf.d/libc.conf (installed by the Ubuntu libc-bin package) adds /usr/local/bin to the system loader's path, so any application that relies on /usr/local/bin libraries will find them.  Why does ./configure fail, then?

   It turns out this particular failure is a known bug (http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42756, January 2010) with the gold linker from the binutils-gold package (specified by the lttng-tools ReadMe): unlike the linker it replaces, gold's linker does not look into /usr/local/lib by default and ignores the ld.so.conf instructions.  Hence the explicit LDFLAGS=-L/usr/local/lib prefix requirement.

   Until this old gold bug is fixed (which looks unlikely considering its age), maybe each package's configure.ac could be made to explicitly look into /usr/local/lib when /lib and /usr/lib fail?  Or the ReadMe files of lttng-ust and lttng-tools could be modified to mention the workaround?

Daniel U. Thibault
R & D pour la défense Canada - Valcartier (RDDC Valcartier) / Defence R&D Canada - Valcartier (DRDC Valcartier)
Cyber sécurité pour les missions essentielles (CME) / Mission Critical Cyber Security (MCCS)
Protection des systèmes et contremesures (PSC) / Systems Protection & Countermeasures (SPC)
2459 route de la Bravoure
Québec, QC  G3J 1X5
CANADA
Vox : (418) 844-4000 x4245
Fax : (418) 844-4538
NAC : 918V QSDJ <http://www.travelgis.com/map.asp?addr=918V%20QSDJ>
Gouvernement du Canada / Government of Canada
<http://www.valcartier.drdc-rddc.gc.ca/>