1 files changed, 128 insertions, 0 deletions
diff --git a/mozglue/linker/BaseElf.h b/mozglue/linker/BaseElf.h
new file mode 100644
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+++ b/mozglue/linker/BaseElf.h
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+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef BaseElf_h
+#define BaseElf_h
+
+#include "ElfLoader.h"
+#include "Elfxx.h"
+
+/**
+ * Base class for ELF libraries. This class includes things that will be
+ * common between SystemElfs and CustomElfs.
+ */
+class BaseElf : public LibHandle {
+ public:
+  /**
+   * Hash function for symbol lookup, as defined in ELF standard for System V.
+   */
+  static unsigned long Hash(const char* symbol);
+
+  /**
+   * Returns the address corresponding to the given symbol name (with a
+   * pre-computed hash).
+   */
+  void* GetSymbolPtr(const char* symbol, unsigned long hash) const;
+
+  /**
+   * Returns a pointer to the Elf Symbol in the Dynamic Symbol table
+   * corresponding to the given symbol name (with a pre-computed hash).
+   */
+  const Elf::Sym* GetSymbol(const char* symbol, unsigned long hash) const;
+
+  explicit BaseElf(const char* path, Mappable* mappable = nullptr)
+      : LibHandle(path), mappable(mappable) {}
+
+ protected:
+  /**
+   * Inherited from LibHandle. Those are temporary and are not supposed to
+   * be used.
+   */
+  virtual void* GetSymbolPtr(const char* symbol) const;
+  virtual bool Contains(void* addr) const;
+  virtual void* GetBase() const { return GetPtr(0); }
+
+#ifdef __ARM_EABI__
+  virtual const void* FindExidx(int* pcount) const;
+#endif
+
+  virtual Mappable* GetMappable() const { return NULL; };
+
+ public:
+  /* private: */
+  /**
+   * Returns a pointer relative to the base address where the library is
+   * loaded.
+   */
+  void* GetPtr(const Elf::Addr offset) const {
+    if (reinterpret_cast<void*>(offset) > base)
+      return reinterpret_cast<void*>(offset);
+    return base + offset;
+  }
+
+  /**
+   * Like the above, but returns a typed (const) pointer
+   */
+  template <typename T>
+  const T* GetPtr(const Elf::Addr offset) const {
+    if (reinterpret_cast<void*>(offset) > base)
+      return reinterpret_cast<const T*>(offset);
+    return reinterpret_cast<const T*>(base + offset);
+  }
+
+  /* Appropriated Mappable */
+  /* /!\ we rely on this being nullptr for BaseElf instances, but not
+   * CustomElf instances. */
+  RefPtr<Mappable> mappable;
+
+  /* Base address where the library is loaded */
+  MappedPtr base;
+
+  /* Buckets and chains for the System V symbol hash table */
+  Array<Elf::Word> buckets;
+  UnsizedArray<Elf::Word> chains;
+
+  /* protected: */
+  /* String table */
+  Elf::Strtab strtab;
+
+  /* Symbol table */
+  UnsizedArray<Elf::Sym> symtab;
+
+#ifdef __ARM_EABI__
+  /* ARM.exidx information used by FindExidx */
+  Array<uint32_t[2]> arm_exidx;
+#endif
+};
+
+/**
+ * Class for ELF libraries that already loaded in memory.
+ */
+class LoadedElf : public BaseElf {
+ public:
+  /**
+   * Returns a LoadedElf corresponding to the already loaded ELF
+   * at the given base address.
+   */
+  static already_AddRefed<LibHandle> Create(const char* path, void* base_addr);
+
+ private:
+  explicit LoadedElf(const char* path) : BaseElf(path) {}
+
+  ~LoadedElf() {
+    /* Avoid base's destructor unmapping something that doesn't actually
+     * belong to it. */
+    base.release();
+    ElfLoader::Singleton.Forget(this);
+  }
+
+  /**
+   * Initializes the library according to information found in the given
+   * PT_DYNAMIC header.
+   * Returns whether this succeeded or failed.
+   */
+  bool InitDyn(const Elf::Phdr* pt_dyn);
+};
+
+#endif /* BaseElf_h */