diff -r 000000000000 -r 6474c204b198 security/sandbox/chromium/base/path_service.cc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/security/sandbox/chromium/base/path_service.cc	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,336 @@
+// Copyright (c) 2012 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 "base/path_service.h"
+
+#if defined(OS_WIN)
+#include <windows.h>
+#include <shellapi.h>
+#include <shlobj.h>
+#endif
+
+#include "base/containers/hash_tables.h"
+#include "base/file_util.h"
+#include "base/files/file_path.h"
+#include "base/lazy_instance.h"
+#include "base/logging.h"
+#include "base/synchronization/lock.h"
+
+using base::FilePath;
+using base::MakeAbsoluteFilePath;
+
+namespace base {
+  bool PathProvider(int key, FilePath* result);
+#if defined(OS_WIN)
+  bool PathProviderWin(int key, FilePath* result);
+#elif defined(OS_MACOSX)
+  bool PathProviderMac(int key, FilePath* result);
+#elif defined(OS_ANDROID)
+  bool PathProviderAndroid(int key, FilePath* result);
+#elif defined(OS_POSIX)
+  // PathProviderPosix is the default path provider on POSIX OSes other than
+  // Mac and Android.
+  bool PathProviderPosix(int key, FilePath* result);
+#endif
+}
+
+namespace {
+
+typedef base::hash_map<int, FilePath> PathMap;
+
+// We keep a linked list of providers.  In a debug build we ensure that no two
+// providers claim overlapping keys.
+struct Provider {
+  PathService::ProviderFunc func;
+  struct Provider* next;
+#ifndef NDEBUG
+  int key_start;
+  int key_end;
+#endif
+  bool is_static;
+};
+
+Provider base_provider = {
+  base::PathProvider,
+  NULL,
+#ifndef NDEBUG
+  base::PATH_START,
+  base::PATH_END,
+#endif
+  true
+};
+
+#if defined(OS_WIN)
+Provider base_provider_win = {
+  base::PathProviderWin,
+  &base_provider,
+#ifndef NDEBUG
+  base::PATH_WIN_START,
+  base::PATH_WIN_END,
+#endif
+  true
+};
+#endif
+
+#if defined(OS_MACOSX)
+Provider base_provider_mac = {
+  base::PathProviderMac,
+  &base_provider,
+#ifndef NDEBUG
+  base::PATH_MAC_START,
+  base::PATH_MAC_END,
+#endif
+  true
+};
+#endif
+
+#if defined(OS_ANDROID)
+Provider base_provider_android = {
+  base::PathProviderAndroid,
+  &base_provider,
+#ifndef NDEBUG
+  base::PATH_ANDROID_START,
+  base::PATH_ANDROID_END,
+#endif
+  true
+};
+#endif
+
+#if defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_ANDROID)
+Provider base_provider_posix = {
+  base::PathProviderPosix,
+  &base_provider,
+#ifndef NDEBUG
+  base::PATH_POSIX_START,
+  base::PATH_POSIX_END,
+#endif
+  true
+};
+#endif
+
+
+struct PathData {
+  base::Lock lock;
+  PathMap cache;        // Cache mappings from path key to path value.
+  PathMap overrides;    // Track path overrides.
+  Provider* providers;  // Linked list of path service providers.
+  bool cache_disabled;  // Don't use cache if true;
+
+  PathData() : cache_disabled(false) {
+#if defined(OS_WIN)
+    providers = &base_provider_win;
+#elif defined(OS_MACOSX)
+    providers = &base_provider_mac;
+#elif defined(OS_ANDROID)
+    providers = &base_provider_android;
+#elif defined(OS_POSIX)
+    providers = &base_provider_posix;
+#endif
+  }
+
+  ~PathData() {
+    Provider* p = providers;
+    while (p) {
+      Provider* next = p->next;
+      if (!p->is_static)
+        delete p;
+      p = next;
+    }
+  }
+};
+
+static base::LazyInstance<PathData> g_path_data = LAZY_INSTANCE_INITIALIZER;
+
+static PathData* GetPathData() {
+  return g_path_data.Pointer();
+}
+
+// Tries to find |key| in the cache. |path_data| should be locked by the caller!
+bool LockedGetFromCache(int key, const PathData* path_data, FilePath* result) {
+  if (path_data->cache_disabled)
+    return false;
+  // check for a cached version
+  PathMap::const_iterator it = path_data->cache.find(key);
+  if (it != path_data->cache.end()) {
+    *result = it->second;
+    return true;
+  }
+  return false;
+}
+
+// Tries to find |key| in the overrides map. |path_data| should be locked by the
+// caller!
+bool LockedGetFromOverrides(int key, PathData* path_data, FilePath* result) {
+  // check for an overridden version.
