// Copyright (c) 2006-2008 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 SANDBOX_SRC_SERVICE_RESOLVER_H__
#define SANDBOX_SRC_SERVICE_RESOLVER_H__

#include "sandbox/src/nt_internals.h"
#include "sandbox/src/resolver.h"

namespace sandbox {

// This is the concrete resolver used to perform service-call type functions
// inside ntdll.dll.
class ServiceResolverThunk : public ResolverThunk {
 public:
  // The service resolver needs a child process to write to.
  ServiceResolverThunk(HANDLE process, bool relaxed)
      : process_(process), ntdll_base_(NULL), win2k_(false),
        relaxed_(relaxed), relative_jump_(0) {}
  virtual ~ServiceResolverThunk() {}

  // Implementation of Resolver::Setup.
  virtual NTSTATUS Setup(const void* target_module,
                         const void* interceptor_module,
                         const char* target_name,
                         const char* interceptor_name,
                         const void* interceptor_entry_point,
                         void* thunk_storage,
                         size_t storage_bytes,
                         size_t* storage_used);

  // Implementation of Resolver::ResolveInterceptor.
  virtual NTSTATUS ResolveInterceptor(const void* module,
                                      const char* function_name,
                                      const void** address);

  // Implementation of Resolver::ResolveTarget.
  virtual NTSTATUS ResolveTarget(const void* module,
                                 const char* function_name,
                                 void** address);

  // Implementation of Resolver::GetThunkSize.
  virtual size_t GetThunkSize() const;

 protected:
  // The unit test will use this member to allow local patch on a buffer.
  HMODULE ntdll_base_;

  // Handle of the child process.
  HANDLE process_;

 protected:
  // Keeps track of a Windows 2000 resolver.
  bool win2k_;

 private:
  // Returns true if the code pointer by target_ corresponds to the expected
  // type of function. Saves that code on the first part of the thunk pointed
  // by local_thunk (should be directly accessible from the parent).
  virtual bool IsFunctionAService(void* local_thunk) const;

  // Performs the actual patch of target_.
  // local_thunk must be already fully initialized, and the first part must
  // contain the original code. The real type of this buffer is ServiceFullThunk
  // (yes, private). remote_thunk (real type ServiceFullThunk), must be
  // allocated on the child, and will contain the thunk data, after this call.
  // Returns the apropriate status code.
  virtual NTSTATUS PerformPatch(void* local_thunk, void* remote_thunk);

  // Provides basically the same functionality as IsFunctionAService but it
  // continues even if it does not recognize the function code. remote_thunk
  // is the address of our memory on the child.
  bool SaveOriginalFunction(void* local_thunk, void* remote_thunk);

  // true if we are allowed to patch already-patched functions.
  bool relaxed_;
  ULONG relative_jump_;

  DISALLOW_EVIL_CONSTRUCTORS(ServiceResolverThunk);
};

// This is the concrete resolver used to perform service-call type functions
// inside ntdll.dll on WOW64 (32 bit ntdll on 64 bit Vista).
class Wow64ResolverThunk : public ServiceResolverThunk {
 public:
  // The service resolver needs a child process to write to.
  Wow64ResolverThunk(HANDLE process, bool relaxed)
      : ServiceResolverThunk(process, relaxed) {}
  virtual ~Wow64ResolverThunk() {}

 private:
  virtual bool IsFunctionAService(void* local_thunk) const;

  DISALLOW_EVIL_CONSTRUCTORS(Wow64ResolverThunk);
};

// This is the concrete resolver used to perform service-call type functions
// inside ntdll.dll on Windows 2000 and XP pre SP2.
class Win2kResolverThunk : public ServiceResolverThunk {
 public:
  // The service resolver needs a child process to write to.
  Win2kResolverThunk(HANDLE process, bool relaxed)
      : ServiceResolverThunk(process, relaxed) {
    win2k_ = true;
  }
  virtual ~Win2kResolverThunk() {}

 private:
  virtual bool IsFunctionAService(void* local_thunk) const;

  DISALLOW_EVIL_CONSTRUCTORS(Win2kResolverThunk);
};

}  // namespace sandbox


#endif  // SANDBOX_SRC_SERVICE_RESOLVER_H__