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| 1 // Copyright (c) 2012 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 "base/files/file_path_watcher_kqueue.h" | |
| 6 | |
| 7 #include <fcntl.h> | |
| 8 #include <sys/param.h> | |
| 9 | |
| 10 #include "base/bind.h" | |
| 11 #include "base/files/file_util.h" | |
| 12 #include "base/logging.h" | |
| 13 #include "base/strings/stringprintf.h" | |
| 14 #include "base/thread_task_runner_handle.h" | |
| 15 | |
| 16 // On some platforms these are not defined. | |
| 17 #if !defined(EV_RECEIPT) | |
| 18 #define EV_RECEIPT 0 | |
| 19 #endif | |
| 20 #if !defined(O_EVTONLY) | |
| 21 #define O_EVTONLY O_RDONLY | |
| 22 #endif | |
| 23 | |
| 24 namespace base { | |
| 25 | |
| 26 FilePathWatcherKQueue::FilePathWatcherKQueue() : kqueue_(-1) {} | |
| 27 | |
| 28 FilePathWatcherKQueue::~FilePathWatcherKQueue() {} | |
| 29 | |
| 30 void FilePathWatcherKQueue::ReleaseEvent(struct kevent& event) { | |
| 31 CloseFileDescriptor(&event.ident); | |
| 32 EventData* entry = EventDataForKevent(event); | |
| 33 delete entry; | |
| 34 event.udata = NULL; | |
| 35 } | |
| 36 | |
| 37 int FilePathWatcherKQueue::EventsForPath(FilePath path, EventVector* events) { | |
| 38 DCHECK(MessageLoopForIO::current()); | |
| 39 // Make sure that we are working with a clean slate. | |
| 40 DCHECK(events->empty()); | |
| 41 | |
| 42 std::vector<FilePath::StringType> components; | |
| 43 path.GetComponents(&components); | |
| 44 | |
| 45 if (components.size() < 1) { | |
| 46 return -1; | |
| 47 } | |
| 48 | |
| 49 int last_existing_entry = 0; | |
| 50 FilePath built_path; | |
| 51 bool path_still_exists = true; | |
| 52 for (std::vector<FilePath::StringType>::iterator i = components.begin(); | |
| 53 i != components.end(); ++i) { | |
| 54 if (i == components.begin()) { | |
| 55 built_path = FilePath(*i); | |
| 56 } else { | |
| 57 built_path = built_path.Append(*i); | |
| 58 } | |
| 59 uintptr_t fd = kNoFileDescriptor; | |
| 60 if (path_still_exists) { | |
| 61 fd = FileDescriptorForPath(built_path); | |
| 62 if (fd == kNoFileDescriptor) { | |
| 63 path_still_exists = false; | |
| 64 } else { | |
| 65 ++last_existing_entry; | |
| 66 } | |
| 67 } | |
| 68 FilePath::StringType subdir = (i != (components.end() - 1)) ? *(i + 1) : ""; | |
| 69 EventData* data = new EventData(built_path, subdir); | |
| 70 struct kevent event; | |
| 71 EV_SET(&event, fd, EVFILT_VNODE, (EV_ADD | EV_CLEAR | EV_RECEIPT), | |
| 72 (NOTE_DELETE | NOTE_WRITE | NOTE_ATTRIB | | |
| 73 NOTE_RENAME | NOTE_REVOKE | NOTE_EXTEND), 0, data); | |
| 74 events->push_back(event); | |
| 75 } | |
| 76 return last_existing_entry; | |
| 77 } | |
| 78 | |
| 79 uintptr_t FilePathWatcherKQueue::FileDescriptorForPath(const FilePath& path) { | |
| 80 int fd = HANDLE_EINTR(open(path.value().c_str(), O_EVTONLY)); | |
| 81 if (fd == -1) | |
| 82 return kNoFileDescriptor; | |
| 83 return fd; | |
| 84 } | |
| 85 | |
| 86 void FilePathWatcherKQueue::CloseFileDescriptor(uintptr_t* fd) { | |
| 87 if (*fd == kNoFileDescriptor) { | |
| 88 return; | |
| 89 } | |
| 90 | |
| 91 if (IGNORE_EINTR(close(*fd)) != 0) { | |
| 92 DPLOG(ERROR) << "close"; | |
| 93 } | |
| 94 *fd = kNoFileDescriptor; | |
| 95 } | |
| 96 | |
| 97 bool FilePathWatcherKQueue::AreKeventValuesValid(struct kevent* kevents, | |
| 98 int count) { | |
| 99 if (count < 0) { | |
| 100 DPLOG(ERROR) << "kevent"; | |
| 101 return false; | |
| 102 } | |
| 103 bool valid = true; | |
| 104 for (int i = 0; i < count; ++i) { | |
| 105 if (kevents[i].flags & EV_ERROR && kevents[i].data) { | |
| 106 // Find the kevent in |events_| that matches the kevent with the error. | |
| 107 EventVector::iterator event = events_.begin(); | |
| 108 for (; event != events_.end(); ++event) { | |
