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
14namespace chrome_launcher_support {
15
16namespace {
17
18// TODO(huangs) Refactor the constants: http://crbug.com/148538
19const wchar_t kGoogleRegClientStateKey[] =
20    L"Software\\Google\\Update\\ClientState";
21
22// Copied from chrome_appid.cc.
23const wchar_t kBinariesAppGuid[] = L"{4DC8B4CA-1BDA-483e-B5FA-D3C12E15B62D}";
24
25// Copied from google_chrome_distribution.cc.
26const wchar_t kBrowserAppGuid[] = L"{8A69D345-D564-463c-AFF1-A69D9E530F96}";
27
28// Copied from util_constants.cc.
29const wchar_t kChromeExe[] = L"chrome.exe";
30const 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.
34bool 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.
56base::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.
69base::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.
83base::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
104base::FilePath GetChromePathForInstallationLevel(InstallationLevel level) {
105  return FindExeRelativeToSetupExe(
106      GetSetupExeForInstallationLevel(level), kChromeExe);
107}
108
109base::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
119