From 1f46cdf06c2527391f9107809566795ade06fdcc Mon Sep 17 00:00:00 2001
From: Dan Albert <danalbert@google.com>
Date: Tue, 14 Feb 2017 13:29:29 -0800
Subject: [PATCH] Use the global stack protector guard for old x86.

https://gcc.gnu.org/ml/gcc/2015-11/msg00060.html changed the default
for this from using a global to using the TLS slot. As noted in
https://github.com/android-ndk/ndk/issues/297 (and in that commit),
this is not compatible with pre-4.2 devices, so we need to guard
against that in the NDK.

Test: ./validate.py --filter mstack-protector-guard
Bug: https://github.com/android-ndk/ndk/issues/297
Change-Id: I48152b452b210ed5d8967c3cb617e6fe97027b10
---
 build/core/build-binary.mk                    |  9 +++
 .../project/jni/Android.mk                    |  6 ++
 .../project/jni/foo.cpp                       |  1 +
 tests/build/mstack-protector-guard/test.py    | 63 +++++++++++++++++++
 4 files changed, 79 insertions(+)
 create mode 100644 tests/build/mstack-protector-guard/project/jni/Android.mk
 create mode 100644 tests/build/mstack-protector-guard/project/jni/foo.cpp
 create mode 100644 tests/build/mstack-protector-guard/test.py

diff --git a/build/core/build-binary.mk b/build/core/build-binary.mk
index 3a3e95da..3ea5b598 100644
--- a/build/core/build-binary.mk
+++ b/build/core/build-binary.mk
@@ -245,6 +245,15 @@ ifeq ($(TARGET_ARCH_ABI),x86)
     LOCAL_CFLAGS += -mstackrealign
 endif
 
+# https://github.com/android-ndk/ndk/issues/297
+ifeq ($(TARGET_ARCH_ABI),x86)
+    ifneq (,$(call lt,$(APP_PLATFORM_LEVEL),17))
+        ifeq ($(NDK_TOOLCHAIN_VERSION),4.9)
+            LOCAL_CFLAGS += -mstack-protector-guard=global
+        endif
+    endif
+endif
+
 #
 # The original Android build system allows you to use the .arm prefix
 # to a source file name to indicate that it should be defined in either
diff --git a/tests/build/mstack-protector-guard/project/jni/Android.mk b/tests/build/mstack-protector-guard/project/jni/Android.mk
new file mode 100644
index 00000000..365bbad8
--- /dev/null
+++ b/tests/build/mstack-protector-guard/project/jni/Android.mk
@@ -0,0 +1,6 @@
+LOCAL_PATH := $(call my-dir)
+
+include $(CLEAR_VARS)
+LOCAL_MODULE := foo
+LOCAL_SRC_FILES := foo.cpp
+include $(BUILD_SHARED_LIBRARY)
diff --git a/tests/build/mstack-protector-guard/project/jni/foo.cpp b/tests/build/mstack-protector-guard/project/jni/foo.cpp
new file mode 100644
index 00000000..85e6cd8c
--- /dev/null
+++ b/tests/build/mstack-protector-guard/project/jni/foo.cpp
@@ -0,0 +1 @@
+void foo() {}
diff --git a/tests/build/mstack-protector-guard/test.py b/tests/build/mstack-protector-guard/test.py
new file mode 100644
index 00000000..1b503633
--- /dev/null
+++ b/tests/build/mstack-protector-guard/test.py
@@ -0,0 +1,63 @@
+#
+# Copyright (C) 2016 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+"""Check for mstack-protector-guard=global when targeting old x86 targets.
+
+https://gcc.gnu.org/ml/gcc/2015-11/msg00060.html changed the default for this
+from using a global to using the TLS slot. As noted in
+https://github.com/android-ndk/ndk/issues/297 (and in that commit), this is not
+compatible with pre-4.2 devices, so we need to guard against that in the NDK.
+"""
+import os
+import subprocess
+import sys
+
+
+def run_test(abi=None, platform=None, toolchain=None, build_flags=None):
+    """Checks ndk-build V=1 output for mstackrealign flag."""
+    if build_flags is None:
+        build_flags = []
+
+    ndk_dir = os.environ['NDK']
+    ndk_build = os.path.join(ndk_dir, 'ndk-build')
+    if sys.platform == 'win32':
+        ndk_build += '.cmd'
+    project_path = 'project'
+    ndk_args = build_flags + [
+        'APP_ABI=' + abi,
+        'APP_PLATFORM=android-{}'.format(platform),
+        'NDK_TOOLCHAIN_VERSION=' + toolchain,
+        'V=1',
+    ]
+    proc = subprocess.Popen([ndk_build, '-C', project_path] + ndk_args,
+                            stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+    out, _ = proc.communicate()
+    if proc.returncode != 0:
+        return proc.returncode == 0, out
+
+    search_text = '-mstack-protector-guard=global'
+    out_words = out.split(' ')
+    if abi == 'x86' and platform < 17 and toolchain == '4.9':
+        if search_text in out_words:
+            return True, out
+        else:
+            out = 'Did not find {} in output:\n{}'.format(search_text, out)
+            return False, out
+    else:
+        if search_text in out_words:
+            print 'Found unexpceted {} in output:\n'.format(search_text, out)
+            return False, out
+        else:
+            return True, out