| Message ID | 20170711172624.7516-1-ps.report@gmx.net |
|---|---|
| State | Superseded |
| Headers | show |
Hello, On Tue, 11 Jul 2017 19:26:24 +0200, Peter Seiderer wrote: > Fixes [1]: > > CXXLD v4l2-compliance > .../output/build/libv4l-1.12.5/lib/libv4lconvert/.libs/libv4lconvert.so: undefined reference to `fork' > collect2: error: ld returned 1 exit status > > [1] http://autobuild.buildroot.net/results/7e8/7e8fbd99a8c091d7bbeedd16066297682bbe29fe > > Signed-off-by: Peter Seiderer <ps.report@gmx.net> > --- > The libv4l build for noMMU platforms was enabled with commit 'package/libv4l: > allow build of v4l2 utilities on noMMU platforms' (see [2]). But libv4lconvert uses > fork internally, so all utils linking against fail to build. Fix this by disabling > the utils on noMMU platforms (so keep building all libraries). > > Alternatives would be: > > - disable libv4l on all noMMU platforms (not only the utils), revert a part > of commit [2] > > - create a patch to disable only libv4lconvert (and all dependend utils) > on noMMU platforms > > [2] https://git.buildroot.net/buildroot/commit/?id=f837251785e9389f53d695ddb8a094707865171b Hugues, could you comment on this, since you originally re-enabled libv4l for noMMU architectures ? Thanks! Thomas
Hi Peter, I have tested on STM32 platform running Cortex F family having no MMU, shared libraries are disabled (no dlopen) and no fork supported on our setup. libv4lconvert should not have been built at all, because entire lib/ folder build is conditional to shared library support: * configure.ac AM_CONDITIONAL([WITH_LIBV4L], [test x$enable_libv4l != xno -a x$enable_shared != xno]) * Makefile.am [...] +if WITH_LIBV4L +SUBDIRS += lib +endif But checking your log I see that --enable-shared is set, so it seems that you are supporting shared libraries on no-MMU platform but without fork() support, is my understanding correct ? What you can do to fix build is to force disabling of libs inside libv4l package: package/libv4l/libv4l.mk +ifeq ($(BR2_USE_MMU),) +LIBV4L_CONF_OPTS += --disable-libv4l +endif Hoping that helps. Best regards, Hugues. On 07/11/2017 07:26 PM, Peter Seiderer wrote: > Fixes [1]: > > CXXLD v4l2-compliance > .../output/build/libv4l-1.12.5/lib/libv4lconvert/.libs/libv4lconvert.so: undefined reference to `fork' > collect2: error: ld returned 1 exit status > > [1] http://autobuild.buildroot.net/results/7e8/7e8fbd99a8c091d7bbeedd16066297682bbe29fe > > Signed-off-by: Peter Seiderer <ps.report@gmx.net> > --- > The libv4l build for noMMU platforms was enabled with commit 'package/libv4l: > allow build of v4l2 utilities on noMMU platforms' (see [2]). But libv4lconvert uses > fork internally, so all utils linking against fail to build. Fix this by disabling > the utils on noMMU platforms (so keep building all libraries). > > Alternatives would be: > > - disable libv4l on all noMMU platforms (not only the utils), revert a part > of commit [2] > > - create a patch to disable only libv4lconvert (and all dependend utils) > on noMMU platforms > > [2] https://git.buildroot.net/buildroot/commit/?id=f837251785e9389f53d695ddb8a094707865171b > --- > package/libv4l/Config.in | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/package/libv4l/Config.in b/package/libv4l/Config.in > index e7f78dc70f..61c290f251 100644 > --- a/package/libv4l/Config.in > +++ b/package/libv4l/Config.in > @@ -19,6 +19,7 @@ comment "libv4l JPEG support not enabled" > > config BR2_PACKAGE_LIBV4L_UTILS > bool "v4l-utils tools" > + depends on BR2_USE_MMU # fork(), used in libv4lconvert linked by various utils eg. v4l2-compliance > help > v4l-utils is a collection of various video4linux and DVB utilities. > Enable this if you want to build the following tools: >
