loader: asan path translation now works for symlinks

Bionic Loader now resolves real path for a library before running
asan path-translation. This fixes situations for bundled loading
libraries which are effectively symlinks to system library;
for example:

 $ adb shell ls -l /system/app/NfcNci/lib/arm64/libnfc_nci_jni.so
 /system/app/NfcNci/lib/arm64/libnfc_nci_jni.so -> /system/lib64/libnfc_nci_jni.so

Bug: http://b/33278445
Test: make and boot
Change-Id: If14a12087c92f8ca628504556332ba0cb67c9118
diff --git a/linker/linker.cpp b/linker/linker.cpp
index 62e6bb6..be4b584 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -1785,18 +1785,21 @@
   std::string asan_name_holder;
 
   const char* translated_name = name;
-  if (g_is_asan) {
-    if (file_is_in_dir(name, kSystemLibDir)) {
-      asan_name_holder = std::string(kAsanSystemLibDir) + "/" + basename(name);
-      if (file_exists(asan_name_holder.c_str())) {
-        translated_name = asan_name_holder.c_str();
-        PRINT("linker_asan dlopen translating \"%s\" -> \"%s\"", name, translated_name);
-      }
-    } else if (file_is_in_dir(name, kVendorLibDir)) {
-      asan_name_holder = std::string(kAsanVendorLibDir) + "/" + basename(name);
-      if (file_exists(asan_name_holder.c_str())) {
-        translated_name = asan_name_holder.c_str();
-        PRINT("linker_asan dlopen translating \"%s\" -> \"%s\"", name, translated_name);
+  if (g_is_asan && translated_name != nullptr && translated_name[0] == '/') {
+    char translated_path[PATH_MAX];
+    if (realpath(translated_name, translated_path) != nullptr) {
+      if (file_is_in_dir(translated_path, kSystemLibDir)) {
+        asan_name_holder = std::string(kAsanSystemLibDir) + "/" + basename(translated_path);
+        if (file_exists(asan_name_holder.c_str())) {
+          translated_name = asan_name_holder.c_str();
+          PRINT("linker_asan dlopen translating \"%s\" -> \"%s\"", name, translated_name);
+        }
+      } else if (file_is_in_dir(translated_path, kVendorLibDir)) {
+        asan_name_holder = std::string(kAsanVendorLibDir) + "/" + basename(translated_path);
+        if (file_exists(asan_name_holder.c_str())) {
+          translated_name = asan_name_holder.c_str();
+          PRINT("linker_asan dlopen translating \"%s\" -> \"%s\"", name, translated_name);
+        }
       }
     }
   }