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- #include <memory>
- #include <poll.h>
- #include <unistd.h>
- #include <fcntl.h>
- #include <sys/stat.h>
- #include "InotifyBackend.hh"
- #define INOTIFY_MASK \
- IN_ATTRIB | IN_CREATE | IN_DELETE | \
- IN_DELETE_SELF | IN_MODIFY | IN_MOVE_SELF | IN_MOVED_FROM | \
- IN_MOVED_TO | IN_DONT_FOLLOW | IN_ONLYDIR | IN_EXCL_UNLINK
- #define BUFFER_SIZE 8192
- #define CONVERT_TIME(ts) ((uint64_t)ts.tv_sec * 1000000000 + ts.tv_nsec)
- void InotifyBackend::start() {
- // Create a pipe that we will write to when we want to end the thread.
- int err = pipe2(mPipe, O_CLOEXEC | O_NONBLOCK);
- if (err == -1) {
- throw std::runtime_error(std::string("Unable to open pipe: ") + strerror(errno));
- }
- // Init inotify file descriptor.
- mInotify = inotify_init1(IN_NONBLOCK | IN_CLOEXEC);
- if (mInotify == -1) {
- throw std::runtime_error(std::string("Unable to initialize inotify: ") + strerror(errno));
- }
- pollfd pollfds[2];
- pollfds[0].fd = mPipe[0];
- pollfds[0].events = POLLIN;
- pollfds[0].revents = 0;
- pollfds[1].fd = mInotify;
- pollfds[1].events = POLLIN;
- pollfds[1].revents = 0;
- notifyStarted();
- // Loop until we get an event from the pipe.
- while (true) {
- int result = poll(pollfds, 2, 500);
- if (result < 0) {
- throw std::runtime_error(std::string("Unable to poll: ") + strerror(errno));
- }
- if (pollfds[0].revents) {
- break;
- }
- if (pollfds[1].revents) {
- handleEvents();
- }
- }
- close(mPipe[0]);
- close(mPipe[1]);
- close(mInotify);
- mEndedSignal.notify();
- }
- InotifyBackend::~InotifyBackend() {
- write(mPipe[1], "X", 1);
- mEndedSignal.wait();
- }
- // This function is called by Backend::watch which takes a lock on mMutex
- void InotifyBackend::subscribe(WatcherRef watcher) {
- // Build a full directory tree recursively, and watch each directory.
- std::shared_ptr<DirTree> tree = getTree(watcher);
- for (auto it = tree->entries.begin(); it != tree->entries.end(); it++) {
- if (it->second.isDir) {
- bool success = watchDir(watcher, it->second.path, tree);
- if (!success) {
- throw WatcherError(std::string("inotify_add_watch on '") + it->second.path + std::string("' failed: ") + strerror(errno), watcher);
- }
- }
- }
- }
- bool InotifyBackend::watchDir(WatcherRef watcher, std::string path, std::shared_ptr<DirTree> tree) {
- int wd = inotify_add_watch(mInotify, path.c_str(), INOTIFY_MASK);
- if (wd == -1) {
- return false;
- }
- std::shared_ptr<InotifySubscription> sub = std::make_shared<InotifySubscription>();
- sub->tree = tree;
- sub->path = path;
- sub->watcher = watcher;
- mSubscriptions.emplace(wd, sub);
- return true;
- }
- void InotifyBackend::handleEvents() {
- char buf[BUFFER_SIZE] __attribute__ ((aligned(__alignof__(struct inotify_event))));;
- struct inotify_event *event;
- // Track all of the watchers that are touched so we can notify them at the end of the events.
