linker: Refactoring step 3 of many

Extract linker executable specific code to linker_main.cpp;
this part of code does not have a place in libdl.a/so.

Bug: http://b/14998480
Bug: http://b/30706810
Test: mm && run bionic-unit-tests
Change-Id: I90f7475e93a919b0f9525da22928089ad35b8f6c
diff --git a/linker/linker_main.h b/linker/linker_main.h
new file mode 100644
index 0000000..0030f49
--- /dev/null
+++ b/linker/linker_main.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef __LINKER_MAIN_H
+#define __LINKER_MAIN_H
+
+#include <android/dlext.h>
+
+#include "linker_namespaces.h"
+#include "linker_soinfo.h"
+
+class ProtectedDataGuard {
+ public:
+  ProtectedDataGuard();
+  ~ProtectedDataGuard();
+
+ private:
+  void protect_data(int protection);
+  static size_t ref_count_;
+};
+
+void init_default_namespace();
+soinfo* soinfo_alloc(android_namespace_t* ns, const char* name,
+                     struct stat* file_stat, off64_t file_offset,
+                     uint32_t rtld_flags);
+
+bool find_libraries(android_namespace_t* ns,
+                    soinfo* start_with,
+                    const char* const library_names[],
+                    size_t library_names_count,
+                    soinfo* soinfos[],
+                    std::vector<soinfo*>* ld_preloads,
+                    size_t ld_preloads_count,
+                    int rtld_flags,
+                    const android_dlextinfo* extinfo,
+                    bool add_as_children);
+
+void solist_add_soinfo(soinfo* si);
+bool solist_remove_soinfo(soinfo* si);
+soinfo* solist_get_head();
+soinfo* solist_get_somain();
+
+#endif