The Tor Browser: security/sandbox/chromium/base/path_service.cc@6474c204b198 (annotated)

security/sandbox/chromium/base/path_service.cc@6474c204b198 (annotated)

security/sandbox/chromium/base/path_service.cc

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 // 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;
 }

The Tor Browser / annotate

security/sandbox/chromium/base/path_service.cc@6474c204b198 (annotated)

security/sandbox/chromium/base/path_service.cc