| 109 if (event->ident == kevents[i].ident) { | |
| 110 break; | |
| 111 } | |
| 112 } | |
| 113 std::string path_name; | |
| 114 if (event != events_.end()) { | |
| 115 EventData* event_data = EventDataForKevent(*event); | |
| 116 if (event_data != NULL) { | |
| 117 path_name = event_data->path_.value(); | |
| 118 } | |
| 119 } | |
| 120 if (path_name.empty()) { | |
| 121 path_name = base::StringPrintf( | |
| 122 "fd %ld", reinterpret_cast<long>(&kevents[i].ident)); | |
| 123 } | |
| 124 DLOG(ERROR) << "Error: " << kevents[i].data << " for " << path_name; | |
| 125 valid = false; | |
| 126 } | |
| 127 } | |
| 128 return valid; | |
| 129 } | |
| 130 | |
| 131 void FilePathWatcherKQueue::HandleAttributesChange( | |
| 132 const EventVector::iterator& event, | |
| 133 bool* target_file_affected, | |
| 134 bool* update_watches) { | |
| 135 EventVector::iterator next_event = event + 1; | |
| 136 EventData* next_event_data = EventDataForKevent(*next_event); | |
| 137 // Check to see if the next item in path is still accessible. | |
| 138 uintptr_t have_access = FileDescriptorForPath(next_event_data->path_); | |
| 139 if (have_access == kNoFileDescriptor) { | |
| 140 *target_file_affected = true; | |
| 141 *update_watches = true; | |
| 142 EventVector::iterator local_event(event); | |
| 143 for (; local_event != events_.end(); ++local_event) { | |
| 144 // Close all nodes from the event down. This has the side effect of | |
| 145 // potentially rendering other events in |updates| invalid. | |
| 146 // There is no need to remove the events from |kqueue_| because this | |
| 147 // happens as a side effect of closing the file descriptor. | |
| 148 CloseFileDescriptor(&local_event->ident); | |
| 149 } | |
| 150 } else { | |
| 151 CloseFileDescriptor(&have_access); | |
| 152 } | |
| 153 } | |
| 154 | |
| 155 void FilePathWatcherKQueue::HandleDeleteOrMoveChange( | |
| 156 const EventVector::iterator& event, | |
| 157 bool* target_file_affected, | |
| 158 bool* update_watches) { | |
| 159 *target_file_affected = true; | |
| 160 *update_watches = true; | |
| 161 EventVector::iterator local_event(event); | |
| 162 for (; local_event != events_.end(); ++local_event) { | |
| 163 // Close all nodes from the event down. This has the side effect of | |
| 164 // potentially rendering other events in |updates| invalid. | |
| 165 // There is no need to remove the events from |kqueue_| because this | |
| 166 // happens as a side effect of closing the file descriptor. | |
| 167 CloseFileDescriptor(&local_event->ident); | |
| 168 } | |
| 169 } | |
| 170 | |
| 171 void FilePathWatcherKQueue::HandleCreateItemChange( | |
| 172 const EventVector::iterator& event, | |
| 173 bool* target_file_affected, | |
| 174 bool* update_watches) { | |
| 175 // Get the next item in the path. | |
| 176 EventVector::iterator next_event = event + 1; | |
| 177 // Check to see if it already has a valid file descriptor. | |
| 178 if (!IsKeventFileDescriptorOpen(*next_event)) { | |
| 179 EventData* next_event_data = EventDataForKevent(*next_event); | |
| 180 // If not, attempt to open a file descriptor for it. | |
| 181 next_event->ident = FileDescriptorForPath(next_event_data->path_); | |
| 182 if (IsKeventFileDescriptorOpen(*next_event)) { | |
| 183 *update_watches = true; | |
| 184 if (next_event_data->subdir_.empty()) { | |
| 185 *target_file_affected = true; | |
| 186 } | |
| 187 } | |
| 188 } | |
| 189 } | |
| 190 | |
| 191 bool FilePathWatcherKQueue::UpdateWatches(bool* target_file_affected) { | |
| 192 // Iterate over events adding kevents for items that exist to the kqueue. | |
| 193 // Then check to see if new components in the path have been created. | |
| 194 // Repeat until no new components in the path are detected. | |
