Check for unknown flags passed to dlopen(3).

Change-Id: I56f4aab0e5a1487bc32d2c4d231e8bd15c4ac8da
diff --git a/linker/Android.mk b/linker/Android.mk
index b757030..5fccf9b 100644
--- a/linker/Android.mk
+++ b/linker/Android.mk
@@ -8,21 +8,21 @@
 endif
 
 LOCAL_SRC_FILES:= \
-	arch/$(TARGET_ARCH)/begin.$(linker_begin_extension) \
-	debugger.cpp \
-	dlfcn.cpp \
-	linker.cpp \
-	linker_environ.cpp \
-	linker_format.cpp \
-	linker_phdr.cpp \
-	rt.cpp
+    arch/$(TARGET_ARCH)/begin.$(linker_begin_extension) \
+    debugger.cpp \
+    dlfcn.cpp \
+    linker.cpp \
+    linker_environ.cpp \
+    linker_format.cpp \
+    linker_phdr.cpp \
+    rt.cpp
 
 LOCAL_LDFLAGS := -shared
 
 LOCAL_CFLAGS += -fno-stack-protector \
         -Wstrict-overflow=5 \
         -fvisibility=hidden \
-        -Wall -Wextra
+        -Wall -Wextra -Werror
 
 # We need to access Bionic private headers in the linker...
 LOCAL_CFLAGS += -I$(LOCAL_PATH)/../libc/
diff --git a/linker/dlfcn.cpp b/linker/dlfcn.cpp
index 24006e2..2184f3a 100644
--- a/linker/dlfcn.cpp
+++ b/linker/dlfcn.cpp
@@ -55,9 +55,9 @@
   return old_value;
 }
 
-void* dlopen(const char* filename, int flag) {
+void* dlopen(const char* filename, int flags) {
   ScopedPthreadMutexLocker locker(&gDlMutex);
-  soinfo* result = do_dlopen(filename);
+  soinfo* result = do_dlopen(filename, flags);
   if (result == NULL) {
     __bionic_format_dlerror("dlopen failed", linker_get_error());
     return NULL;
diff --git a/linker/linker.cpp b/linker/linker.cpp
index 0d0a8a9..0bdff99 100755
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -966,7 +966,11 @@
   return 0;
 }
 
-soinfo* do_dlopen(const char* name) {
+soinfo* do_dlopen(const char* name, int flags) {
+  if ((flags & ~(RTLD_NOW|RTLD_LAZY|RTLD_LOCAL|RTLD_GLOBAL)) != 0) {
+    DL_ERR("invalid flags to dlopen: %x", flags);
+    return NULL;
+  }
   set_soinfo_pool_protection(PROT_READ | PROT_WRITE);
   soinfo* si = find_library(name);
   if (si != NULL) {
diff --git a/linker/linker.h b/linker/linker.h
index 51869e7..60c76fa 100644
--- a/linker/linker.h
+++ b/linker/linker.h
@@ -207,7 +207,7 @@
 #define DT_PREINIT_ARRAYSZ 33
 #endif
 
-soinfo* do_dlopen(const char* name);
+soinfo* do_dlopen(const char* name, int flags);
 int do_dlclose(soinfo* si);
 
 Elf32_Sym* lookup(const char* name, soinfo** found, soinfo* start);