- std::unordered_set<WatcherRef> watchers;
- while (true) {
- int n = read(mInotify, &buf, BUFFER_SIZE);
- if (n < 0) {
- if (errno == EAGAIN || errno == EWOULDBLOCK) {
- break;
- }
- throw std::runtime_error(std::string("Error reading from inotify: ") + strerror(errno));
- }
- if (n == 0) {
- break;
- }
- for (char *ptr = buf; ptr < buf + n; ptr += sizeof(*event) + event->len) {
- event = (struct inotify_event *)ptr;
- if ((event->mask & IN_Q_OVERFLOW) == IN_Q_OVERFLOW) {
- // overflow
- continue;
- }
- handleEvent(event, watchers);
- }
- }
- for (auto it = watchers.begin(); it != watchers.end(); it++) {
- (*it)->notify();
- }
- }
- void InotifyBackend::handleEvent(struct inotify_event *event, std::unordered_set<WatcherRef> &watchers) {
- std::unique_lock<std::mutex> lock(mMutex);
- // Find the subscriptions for this watch descriptor
- auto range = mSubscriptions.equal_range(event->wd);
- std::unordered_set<std::shared_ptr<InotifySubscription>> set;
- for (auto it = range.first; it != range.second; it++) {
- set.insert(it->second);
- }
- for (auto it = set.begin(); it != set.end(); it++) {
- if (handleSubscription(event, *it)) {
- watchers.insert((*it)->watcher);
- }
- }
- }
- bool InotifyBackend::handleSubscription(struct inotify_event *event, std::shared_ptr<InotifySubscription> sub) {
- // Build full path and check if its in our ignore list.
- std::shared_ptr<Watcher> watcher = sub->watcher;
- std::string path = std::string(sub->path);
- bool isDir = event->mask & IN_ISDIR;
- if (event->len > 0) {
- path += "/" + std::string(event->name);
- }
- if (watcher->isIgnored(path)) {
- return false;
- }
- // If this is a create, check if it's a directory and start watching if it is.
- // In any case, keep the directory tree up to date.
- if (event->mask & (IN_CREATE | IN_MOVED_TO)) {
- watcher->mEvents.create(path);
- struct stat st;
- // Use lstat to avoid resolving symbolic links that we cannot watch anyway
- // https://github.com/parcel-bundler/watcher/issues/76
- lstat(path.c_str(), &st);
- DirEntry *entry = sub->tree->add(path, CONVERT_TIME(st.st_mtim), S_ISDIR(st.st_mode));
- if (entry->isDir) {
- bool success = watchDir(watcher, path, sub->tree);
- if (!success) {
- sub->tree->remove(path);
- return false;
- }
- }
- } else if (event->mask & (IN_MODIFY | IN_ATTRIB)) {
- watcher->mEvents.update(path);
- struct stat st;
- stat(path.c_str(), &st);
- sub->tree->update(path, CONVERT_TIME(st.st_mtim));
- } else if (event->mask & (IN_DELETE | IN_DELETE_SELF | IN_MOVED_FROM | IN_MOVE_SELF)) {
- bool isSelfEvent = (event->mask & (IN_DELETE_SELF | IN_MOVE_SELF));
- // Ignore delete/move self events unless this is the recursive watch root
- if (isSelfEvent && path != watcher->mDir) {
- return false;
- }
- // If the entry being deleted/moved is a directory, remove it from the list of subscriptions
- // XXX: self events don't have the IN_ISDIR mask
- if (isSelfEvent || isDir) {
- for (auto it = mSubscriptions.begin(); it != mSubscriptions.end();) {
- if (it->second->path == path) {
- it = mSubscriptions.erase(it);
- } else {
- ++it;
- }
- }
- }
- watcher->mEvents.remove(path);
- sub->tree->remove(path);
- }
- return true;
- }
- // This function is called by Backend::unwatch which takes a lock on mMutex
- void InotifyBackend::unsubscribe(WatcherRef watcher) {
- // Find any subscriptions pointing to this watcher, and remove them.
- for (auto it = mSubscriptions.begin(); it != mSubscriptions.end();) {
- if (it->second->watcher.get() == watcher.get()) {
- if (mSubscriptions.count(it->first) == 1) {
- int err = inotify_rm_watch(mInotify, it->first);
- if (err == -1) {
- throw WatcherError(std::string("Unable to remove watcher: ") + strerror(errno), watcher);
- }
- }
- it = mSubscriptions.erase(it);
- } else {
- it++;
- }
- }
- }
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