libcap: fix static linking issue
PATCH 1/1 libcap: fix static linking issue
Add -fPIC flag
Fixes:
http://autobuild.buildroot.net/results/619bceb3491ecd2ed4e1ae552fdb237a0ed2fa47/
--- package/libcap/libcap.mk | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
package/libcap/libcap.mk +6 -1
@@ -25,10 +25,15 @@ endif # we don't have host-attr HOST_LIBCAP_DEPENDENCIES = +ifeq ($(BR2_PREFER_STATIC_LIB),y) +LIBCAP_LDFLAGS=-fPIC +endif + define LIBCAP_BUILD_CMDS $(TARGET_MAKE_ENV) $(TARGET_CONFIGURE_OPTS) $(MAKE) -C $(@D) \ LIBATTR=$(LIBCAP_HAVE_LIBATTR) BUILD_CC="$(HOSTCC)" \ - BUILD_CFLAGS="$(HOST_CFLAGS)" + BUILD_CFLAGS="$(HOST_CFLAGS)" \ + LDFLAGS="$(LIBCAP_LDFLAGS)" endef define LIBCAP_INSTALL_STAGING_CMDS
Signature · 1 line
1.8.4
PATCH 1/1 libcap: fix static linking issue
Dear Romain Naour,
Quoted 15 lines · Romain Naour
Add -fPIC flag
Fixes:
http://autobuild.buildroot.net/results/619bceb3491ecd2ed4e1ae552fdb237a0ed2fa47/Signed-off-by Romain Naour <[email protected]>--- package/libcap/libcap.mk | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)package/libcap/libcap.mk +0
-0
package/libcap/libcap.mk endif · line 30
Quoted 6 lines
package/libcap/libcap.mk +3
-0@@ -25,10 +25,15 @@ endif # we don't have host-attr HOST_LIBCAP_DEPENDENCIES = +ifeq ($(BR2_PREFER_STATIC_LIB),y) +LIBCAP_LDFLAGS=-fPIC +endif
This seems really weird, because normally, we would expect exactly the
opposite: position independent code is needed for shared libraries, not for static libraries.
Thomas
Signature · 3 lines
Thomas Petazzoni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com
PATCH 1/1 libcap: fix static linking issue
Hi Thomas,
----- Mail original -----
| De: "Thomas Petazzoni" <[email protected]> | ?: "Romain Naour" <[email protected]> | Cc: "buildroot" <[email protected]> | Envoy?: Dimanche 6 Octobre 2013 23:29:54 | Objet: Re: [Buildroot] [PATCH 1/1] libcap: fix static linking issue | | Dear Romain Naour, | | On Sun, 06 Oct 2013 22:10:24 +0200, Romain Naour wrote: | > Add -fPIC flag | > | > Fixes: | > http://autobuild.buildroot.net/results/619bceb3491ecd2ed4e1ae552fdb237a0ed2fa47/ | > | > Signed-off-by: Romain Naour <[email protected]> | > --- | > package/libcap/libcap.mk | 7 ++++++- | > 1 file changed, 6 insertions(+), 1 deletion(-) | > | > diff --git a/package/libcap/libcap.mk b/package/libcap/libcap.mk | > index 16afaef..6248fed 100644 | > --- a/package/libcap/libcap.mk | > +++ b/package/libcap/libcap.mk | > @@ -25,10 +25,15 @@ endif | > # we don't have host-attr | > HOST_LIBCAP_DEPENDENCIES = | > | > +ifeq ($(BR2_PREFER_STATIC_LIB),y) | > +LIBCAP_LDFLAGS=-fPIC | > +endif | | This seems really weird, because normally, we would expect exactly | the | opposite: position independent code is needed for shared libraries, | not | for static libraries.
Ok, I'll take the problem from the beginning.
Sorry for that mistake.
Best regards,
Romain
| | Thomas | -- | Thomas Petazzoni, Free Electrons | Embedded Linux, Kernel and Android engineering | http://free-electrons.com |
PATCH 1/1 libcap: fix static linking issue
Dear Romain Naour,
Quoted 10 lines · Romain Naour
| > +ifeq ($(BR2_PREFER_STATIC_LIB),y) | > +LIBCAP_LDFLAGS=-fPIC | > +endif | | This seems really weird, because normally, we would expect exactly | the | opposite: position independent code is needed for shared libraries, | not | for static libraries.
