extensions/browser/user_script_loader.cc

   1 // Copyright 2014 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 #include "extensions/browser/user_script_loader.h"
   6
   7 #include <set>
   8 #include <string>
   9
  10 #include "base/version.h"
  11 #include "content/public/browser/browser_context.h"
  12 #include "content/public/browser/browser_thread.h"
  13 #include "content/public/browser/notification_service.h"
  14 #include "content/public/browser/notification_types.h"
  15 #include "content/public/browser/render_process_host.h"
  16 #include "extensions/browser/extensions_browser_client.h"
  17 #include "extensions/browser/notification_types.h"
  18 #include "extensions/common/extension_messages.h"
  19
  20 using content::BrowserThread;
  21 using content::BrowserContext;
  22
  23 namespace extensions {
  24
  25 namespace {
  26
  27 // Helper function to parse greasesmonkey headers
  28 bool GetDeclarationValue(const base::StringPiece& line,
  29                          const base::StringPiece& prefix,
  30                          std::string* value) {
  31   base::StringPiece::size_type index = line.find(prefix);
  32   if (index == base::StringPiece::npos)
  33     return false;
  34
  35   std::string temp(line.data() + index + prefix.length(),
  36                    line.length() - index - prefix.length());
  37
  38   if (temp.empty() || !IsWhitespace(temp[0]))
  39     return false;
  40
  41   base::TrimWhitespaceASCII(temp, base::TRIM_ALL, value);
  42   return true;
  43 }
  44
  45 }  // namespace
  46
  47 // static
  48 bool UserScriptLoader::ParseMetadataHeader(const base::StringPiece& script_text,
  49                                            UserScript* script) {
  50   // http://wiki.greasespot.net/Metadata_block
  51   base::StringPiece line;
  52   size_t line_start = 0;
  53   size_t line_end = line_start;
  54   bool in_metadata = false;
  55
  56   static const base::StringPiece kUserScriptBegin("// ==UserScript==");
  57   static const base::StringPiece kUserScriptEng("// ==/UserScript==");
  58   static const base::StringPiece kNamespaceDeclaration("// @namespace");
  59   static const base::StringPiece kNameDeclaration("// @name");
  60   static const base::StringPiece kVersionDeclaration("// @version");
  61   static const base::StringPiece kDescriptionDeclaration("// @description");
  62   static const base::StringPiece kIncludeDeclaration("// @include");
  63   static const base::StringPiece kExcludeDeclaration("// @exclude");
  64   static const base::StringPiece kMatchDeclaration("// @match");
  65   static const base::StringPiece kExcludeMatchDeclaration("// @exclude_match");
  66   static const base::StringPiece kRunAtDeclaration("// @run-at");
  67   static const base::StringPiece kRunAtDocumentStartValue("document-start");
  68   static const base::StringPiece kRunAtDocumentEndValue("document-end");
  69   static const base::StringPiece kRunAtDocumentIdleValue("document-idle");
  70
  71   while (line_start < script_text.length()) {
  72     line_end = script_text.find('\n', line_start);
  73
  74     // Handle the case where there is no trailing newline in the file.
  75     if (line_end == std::string::npos)
  76       line_end = script_text.length() - 1;
  77
  78     line.set(script_text.data() + line_start, line_end - line_start);
  79
  80     if (!in_metadata) {
  81       if (line.starts_with(kUserScriptBegin))
  82         in_metadata = true;
  83     } else {
  84       if (line.starts_with(kUserScriptEng))
  85         break;
  86
  87       std::string value;
  88       if (GetDeclarationValue(line, kIncludeDeclaration, &value)) {
  89         // We escape some characters that MatchPattern() considers special.
