Check that registry external extension records point to a readable CRX file.

Some refactoring to make all error paths consistent.

BUG=81687
TEST=Create registry values for every error case, watch that I can hit them in the debugger, and a key without any errors leads to an install.

Review URL: http://codereview.chromium.org/7650014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@97134 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/extensions/external_registry_extension_loader_win.cc

-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
 #include "chrome/browser/extensions/external_registry_extension_loader_win.h"
 
 #include "base/file_path.h"
+#include "base/file_util.h"
+#include "base/memory/scoped_handle.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
@@ -27,6 +29,11 @@ const wchar_t kRegistryExtensionPath[] = L"path";
 // Registry value of that key that defines the current version of the .crx file.
 const wchar_t kRegistryExtensionVersion[] = L"version";
 
+bool CanOpenFileForReading(const FilePath& path) {
+  ScopedStdioHandle file_handle(file_util::OpenFile(path, "rb"));
+  return file_handle.get() != NULL;
+}
+
 }  // namespace
 
 void ExternalRegistryExtensionLoader::StartLoading() {
@@ -44,33 +51,62 @@ void ExternalRegistryExtensionLoader::LoadOnFileThread() {
 
   base::win::RegistryKeyIterator iterator(
       kRegRoot, ASCIIToWide(kRegistryExtensions).c_str());
-  while (iterator.Valid()) {
+  for (; iterator.Valid(); ++iterator) {
     base::win::RegKey key;
     std::wstring key_path = ASCIIToWide(kRegistryExtensions);
     key_path.append(L"\\");
     key_path.append(iterator.Name());
-    if (key.Open(kRegRoot, key_path.c_str(), KEY_READ)  == ERROR_SUCCESS) {
+    if (key.Open(kRegRoot, key_path.c_str(), KEY_READ) != ERROR_SUCCESS) {
+      LOG(ERROR) << "Unable to read registry key at path: " << key_path << ".";
+      continue;
+    }
+
     std::wstring extension_path_str;
     if (key.ReadValue(kRegistryExtensionPath, &extension_path_str)
-          == ERROR_SUCCESS) {
+        != ERROR_SUCCESS) {
+      // TODO(erikkay): find a way to get this into about:extensions
+      LOG(ERROR) << "Missing value " << kRegistryExtensionPath
+                 << " for key " << key_path << ".";
+      continue;
+    }
+
     FilePath extension_path(extension_path_str);
     if (!extension_path.IsAbsolute()) {
-          LOG(ERROR) << "Path " << extension_path_str
+      LOG(ERROR) << "File path " << extension_path_str
                  << " needs to be absolute in key "
                  << key_path;
-          ++iterator;
       continue;
     }
+
+    if (!file_util::PathExists(extension_path)) {
+      LOG(ERROR) << "File " << extension_path_str
+                 << " for key " << key_path
+                 << " does not exist or is not readable.";
+      continue;
+    }
+
+    if (!CanOpenFileForReading(extension_path)) {
+      LOG(ERROR) << "File " << extension_path_str
+                 << " for key " << key_path << " can not be read. "
+                 << "Check that users who should have the extension "
+                 << "installed have permission to read it.";
+      continue;
+    }
+
     std::wstring extension_version;
     if (key.ReadValue(kRegistryExtensionVersion, &extension_version)
-            == ERROR_SUCCESS) {
+        != ERROR_SUCCESS) {
+      // TODO(erikkay): find a way to get this into about:extensions
+      LOG(ERROR) << "Missing value " << kRegistryExtensionVersion
+                 << " for key " << key_path << ".";
+      continue;
+    }
+
     std::string id = WideToASCII(iterator.Name());
     StringToLowerASCII(&id);
-
     if (!Extension::IdIsValid(id)) {
       LOG(ERROR) << "Invalid id value " << id
-                       << " for key " << key_path << " .";
-            ++iterator;
+                 << " for key " << key_path << ".";
       continue;
     }
 
@@ -79,8 +115,7 @@ void ExternalRegistryExtensionLoader::LoadOnFileThread() {
                       WideToASCII(extension_version)));
     if (!version.get()) {
       LOG(ERROR) << "Invalid version value " << extension_version
-                       << " for key " << key_path << " .";
-            ++iterator;
+                 << " for key " << key_path << ".";
       continue;
     }
 
@@ -90,18 +125,6 @@ void ExternalRegistryExtensionLoader::LoadOnFileThread() {
     prefs->SetString(
         id + "." + ExternalExtensionProviderImpl::kExternalCrx,
         extension_path_str);
-        } else {
-          // TODO(erikkay): find a way to get this into about:extensions
-          LOG(ERROR) << "Missing value " << kRegistryExtensionVersion
-                     << " for key " << key_path << " .";
-        }
-      } else {
-        // TODO(erikkay): find a way to get this into about:extensions
-        LOG(ERROR) << "Missing value " << kRegistryExtensionPath
-                   << " for key " << key_path << " .";
-      }
-    }
-    ++iterator;
   }
 
   prefs_.reset(prefs.release());