Fix x86 system calls made from ELF preinit.
Used by CFI, so broke cfi_test#early_init@x86, but I've added a specific
test for this (and a similar test for getauxval from preinit, which this
patch does not fix).
Bug: http://b/35885875
Test: ran tests
Change-Id: I43885bedfb88c0a26b4474bd3c27a87dec7bbc97
diff --git a/tests/libs/preinit_syscall_test_helper.cpp b/tests/libs/preinit_syscall_test_helper.cpp
new file mode 100644
index 0000000..9b6b6df
--- /dev/null
+++ b/tests/libs/preinit_syscall_test_helper.cpp
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2017 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.
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/auxv.h>
+
+#include "libs_utils.h"
+
+static ssize_t g_result;
+static int g_errno;
+
+static void preinit_ctor() {
+ // Can we make a system call?
+ g_result = write(-1, "", 1);
+ g_errno = errno;
+}
+
+__attribute__((section(".preinit_array"), used)) void (*preinit_ctor_p)(void) = preinit_ctor;
+
+int main() {
+ // Did we get the expected failure?
+ CHECK(g_result == -1);
+ CHECK(g_errno == EBADF);
+ return 0;
+}