| 195 // This is to get around races in directory creation in a watched path. | |
| 196 bool update_watches = true; | |
| 197 while (update_watches) { | |
| 198 size_t valid; | |
| 199 for (valid = 0; valid < events_.size(); ++valid) { | |
| 200 if (!IsKeventFileDescriptorOpen(events_[valid])) { | |
| 201 break; | |
| 202 } | |
| 203 } | |
| 204 if (valid == 0) { | |
| 205 // The root of the file path is inaccessible? | |
| 206 return false; | |
| 207 } | |
| 208 | |
| 209 EventVector updates(valid); | |
| 210 int count = HANDLE_EINTR(kevent(kqueue_, &events_[0], valid, &updates[0], | |
| 211 valid, NULL)); | |
| 212 if (!AreKeventValuesValid(&updates[0], count)) { | |
| 213 return false; | |
| 214 } | |
| 215 update_watches = false; | |
| 216 for (; valid < events_.size(); ++valid) { | |
| 217 EventData* event_data = EventDataForKevent(events_[valid]); | |
| 218 events_[valid].ident = FileDescriptorForPath(event_data->path_); | |
| 219 if (IsKeventFileDescriptorOpen(events_[valid])) { | |
| 220 update_watches = true; | |
| 221 if (event_data->subdir_.empty()) { | |
| 222 *target_file_affected = true; | |
| 223 } | |
| 224 } else { | |
| 225 break; | |
| 226 } | |
| 227 } | |
| 228 } | |
| 229 return true; | |
| 230 } | |
| 231 | |
| 232 void FilePathWatcherKQueue::OnFileCanReadWithoutBlocking(int fd) { | |
| 233 DCHECK(MessageLoopForIO::current()); | |
| 234 DCHECK_EQ(fd, kqueue_); | |
| 235 DCHECK(events_.size()); | |
| 236 | |
| 237 // Request the file system update notifications that have occurred and return | |
| 238 // them in |updates|. |count| will contain the number of updates that have | |
| 239 // occurred. | |
| 240 EventVector updates(events_.size()); | |
| 241 struct timespec timeout = {0, 0}; | |
| 242 int count = HANDLE_EINTR(kevent(kqueue_, NULL, 0, &updates[0], updates.size(), | |
| 243 &timeout)); | |
| 244 | |
| 245 // Error values are stored within updates, so check to make sure that no | |
| 246 // errors occurred. | |
| 247 if (!AreKeventValuesValid(&updates[0], count)) { | |
| 248 callback_.Run(target_, true /* error */); | |
| 249 Cancel(); | |
| 250 return; | |
| 251 } | |
| 252 | |
| 253 bool update_watches = false; | |
| 254 bool send_notification = false; | |
| 255 | |
| 256 // Iterate through each of the updates and react to them. | |
| 257 for (int i = 0; i < count; ++i) { | |
| 258 // Find our kevent record that matches the update notification. | |
| 259 EventVector::iterator event = events_.begin(); | |
| 260 for (; event != events_.end(); ++event) { | |
| 261 if (!IsKeventFileDescriptorOpen(*event) || | |
| 262 event->ident == updates[i].ident) { | |
| 263 break; | |
| 264 } | |
| 265 } | |
| 266 if (event == events_.end() || !IsKeventFileDescriptorOpen(*event)) { | |
| 267 // The event may no longer exist in |events_| because another event | |
| 268 // modified |events_| in such a way to make it invalid. For example if | |
| 269 // the path is /foo/bar/bam and foo is deleted, NOTE_DELETE events for | |
| 270 // foo, bar and bam will be sent. If foo is processed first, then | |
| 271 // the file descriptors for bar and bam will already be closed and set | |
| 272 // to -1 before they get a chance to be processed. | |
| 273 continue; | |
| 274 } | |
| 275 | |
| 276 EventData* event_data = EventDataForKevent(*event); | |
| 277 | |
| 278 // If the subdir is empty, this is the last item on the path and is the | |
| 279 // target file. | |
| 280 bool target_file_affected = event_data->subdir_.empty(); | |
| 281 if ((updates[i].fflags & NOTE_ATTRIB) && !target_file_affected) { | |
| 282 HandleAttributesChange(event, &target_file_affected, &update_watches); | |
| 283 } | |
| 284 if (updates[i].fflags & (NOTE_DELETE | NOTE_REVOKE | NOTE_RENAME)) { | |
