Make Crashpad use the user data dir, rather than always default location

chrome/install_static/policy_path_parser.cc

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright 2016 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/policy/policy_path_parser.h"
+#include "chrome/install_static/policy_path_parser.h"
 
+#include <assert.h>
 #include <shlobj.h>
 #include <stddef.h>
+#include <stdlib.h>
 #include <wtsapi32.h>
 
 #include <memory>
 
-#include "base/macros.h"
-#include "base/strings/utf_string_conversions.h"
-#include "base/win/registry.h"
-#include "chrome/common/chrome_switches.h"
-#include "components/policy/policy_constants.h"
-
 namespace {
 
-// Checks if the key exists in the given hive and expands any string variables.
-bool LoadUserDataDirPolicyFromRegistry(HKEY hive,
-                                       const char* key_name_str,
-                                       base::FilePath* dir) {
-  base::string16 value;
-  base::string16 key_name(base::ASCIIToUTF16(key_name_str));
-  base::win::RegKey key(hive, policy::kRegistryChromePolicyKey, KEY_READ);
-  if (key.ReadValue(key_name.c_str(), &value) == ERROR_SUCCESS) {
-    *dir = base::FilePath(policy::path_parser::ExpandPathVariables(value));
-    return true;
-  }
-  return false;
-}
-
 const WCHAR* kMachineNamePolicyVarName = L"${machine_name}";
 const WCHAR* kUserNamePolicyVarName = L"${user_name}";
 const WCHAR* kWinDocumentsFolderVarName = L"${documents}";
 const WCHAR* kWinLocalAppDataFolderVarName = L"${local_app_data}";
 const WCHAR* kWinRoamingAppDataFolderVarName = L"${roaming_app_data}";
 const WCHAR* kWinProfileFolderVarName = L"${profile}";
 const WCHAR* kWinProgramDataFolderVarName = L"${global_app_data}";
 const WCHAR* kWinProgramFilesFolderVarName = L"${program_files}";
 const WCHAR* kWinWindowsFolderVarName = L"${windows}";
 const WCHAR* kWinClientName = L"${client_name}";
 const WCHAR* kWinSessionName = L"${session_name}";
 
 struct WinFolderNamesToCSIDLMapping {
   const WCHAR* name;
   int id;
 };
 
 // Mapping from variable names to Windows CSIDL ids.
-const WinFolderNamesToCSIDLMapping win_folder_mapping[] = {
+const WinFolderNamesToCSIDLMapping kWinFolderMapping[] = {
     { kWinWindowsFolderVarName,        CSIDL_WINDOWS},
     { kWinProgramFilesFolderVarName,   CSIDL_PROGRAM_FILES},
     { kWinProgramDataFolderVarName,    CSIDL_COMMON_APPDATA},
     { kWinProfileFolderVarName,        CSIDL_PROFILE},
     { kWinLocalAppDataFolderVarName,   CSIDL_LOCAL_APPDATA},
     { kWinRoamingAppDataFolderVarName, CSIDL_APPDATA},
     { kWinDocumentsFolderVarName,      CSIDL_PERSONAL}
 };
 
+template <class FunctionType>
+struct ScopedFunctionHelper {
+  ScopedFunctionHelper(const wchar_t* library_name, const char* function_name) {
+    library_ = LoadLibrary(library_name);
+    assert(library_);
+    if (library_) {
+      // Strip off any leading :: that may have come from stringifying the
+      // function's name.
+      if (function_name[0] == ':' && function_name[1] == ':' &&
+          function_name[2] && function_name[2] != ':') {
+        function_name += 2;
+      }
+      function_ = reinterpret_cast<FunctionType *>(
+          GetProcAddress(library_, function_name));
+      assert(function_);
+    }
+  }
+
+  ~ScopedFunctionHelper() {
+    if (library_)
+      FreeLibrary(library_);
+  }
+
+  template <class... Args> auto operator()(Args... a) {
+    return function_(a...);
+  }
+
+ private:
+  HMODULE library_;
+  FunctionType* function_;
+};
+
+#define SCOPED_LOAD_FUNCTION(library, function)                                \
+  ScopedFunctionHelper<decltype(function)>(library, #function)
+
 }  // namespace
 