Quoted 2 lines
Ok, I'll take the problem from the beginning.
Sorry for that mistake.
Note that I'm not sure about what I said, but having to build with -fPIC in the static lib case seems really strange.
Thanks!
Thomas
Signature · 3 lines
Thomas Petazzoni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com
PATCH 1/1 libcap: fix static linking issue
Hi,
Le 08/10/2013 10:13, Thomas Petazzoni a ?crit :
Quoted 17 lines
Dear Romain Naour,
Quoted 10 lines · Romain Naour
| > +ifeq ($(BR2_PREFER_STATIC_LIB),y) | > +LIBCAP_LDFLAGS=-fPIC | > +endif | | This seems really weird, because normally, we would expect exactly | the | opposite: position independent code is needed for shared libraries, | not | for static libraries.Quoted 2 lines
Ok, I'll take the problem from the beginning.
Sorry for that mistake.
Quoted 7 lines
Note that I'm not sure about what I said, but having to build with -fPIC in the static lib case seems really strange.
Thanks!
Thomas
You're right, the static lib isn?t built with -fPIC. But the libcap build system build the static and shared libraries, even if you don't want one of them.
The build failure [1] is caused by the missing -fPIC during the build of libcap.so.2.22
So, we may add -fPIC if BR2_PREFER_STATIC_LIB=y and the shared lib is build correctly (ok it's weird)
Or add a patch for enable/disable separately the static/shared build.
Best regards,
Romain Naour
[1] http://autobuild.buildroot.net/results/619bceb3491ecd2ed4e1ae552fdb237a0ed2fa47/
PATCH 1/1 libcap: fix static linking issue
Dear Romain Naour,
Quoted 9 lines · Romain Naour
You're right, the static lib isn?t built with -fPIC. But the libcap build system build the static and shared libraries, even if you don't want one of them.
The build failure [1] is caused by the missing -fPIC during the build of libcap.so.2.22
So, we may add -fPIC if BR2_PREFER_STATIC_LIB=y and the shared lib is build correctly (ok it's weird)
Or add a patch for enable/disable separately the static/shared build.
If BR2_PREFER_STATIC_LIB=y, then not shared library should be built at all. Even though the naming of the option doesn't make it clear for the moment.
And therefore, when BR2_PREFER_STATIC_LIB=y, passing -fPIC should not be needed, as we're building only static libraries.
I had a quick look at libcap, and we can easily build only the static or shared library by doing the $(MAKE) only in $(@D)/libcap, and using the libcap.a and libcap.so targets. But the install target is not really adapted to that, so we would have to install things manually.
Maybe a little patch to the libcap/Makefile which understands BUILD_STATIC and BUILD_SHARED variables would be good.
Best regards,
Thomas
Signature · 3 lines
Thomas Petazzoni, CTO, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com
PATCH 1/1 libcap: fix static linking issue
In reply to Romain NaourDear Romain Naour,
Quoted 6 lines · Romain Naour
Add -fPIC flag
Fixes:
http://autobuild.buildroot.net/results/619bceb3491ecd2ed4e1ae552fdb237a0ed2fa47/Signed-off-by Romain Naour <[email protected]>
I've just sent a patch which I believe is a better fix than this one. The problem was that libcap was building the shared library unconditionally. By adjusting the libcap build system, we can make it build only the static library, and therefore make things work properly.
Best regards,
Thomas
Signature · 3 lines
Thomas Petazzoni, CTO, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com
PATCH 1/1 libcap: fix static linking issue
Le 01/11/2013 18:48, Thomas Petazzoni a ?crit :
Quoted 9 lines
Dear Romain Naour,
Quoted 6 lines · Romain Naour
Add -fPIC flag
Fixes:
http://autobuild.buildroot.net/results/619bceb3491ecd2ed4e1ae552fdb237a0ed2fa47/Signed-off-by Romain Naour <[email protected]>
Quoted 8 lines
I've just sent a patch which I believe is a better fix than this one. The problem was that libcap was building the shared library unconditionally. By adjusting the libcap build system, we can make it build only the static library, and therefore make things work properly.
Best regards,
Thomas
Hi Thomas,
I haven't take time to rework on this path :-/
Thanks.
Best regards,
Romain