Improve personality initialization

1. Personality parameter should be unsigned int (not long)
2. Do not reset bits outside of PER_MASK when setting
   personality value.
3. Set personality for static executables.

Bug: http://b/21900686
Change-Id: I4c7e34079cbd59b818ce221eed325c05b9bb2303

4 files changed, 19 insertions, 9 deletions

diff --git a/libc/bionic/libc_init_common.cpp b/libc/bionic/libc_init_common.cpp
index 9b23ece5a..bd716286a 100644
--- a/libc/bionic/libc_init_common.cpp
+++ b/libc/bionic/libc_init_common.cpp
@@ -37,6 +37,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/auxv.h>
+#include <sys/personality.h>
 #include <sys/time.h>
 #include <unistd.h>
 
@@ -44,6 +45,7 @@
 #include "private/bionic_ssp.h"
 #include "private/bionic_tls.h"
 #include "private/KernelArgumentBlock.h"
+#include "private/libc_logging.h"
 #include "pthread_internal.h"
 
 extern "C" abort_msg_t** __abort_message_ptr;
@@ -289,6 +291,19 @@ static void __sanitize_environment_variables(char** env) {
   dst[0] = nullptr;
 }
 
+static void __initialize_personality() {
+#if !defined(__LP64__)
+  int old_value = personality(0xffffffff);
+  if (old_value == -1) {
+    __libc_fatal("error getting old personality value: %s", strerror(errno));
+  }
+
+  if (personality((static_cast<unsigned int>(old_value) & ~PER_MASK) | PER_LINUX32) == -1) {
+    __libc_fatal("error setting PER_LINUX32 personality: %s", strerror(errno));
+  }
+#endif
+}
+
 void __libc_init_AT_SECURE(KernelArgumentBlock& args) {
   __libc_auxv = args.auxv;
 
@@ -312,6 +327,8 @@ void __libc_init_AT_SECURE(KernelArgumentBlock& args) {
 
   // Now the environment has been sanitized, make it available.
   environ = args.envp;
+
+  __initialize_personality();
 }
 
 /* This function will be called during normal program termination
diff --git a/libc/include/sys/personality.h b/libc/include/sys/personality.h
index 8a023f967..776446856 100644
--- a/libc/include/sys/personality.h
+++ b/libc/include/sys/personality.h
@@ -34,7 +34,7 @@
 
 __BEGIN_DECLS
 
-extern int personality (unsigned long persona);
+extern int personality (unsigned int persona);
 
 __END_DECLS
 
diff --git a/linker/linker.cpp b/linker/linker.cpp
index f7b58c4c9..60f848956 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -37,7 +37,6 @@
 #include <string.h>
 #include <sys/mman.h>
 #include <sys/param.h>
-#include <sys/personality.h>
 #include <unistd.h>
 
 #include <new>
@@ -3111,12 +3110,6 @@ static ElfW(Addr) __linker_init_post_relocation(KernelArgumentBlock& args, ElfW(
     ldpreload_env = getenv("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);
diff --git a/tests/sys_personality_test.cpp b/tests/sys_personality_test.cpp
index 55a023dfa..2dfaa658c 100644
--- a/tests/sys_personality_test.cpp
+++ b/tests/sys_personality_test.cpp
@@ -19,7 +19,7 @@
 #include <sys/personality.h>
 
 TEST(sys_personality, current_persona) {
-  int persona = personality(0xffffffff);
+  int persona = personality(0xffffffff) & PER_MASK;
 #if defined(__BIONIC__)
 #if defined(__LP64__)
   ASSERT_EQ(PER_LINUX, persona);