csu: Implement and use _dl_early_allocate during static startup

This implements mmap fallback for a brk failure during TLS
allocation.

scripts/tls-elf-edit.py is updated to support the new patching method.
The script no longer requires that in the input object is of ET_DYN
type.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

1 files changed, 30 insertions, 0 deletions

diff --git a/elf/dl-early_allocate.c b/elf/dl-early_allocate.c
new file mode 100644
index 0000000000..61677aaa03
--- /dev/null
+++ b/elf/dl-early_allocate.c
@@ -0,0 +1,30 @@
+/* Early memory allocation for the dynamic loader.  Generic version.
+   Copyright (C) 2022 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 <ldsodefs.h>
+#include <stddef.h>
+#include <unistd.h>
+
+void *
+_dl_early_allocate (size_t size)
+{
+  void *result = __sbrk (size);
+  if (result == (void *) -1)
+    result = NULL;
+  return result;
+}