1// Copyright (c) 2011 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// Implementation of a work item that replaces the contents of one registry key
6// with that of another (i.e., the destination is erased prior to the copy).
7
8#include "chrome/installer/util/copy_reg_key_work_item.h"
9
10#include <shlwapi.h>
11
12#include "base/logging.h"
13#include "base/win/registry.h"
14
15using base::win::RegKey;
16
17CopyRegKeyWorkItem::~CopyRegKeyWorkItem() {
18}
19
20CopyRegKeyWorkItem::CopyRegKeyWorkItem(HKEY predefined_root,
21                                       const std::wstring& source_key_path,
22                                       const std::wstring& dest_key_path,
23                                       CopyOverWriteOption overwrite_option)
24    : predefined_root_(predefined_root),
25      source_key_path_(source_key_path),
26      dest_key_path_(dest_key_path),
27      overwrite_option_(overwrite_option),
28      cleared_destination_(false) {
29  DCHECK(predefined_root);
30  // It's a safe bet that we don't want to copy or overwrite one of the root
31  // trees.
32  DCHECK(!source_key_path.empty());
33  DCHECK(!dest_key_path.empty());
34  DCHECK(overwrite_option == ALWAYS || overwrite_option == IF_NOT_PRESENT);
35}
36
37bool CopyRegKeyWorkItem::Do() {
38  if (source_key_path_.empty() || dest_key_path_.empty())
39    return false;
40
41  // Leave immediately if we're not supposed to overwrite an existing key and
42  // one is there.
43  if (overwrite_option_ == IF_NOT_PRESENT &&
44      RegKey(predefined_root_, dest_key_path_.c_str(),
45             KEY_QUERY_VALUE).Valid()) {
46    return true;
47  }
48
49  RegistryKeyBackup backup;
50  RegKey dest_key;
51
52  // Only try to make a backup if we're not configured to ignore failures.
53  if (!ignore_failure_) {
54    if (!backup.Initialize(predefined_root_, dest_key_path_.c_str())) {
55      LOG(ERROR) << "Failed to backup destination for registry key copy.";
56      return false;
57    }
58  }
59
60  // Delete the destination before attempting to copy.
61  LONG result = SHDeleteKey(predefined_root_, dest_key_path_.c_str());
62  if (result != ERROR_SUCCESS && result != ERROR_FILE_NOT_FOUND) {
63    LOG(ERROR) << "Failed to delete key at " << dest_key_path_ << ", result: "
64               << result;
65  } else {
66    cleared_destination_ = true;
67    // We've just modified the registry, so remember any backup we may have
68    // made so that Rollback can take us back where we started.
69    backup_.swap(backup);
70    // Make the copy.
71    result = dest_key.Create(predefined_root_, dest_key_path_.c_str(),
72                             KEY_WRITE);
73    if (result != ERROR_SUCCESS) {
74      LOG(ERROR) << "Failed to open destination key at " << dest_key_path_
75                 << ", result: " << result;
76    } else {
77      result = SHCopyKey(predefined_root_, source_key_path_.c_str(),
78                         dest_key.Handle(), 0);
79      switch (result) {
80        case ERROR_FILE_NOT_FOUND:
81          // The source didn't exist, so neither should the destination.
82          dest_key.Close();
83          SHDeleteKey(predefined_root_, dest_key_path_.c_str());
84          // Handle like a success.
85          result = ERROR_SUCCESS;
86          // -- Fall through to success case. --
87        case ERROR_SUCCESS:
88          break;
89        default:
90          LOG(ERROR) << "Failed to copy key from " << source_key_path_ << " to "
91                     << dest_key_path_ << ", result: " << result;
92          break;
93      }
94    }
95  }
96
97  return ignore_failure_ ? true : (result == ERROR_SUCCESS);
98}
99
100void CopyRegKeyWorkItem::Rollback() {
101  if (ignore_failure_)
102    return;
103
104  if (cleared_destination_) {
105    // Delete anything in the key before restoring the backup in case new data
106    // was written after Do().
107    LONG result = SHDeleteKey(predefined_root_, dest_key_path_.c_str());
108    if (result != ERROR_SUCCESS && result != ERROR_FILE_NOT_FOUND) {
109      LOG(ERROR) << "Failed to delete key at " << dest_key_path_
110                 << " in rollback, result: " << result;
111    }
112
113    // Restore the old contents.  The restoration takes on its default security
114    // attributes; any custom attributes are lost.
115    if (!backup_.WriteTo(predefined_root_, dest_key_path_.c_str()))
116      LOG(ERROR) << "Failed to restore key in rollback.";
117  }
118}
119