+  PathMap::const_iterator it = path_data->overrides.find(key);
+  if (it != path_data->overrides.end()) {
+    if (!path_data->cache_disabled)
+      path_data->cache[key] = it->second;
+    *result = it->second;
+    return true;
+  }
+  return false;
+}
+
+}  // namespace
+
+// TODO(brettw): this function does not handle long paths (filename > MAX_PATH)
+// characters). This isn't supported very well by Windows right now, so it is
+// moot, but we should keep this in mind for the future.
+// static
+bool PathService::Get(int key, FilePath* result) {
+  PathData* path_data = GetPathData();
+  DCHECK(path_data);
+  DCHECK(result);
+  DCHECK_GE(key, base::DIR_CURRENT);
+
+  // special case the current directory because it can never be cached
+  if (key == base::DIR_CURRENT)
+    return file_util::GetCurrentDirectory(result);
+
+  Provider* provider = NULL;
+  {
+    base::AutoLock scoped_lock(path_data->lock);
+    if (LockedGetFromCache(key, path_data, result))
+      return true;
+
+    if (LockedGetFromOverrides(key, path_data, result))
+      return true;
+
+    // Get the beginning of the list while it is still locked.
+    provider = path_data->providers;
+  }
+
+  FilePath path;
+
+  // Iterating does not need the lock because only the list head might be
+  // modified on another thread.
+  while (provider) {
+    if (provider->func(key, &path))
+      break;
+    DCHECK(path.empty()) << "provider should not have modified path";
+    provider = provider->next;
+  }
+
+  if (path.empty())
+    return false;
+
+  if (path.ReferencesParent()) {
+    // Make sure path service never returns a path with ".." in it.
+    path = MakeAbsoluteFilePath(path);
+    if (path.empty())
+      return false;
+  }
+  *result = path;
+
+  base::AutoLock scoped_lock(path_data->lock);
+  if (!path_data->cache_disabled)
+    path_data->cache[key] = path;
+
+  return true;
+}
+
+// static
+bool PathService::Override(int key, const FilePath& path) {
+  // Just call the full function with true for the value of |create|.
+  return OverrideAndCreateIfNeeded(key, path, true);
+}
+
+// static
+bool PathService::OverrideAndCreateIfNeeded(int key,
+                                            const FilePath& path,
+                                            bool create) {
+  PathData* path_data = GetPathData();
+  DCHECK(path_data);
+  DCHECK_GT(key, base::DIR_CURRENT) << "invalid path key";
+
+  FilePath file_path = path;
+
+  // For some locations this will fail if called from inside the sandbox there-
+  // fore we protect this call with a flag.
+  if (create) {
+    // Make sure the directory exists. We need to do this before we translate
+    // this to the absolute path because on POSIX, MakeAbsoluteFilePath fails
+    // if called on a non-existent path.
+    if (!base::PathExists(file_path) &&
+        !file_util::CreateDirectory(file_path))
+      return false;
+  }
+
+  // We need to have an absolute path.
+  file_path = MakeAbsoluteFilePath(file_path);
+  if (file_path.empty())
+    return false;
+
+  base::AutoLock scoped_lock(path_data->lock);
+
+  // Clear the cache now. Some of its entries could have depended
+  // on the value we are overriding, and are now out of sync with reality.
+  path_data->cache.clear();
+
+  path_data->overrides[key] = file_path;
+
+  return true;
+}
+
+// static
+bool PathService::RemoveOverride(int key) {
+  PathData* path_data = GetPathData();
+  DCHECK(path_data);
+
+  base::AutoLock scoped_lock(path_data->lock);
+
+  if (path_data->overrides.find(key) == path_data->overrides.end())
+    return false;
+
+  // Clear the cache now. Some of its entries could have depended on the value
+  // we are going to remove, and are now out of sync.
+  path_data->cache.clear();
+
+  path_data->overrides.erase(key);
+
+  return true;
+}
+
+// static
+void PathService::RegisterProvider(ProviderFunc func, int key_start,
+                                   int key_end) {
+  PathData* path_data = GetPathData();
+  DCHECK(path_data);
+  DCHECK_GT(key_end, key_start);
+
+  Provider* p;
+
+  p = new Provider;
+  p->is_static = false;
+  p->func = func;
+#ifndef NDEBUG
+  p->key_start = key_start;
+  p->key_end = key_end;
+#endif
+
+  base::AutoLock scoped_lock(path_data->lock);
+
+#ifndef NDEBUG
+  Provider *iter = path_data->providers;
+  while (iter) {
+    DCHECK(key_start >= iter->key_end || key_end <= iter->key_start) <<
+      "path provider collision";
+    iter = iter->next;
+  }
+#endif
+
+  p->next = path_data->providers;
+  path_data->providers = p;
+}
+
+// static
+void PathService::DisableCache() {
+  PathData* path_data = GetPathData();
+  DCHECK(path_data);
+
+  base::AutoLock scoped_lock(path_data->lock);
+  path_data->cache.clear();
+  path_data->cache_disabled = true;
+}