| 285 HandleDeleteOrMoveChange(event, &target_file_affected, &update_watches); | |
| 286 } | |
| 287 if ((updates[i].fflags & NOTE_WRITE) && !target_file_affected) { | |
| 288 HandleCreateItemChange(event, &target_file_affected, &update_watches); | |
| 289 } | |
| 290 send_notification |= target_file_affected; | |
| 291 } | |
| 292 | |
| 293 if (update_watches) { | |
| 294 if (!UpdateWatches(&send_notification)) { | |
| 295 callback_.Run(target_, true /* error */); | |
| 296 Cancel(); | |
| 297 } | |
| 298 } | |
| 299 | |
| 300 if (send_notification) { | |
| 301 callback_.Run(target_, false); | |
| 302 } | |
| 303 } | |
| 304 | |
| 305 void FilePathWatcherKQueue::OnFileCanWriteWithoutBlocking(int fd) { | |
| 306 NOTREACHED(); | |
| 307 } | |
| 308 | |
| 309 void FilePathWatcherKQueue::WillDestroyCurrentMessageLoop() { | |
| 310 CancelOnMessageLoopThread(); | |
| 311 } | |
| 312 | |
| 313 bool FilePathWatcherKQueue::Watch(const FilePath& path, | |
| 314 bool recursive, | |
| 315 const FilePathWatcher::Callback& callback) { | |
| 316 DCHECK(MessageLoopForIO::current()); | |
| 317 DCHECK(target_.value().empty()); // Can only watch one path. | |
| 318 DCHECK(!callback.is_null()); | |
| 319 DCHECK_EQ(kqueue_, -1); | |
| 320 | |
| 321 if (recursive) { | |
| 322 // Recursive watch is not supported using kqueue. | |
| 323 NOTIMPLEMENTED(); | |
| 324 return false; | |
| 325 } | |
| 326 | |
| 327 callback_ = callback; | |
| 328 target_ = path; | |
| 329 | |
| 330 MessageLoop::current()->AddDestructionObserver(this); | |
| 331 io_task_runner_ = ThreadTaskRunnerHandle::Get(); | |
| 332 | |
| 333 kqueue_ = kqueue(); | |
| 334 if (kqueue_ == -1) { | |
| 335 DPLOG(ERROR) << "kqueue"; | |
| 336 return false; | |
| 337 } | |
| 338 | |
| 339 int last_entry = EventsForPath(target_, &events_); | |
| 340 DCHECK_NE(last_entry, 0); | |
| 341 | |
| 342 EventVector responses(last_entry); | |
| 343 | |
| 344 int count = HANDLE_EINTR(kevent(kqueue_, &events_[0], last_entry, | |
| 345 &responses[0], last_entry, NULL)); | |
| 346 if (!AreKeventValuesValid(&responses[0], count)) { | |
| 347 // Calling Cancel() here to close any file descriptors that were opened. | |
| 348 // This would happen in the destructor anyways, but FilePathWatchers tend to | |
| 349 // be long lived, and if an error has occurred, there is no reason to waste | |
| 350 // the file descriptors. | |
| 351 Cancel(); | |
| 352 return false; | |
| 353 } | |
| 354 | |
| 355 return MessageLoopForIO::current()->WatchFileDescriptor( | |
| 356 kqueue_, true, MessageLoopForIO::WATCH_READ, &kqueue_watcher_, this); | |
| 357 } | |
| 358 | |
| 359 void FilePathWatcherKQueue::Cancel() { | |
| 360 SingleThreadTaskRunner* task_runner = io_task_runner_.get(); | |
| 361 if (!task_runner) { | |
| 362 set_cancelled(); | |
| 363 return; | |
| 364 } | |
| 365 if (!task_runner->BelongsToCurrentThread()) { | |
| 366 task_runner->PostTask(FROM_HERE, | |
| 367 base::Bind(&FilePathWatcherKQueue::Cancel, this)); | |
| 368 return; | |
| 369 } | |
| 370 CancelOnMessageLoopThread(); | |
| 371 } | |
| 372 | |
| 373 void FilePathWatcherKQueue::CancelOnMessageLoopThread() { | |
| 374 DCHECK(MessageLoopForIO::current()); | |
| 375 if (!is_cancelled()) { | |
| 376 set_cancelled(); | |
| 377 kqueue_watcher_.StopWatchingFileDescriptor(); | |
| 378 if (IGNORE_EINTR(close(kqueue_)) != 0) { | |
| 379 DPLOG(ERROR) << "close kqueue"; | |
| 380 } | |
| 381 kqueue_ = -1; | |
| 382 std::for_each(events_.begin(), events_.end(), ReleaseEvent); | |
| 383 events_.clear(); | |
| 384 io_task_runner_ = NULL; | |
| 385 MessageLoop::current()->RemoveDestructionObserver(this); | |
| 386 callback_.Reset(); | |
| 387 } | |
| 388 } | |
| 389 | |
| 390 } // namespace base | |
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