  90         ReplaceSubstringsAfterOffset(&value, 0, "\\", "\\\\");
  91         ReplaceSubstringsAfterOffset(&value, 0, "?", "\\?");
  92         script->add_glob(value);
  93       } else if (GetDeclarationValue(line, kExcludeDeclaration, &value)) {
  94         ReplaceSubstringsAfterOffset(&value, 0, "\\", "\\\\");
  95         ReplaceSubstringsAfterOffset(&value, 0, "?", "\\?");
  96         script->add_exclude_glob(value);
  97       } else if (GetDeclarationValue(line, kNamespaceDeclaration, &value)) {
  98         script->set_name_space(value);
  99       } else if (GetDeclarationValue(line, kNameDeclaration, &value)) {
 100         script->set_name(value);
 101       } else if (GetDeclarationValue(line, kVersionDeclaration, &value)) {
 102         Version version(value);
 103         if (version.IsValid())
 104           script->set_version(version.GetString());
 105       } else if (GetDeclarationValue(line, kDescriptionDeclaration, &value)) {
 106         script->set_description(value);
 107       } else if (GetDeclarationValue(line, kMatchDeclaration, &value)) {
 108         URLPattern pattern(UserScript::ValidUserScriptSchemes());
 109         if (URLPattern::PARSE_SUCCESS != pattern.Parse(value))
 110           return false;
 111         script->add_url_pattern(pattern);
 112       } else if (GetDeclarationValue(line, kExcludeMatchDeclaration, &value)) {
 113         URLPattern exclude(UserScript::ValidUserScriptSchemes());
 114         if (URLPattern::PARSE_SUCCESS != exclude.Parse(value))
 115           return false;
 116         script->add_exclude_url_pattern(exclude);
 117       } else if (GetDeclarationValue(line, kRunAtDeclaration, &value)) {
 118         if (value == kRunAtDocumentStartValue)
 119           script->set_run_location(UserScript::DOCUMENT_START);
 120         else if (value == kRunAtDocumentEndValue)
 121           script->set_run_location(UserScript::DOCUMENT_END);
 122         else if (value == kRunAtDocumentIdleValue)
 123           script->set_run_location(UserScript::DOCUMENT_IDLE);
 124         else
 125           return false;
 126       }
 127
 128       // TODO(aa): Handle more types of metadata.
 129     }
 130
 131     line_start = line_end + 1;
 132   }
 133
 134   // If no patterns were specified, default to @include *. This is what
 135   // Greasemonkey does.
 136   if (script->globs().empty() && script->url_patterns().is_empty())
 137     script->add_glob("*");
 138
 139   return true;
 140 }
 141
 142 UserScriptLoader::UserScriptLoader(BrowserContext* browser_context,
 143                                    const HostID& host_id)
 144     : user_scripts_(new UserScriptList()),
 145       clear_scripts_(false),
 146       ready_(false),
 147       pending_load_(false),
 148       browser_context_(browser_context),
 149       host_id_(host_id),
 150       weak_factory_(this) {
 151   registrar_.Add(this,
 152                  content::NOTIFICATION_RENDERER_PROCESS_CREATED,
 153                  content::NotificationService::AllBrowserContextsAndSources());
 154 }
 155
 156 UserScriptLoader::~UserScriptLoader() {
 157 }
 158
 159 void UserScriptLoader::AddScripts(const std::set<UserScript>& scripts) {
 160   for (std::set<UserScript>::const_iterator it = scripts.begin();
 161        it != scripts.end();
 162        ++it) {
 163     removed_scripts_.erase(*it);
 164     added_scripts_.insert(*it);
 165   }
 166   AttemptLoad();
 167 }
 168
 169 void UserScriptLoader::AddScripts(const std::set<UserScript>& scripts,
 170                                   int render_process_id,
 171                                   int render_view_id) {
 172   AddScripts(scripts);
 173 }
 174
 175 void UserScriptLoader::RemoveScripts(const std::set<UserScript>& scripts) {
 176   for (std::set<UserScript>::const_iterator it = scripts.begin();
 177        it != scripts.end();
 178        ++it) {
 179     added_scripts_.erase(*it);
 180     removed_scripts_.insert(*it);
 181   }
 182   AttemptLoad();
 183 }
 184
 185 void UserScriptLoader::ClearScripts() {
 186   clear_scripts_ = true;
 187   added_scripts_.clear();
 188   removed_scripts_.clear();
 189   AttemptLoad();
 190 }
 191
 192 void UserScriptLoader::Observe(int type,
 193                                const content::NotificationSource& source,
 194                                const content::NotificationDetails& details) {
 195   DCHECK_EQ(type, content::NOTIFICATION_RENDERER_PROCESS_CREATED);
 196   content::RenderProcessHost* process =
 197       content::Source<content::RenderProcessHost>(source).ptr();
 198   if (!ExtensionsBrowserClient::Get()->IsSameContext(
 199           browser_context_, process->GetBrowserContext()))
 200     return;
 201   if (scripts_ready()) {
 202     SendUpdate(process, shared_memory_.get(),
 203                std::set<HostID>());  // Include all hosts.