-namespace policy {
-
-namespace path_parser {
+namespace install_static {
 
 // Replaces all variable occurances in the policy string with the respective
 // system settings values.
-base::FilePath::StringType ExpandPathVariables(
-    const base::FilePath::StringType& untranslated_string) {
-  base::FilePath::StringType result(untranslated_string);
+// Note that this uses GetProcAddress to load DLLs that cannot be loaded before
+// the blacklist in the DllMain of chrome_elf has been applied. This function
+// should only be used after DllMain() has run.
+std::wstring ExpandPathVariables(
+    const std::wstring& untranslated_string) {
+  std::wstring result(untranslated_string);
   if (result.length() == 0)
     return result;
   // Sanitize quotes in case of any around the whole string.
   if (result.length() > 1 &&
       ((result.front() == L'"' && result.back() == L'"') ||
        (result.front() == L'\'' && result.back() == L'\''))) {
     // Strip first and last char which should be matching quotes now.
-    result = result.substr(1, result.length() - 2);
+    result.pop_back();
+    result.erase(0, 1);
   }
+  auto sh_get_special_folder_path =
+      SCOPED_LOAD_FUNCTION(L"shell32.dll", ::SHGetSpecialFolderPathW);
   // First translate all path variables we recognize.
-  for (size_t i = 0; i < arraysize(win_folder_mapping); ++i) {
-    size_t position = result.find(win_folder_mapping[i].name);
+  for (size_t i = 0; i < _countof(kWinFolderMapping); ++i) {
+    size_t position = result.find(kWinFolderMapping[i].name);
     if (position != std::wstring::npos) {
       WCHAR path[MAX_PATH];
-      ::SHGetSpecialFolderPath(0, path, win_folder_mapping[i].id, false);
+      sh_get_special_folder_path(nullptr, path, kWinFolderMapping[i].id, false);
       std::wstring path_string(path);
-      result.replace(position, wcslen(win_folder_mapping[i].name), path_string);
+      result.replace(position, wcslen(kWinFolderMapping[i].name), path_string);
     }
   }
   // Next translate other windows specific variables.
+  auto get_user_name = SCOPED_LOAD_FUNCTION(L"advapi32.dll", ::GetUserNameW);
   size_t position = result.find(kUserNamePolicyVarName);
   if (position != std::wstring::npos) {
     DWORD return_length = 0;
-    ::GetUserName(NULL, &return_length);
+    get_user_name(nullptr, &return_length);
     if (return_length != 0) {
       std::unique_ptr<WCHAR[]> username(new WCHAR[return_length]);
-      ::GetUserName(username.get(), &return_length);
+      get_user_name(username.get(), &return_length);
       std::wstring username_string(username.get());
       result.replace(position, wcslen(kUserNamePolicyVarName), username_string);
     }
   }
   position = result.find(kMachineNamePolicyVarName);
   if (position != std::wstring::npos) {
     DWORD return_length = 0;
     ::GetComputerNameEx(ComputerNamePhysicalDnsHostname, NULL, &return_length);
     if (return_length != 0) {
       std::unique_ptr<WCHAR[]> machinename(new WCHAR[return_length]);
       ::GetComputerNameEx(ComputerNamePhysicalDnsHostname,
                           machinename.get(), &return_length);
       std::wstring machinename_string(machinename.get());
       result.replace(
           position, wcslen(kMachineNamePolicyVarName), machinename_string);
     }
   }
+  auto wts_query_session_information =
+      SCOPED_LOAD_FUNCTION(L"wtsapi32.dll", ::WTSQuerySessionInformationW);
+  auto wts_free_memory = SCOPED_LOAD_FUNCTION(L"wtsapi32.dll", ::WTSFreeMemory);
   position = result.find(kWinClientName);
   if (position != std::wstring::npos) {
     LPWSTR buffer = NULL;
     DWORD buffer_length = 0;
-    if (::WTSQuerySessionInformation(WTS_CURRENT_SERVER, WTS_CURRENT_SESSION,
-                                     WTSClientName,
-                                     &buffer, &buffer_length)) {
+    if (wts_query_session_information(WTS_CURRENT_SERVER, WTS_CURRENT_SESSION,
+                                      WTSClientName, &buffer, &buffer_length)) {
       std::wstring clientname_string(buffer);
       result.replace(position, wcslen(kWinClientName), clientname_string);
-      ::WTSFreeMemory(buffer);
+      wts_free_memory(buffer);
     }
   }
   position = result.find(kWinSessionName);
   if (position != std::wstring::npos) {
     LPWSTR buffer = NULL;
     DWORD buffer_length = 0;
-    if (::WTSQuerySessionInformation(WTS_CURRENT_SERVER, WTS_CURRENT_SESSION,
-                                     WTSWinStationName,
-                                     &buffer, &buffer_length)) {
+    if (wts_query_session_information(WTS_CURRENT_SERVER, WTS_CURRENT_SESSION,
+                                      WTSWinStationName, &buffer,
+                                      &buffer_length)) {
       std::wstring sessionname_string(buffer);
       result.replace(position, wcslen(kWinSessionName), sessionname_string);
-      ::WTSFreeMemory(buffer);
+      wts_free_memory(buffer);
     }
   }
   // TODO(pastarmovj): Consider reorganizing this code once there are even more
   // variables to be supported. The search for the var and its replacement can
   // be extracted as common functionality.
 
   return result;
 }
 
-void CheckUserDataDirPolicy(base::FilePath* user_data_dir) {
-  DCHECK(user_data_dir);
-  // Policy from the HKLM hive has precedence over HKCU.
-  if (!LoadUserDataDirPolicyFromRegistry(HKEY_LOCAL_MACHINE, key::kUserDataDir,
-                                         user_data_dir)) {
-    LoadUserDataDirPolicyFromRegistry(HKEY_CURRENT_USER, key::kUserDataDir,
-                                      user_data_dir);
-  }
-}
-
-void CheckDiskCacheDirPolicy(base::FilePath* disk_cache_dir) {
-  DCHECK(disk_cache_dir);
-  if (!LoadUserDataDirPolicyFromRegistry(HKEY_LOCAL_MACHINE, key::kDiskCacheDir,
-                                         disk_cache_dir)) {
-    LoadUserDataDirPolicyFromRegistry(HKEY_CURRENT_USER, key::kDiskCacheDir,
-                                      disk_cache_dir);
-  }
-}
-
-}  // namespace path_parser
-
-}  // namespace policy
+}  // namespace install_static