Re: [libvirt] [PATCH] tests: link virpcimock with utils

On Mon, Apr 10, 2017 at 01:18:05PM +0200, Michal Privoznik wrote: > On 04/10/2017 01:04 PM, Daniel P. Berrange wrote: > > On Mon, Apr 10, 2017 at 01:00:58PM +0200, Michal Privoznik wrote: > >> On 04/10/2017 09:52 AM, Pavel Hrdina wrote: > >>> In virpcimock we use some functions from utils so we should link > >>> utils library to provide required symbols. > >>> > >>> Signed-off-by: Pavel Hrdina <phrdina(a)redhat.com&gt; > >>> --- > >>> tests/Makefile.am | 3 ++- > >>> 1 file changed, 2 insertions(+), 1 deletion(-) > >>> > >>> diff --git a/tests/Makefile.am b/tests/Makefile.am > >>> index 279e9b7da8..8b9bba31ce 100644 > >>> --- a/tests/Makefile.am > >>> +++ b/tests/Makefile.am > >>> @@ -1131,7 +1131,8 @@ virpcimock_la_SOURCES = \ > >>> virpcimock.c > >>> virpcimock_la_CFLAGS = $(AM_CFLAGS) > >>> virpcimock_la_LDFLAGS = $(MOCKLIBS_LDFLAGS) > >>> -virpcimock_la_LIBADD = $(MOCKLIBS_LIBS) > >>> +virpcimock_la_LIBADD = $(MOCKLIBS_LIBS) \ > >>> + ../src/libvirt_util.la > >> > >> You forgot to include $(PROBES_O). But even with that added in, this will > >> not fly. While you make it work under libvirt it fails without it because > >> 'stat' is undefined but called. Look into virtestmock.c for explanation. > >> > >> I'm not sure how to address this issue. I know about it for quite some time > >> now but all my previous attempts to fix it (including this one) failed. I've > >> tried to mimic what virtestmock.c does, but without any luck. > > > > What is the actual build problem with the virpcimock ? It seems to work > > fine for me right now. > > It does build fine. You want to run it under valgrind: > > libvirt.git/tests $ ../run valgrind --trace-children=yes ./virpcitest > ==30672== Memcheck, a memory error detector > ==30672== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al. > ==30672== Using Valgrind-3.12.0 and LibVEX; rerun with -h for copyright info > ==30672== Command: libvirt.git/tests/.libs/virpcitest > ==30672== > valgrind: symbol lookup error: libvirt.git/tests/.libs/virpcimock.so: undefined symbol: virFree > > > > > > > FWIW, the original intenion was that the mock impls should not use any > > libvirt APIs, just pure POSIX / Linux APIs, so as to avoid dependancies > > which could end up being circular. > > Yeah, I was just about to suggests this. However, in general would > it be a problem if a mock library would link with say libvirt_utils > statically? That way we shouldn't have any dependency problems, > should we? Yep, static linking makes you immune from LD_PRELOADs. The one caveat is about global data & any 3rd party library initialization though. eg You'd now have 2 copies of any global variables, and if you trigger code that initializes 3rd party libraries that'd get run twice. Probably ok if we're only using very simple things like virfile & virstring but if we get into the more advanced modules it could cause trouble.