 204   }
 205 }
 206
 207 bool UserScriptLoader::ScriptsMayHaveChanged() const {
 208   // Scripts may have changed if there are scripts added, scripts removed, or
 209   // if scripts were cleared and either:
 210   // (1) A load is in progress (which may result in a non-zero number of
 211   //     scripts that need to be cleared), or
 212   // (2) The current set of scripts is non-empty (so they need to be cleared).
 213   return (added_scripts_.size() ||
 214           removed_scripts_.size() ||
 215           (clear_scripts_ &&
 216            (is_loading() || user_scripts_->size())));
 217 }
 218
 219 void UserScriptLoader::AttemptLoad() {
 220   if (ready_ && ScriptsMayHaveChanged()) {
 221     if (is_loading())
 222       pending_load_ = true;
 223     else
 224       StartLoad();
 225   }
 226 }
 227
 228 void UserScriptLoader::StartLoad() {
 229   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 230   DCHECK(!is_loading());
 231
 232   // If scripts were marked for clearing before adding and removing, then clear
 233   // them.
 234   if (clear_scripts_) {
 235     user_scripts_->clear();
 236   } else {
 237     for (UserScriptList::iterator it = user_scripts_->begin();
 238          it != user_scripts_->end();) {
 239       if (removed_scripts_.count(*it))
 240         it = user_scripts_->erase(it);
 241       else
 242         ++it;
 243     }
 244   }
 245
 246   user_scripts_->insert(
 247       user_scripts_->end(), added_scripts_.begin(), added_scripts_.end());
 248
 249   std::set<int> added_script_ids;
 250   for (std::set<UserScript>::const_iterator it = added_scripts_.begin();
 251        it != added_scripts_.end();
 252        ++it) {
 253     added_script_ids.insert(it->id());
 254   }
 255
 256   // Expand |changed_hosts_| for OnScriptsLoaded, which will use it in
 257   // its IPC message. This must be done before we clear |added_scripts_| and
 258   // |removed_scripts_| below.
 259   std::set<UserScript> changed_scripts(added_scripts_);
 260   changed_scripts.insert(removed_scripts_.begin(), removed_scripts_.end());
 261   for (const UserScript& script : changed_scripts)
 262     changed_hosts_.insert(script.host_id());
 263
 264   LoadScripts(user_scripts_.Pass(), changed_hosts_, added_script_ids,
 265               base::Bind(&UserScriptLoader::OnScriptsLoaded,
 266                          weak_factory_.GetWeakPtr()));
 267
 268   clear_scripts_ = false;
 269   added_scripts_.clear();
 270   removed_scripts_.clear();
 271   user_scripts_.reset();
 272 }
 273
 274 // static
 275 scoped_ptr<base::SharedMemory> UserScriptLoader::Serialize(
 276     const UserScriptList& scripts) {
 277   Pickle pickle;
 278   pickle.WriteSizeT(scripts.size());
 279   for (const UserScript& script : scripts) {
 280     // TODO(aa): This can be replaced by sending content script metadata to
 281     // renderers along with other extension data in ExtensionMsg_Loaded.
 282     // See crbug.com/70516.
 283     script.Pickle(&pickle);
 284     // Write scripts as 'data' so that we can read it out in the slave without
 285     // allocating a new string.
 286     for (const UserScript::File& script_file : script.js_scripts()) {
 287       base::StringPiece contents = script_file.GetContent();
 288       pickle.WriteData(contents.data(), contents.length());
 289     }
 290     for (const UserScript::File& script_file : script.css_scripts()) {
 291       base::StringPiece contents = script_file.GetContent();
 292       pickle.WriteData(contents.data(), contents.length());
 293     }
 294   }
 295
 296   // Create the shared memory object.
