AdbWinApi.cpp revision acc6f826433e639b1ba00c021ab5f9161eb56e59 
1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17// AdbWinApi.cpp : Implementation of DLL Exports.
18
19#include "stdafx.h"
20#include "adb_api.h"
21#include "adb_winusb_api.h"
22
23extern "C" {
24int _forceCRTManifest;
25int _forceMFCManifest;
26int _forceAtlDllManifest;
27};
28
29/// References InstantiateWinUsbInterface declared in adb_api.cpp
30extern PFN_INSTWINUSBINTERFACE InstantiateWinUsbInterface;
31
32class CAdbWinApiModule : public CAtlDllModuleT< CAdbWinApiModule > {
33 public:
34  CAdbWinApiModule()
35      : CAtlDllModuleT< CAdbWinApiModule >(),
36        adbwinusbapi_handle_(NULL),
37        is_initialized_(false) {
38  }
39
40  ~CAdbWinApiModule() {
41    // Unload AdbWinUsbApi.dll before we exit
42    if (NULL != adbwinusbapi_handle_) {
43      FreeLibrary(adbwinusbapi_handle_);
44    }
45  }
46
47  /** \brief Loads AdbWinUsbApi.dll and caches its InstantiateWinUsbInterface
48    export.
49
50    This method is called from DllMain on DLL_PROCESS_ATTACH event. In this
51    method we will check if WINUSB.DLL required by AdbWinUsbApi.dll is
52    installed, and if it is we will load AdbWinUsbApi.dll and cache address of
53    InstantiateWinUsbInterface routine exported from AdbWinUsbApi.dll
54  */
55  void AttachToAdbWinUsbApi() {
56    // We only need to run this only once.
57    if (is_initialized_) {
58      return;
59    }
60
61    // Just mark that we have ran initialization.
62    is_initialized_ = true;
63
64    // Before we can load AdbWinUsbApi.dll we must make sure that WINUSB.DLL
65    // has been installed. Build path to the file.
66    wchar_t path_to_winusb_dll[MAX_PATH+1];
67    if (!GetSystemDirectory(path_to_winusb_dll, MAX_PATH)) {
68      return;
69    }
70    wcscat(path_to_winusb_dll, L"\\WINUSB.DLL");
71
72    if (0xFFFFFFFF == GetFileAttributes(path_to_winusb_dll)) {
73      // WINUSB.DLL is not installed. We don't (in fact, can't) load
74      // AdbWinUsbApi.dll
75      return;
76    }
77
78    // WINUSB.DLL is installed. Lets load AdbWinUsbApi.dll and cache its
79    // InstantiateWinUsbInterface export.
80    // We require that AdbWinUsbApi.dll is located in the same folder
81    // where AdbWinApi.dll and adb.exe are located, so by Windows
82    // conventions we can pass just module name, and not the full path.
83    adbwinusbapi_handle_ = LoadLibrary(L"AdbWinUsbApi.dll");
84    if (NULL != adbwinusbapi_handle_) {
85      InstantiateWinUsbInterface = reinterpret_cast<PFN_INSTWINUSBINTERFACE>
86          (GetProcAddress(adbwinusbapi_handle_, "InstantiateWinUsbInterface"));
87    }
88  }
89
90 protected:
91  /// Handle to the loaded AdbWinUsbApi.dll
92  HINSTANCE adbwinusbapi_handle_;
93
94  /// Flags whether or not this module has been initialized.
95  bool      is_initialized_;
96};
97
98CAdbWinApiModule _AtlModule;
99
100// DLL Entry Point
101extern "C" BOOL WINAPI DllMain(HINSTANCE instance,
102                               DWORD reason,
103                               LPVOID reserved) {
104  // Lets see if we need to initialize InstantiateWinUsbInterface
105  // variable. We do that only once, on condition that this DLL is
106  // being attached to the process and InstantiateWinUsbInterface
107  // address has not been calculated yet.
108  if (DLL_PROCESS_ATTACH == reason) {
109    _AtlModule.AttachToAdbWinUsbApi();
110  }
111  return _AtlModule.DllMain(reason, reserved);
112}
113