Fork of the Android NDK crazy linker.

third_party/android_crazy_linker/src/src/crazy_linker_shared_library.h

Index: third_party/android_crazy_linker/src/src/crazy_linker_shared_library.h
diff --git a/third_party/android_crazy_linker/src/src/crazy_linker_shared_library.h b/third_party/android_crazy_linker/src/src/crazy_linker_shared_library.h
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+// Copyright (c) 2013 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 CRAZY_LINKER_SHARED_LIBRARY_H
+#define CRAZY_LINKER_SHARED_LIBRARY_H
+
+#include <link.h>
+
+#include "crazy_linker_elf_relro.h"
+#include "crazy_linker_elf_symbols.h"
+#include "crazy_linker_elf_view.h"
+#include "crazy_linker_error.h"
+#include "crazy_linker_rdebug.h"
+#include "crazy_linker_util.h"
+#include "elf_traits.h"
+
+namespace crazy {
+
+class LibraryList;
+class LibraryView;
+
+// A class that models a shared library loaded by the crazy linker.
+
+// Libraries have dependencies (which are listed in their dynamic section
+// as DT_NEEDED entries). Circular dependencies are forbidden, so they
+// form an ADG, where the root is the crazy linker itself, since all
+// libraries that it loads will depend on it (to ensure their
+// dlopen/dlsym/dlclose calls are properly wrapped).
+
+class SharedLibrary {
+ public:
+  SharedLibrary();
+  ~SharedLibrary();
+
+  size_t load_address() const { return view_.load_address(); }
+  size_t load_size() const { return view_.load_size(); }
+  size_t load_bias() const { return view_.load_bias(); }
+  const ELF::Phdr* phdr() const { return view_.phdr(); }
+  size_t phdr_count() const { return view_.phdr_count(); }
+  const char* base_name() const { return base_name_; }
+
+  // Load a library (without its dependents) from an ELF file.
+  // Note: This does not apply relocations, nor runs constructors.
+  // |full_path| if the file full path.
+  // |load_address| is the page-aligned load address in memory, or 0.
+  // |file_offset| is the page-aligned file offset.
+  // On failure, return false and set |error| message.
+  //
+  // After this, the caller should load all library dependencies,
+  // Then call Relocate() and CallConstructors() to complete the
+  // operation.
+  bool Load(const char* full_path,
+            size_t load_address,
+            size_t file_offset,
+            Error* error);
+
+  // Relocate this library, assuming all its dependencies are already
+  // loaded in |lib_list|. On failure, return false and set |error|
+  // message.
+  bool Relocate(LibraryList* lib_list,
+                Vector<LibraryView*>* dependencies,
+                Error* error);
+
+  void GetInfo(size_t* load_address,
+               size_t* load_size,
+               size_t* relro_start,
+               size_t* relro_size) {
+    *load_address = view_.load_address();
+    *load_size = view_.load_size();
+    *relro_start = relro_start_;
+    *relro_size = relro_size_;
+  }
+
+  // Returns true iff a given library is mapped to a virtual address range
+  // that contains a given address.
+  bool ContainsAddress(void* address) const {
+    size_t addr = reinterpret_cast<size_t>(address);
+    return load_address() <= addr && addr <= load_address() + load_size();
+  }
+
+  // Call all constructors in the library.
+  void CallConstructors();
+
+  // Call all destructors in the library.
+  void CallDestructors();
+
+  // Return the ELF symbol entry for a given symbol, if defined by
+  // this library, or NULL otherwise.
+  const ELF::Sym* LookupSymbolEntry(const char* symbol_name);
+
+  // Find the nearest symbol near a given |address|. On success, return
+  // true and set |*sym_name| to the symbol name, |*sym_addr| to its address
+  // in memory, and |*sym_size| to its size in bytes, if any.
