chrome/installer/launcher_support/chrome_launcher_support.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/installer/launcher_support/chrome_launcher_support.h"
   6
   7 #include <windows.h>
   8
   9 #include "base/files/file_path.h"
  10 #include "base/files/file_util.h"
  11 #include "base/strings/string16.h"
  12 #include "base/win/registry.h"
  13
  14 namespace chrome_launcher_support {
  15
  16 namespace {
  17
  18 // TODO(huangs) Refactor the constants: http://crbug.com/148538
  19 const wchar_t kGoogleRegClientStateKey[] =
  20     L"Software\\Google\\Update\\ClientState";
  21
  22 // Copied from chrome_appid.cc.
  23 const wchar_t kBinariesAppGuid[] = L"{4DC8B4CA-1BDA-483e-B5FA-D3C12E15B62D}";
  24
  25 // Copied from google_chrome_distribution.cc.
  26 const wchar_t kBrowserAppGuid[] = L"{8A69D345-D564-463c-AFF1-A69D9E530F96}";
  27
  28 // Copied from util_constants.cc.
  29 const wchar_t kChromeExe[] = L"chrome.exe";
  30 const wchar_t kUninstallStringField[] = L"UninstallString";
  31
  32 // Reads a string value from the specified product's "ClientState" registry key.
  33 // Returns true iff the value is present and successfully read.
  34 bool GetClientStateValue(InstallationLevel level,
  35                          const wchar_t* app_guid,
  36                          const wchar_t* value_name,
  37                          base::string16* value) {
  38   HKEY root_key = (level == USER_LEVEL_INSTALLATION) ?
  39       HKEY_CURRENT_USER : HKEY_LOCAL_MACHINE;
  40   base::string16 subkey(kGoogleRegClientStateKey);
  41   subkey.append(1, L'\\').append(app_guid);
  42   base::win::RegKey reg_key;
  43   // Google Update always uses 32bit hive.
  44   if (reg_key.Open(root_key, subkey.c_str(),
  45                    KEY_QUERY_VALUE | KEY_WOW64_32KEY) == ERROR_SUCCESS) {
  46     if (reg_key.ReadValue(value_name, value) == ERROR_SUCCESS) {
  47       return true;
  48     }
  49   }
  50   return false;
  51 }
  52
  53 // Reads the path to setup.exe from the value "UninstallString" within the
  54 // specified product's "ClientState" registry key. Returns an empty FilePath if
  55 // an error occurs or the product is not installed at the specified level.
  56 base::FilePath GetSetupExeFromRegistry(InstallationLevel level,
  57                                        const wchar_t* app_guid) {
  58   base::string16 uninstall;
  59   if (GetClientStateValue(level, app_guid, kUninstallStringField, &uninstall)) {
  60     base::FilePath setup_exe_path(uninstall);
  61     if (base::PathExists(setup_exe_path))
  62       return setup_exe_path;
  63   }
  64   return base::FilePath();
  65 }
  66
  67 // Returns the path to an existing setup.exe at the specified level, if it can
  68 // be found via Omaha client state.
  69 base::FilePath GetSetupExeForInstallationLevel(InstallationLevel level) {
  70   // Look in the registry for Chrome Binaries first.
  71   base::FilePath setup_exe_path(
  72       GetSetupExeFromRegistry(level, kBinariesAppGuid));
  73   // If the above fails, look in the registry for Chrome next.
  74   if (setup_exe_path.empty())
  75     setup_exe_path = GetSetupExeFromRegistry(level, kBrowserAppGuid);
  76   // If we fail again, then setup_exe_path would be empty.
  77   return setup_exe_path;
  78 }
  79
  80 // Returns the path to an installed |exe_file| (e.g. chrome.exe) at the
  81 // specified level, given |setup_exe_path| from Omaha client state.  Returns
  82 // empty base::FilePath if none found, or if |setup_exe_path| is empty.
  83 base::FilePath FindExeRelativeToSetupExe(const base::FilePath setup_exe_path,
  84                                          const wchar_t* exe_file) {
  85   if (!setup_exe_path.empty()) {
  86     // The uninstall path contains the path to setup.exe, which is two levels
  87     // down from |exe_file|. Move up two levels (plus one to drop the file
  88     // name) and look for chrome.exe from there.
  89     base::FilePath exe_path(
  90         setup_exe_path.DirName().DirName().DirName().Append(exe_file));
  91     if (base::PathExists(exe_path))
  92       return exe_path;
  93     // By way of mild future proofing, look up one to see if there's a
  94     // |exe_file| in the version directory
  95     exe_path = setup_exe_path.DirName().DirName().Append(exe_file);
  96     if (base::PathExists(exe_path))
  97       return exe_path;
  98   }
  99   return base::FilePath();
 100 }
 101
 102 }  // namespace
 103
 104 base::FilePath GetChromePathForInstallationLevel(InstallationLevel level) {
 105   return FindExeRelativeToSetupExe(
 106       GetSetupExeForInstallationLevel(level), kChromeExe);
 107 }
 108
 109 base::FilePath GetAnyChromePath() {
 110   base::FilePath chrome_path;
 111   if (chrome_path.empty())
 112     chrome_path = GetChromePathForInstallationLevel(SYSTEM_LEVEL_INSTALLATION);
 113   if (chrome_path.empty())
 114     chrome_path = GetChromePathForInstallationLevel(USER_LEVEL_INSTALLATION);
 115   return chrome_path;
 116 }
 117
 118 }  // namespace chrome_launcher_support