Set linux 32bit personality for 32 bit processes

Bug: 18069809
Change-Id: Ie143d56b0f8f03510dc451649291067e1add1d2f

linker/linker.cpp

@@ -36,6 +36,7 @@
 #include <string.h>
 #include <sys/mman.h>
 #include <sys/param.h>
+#include <sys/personality.h>
 #include <unistd.h>
 
 #include <new>
@@ -2663,6 +2664,12 @@ static ElfW(Addr) __linker_init_post_relocation(KernelArgumentBlock& args, ElfW(
     ldpreload_env = linker_env_get("LD_PRELOAD");
   }
 
+#if !defined(__LP64__)
+  if (personality(PER_LINUX32) == -1) {
+    __libc_fatal("error setting PER_LINUX32 personality: %s", strerror(errno));
+  }
+#endif
+
   INFO("[ android linker & debugger ]");
 
   soinfo* si = soinfo_alloc(args.argv[0], nullptr, 0, RTLD_GLOBAL);

tests/Android.mk

@@ -93,6 +93,7 @@ libBionicStandardTests_src_files := \
     sstream_test.cpp \
     sys_epoll_test.cpp \
     sys_mman_test.cpp \
+    sys_personality_test.cpp \
     sys_resource_test.cpp \
     sys_select_test.cpp \
     sys_sendfile_test.cpp \

tests/sys_personality_test.cpp

@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2015 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 <gtest/gtest.h>
+
+#include <sys/personality.h>
+
+TEST(sys_personality, current_persona) {
+  int persona = personality(0xffffffff);
+#if defined(__BIONIC__)
+#if defined(__LP64__)
+  ASSERT_EQ(PER_LINUX, persona);
+#else
+  ASSERT_EQ(PER_LINUX32, persona);
+#endif
+#else
+  // GLIBC does not set persona prior process startup - it is always PER_LINUX;
+  ASSERT_EQ(PER_LINUX, persona);
+#endif
+}