[Buildroot] [lttng-dev] [PATCH 1/1] Disable liblttng-ust-dl if dlinfo is not available in C library.

[Buildroot] [lttng-dev] [PATCH 1/1] Disable liblttng-ust-dl if dlinfo is not available in C library.

[Romain Naour]

Hi Mathieu,

Le 07/04/2014 22:42, Mathieu Desnoyers a ?crit :
> Merged into master and stable-2.4, thanks!
>
> Mathieu
You're welcome.

Best regards,
Romain Naour

>
> ----- Original Message -----
>> From: "Romain Naour" <romain.naour@openwide.fr>
>> To: lttng-dev at lists.lttng.org
>> Cc: "Romain Naour" <romain.naour@openwide.fr>
>> Sent: Sunday, April 6, 2014 5:02:41 PM
>> Subject: [lttng-dev] [PATCH 1/1] Disable liblttng-ust-dl if dlinfo is not	available in C library.
>>
>> According to uClibc commit [1], dlinfo is not available.
>> To be able to use LTTng UST with uClibc, we need to disable
>> the Dynamic Linker Tracing functionality [2].
>>
>> [1]
>> http://git.uclibc.org/uClibc/commit/?id=f3c9dc499c5c787ddd8c4320f2d44d2ae6e40c22
>> [2] http://lists.lttng.org/pipermail/lttng-dev/2014-February/022423.html
>>
>> Signed-off-by: Romain Naour <romain.naour@openwide.fr>
>> ---
>>   Makefile.am  | 5 ++++-
>>   configure.ac | 3 +++
>>   2 files changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/Makefile.am b/Makefile.am
>> index b79d2dd..c907ff1 100644
>> --- a/Makefile.am
>> +++ b/Makefile.am
>> @@ -4,11 +4,14 @@ SUBDIRS = . include snprintf libringbuffer
>> liblttng-ust-comm \
>>   		liblttng-ust \
>>   		liblttng-ust-ctl \
>>   		liblttng-ust-fork \
>> -		liblttng-ust-dl \
>>   		liblttng-ust-libc-wrapper \
>>   		liblttng-ust-cyg-profile \
>>   		tools
>>   
>> +if HAVE_DLINFO
>> +SUBDIRS += liblttng-ust-dl
>> +endif
>> +
>>   if BUILD_JNI_INTERFACE
>>   SUBDIRS += liblttng-ust-java liblttng-ust-jul
>>   endif
>> diff --git a/configure.ac b/configure.ac
>> index b04d4e3..de6300e 100644
>> --- a/configure.ac
>> +++ b/configure.ac
>> @@ -146,6 +146,9 @@ AC_C_INLINE
>>   AC_FUNC_MALLOC
>>   AC_CHECK_FUNCS([gettimeofday munmap socket strerror strtol sched_getcpu
>>   sysconf])
>>   
>> +AC_CHECK_FUNCS([dlinfo])
>> +AM_CONDITIONAL([HAVE_DLINFO], [test "${ac_cv_func_dlinfo}" = "yes"])
>> +
>>   CFLAGS="-Wall $CFLAGS"
>>   
>>   # URCU
>> --
>> 1.9.0
>>
>>
>> _______________________________________________
>> lttng-dev mailing list
>> lttng-dev at lists.lttng.org
>> http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
>>

[Buildroot] [lttng-dev] [PATCH 1/1] Disable liblttng-ust-dl if dlinfo is not available in C library.

[Yann E. MORIN]

Simon, All,

On 2014-04-08 13:03 -0400, Simon Marchi spake thusly:
> Hi Romain,
> 
> It seems like with that commit, dlinfo is not found even on a glibc
> based system, where it is present.
> 
> See https://bugs.lttng.org/issues/778
> 
> Do you have a suggestion to fix that ?

I think we should use AC_CHECK_DECL instead of AC_CHECK_FUNCS.

dlinfo is in dlfcn.h so we need a check that allows us to include that
header, and we must check for that header first, of course. So, maybe
something like (completely untested, directly written in the mail):

    AC_CHECK_HEADER([dlfcn.h])
    AS_IF([test "${ac_cv_header_dlfcn_h}" = "yes"],
          [AC_CHECK_DECL([dlinfo],,,[dlfcn.h])],
          [ac_cv_have_decl_dlinfo="no"])
    AM_CONDITIONAL([HAVE_DLINFO], [test "${ac_cv_have_decl_dlinfo}" = "yes"])

But I'm no expert in autoconf, so the actual solution may be slightly
different.

Regards,
Yann E. MORIN.

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| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
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[Buildroot] [lttng-dev] [PATCH 1/1] Disable liblttng-ust-dl if dlinfo is not available in C library.

[Romain Naour]

Hi Simon, Yann,

Le 08/04/2014 19:24, Yann E. MORIN a ?crit :
> Simon, All,
>
> On 2014-04-08 13:03 -0400, Simon Marchi spake thusly:
>> Hi Romain,
>>
>> It seems like with that commit, dlinfo is not found even on a glibc
>> based system, where it is present.
>>
>> See https://bugs.lttng.org/issues/778
>>
>> Do you have a suggestion to fix that ?
> I think we should use AC_CHECK_DECL instead of AC_CHECK_FUNCS.
>
> dlinfo is in dlfcn.h so we need a check that allows us to include that
> header, and we must check for that header first, of course. So, maybe
> something like (completely untested, directly written in the mail):
>
>      AC_CHECK_HEADER([dlfcn.h])
>      AS_IF([test "${ac_cv_header_dlfcn_h}" = "yes"],
>            [AC_CHECK_DECL([dlinfo],,,[dlfcn.h])],
>            [ac_cv_have_decl_dlinfo="no"])
>      AM_CONDITIONAL([HAVE_DLINFO], [test "${ac_cv_have_decl_dlinfo}" = "yes"])
>
> But I'm no expert in autoconf, so the actual solution may be slightly
> different.
>
> Regards,
> Yann E. MORIN.
>
Sorry for the mistake, here is a new try:


AC_CHECK_HEADER([dlfcn.h])
AS_IF([test "${ac_cv_header_dlfcn_h}" = "yes"],
     [AC_CHECK_DECLS([RTLD_DI_LINKMAP],,,
         [#define _GNU_SOURCE /* Required on Linux to get GNU extensions */
         #include <dlfcn.h>])
     ],
     [ac_cv_have_decl_RTLD_DI_LINKMAP="no"])
AM_CONDITIONAL([HAVE_DLINFO], [test "${ac_cv_have_decl_RTLD_DI_LINKMAP}" 
= "yes"])


I can't use dlinfo directly here because it isdetected
even if it is not available in uClibc. (detected fromust-dlfcn.h ?)
So, I use RTLD_DI_LINKMAP which is not defined in uClibc.

I'll send the patch later (after doing some test)

Best regards,
Romain Naour