[OE-core] [PATCH 3/3] libcap-ng: fix built failure with some external toolchains due to missing pthread

[Christopher Larson]

Testing with https://github.com/stevegrubb/libcap-ng/pull/10 + HAVE_PTHREAD_H conditional now. Thanks.
On Nov 25, 2019, 3:27 PM -0700, Khem Raj <raj.khem at gmail.com>, wrote:
> On Mon, Nov 25, 2019 at 2:13 PM Christopher Larson <kergoth at gmail.com> wrote:
> >
> > From: Christopher Larson <chris_larson at mentor.com>
> >
> > The libcap-ng build doesn't pass -pthread and can fail to link.
> >
>
> perhaps, adding a configure time check for pthread.h would be possible
>
> AC_CHECK_HEADERS(pthread.h, [], [AC_MSG_WARN(pthread.h not found,
> pthread_atfork disabled.)])
>
> then include pthread.h inside conditional like below in source files.
>
> #ifdef HAVE_PTHREAD_H
> #endif
>
>
>
> > Signed-off-by: Christopher Larson <chris_larson at mentor.com>
> > ---
> > meta/recipes-support/libcap-ng/libcap-ng.inc | 1 +
> > .../libcap-ng/revert-pthread_atfork-fix.patch | 56 ++++++++++++++++++++++
> > 2 files changed, 57 insertions(+)
> > create mode 100644 meta/recipes-support/libcap-ng/libcap-ng/revert-pthread_atfork-fix.patch
> >
> > diff --git a/meta/recipes-support/libcap-ng/libcap-ng.inc b/meta/recipes-support/libcap-ng/libcap-ng.inc
> > index aec83896e4..46d37e6807 100644
> > --- a/meta/recipes-support/libcap-ng/libcap-ng.inc
> > +++ b/meta/recipes-support/libcap-ng/libcap-ng.inc
> > @@ -9,6 +9,7 @@ LIC_FILES_CHKSUM = "file://COPYING;md5=94d55d512a9ba36caa9b7df079bae19f \
> >
> > SRC_URI = "http://people.redhat.com/sgrubb/libcap-ng/libcap-ng-${PV}.tar.gz \
> > file://python.patch \
> > + file://revert-pthread_atfork-fix.patch \
> > "
> >
> > SRC_URI[md5sum] = "57dc267e2949cdecb651a929f9206572"
> > diff --git a/meta/recipes-support/libcap-ng/libcap-ng/revert-pthread_atfork-fix.patch b/meta/recipes-support/libcap-ng/libcap-ng/revert-pthread_atfork-fix.patch
> > new file mode 100644
> > index 0000000000..d3f7790b1e
> > --- /dev/null
> > +++ b/meta/recipes-support/libcap-ng/libcap-ng/revert-pthread_atfork-fix.patch
> > @@ -0,0 +1,56 @@
> > +From 81dc82393fae9851397fa5d94094434aa1d5c3d1 Mon Sep 17 00:00:00 2001
> > +From: Christopher Larson <chris_larson at mentor.com>
> > +Date: Thu, 14 Nov 2019 21:13:24 +0500
> > +Subject: [PATCH] Revert "Fix usage of pthread_atfork a whole different way"
> > +
> > +This reverts commit 08a09cba90f3d960c080a20833fb8c0908f1cea6.
> > +
> > +The fix was breaking builds with some toolchains.
> > +
> > +Signed-off-by: Christopher Larson <chris_larson at mentor.com>
> > +---
> > + src/Makefile.am | 2 +-
> > + src/cap-ng.c | 12 +++++++++++-
> > + 2 files changed, 12 insertions(+), 2 deletions(-)
> > +
> > +diff --git a/src/Makefile.am b/src/Makefile.am
> > +index 5a66d4e..d46d02b 100644
> > +--- a/src/Makefile.am
> > ++++ b/src/Makefile.am
> > +@@ -34,5 +34,5 @@ noinst_HEADERS = captab.h
> > + libcap_ng_la_SOURCES = cap-ng.c lookup_table.c
> > + libcap_ng_la_LIBADD =
> > + libcap_ng_la_DEPENDENCIES = $(libcap_ng_la_SOURCES) ../config.h
> > +-libcap_ng_la_LDFLAGS = -Wl,-z,relro
> > ++libcap_ng_la_LDFLAGS = -Wl,-z,relro -Wl,-z,nodelete
> > +
> > +diff --git a/src/cap-ng.c b/src/cap-ng.c
> > +index 35fcd7a..ed31afa 100644
> > +--- a/src/cap-ng.c
> > ++++ b/src/cap-ng.c
> > +@@ -155,6 +155,15 @@ static __thread struct cap_ng m = { 1,
> > + CAPNG_NEW,
> > + {0, 0} };
> > +
> > ++
> > ++/*
> > ++ * The pthread_atfork function is being made weak so that we can use it
> > ++ * if the program is linked with pthreads and not requiring it for
> > ++ * everything that uses libcap-ng.
> > ++ */
> > ++extern int __attribute__((weak)) pthread_atfork(void (*prepare)(void),
> > ++ void (*parent)(void), void (*child)(void));
> > ++
> > + /*
> > + * Reset the state so that init gets called to erase everything
> > + */
> > +@@ -166,7 +175,8 @@ static void deinit(void)
> > + static void init_lib(void) __attribute__ ((constructor));
> > + static void init_lib(void)
> > + {
> > +- pthread_atfork(NULL, NULL, deinit);
> > ++ if (pthread_atfork)
> > ++ pthread_atfork(NULL, NULL, deinit);
> > + }
> > +
> > + static void init(void)
> > --
> > 2.11.1
> >
> > --
> > _______________________________________________
> > Openembedded-core mailing list
> > Openembedded-core at lists.openembedded.org
> > http://lists.openembedded.org/mailman/listinfo/openembedded-core
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