1 files changed, 91 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/clone-internal.c b/sysdeps/unix/sysv/linux/clone-internal.c
new file mode 100644
index 0000000000..1e7a8f6b35
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/clone-internal.c
@@ -0,0 +1,91 @@
+/* The internal wrapper of clone and clone3.
+   Copyright (C) 2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+#include <stddef.h>
+#include <errno.h>
+#include <sched.h>
+#include <clone_internal.h>
+#include <libc-pointer-arith.h>	/* For cast_to_pointer.  */
+#include <stackinfo.h>		/* For _STACK_GROWS_{UP,DOWN}.  */
+
+#define CLONE_ARGS_SIZE_VER0 64 /* sizeof first published struct */
+#define CLONE_ARGS_SIZE_VER1 80 /* sizeof second published struct */
+#define CLONE_ARGS_SIZE_VER2 88 /* sizeof third published struct */
+
+#define sizeof_field(TYPE, MEMBER) sizeof ((((TYPE *)0)->MEMBER))
+#define offsetofend(TYPE, MEMBER) \
+  (offsetof (TYPE, MEMBER) + sizeof_field (TYPE, MEMBER))
+
+_Static_assert (__alignof (struct clone_args) == 8,
+		"__alignof (struct clone_args) != 8");
+_Static_assert (offsetofend (struct clone_args, tls) == CLONE_ARGS_SIZE_VER0,
+		"offsetofend (struct clone_args, tls) != CLONE_ARGS_SIZE_VER0");
+_Static_assert (offsetofend (struct clone_args, set_tid_size) == CLONE_ARGS_SIZE_VER1,
+		"offsetofend (struct clone_args, set_tid_size) != CLONE_ARGS_SIZE_VER1");
+_Static_assert (offsetofend (struct clone_args, cgroup) == CLONE_ARGS_SIZE_VER2,
+		"offsetofend (struct clone_args, cgroup) != CLONE_ARGS_SIZE_VER2");
+_Static_assert (sizeof (struct clone_args) == CLONE_ARGS_SIZE_VER2,
+		"sizeof (struct clone_args) != CLONE_ARGS_SIZE_VER2");
+
+int
+__clone_internal (struct clone_args *cl_args,
+		  int (*func) (void *arg), void *arg)
+{
+  int ret;
+#ifdef HAVE_CLONE3_WAPPER
+  /* 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
+     is an internal function.  */
+  int flags = cl_args->flags | cl_args->exit_signal;
+  void *stack = cast_to_pointer (cl_args->stack);
+
+#ifdef __ia64__
+  ret = __clone2 (func, stack, cl_args->stack_size,
+		  flags, arg,
+		  cast_to_pointer (cl_args->parent_tid),
+		  cast_to_pointer (cl_args->tls),
+		  cast_to_pointer (cl_args->child_tid));
+#else
+# if !_STACK_GROWS_DOWN && !_STACK_GROWS_UP
+#  error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
+# endif
+
+# if _STACK_GROWS_DOWN
+  stack += cl_args->stack_size;
+# endif
+  ret = __clone (func, stack, flags, arg,
+		 cast_to_pointer (cl_args->parent_tid),
+		 cast_to_pointer (cl_args->tls),
+		 cast_to_pointer (cl_args->child_tid));
+#endif
+  return ret;
+}
+
+libc_hidden_def (__clone_internal)