Re: [PATCH] Add implicit lib requirements to LDLIBS

[Joshua Brindle <jbrindle@tresys.com>]

Eamon Walsh wrote:
> On 03/30/2010 05:08 PM, Joshua Brindle wrote:
>> Fedora 13 changed their linker behavior to not link indirect libraries.
>> See information at: http://fedoraproject.org/wiki/UnderstandingDSOLinkChange
>>
>
> I skimmed over semodule.c and setsebool.c and I didn't see any
> references to bzip2 or ustr symbols.  My reading of the article suggests
> the below fix should only be needed if that were the case.  Most likely
> I missed them?
>

The link above is confusing. The change was made so that people who 
_did_ use eg., libxml but didn't explicitly link against it would have 
to do so even if other libraries they link against already did.

In our case it means that anything libsemanage needs semodule and 
setsebool will also need to link against explicitly.

Here is another page about the "feature":
http://fedoraproject.org/wiki/Features/ChangeInImplicitDSOLinking

The summary pretty much covers it I think:
""Change DSO-linking semantics of the gcc compiler. Previously calls to 
the linker (ld) from gcc would result in dangerous default behaviour 
where ld would attempt to implicitly satisfy link requirements. The 
proposed change will prevent ld from automatically searching in the 
dependencies of linked objects.""

> Without this patch, do you get the linker error that says to add them?
>

Yes. It complains about missing bz2 and ustr symbols on my F13 system.

>
>
>> Resent, it doesn't look like it made it to the list the first time (and the subject had a typo)
>>
>> Signed-off-by: Joshua Brindle<jbrindle@tresys.com>
>> ---
>>   policycoreutils/semodule/Makefile  |    2 +-
>>   policycoreutils/setsebool/Makefile |    2 +-
>>   2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/policycoreutils/semodule/Makefile b/policycoreutils/semodule/Makefile
>> index c96a286..a0bbc21 100644
>> --- a/policycoreutils/semodule/Makefile
>> +++ b/policycoreutils/semodule/Makefile
>> @@ -7,7 +7,7 @@ LIBDIR ?= ${PREFIX}/lib
>>
>>   CFLAGS ?= -Werror -Wall -W
>>   override CFLAGS += -I$(INCLUDEDIR)
>> -LDLIBS = -lsepol -lselinux -lsemanage -L$(LIBDIR)
>> +LDLIBS = -lsepol -lselinux -lsemanage -lbz2 -lustr -L$(LIBDIR)
>>   SEMODULE_OBJS = semodule.o
>>
>>   all: semodule
>> diff --git a/policycoreutils/setsebool/Makefile b/policycoreutils/setsebool/Makefile
>> index 556b780..1b89d5c 100644
>> --- a/policycoreutils/setsebool/Makefile
>> +++ b/policycoreutils/setsebool/Makefile
>> @@ -7,7 +7,7 @@ LIBDIR ?= ${PREFIX}/lib
>>
>>   CFLAGS ?= -Werror -Wall -W
>>   override CFLAGS += -I$(INCLUDEDIR)
>> -LDLIBS = -lsepol -lselinux -lsemanage -L$(LIBDIR)
>> +LDLIBS = -lsepol -lselinux -lsemanage -lbz2 -lustr -L$(LIBDIR)
>>   SETSEBOOL_OBJS = setsebool.o
>>
>>   all: setsebool
>>
>
>

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