libc: add getauxval()
Add support for getauxval(). This method allows a program an easy way
to retrieve information from the kernel auxiliary vector, and will
hopefully replace other clumsy ways of accessing this same information.
This particular function was also added to glibc in glibc 2.16.
See the following URLs for more details.
* http://lwn.net/Articles/519085/
* http://www.gnu.org/software/libc/manual/html_node/Auxiliary-Vector.html
This change is a prerequisite for bug 7959813.
Bug: http://code.google.com/p/android/issues/detail?id=38441
Change-Id: Iba19d899df334bddc6f4899077ece2fc87564ea8
diff --git a/tests/getauxval_test.cpp b/tests/getauxval_test.cpp
new file mode 100644
index 0000000..01c11c3
--- /dev/null
+++ b/tests/getauxval_test.cpp
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2013 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 <sys/cdefs.h>
+#include <features.h>
+#include <gtest/gtest.h>
+
+// getauxval() was only added as of glibc version 2.16.
+// See: http://lwn.net/Articles/519085/
+// Don't try to compile this code on older glibc versions.
+
+#if defined(__BIONIC__)
+ #define GETAUXVAL_CAN_COMPILE 1
+#elif defined(__GLIBC_PREREQ)
+ #if __GLIBC_PREREQ(2, 16)
+ #define GETAUXVAL_CAN_COMPILE 1
+ #endif
+#endif
+
+#if defined(GETAUXVAL_CAN_COMPILE)
+
+#include <sys/auxv.h>
+
+TEST(getauxval, expected_values) {
+ ASSERT_EQ((unsigned long int) 0, getauxval(AT_SECURE));
+ ASSERT_EQ(getuid(), getauxval(AT_UID));
+ ASSERT_EQ(geteuid(), getauxval(AT_EUID));
+ ASSERT_EQ(getgid(), getauxval(AT_GID));
+ ASSERT_EQ(getegid(), getauxval(AT_EGID));
+ ASSERT_EQ((unsigned long int) getpagesize(), getauxval(AT_PAGESZ));
+
+ ASSERT_NE((unsigned long int) 0, getauxval(AT_PHDR));
+ ASSERT_NE((unsigned long int) 0, getauxval(AT_PHNUM));
+ ASSERT_NE((unsigned long int) 0, getauxval(AT_ENTRY));
+ ASSERT_NE((unsigned long int) 0, getauxval(AT_PAGESZ));
+}
+
+TEST(getauxval, unexpected_values) {
+ ASSERT_EQ((unsigned long int) 0, getauxval(0xdeadbeef));
+}
+
+#endif /* GETAUXVAL_CAN_COMPILE */