sys-libs/glibc: make non-functional changes to clone3 patch

Making it conditional based on a #define so that we can
easily unconditionally apply it.

Signed-off-by: Sam James <sam@gentoo.org>

2 files changed, 31 insertions, 17 deletions

diff --git a/sys-libs/glibc/files/glibc-2.34-disable-clone3-syscall.patch b/sys-libs/glibc/files/glibc-2.34-make-clone3-syscall-optional.patch
index 3c65a125c3b4..bbc6cabb463d 100644
--- a/sys-libs/glibc/files/glibc-2.34-disable-clone3-syscall.patch
+++ b/sys-libs/glibc/files/glibc-2.34-make-clone3-syscall-optional.patch
@@ -1,6 +1,14 @@
+From 22afb7abbfa0e2d4d168dcd2844aa9935a71cb37 Mon Sep 17 00:00:00 2001
+From: Sam James <sam@gentoo.org>
+Date: Wed, 1 Dec 2021 14:58:40 +0000
+Subject: [PATCH] clone-internal.c: disable use of clone3 conditinally
+
 We're disabling clone3 for now _CONDITIONALLY_ (not by default) to allow
 compatibility with applications using older Electron.
 
+Use -DGENTOO_USE_CLONE3 to enable clone3 for now. In future, we will
+revert back to always using clone3.
+
 This was impacting e.g. Discord and Skype. This patch stops glibc from using
 clone3 internally (which is the only real use of it) and falls back to the old
 behaviour.
@@ -16,23 +24,25 @@ https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/glibc/plain/debian/pat
 This is the same as the patch that was considered but ultimately rejected
 for 2.34 because Docker got sorted out in time:
 https://patchwork.ozlabs.org/project/glibc/patch/87eebkf8ph.fsf@oldenburg.str.redhat.com/.
+
+Signed-off-by: Sam James <sam@gentoo.org>
+---
+ sysdeps/unix/sysv/linux/clone-internal.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/sysdeps/unix/sysv/linux/clone-internal.c b/sysdeps/unix/sysv/linux/clone-internal.c
+index 979f7880be..c5566daf73 100644
 --- a/sysdeps/unix/sysv/linux/clone-internal.c
 +++ b/sysdeps/unix/sysv/linux/clone-internal.c
-@@ -48,17 +48,6 @@
+@@ -48,7 +48,7 @@ __clone_internal (struct clone_args *cl_args,
  		  int (*func) (void *arg), void *arg)
  {
    int ret;
 -#ifdef HAVE_CLONE3_WRAPPER
--  /* Try clone3 first.  */
--  int saved_errno = errno;
--  ret = __clone3 (cl_args, sizeof (*cl_args), func, arg);
--  if (ret != -1 || errno != ENOSYS)
--    return ret;
--
--  /* NB: Restore errno since errno may be checked against non-zero
--     return value.  */
--  __set_errno (saved_errno);
--#endif
- 
-   /* Map clone3 arguments to clone arguments.  NB: No need to check
-      invalid clone3 specific bits in flags nor exit_signal since this
++#if defined(HAVE_CLONE3_WRAPPER) && defined(GENTOO_USE_CLONE3)
+   /* Try clone3 first.  */
+   int saved_errno = errno;
+   ret = __clone3 (cl_args, sizeof (*cl_args), func, arg);
+-- 
+2.34.1
+
diff --git a/sys-libs/glibc/glibc-2.34-r3.ebuild b/sys-libs/glibc/glibc-2.34-r3.ebuild
index d98d8a72fba5..7053b85282f1 100644
--- a/sys-libs/glibc/glibc-2.34-r3.ebuild
+++ b/sys-libs/glibc/glibc-2.34-r3.ebuild
@@ -791,11 +791,15 @@ src_prepare() {
 		einfo "Done."
 	fi
 
-	if ! use clone3 ; then
+	# Apply patch to allow conditional disabling of clone3
+	eapply "${FILESDIR}"/${PN}-2.34-make-clone3-syscall-optional.patch
+
+	if use clone3 ; then
+		append-cppflags -DGENTOO_USE_CLONE3
+	else
+		# See e.g. bug #827386, bug #819045.
 		elog "Disabling the clone3 syscall for compatibility with older Electron apps."
 		elog "Please re-enable this flag before filing bugs!"
-		# See e.g. bug #827386, bug #819045.
-		eapply "${FILESDIR}"/${P}-disable-clone3-syscall.patch
 	fi
 
 	default