 297   base::SharedMemory shared_memory;
 298
 299   base::SharedMemoryCreateOptions options;
 300   options.size = pickle.size();
 301   options.share_read_only = true;
 302   if (!shared_memory.Create(options))
 303     return scoped_ptr<base::SharedMemory>();
 304
 305   if (!shared_memory.Map(pickle.size()))
 306     return scoped_ptr<base::SharedMemory>();
 307
 308   // Copy the pickle to shared memory.
 309   memcpy(shared_memory.memory(), pickle.data(), pickle.size());
 310
 311   base::SharedMemoryHandle readonly_handle;
 312   if (!shared_memory.ShareReadOnlyToProcess(base::GetCurrentProcessHandle(),
 313                                             &readonly_handle))
 314     return scoped_ptr<base::SharedMemory>();
 315
 316   return make_scoped_ptr(new base::SharedMemory(readonly_handle,
 317                                                 /*read_only=*/true));
 318 }
 319
 320 void UserScriptLoader::SetReady(bool ready) {
 321   bool was_ready = ready_;
 322   ready_ = ready;
 323   if (ready_ && !was_ready)
 324     AttemptLoad();
 325 }
 326
 327 void UserScriptLoader::OnScriptsLoaded(
 328     scoped_ptr<UserScriptList> user_scripts,
 329     scoped_ptr<base::SharedMemory> shared_memory) {
 330   user_scripts_.reset(user_scripts.release());
 331   if (pending_load_) {
 332     // While we were loading, there were further changes. Don't bother
 333     // notifying about these scripts and instead just immediately reload.
 334     pending_load_ = false;
 335     StartLoad();
 336     return;
 337   }
 338
 339   if (shared_memory.get() == NULL) {
 340     // This can happen if we run out of file descriptors.  In that case, we
 341     // have a choice between silently omitting all user scripts for new tabs,
 342     // by nulling out shared_memory_, or only silently omitting new ones by
 343     // leaving the existing object in place. The second seems less bad, even
 344     // though it removes the possibility that freeing the shared memory block
 345     // would open up enough FDs for long enough for a retry to succeed.
 346
 347     // Pretend the extension change didn't happen.
 348     return;
 349   }
 350
 351   // We've got scripts ready to go.
 352   shared_memory_.reset(shared_memory.release());
 353
 354   for (content::RenderProcessHost::iterator i(
 355            content::RenderProcessHost::AllHostsIterator());
 356        !i.IsAtEnd(); i.Advance()) {
 357     SendUpdate(i.GetCurrentValue(), shared_memory_.get(), changed_hosts_);
 358   }
 359   changed_hosts_.clear();
 360
 361   content::NotificationService::current()->Notify(
 362       extensions::NOTIFICATION_USER_SCRIPTS_UPDATED,
 363       content::Source<BrowserContext>(browser_context_),
 364       content::Details<base::SharedMemory>(shared_memory_.get()));
 365 }
 366
 367 void UserScriptLoader::SendUpdate(content::RenderProcessHost* process,
 368                                   base::SharedMemory* shared_memory,
 369                                   const std::set<HostID>& changed_hosts) {
 370   // Don't allow injection of extensions' content scripts into <webview>.
 371   if (process->IsIsolatedGuest() && host_id().id().empty())
 372     return;
 373
 374   // Make sure we only send user scripts to processes in our browser_context.
 375   if (!ExtensionsBrowserClient::Get()->IsSameContext(
 376           browser_context_, process->GetBrowserContext()))
 377     return;
 378
 379   // If the process is being started asynchronously, early return.  We'll end up
 380   // calling InitUserScripts when it's created which will call this again.
 381   base::ProcessHandle handle = process->GetHandle();
 382   if (!handle)
 383     return;
 384
 385   base::SharedMemoryHandle handle_for_process;
 386   if (!shared_memory->ShareToProcess(handle, &handle_for_process))
 387     return;  // This can legitimately fail if the renderer asserts at startup.
 388
 389   if (base::SharedMemory::IsHandleValid(handle_for_process)) {
 390     process->Send(new ExtensionMsg_UpdateUserScripts(handle_for_process,
 391                                                      host_id(), changed_hosts));
 392   }
 393 }
 394
 395 }  // namespace extensions