#
# Posted upstream:
# https://sourceware.org/ml/libc-alpha/2013-10/msg00065.html
#
# This is related to bug 1013801 in that it fixes the problem
# by modifying the runtime. In bug 1013801 we have libselinux
# using pthread_atfork which pulls in libpthread, but we don't
# want that, we want libpthread to be pulled in only when
# actually needed by the application. This patch makes it
# possible to avoid requiring libpthread and still use
# pthread_atfork.
#
# The general idea for the design is in the leading comment
# in the source code.
#
diff --git a/nptl/sysdeps/unix/sysv/linux/Makefile b/nptl/sysdeps/unix/sysv/linux/Makefile
index 6078e2d..36fd50b 100644
--- a/nptl/Makefile
+++ b/nptl/Makefile
@@ -18,7 +18,9 @@
routines = alloca_cutoff forward libc-lowlevellock libc-cancellation \
libc-cleanup libc_pthread_init libc_multiple_threads \
- register-atfork unregister-atfork
+ register-atfork unregister-atfork libc_pthread_atfork
+
+static-only-routines += libc_pthread_atfork
shared-only-routines = forward
libpthread-routines = nptl-init vars events version pt-interp \
diff --git a/nptl/libc_pthread_atfork.c b/nptl/libc_pthread_atfork.c
new file mode 100644
index 0000000..667049a
--- /dev/null
+++ b/nptl/libc_pthread_atfork.c
@@ -0,0 +1,54 @@
+/* Copyright (C) 2013 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+/* The standard design pattern for making it optional to link against
+ libpthread is to mark the function weak, test if the function
+ address is non-zero and call the function, otherwise use a fallback.
+ The problem with pthread_atfork is that there is no viable
+ fallback. If you need to do something during fork it has to be done
+ via pthread_atfork. This makes having libpthread optional and using
+ pthread_atfork impossible. We make it possible by providing
+ pthread_atfork in libc_nonshared.a. The real work of pthread_atfork
+ is done by __register_atfork which is already provided in
+ libc_nonshared.a. It's included in libc_nonshared.a because
+ __dso_handle has to be unique to each DSO such that unloading the DSO
+ can unregister the atfork handlers. We build pthread_atfork again
+ under a different file name and include it into libc_nonshared.a and
+ libc.a. We keep pthread_atfork in libpthread_nonshared.a and
+ libpthread.a for compatibility and completeness.
+
+ Applications that can't rely on a new glibc should use the following
+ code to optionally include libpthread and still register a function
+ via pthread_atfork i.e. use __register_atfork directly:
+
+ extern void *__dso_handle __attribute__ ((__weak__, __visibility__ ("hidden")));
+ extern int __register_atfork (void (*) (void), void (*) (void), void (*) (void), void *);
+
+ static int __app_atfork (void (*prepare) (void), void (*parent) (void), void (*child) (void))
+ {
+ return __register_atfork (prepare, parent, child,
+ &__dso_handle == NULL ? NULL : __dso_handle);
+ }
+
+ This code requires glibc 2.3.2 or newer. Previous to 2.3.2 no such
+ interfaces exist and at that point is is impossible to have an
+ optional libpthread and call pthread_atfork.
+
+ This code adds no more ABI requirements than already exist since
+ __dso_handle and __register_atfork are already part of the ABI. */
+#include <pthread_atfork.c>