Hello Hugues, On Mon, 17 Jul 2017 10:07:07 +0000, Hugues FRUCHET <hugues.fruchet@st.com> wrote: > Hi Peter, > > I have tested on STM32 platform running Cortex F family having no MMU, > shared libraries are disabled (no dlopen) and no fork supported on our > setup. > > libv4lconvert should not have been built at all, because entire lib/ > folder build is conditional to shared library support: > * configure.ac > AM_CONDITIONAL([WITH_LIBV4L], [test x$enable_libv4l != xno -a > x$enable_shared != xno]) > * Makefile.am > [...] > +if WITH_LIBV4L > +SUBDIRS += lib > +endif A little bit confused, one of the patches you introduced changed it to: - without WITH_LIBV4L: no libv4l libraries at all - without WITH_DYN_LIBV4L: only static libraries, no dynamic libraries And from configure --help: --disable-libv4l disable libv4l compilation --disable-dyn-libv4l disable dynamic libv4l support > > But checking your log I see that --enable-shared is set, so it seems > that you are supporting shared libraries on no-MMU platform but without > fork() support, is my understanding correct ? > Yes... > What you can do to fix build is to force disabling of libs inside libv4l > package: > > package/libv4l/libv4l.mk > +ifeq ($(BR2_USE_MMU),) > +LIBV4L_CONF_OPTS += --disable-libv4l > +endif Works, but feels wrong: A package named libv4l enabled and building/installing nothing (except when LIBV4L_UTILS is enabled)... Regards, Peter > > Hoping that helps. > > Best regards, > Hugues. > > On 07/11/2017 07:26 PM, Peter Seiderer wrote: > > Fixes [1]: > > > > CXXLD v4l2-compliance > > .../output/build/libv4l-1.12.5/lib/libv4lconvert/.libs/libv4lconvert.so: undefined reference to `fork' > > collect2: error: ld returned 1 exit status > > > > [1] http://autobuild.buildroot.net/results/7e8/7e8fbd99a8c091d7bbeedd16066297682bbe29fe > > > > Signed-off-by: Peter Seiderer <ps.report@gmx.net> > > --- > > The libv4l build for noMMU platforms was enabled with commit 'package/libv4l: > > allow build of v4l2 utilities on noMMU platforms' (see [2]). But libv4lconvert uses > > fork internally, so all utils linking against fail to build. Fix this by disabling > > the utils on noMMU platforms (so keep building all libraries). > > > > Alternatives would be: > > > > - disable libv4l on all noMMU platforms (not only the utils), revert a part > > of commit [2] > > > > - create a patch to disable only libv4lconvert (and all dependend utils) > > on noMMU platforms > > > > [2] https://git.buildroot.net/buildroot/commit/?id=f837251785e9389f53d695ddb8a094707865171b > > --- > > package/libv4l/Config.in | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/package/libv4l/Config.in b/package/libv4l/Config.in > > index e7f78dc70f..61c290f251 100644 > > --- a/package/libv4l/Config.in > > +++ b/package/libv4l/Config.in > > @@ -19,6 +19,7 @@ comment "libv4l JPEG support not enabled" > > > > config BR2_PACKAGE_LIBV4L_UTILS > > bool "v4l-utils tools" > > + depends on BR2_USE_MMU # fork(), used in libv4lconvert linked by various utils eg. v4l2-compliance > > help > > v4l-utils is a collection of various video4linux and DVB utilities. > > Enable this if you want to build the following tools: > > > _______________________________________________ > buildroot mailing list > buildroot@busybox.net > http://lists.busybox.net/mailman/listinfo/buildroot
diff --git a/package/libv4l/Config.in b/package/libv4l/Config.in index e7f78dc70f..61c290f251 100644 --- a/package/libv4l/Config.in +++ b/package/libv4l/Config.in @@ -19,6 +19,7 @@ comment "libv4l JPEG support not enabled" config BR2_PACKAGE_LIBV4L_UTILS bool "v4l-utils tools" + depends on BR2_USE_MMU # fork(), used in libv4lconvert linked by various utils eg. v4l2-compliance help v4l-utils is a collection of various video4linux and DVB utilities. Enable this if you want to build the following tools:
Fixes [1]: CXXLD v4l2-compliance .../output/build/libv4l-1.12.5/lib/libv4lconvert/.libs/libv4lconvert.so: undefined reference to `fork' collect2: error: ld returned 1 exit status [1] http://autobuild.buildroot.net/results/7e8/7e8fbd99a8c091d7bbeedd16066297682bbe29fe Signed-off-by: Peter Seiderer <ps.report@gmx.net> --- The libv4l build for noMMU platforms was enabled with commit 'package/libv4l: allow build of v4l2 utilities on noMMU platforms' (see [2]). But libv4lconvert uses fork internally, so all utils linking against fail to build. Fix this by disabling the utils on noMMU platforms (so keep building all libraries). Alternatives would be: - disable libv4l on all noMMU platforms (not only the utils), revert a part of commit [2] - create a patch to disable only libv4lconvert (and all dependend utils) on noMMU platforms [2] https://git.buildroot.net/buildroot/commit/?id=f837251785e9389f53d695ddb8a094707865171b --- package/libv4l/Config.in | 1 + 1 file changed, 1 insertion(+)