[lxc-devel] [PATCH] Link against pthread when not on bionic.

[Stéphane Graber]

On 02/18/2013 04:10 PM, Dwight Engen wrote:
> On Mon, 18 Feb 2013 15:46:24 -0500
> Stéphane Graber <stgraber at ubuntu.com> wrote:
> 
>> On 02/18/2013 03:40 PM, Daniel Lezcano wrote:
>>> On 02/18/2013 06:23 PM, Stéphane Graber wrote:
>>>> dpkg spotted that we're not explicitly linking against pthread
>>>> even though we use some of its symbols (sem_*).
>>>
>>> uh ? wait.
>>>
>>> We shouldn't link against the lib pthread.
>>>
>>> I don't think sem_* is a symbol coming from the pthread library.
> 
> Also see commit 5f29734f. I believe we found that nm showed sem_* to be
> coming from libpthread and not librt, in spite of the fact that I've
> seen some (older?) man pages that say "Link with -lrt or -pthread".

nm says that librt doesn't have any symbol here, I guess that's part of
the issue then...

>>>
>>> Could you give the output of dpkg ?
>>
>> From "man sem_open":
>>        Link with -pthread.
>>
>> dpkg-shlibdeps output:
>> dpkg-shlibdeps: warning: symbol sem_post used by
>> debian/liblxc0/usr/lib/x86_64-linux-gnu/liblxc.so.0.9.0.alpha3 found
>> in none of the libraries
>> dpkg-shlibdeps: warning: symbol sem_open used by
>> debian/liblxc0/usr/lib/x86_64-linux-gnu/liblxc.so.0.9.0.alpha3 found
>> in none of the libraries
>> dpkg-shlibdeps: warning: symbol sem_close used by
>> debian/liblxc0/usr/lib/x86_64-linux-gnu/liblxc.so.0.9.0.alpha3 found
>> in none of the libraries
>> dpkg-shlibdeps: warning: symbol sem_init used by
>> debian/liblxc0/usr/lib/x86_64-linux-gnu/liblxc.so.0.9.0.alpha3 found
>> in none of the libraries
>> dpkg-shlibdeps: warning: symbol sem_timedwait used by
>> debian/liblxc0/usr/lib/x86_64-linux-gnu/liblxc.so.0.9.0.alpha3 found
>> in none of the libraries
>> dpkg-shlibdeps: warning: symbol sem_destroy used by
>> debian/liblxc0/usr/lib/x86_64-linux-gnu/liblxc.so.0.9.0.alpha3 found
>> in none of the libraries
>> dpkg-shlibdeps: warning: symbol sem_wait used by
>> debian/liblxc0/usr/lib/x86_64-linux-gnu/liblxc.so.0.9.0.alpha3 found
>> in none of the libraries
>>
>>
>> Looking at pthread.so it appears to provide:
>> sem_init
>> sem_destroy
>> sem_open
>> sem_close
>> sem_unlink
>> sem_getvalue
>> sem_wait
>> sem_trywait
>> sem_timedwait
>> sem_post
>>
>>>>
>>>> Signed-off-by: Stéphane Graber <stgraber at ubuntu.com>
>>>> ---
>>>>  src/lxc/Makefile.am | 2 +-
>>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/src/lxc/Makefile.am b/src/lxc/Makefile.am
>>>> index 8974ca9..a0077aa 100644
>>>> --- a/src/lxc/Makefile.am
>>>> +++ b/src/lxc/Makefile.am
>>>> @@ -115,7 +115,7 @@ liblxc_so_LDFLAGS = \
>>>>  liblxc_so_LDADD = $(CAP_LIBS) $(APPARMOR_LIBS) $(SECCOMP_LIBS)
>>>>  
>>>>  if !IS_BIONIC
>>>> -liblxc_so_LDADD += -lutil -lrt
>>>> +liblxc_so_LDADD += -lutil -lrt -lpthread
>>>>  endif
>>>>  
>>>>  bin_SCRIPTS = \
>>>
>>
>>
> 


-- 
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com

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