Don't load libc_malloc_* libs from runtime ns for libc_scudo

malloc_common_dynamic.cpp is compiled into both libc.so and
libc_scudo.so. When compiled for libc_scudo.so, it doesn't try to load
libc_malloc_* libs from the runtime linker namespace. This is because,
unlike libc.so which is shared from the runtime APEX, libc_scudo.so is
copied to any APEX that it needs. Furthermore, libdl_android which
provides android_get_exported_namespace is not available for vendors. So
the vendor variant of libc_scudo.so can't anyway locate the runtime
namespace.

Bug: 130213757
Bug: 122566199
Test: `m libc_scudo libc_scudo` is successful
Test: inspect the built library to see if it has reference to
android_get_exported_namespace

Change-Id: I4c41de361fdb3fa34b95218923f4ce4e9c010f9e

1 files changed, 8 insertions, 0 deletions

diff --git a/libc/bionic/malloc_common_dynamic.cpp b/libc/bionic/malloc_common_dynamic.cpp
index cf25f8ef0..e7147a0e8 100644
--- a/libc/bionic/malloc_common_dynamic.cpp
+++ b/libc/bionic/malloc_common_dynamic.cpp
@@ -279,10 +279,17 @@ bool InitSharedLibrary(void* impl_handle, const char* shared_lib, const char* pr
   return true;
 }
 
+// Note about USE_SCUDO. This file is compiled into libc.so and libc_scudo.so.
+// When compiled into libc_scudo.so, the libc_malloc_* libraries don't need
+// to be loaded from the runtime namespace since libc_scudo.so is not from
+// the runtime APEX, but is copied to any APEX that needs it.
+#ifndef USE_SCUDO
 extern "C" struct android_namespace_t* android_get_exported_namespace(const char* name);
+#endif
 
 void* LoadSharedLibrary(const char* shared_lib, const char* prefix, MallocDispatch* dispatch_table) {
   void* impl_handle = nullptr;
+#ifndef USE_SCUDO
   // Try to load the libc_malloc_* libs from the "runtime" namespace and then
   // fall back to dlopen() to load them from the default namespace.
   //
@@ -301,6 +308,7 @@ void* LoadSharedLibrary(const char* shared_lib, const char* prefix, MallocDispat
     };
     impl_handle = android_dlopen_ext(shared_lib, RTLD_NOW | RTLD_LOCAL, &dlextinfo);
   }
+#endif
 
   if (impl_handle == nullptr) {
     impl_handle = dlopen(shared_lib, RTLD_NOW | RTLD_LOCAL);