On 4/26/2013 4:51 PM, ANDY KENNEDY wrote:
From: Filippo ARCIDIACONO [mailto:[email protected]]
On 4/26/2013 5:30 AM, ANDY KENNEDY wrote:
I'm attempting to link static an app that contains backtrace. I
set LDFLAGS to "-lubacktrace -ldl" and I get a viable file which
does run. The app crashes. During the call to backtrace, I get
an error:
libgcc_s.so.1 must be installed for backtrace to work
I have attempted to launch the app with LD_LIBRARY_PATH, however,
it appears that this has an unobtainable path:
~/working/uClibc-0.9.33.2$ grep -R __LDSO_LIBRARY_PATH__ .
./ldso/libdl/libdl.c:#if !defined SHARED && defined __LDSO_LIBRARY_PATH__
Does anyone know why the __LDSO_LIBRARY_PATH__ is here?
Indeed there was a typo error in commit
e4aa966cf25e83cd0c72f34f7855a995ff93944d
</uClibc/commit/ldso/libdl/libdl.c?id=e4aa966cf25e83cd0c72f34f7855a995ff93944d>.
It should be __LDSO_LD_LIBRARY_PATH__, it has been introduced to disable
the use of
LD_LIBRARY_PATH on hardened systems.
We take care to fix it soon.
Thanks,
Andy
Regards,
Filippo
To answer Carmelo's question:
123456789012345678901234567890123456789012345678901234567890123456789012
This code can never be reached through a standard build of uClibc.
Using CrossTool-NG, I have no way to affect the #defines of the build,
thus I would be unable to -D__LDSO_LD_LIBRARY_PATH__ and, even with
Filippo's suggested changes, this code can still not be reached.
You have to enable LDSO_LD_LIBRARY_PATH=y in your .config, then when you
build the uClibc,
__LDSO_LD_LIBRARY_PATH__ will be defined in uClibc_config.h, as
"#define __LDSO_LD_LIBRARY_PATH__ 1", this is automatically
included by features.h, so you don't need to pass any
"-D__LDSO_LD_LIBRARY_PATH__"
to the build system.
/work/uClibc-0.9.33.2# grep -R --color __LDSO_LD_LIBRARY_PATH__ .
./ldso/ldso/ldso.c:#ifdef __LDSO_LD_LIBRARY_PATH__
./ldso/ldso/ldso.c:#ifdef __LDSO_LD_LIBRARY_PATH__
./ldso/ldso/ldso.c:#ifdef __LDSO_LD_LIBRARY_PATH__
./ldso/ldso/ldso.c:#ifdef __LDSO_LD_LIBRARY_PATH__
./ldso/ldso/dl-elf.c:#ifdef __LDSO_LD_LIBRARY_PATH__
./ldso/libdl/libdl.c:#ifdef __LDSO_LD_LIBRARY_PATH__
It is _used_ all over the place, but there is never a time when it is
_SET_. There is no way to get to any of the code that this #define
protects. Should we put in a config option for this somewhere, or set
this variable if for building these libraries as the static libraries?
This code will not exist in the libdl.a library.
As far as a test case goes, no I don't have one to share at the moment,
and I'm pressed for time getting this done, but I'll get one for you
later.
At the moment, however, what can we do to make it so this is not
unreachable code?
Simply fix the typo error as described in my previous comment.
Andy
Filippo
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