+  bool FindNearestSymbolForAddress(void* address,
+                                   const char** sym_name,
+                                   void** sym_addr,
+                                   size_t* sym_size) {
+    return symbols_.LookupNearestByAddress(
+        address, load_bias(), sym_name, sym_addr, sym_size);
+  }
+
+  // Return the address of a given |symbol_name| if it is exported
+  // by the library, NULL otherwise.
+  void* FindAddressForSymbol(const char* symbol_name);
+
+  // Create a new Ashmem region holding a copy of the library's RELRO section,
+  // potentially relocated for a new |load_address|. On success, return true
+  // and sets |*relro_start|, |*relro_size| and |*relro_fd|. Note that the
+  // RELRO start address is adjusted for |load_address|, and that the caller
+  // becomes the owner of |*relro_fd|. On failure, return false and set
+  // |error| message.
+  bool CreateSharedRelro(size_t load_address,
+                         size_t* relro_start,
+                         size_t* relro_size,
+                         int* relro_fd,
+                         Error* error);
+
+  // Try to use a shared relro section from another process.
+  // On success, return true. On failure return false and
+  // sets |error| message.
+  bool UseSharedRelro(size_t relro_start,
+                      size_t relro_size,
+                      int relro_fd,
+                      Error* error);
+
+  // Look for a symbol named 'JNI_OnLoad' in this library, and if it
+  // exists, call it with |java_vm| as the first parameter. If the
+  // function result is less than |minimum_jni_version|, fail with
+  // a message in |error|. On success, return true, and record
+  // |java_vm| to call 'JNI_OnUnload' at unload time, if present.
+  bool SetJavaVM(void* java_vm, int minimum_jni_version, Error* error);
+
+  // Call 'JNI_OnUnload()' is necessary, i.e. if there was a succesful call
+  // to SetJavaVM() before. This will pass the same |java_vm| value to the
+  // callback, if it is present in the library.
+  void CallJniOnUnload();
+
+  // Helper class to iterate over dependencies in a given SharedLibrary.
+  // Usage:
+  //    SharedLibary::DependencyIterator iter(lib);
+  //    while (iter.GetNext() {
+  //      dependency_name = iter.GetName();
+  //      ...
+  //    }
+  class DependencyIterator {
+   public:
+    DependencyIterator(SharedLibrary* lib)
+        : iter_(&lib->view_), symbols_(&lib->symbols_), dep_name_(NULL) {}
+
+    bool GetNext();
+
+    const char* GetName() const { return dep_name_; }
+
+   private:
+    DependencyIterator();
+    DependencyIterator(const DependencyIterator&);
+    DependencyIterator& operator=(const DependencyIterator&);
+
+    ElfView::DynamicIterator iter_;
+    const ElfSymbols* symbols_;
+    const char* dep_name_;
+  };
+
+  typedef void (*linker_function_t)();
+
+ private:
+  friend class LibraryList;
+
+  ElfView view_;
+  ElfSymbols symbols_;
+
+  size_t relro_start_;
+  size_t relro_size_;
+  bool relro_used_;
+
+  SharedLibrary* list_next_;
+  SharedLibrary* list_prev_;
+  unsigned flags_;
+
+  linker_function_t* preinit_array_;
+  size_t preinit_array_count_;
+  linker_function_t* init_array_;
+  size_t init_array_count_;
+  linker_function_t* fini_array_;
+  size_t fini_array_count_;
+  linker_function_t init_func_;
+  linker_function_t fini_func_;
+
+#ifdef __arm__
+  // ARM EABI section used for stack unwinding.
+  unsigned* arm_exidx_;
+  size_t arm_exidx_count_;
+#endif
+
+  link_map_t link_map_;
+
+  bool has_DT_SYMBOLIC_;
+
+  void* java_vm_;
+
+  const char* base_name_;
+  char full_path_[512];
+};
+
+}  // namespace crazy
+
+#endif  // CRAZY_LINKER_SHARED_LIBRARY_H