Enable loading native libraries with RTLD_DEEPBIND

base/native_library.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_NATIVE_LIBRARY_H_
 #define BASE_NATIVE_LIBRARY_H_
 
 // This file defines a cross-platform "NativeLibrary" type which represents
 // a loadable module.
 
@@ skipping 47 matching lines @@
   // Returns a string representation of the load error.
   std::string ToString() const;
 
 #if defined(OS_WIN)
   DWORD code;
 #else
   std::string message;
 #endif  // OS_WIN
 };
 
+struct BASE_EXPORT NativeLibraryOptions {

[Primiano Tucci (use gerrit), 2016/08/24 22:14:09]

If there are no other use cases this IMHO should be just an enum or a bitfield
(long arg +  constants to be or-ed) .

[Ken Rockot(use gerrit already), 2016/08/24 23:23:57]

I'd prefer to use a struct here only because it's more easily extensible to
non-boolean option types, and because (to me anyway) it seems easier to read and
understand code which uses actual types instead of integer bitfields. I don't
feel strongly about this though, so if you really want me to change it I will :)

[Primiano Tucci (use gerrit), 2016/08/25 10:20:44]

I leave this to base owners, as I'm not an owner here. No particularly strong
opinion, I just tend to keep things as simple as possible unless there is a use
case and refactor later if I need something fancier..

+  NativeLibraryOptions() {}
+
+  // If |true| the library will prefer its own symbols in lieu of symbols in the
+  // global scope. This is ignored on non-POSIX platforms. On POSIX the behavior
+  // when |true| corresponds to setting RTLD_DEEPBIND on dlopen().

[Primiano Tucci (use gerrit), 2016/08/24 22:14:09]

Interestingly it seems that on Mac OSX DEEPBIND is tthe default behavior.
I didn't test it but from [1] I read "Note: This doesn't apply to Mac OS* X
where the default is the RTLD_DEEPBIND behavior."

https://software.intel.com/en-us/articles/ensuring-shared-library-uses-intel-...

[Ken Rockot(use gerrit already), 2016/08/24 23:23:57]

Added a note about this

+  bool prefer_own_symbols = false;
+};
+
 // Loads a native library from disk.  Release it with UnloadNativeLibrary when
 // you're done.  Returns NULL on failure.
 // If |error| is not NULL, it may be filled in on load error.
 BASE_EXPORT NativeLibrary LoadNativeLibrary(const FilePath& library_path,
                                             NativeLibraryLoadError* error);
 
+// Loads a native library from disk.  Release it with UnloadNativeLibrary when
+// you're done.  Returns NULL on failure.
+// If |error| is not NULL, it may be filled in on load error.
+BASE_EXPORT NativeLibrary LoadNativeLibraryWithOptions(
+    const FilePath& library_path,
+    const NativeLibraryOptions& options,
+    NativeLibraryLoadError* error);
+
 #if defined(OS_WIN)
 // Loads a native library from disk.  Release it with UnloadNativeLibrary when
 // you're done.
 // This function retrieves the LoadLibrary function exported from kernel32.dll
 // and calls it instead of directly calling the LoadLibrary function via the
 // import table.
 BASE_EXPORT NativeLibrary LoadNativeLibraryDynamically(
     const FilePath& library_path);
 #endif  // OS_WIN
 
 // Unloads a native library.
 BASE_EXPORT void UnloadNativeLibrary(NativeLibrary library);
 
 // Gets a function pointer from a native library.
 BASE_EXPORT void* GetFunctionPointerFromNativeLibrary(NativeLibrary library,
                                                       StringPiece name);
 
 // Returns the full platform specific name for a native library.
 // |name| must be ASCII.
 // For example:
 // "mylib" returns "mylib.dll" on Windows, "libmylib.so" on Linux,
 // "libmylib.dylib" on Mac.
 BASE_EXPORT std::string GetNativeLibraryName(StringPiece name);
 
 }  // namespace base
 
 #endif  // BASE_NATIVE_LIBRARY_H_