[krbdev.mit.edu #6667] Problem with krb5 libcom_err vs. system libcom_err

Mon Feb 22 11:14:24 EST 2010

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>Submitter-Id:	net
>Originator: W. Michael Petullo	
>Organization: The Oakbud Company
>Confidential:	no
>Synopsis:	Problem with krb5 libcom_err vs. system libcom_err
>Severity:	serious
>Priority:	low
>Category:	krb5-build
>Class:		sw-bug
>Release:	1.7
>Environment:
System: OpenWRT Linux-based cross-compile environment
Architecture: MIPS32

>Description:
I am building krb5 within OpenWRT, a Linux/GCC-based cross-compile
environment that targets embedded systems. I have found a problem in
krb5's build system with regard to libcom_err. In my build environment,
there exists both libcom_err.so.3 (in the krb5 tree) and libcom_err.so.2
(installed in the build system library directory). I want to use krb5's
libcom_err.so.3. In fact, libcom_err.so.2 is merely a side affect of
building another package and is not ever installed on the target device.

The makefile for krb5kdc is fine. It contains the following rule:

CC_LINK=$(CC) $(PROG_LIBPATH) $(PROG_RPATH_FLAGS) $(CFLAGS) $(LDFLAGS)

This means that the linker finds libcom_err.so.3 first (-L../lib before
-L/BUILD/SYSTEM/LIBS)

However, the makefiles for the libraries (for example, libkadm5clnt.so)
are broken:

MAKE_SHLIB_COMMAND=$(CC) -shared -fPIC -Wl,-h,$(LIBPREFIX)$(LIBBASE)$(SHLIBSEXT),--no-undefined $(LDFLAGS) -o $@ $$objlist $(SHLIB_EXPFLAGS) -Wl,--version-script binutils.versions && $(PERL) -w $(SRCTOP)/util/export-check.pl $(SHLIB_EXPORT_FILE) $@

Here, $(LDFLAGS) is before $(SHLIB_EXPFLAGS). The result is the
-L/BUILD/SYSTEM/LIBS is before -L../../../lib and the libraries link
against libcom_err.so.2.
>How-To-Repeat:
Set LDCONFIG to point to a directory with libcom_err and build krb5.

>Fix:
diff -u --recursive krb5-1.7-vanilla/src/config/shlib.conf krb5-1.7/src/config/shlib.conf

--- krb5-1.7-vanilla/src/config/shlib.conf      2008-12-08 17:33:07.000000000 -0500
+++ krb5-1.7/src/config/shlib.conf      2010-01-15 22:04:16.345151448 -0500
@@ -409,9 +409,9 @@
        SHLIBEXT=.so
        # Linux ld doesn't default to stuffing the SONAME field...
        # Use objdump -x to examine the fields of the library
-       LDCOMBINE='$(CC) -shared -fPIC -Wl,-h,$(LIBPREFIX)$(LIBBASE)$(SHLIBSEXT),--no-undefined $(LDFLAGS)'
+       LDCOMBINE='$(CC) -shared -fPIC -Wl,-h,$(LIBPREFIX)$(LIBBASE)$(SHLIBSEXT),--no-undefined'
        #
-       LDCOMBINE_TAIL='-Wl,--version-script binutils.versions && $(PERL) -w $(SRCTOP)/util/export-check.pl $(SHLIB_EXPORT_FILE) $@'
+       LDCOMBINE_TAIL='-Wl,--version-script binutils.versions $(LDFLAGS) && $(PERL) -w $(SRCTOP)/util/export-check.pl $(SHLIB_EXPORT_FILE) $@'
        SHLIB_EXPORT_FILE_DEP=binutils.versions
        # For cases where we do have dependencies on other libraries
        # built in this tree...



