ns_anonymous test: Make it work for natively bridged environment

The executable flag might not be present for the executable segment
if the code is being handled by native bridge implementation. This
commit changes the test to restore executable flag for first segment
if it was removed.

Test: bionic-unit-tests
Change-Id: Ie930539135edc4db3245574b5cbe476aa1ad49c7
diff --git a/tests/dlext_test.cpp b/tests/dlext_test.cpp
index 0dc54d0..7028ca7 100644
--- a/tests/dlext_test.cpp
+++ b/tests/dlext_test.cpp
@@ -1635,6 +1635,7 @@
 
   uintptr_t addr_start = 0;
   uintptr_t addr_end = 0;
+  bool has_executable_segment = false;
   std::vector<map_record> maps_to_copy;
 
   for (const auto& rec : maps) {
@@ -1643,6 +1644,7 @@
         addr_start = rec.addr_start;
       }
       addr_end = rec.addr_end;
+      has_executable_segment = has_executable_segment || (rec.perms & PROT_EXEC) != 0;
 
       maps_to_copy.push_back(rec);
     }
@@ -1655,6 +1657,16 @@
   ASSERT_TRUE(ns_get_dlopened_string_addr > addr_start);
   ASSERT_TRUE(ns_get_dlopened_string_addr < addr_end);
 
+  if (!has_executable_segment) {
+    // For some natively bridged environments this code might be missing
+    // the executable flag. This is because the guest code is not supposed
+    // to be executed directly and making it non-executable is more secure.
+    // If this is the case we assume that the first segment is the one that
+    // has this flag.
+    ASSERT_TRUE((maps_to_copy[0].perms & PROT_WRITE) == 0);
+    maps_to_copy[0].perms |= PROT_EXEC;
+  }
+
   // copy
   uintptr_t reserved_addr = reinterpret_cast<uintptr_t>(mmap(nullptr, addr_end - addr_start,
                                                              PROT_NONE, MAP_ANON | MAP_PRIVATE,