diff -r 8f478162d991 -r 05c40b36d3b2 vendor/github.com/fsnotify/fsnotify/backend_kqueue.go --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/vendor/github.com/fsnotify/fsnotify/backend_kqueue.go Sat Feb 04 12:58:35 2023 +0100 @@ -0,0 +1,707 @@ +//go:build freebsd || openbsd || netbsd || dragonfly || darwin +// +build freebsd openbsd netbsd dragonfly darwin + +package fsnotify + +import ( + "errors" + "fmt" + "io/ioutil" + "os" + "path/filepath" + "sync" + + "golang.org/x/sys/unix" +) + +// Watcher watches a set of paths, delivering events on a channel. +// +// A watcher should not be copied (e.g. pass it by pointer, rather than by +// value). +// +// # Linux notes +// +// When a file is removed a Remove event won't be emitted until all file +// descriptors are closed, and deletes will always emit a Chmod. For example: +// +// fp := os.Open("file") +// os.Remove("file") // Triggers Chmod +// fp.Close() // Triggers Remove +// +// This is the event that inotify sends, so not much can be changed about this. +// +// The fs.inotify.max_user_watches sysctl variable specifies the upper limit +// for the number of watches per user, and fs.inotify.max_user_instances +// specifies the maximum number of inotify instances per user. Every Watcher you +// create is an "instance", and every path you add is a "watch". +// +// These are also exposed in /proc as /proc/sys/fs/inotify/max_user_watches and +// /proc/sys/fs/inotify/max_user_instances +// +// To increase them you can use sysctl or write the value to the /proc file: +// +// # Default values on Linux 5.18 +// sysctl fs.inotify.max_user_watches=124983 +// sysctl fs.inotify.max_user_instances=128 +// +// To make the changes persist on reboot edit /etc/sysctl.conf or +// /usr/lib/sysctl.d/50-default.conf (details differ per Linux distro; check +// your distro's documentation): +// +// fs.inotify.max_user_watches=124983 +// fs.inotify.max_user_instances=128 +// +// Reaching the limit will result in a "no space left on device" or "too many open +// files" error. +// +// # kqueue notes (macOS, BSD) +// +// kqueue requires opening a file descriptor for every file that's being watched; +// so if you're watching a directory with five files then that's six file +// descriptors. You will run in to your system's "max open files" limit faster on +// these platforms. +// +// The sysctl variables kern.maxfiles and kern.maxfilesperproc can be used to +// control the maximum number of open files, as well as /etc/login.conf on BSD +// systems. +// +// # macOS notes +// +// Spotlight indexing on macOS can result in multiple events (see [#15]). A +// temporary workaround is to add your folder(s) to the "Spotlight Privacy +// Settings" until we have a native FSEvents implementation (see [#11]). +// +// [#11]: https://github.com/fsnotify/fsnotify/issues/11 +// [#15]: https://github.com/fsnotify/fsnotify/issues/15 +type Watcher struct { + // Events sends the filesystem change events. + // + // fsnotify can send the following events; a "path" here can refer to a + // file, directory, symbolic link, or special file like a FIFO. + // + // fsnotify.Create A new path was created; this may be followed by one + // or more Write events if data also gets written to a + // file. + // + // fsnotify.Remove A path was removed. + // + // fsnotify.Rename A path was renamed. A rename is always sent with the + // old path as Event.Name, and a Create event will be + // sent with the new name. Renames are only sent for + // paths that are currently watched; e.g. moving an + // unmonitored file into a monitored directory will + // show up as just a Create. Similarly, renaming a file + // to outside a monitored directory will show up as + // only a Rename. + // + // fsnotify.Write A file or named pipe was written to. A Truncate will + // also trigger a Write. A single "write action" + // initiated by the user may show up as one or multiple + // writes, depending on when the system syncs things to + // disk. For example when compiling a large Go program + // you may get hundreds of Write events, so you + // probably want to wait until you've stopped receiving + // them (see the dedup example in cmd/fsnotify). + // + // fsnotify.Chmod Attributes were changed. On Linux this is also sent + // when a file is removed (or more accurately, when a + // link to an inode is removed). On kqueue it's sent + // and on kqueue when a file is truncated. On Windows + // it's never sent. + Events chan Event + + // Errors sends any errors. + Errors chan error + + done chan struct{} + kq int // File descriptor (as returned by the kqueue() syscall). + closepipe [2]int // Pipe used for closing. + mu sync.Mutex // Protects access to watcher data + watches map[string]int // Watched file descriptors (key: path). + watchesByDir map[string]map[int]struct{} // Watched file descriptors indexed by the parent directory (key: dirname(path)). + userWatches map[string]struct{} // Watches added with Watcher.Add() + dirFlags map[string]uint32 // Watched directories to fflags used in kqueue. + paths map[int]pathInfo // File descriptors to path names for processing kqueue events. + fileExists map[string]struct{} // Keep track of if we know this file exists (to stop duplicate create events). + isClosed bool // Set to true when Close() is first called +} + +type pathInfo struct { + name string + isDir bool +} + +// NewWatcher creates a new Watcher. +func NewWatcher() (*Watcher, error) { + kq, closepipe, err := newKqueue() + if err != nil { + return nil, err + } + + w := &Watcher{ + kq: kq, + closepipe: closepipe, + watches: make(map[string]int), + watchesByDir: make(map[string]map[int]struct{}), + dirFlags: make(map[string]uint32), + paths: make(map[int]pathInfo), + fileExists: make(map[string]struct{}), + userWatches: make(map[string]struct{}), + Events: make(chan Event), + Errors: make(chan error), + done: make(chan struct{}), + } + + go w.readEvents() + return w, nil +} + +// newKqueue creates a new kernel event queue and returns a descriptor. +// +// This registers a new event on closepipe, which will trigger an event when +// it's closed. This way we can use kevent() without timeout/polling; without +// the closepipe, it would block forever and we wouldn't be able to stop it at +// all. +func newKqueue() (kq int, closepipe [2]int, err error) { + kq, err = unix.Kqueue() + if kq == -1 { + return kq, closepipe, err + } + + // Register the close pipe. + err = unix.Pipe(closepipe[:]) + if err != nil { + unix.Close(kq) + return kq, closepipe, err + } + + // Register changes to listen on the closepipe. + changes := make([]unix.Kevent_t, 1) + // SetKevent converts int to the platform-specific types. + unix.SetKevent(&changes[0], closepipe[0], unix.EVFILT_READ, + unix.EV_ADD|unix.EV_ENABLE|unix.EV_ONESHOT) + + ok, err := unix.Kevent(kq, changes, nil, nil) + if ok == -1 { + unix.Close(kq) + unix.Close(closepipe[0]) + unix.Close(closepipe[1]) + return kq, closepipe, err + } + return kq, closepipe, nil +} + +// Returns true if the event was sent, or false if watcher is closed. +func (w *Watcher) sendEvent(e Event) bool { + select { + case w.Events <- e: + return true + case <-w.done: + } + return false +} + +// Returns true if the error was sent, or false if watcher is closed. +func (w *Watcher) sendError(err error) bool { + select { + case w.Errors <- err: + return true + case <-w.done: + } + return false +} + +// Close removes all watches and closes the events channel. +func (w *Watcher) Close() error { + w.mu.Lock() + if w.isClosed { + w.mu.Unlock() + return nil + } + w.isClosed = true + + // copy paths to remove while locked + pathsToRemove := make([]string, 0, len(w.watches)) + for name := range w.watches { + pathsToRemove = append(pathsToRemove, name) + } + w.mu.Unlock() // Unlock before calling Remove, which also locks + for _, name := range pathsToRemove { + w.Remove(name) + } + + // Send "quit" message to the reader goroutine. + unix.Close(w.closepipe[1]) + close(w.done) + + return nil +} + +// Add starts monitoring the path for changes. +// +// A path can only be watched once; attempting to watch it more than once will +// return an error. Paths that do not yet exist on the filesystem cannot be +// added. A watch will be automatically removed if the path is deleted. +// +// A path will remain watched if it gets renamed to somewhere else on the same +// filesystem, but the monitor will get removed if the path gets deleted and +// re-created, or if it's moved to a different filesystem. +// +// Notifications on network filesystems (NFS, SMB, FUSE, etc.) or special +// filesystems (/proc, /sys, etc.) generally don't work. +// +// # Watching directories +// +// All files in a directory are monitored, including new files that are created +// after the watcher is started. Subdirectories are not watched (i.e. it's +// non-recursive). +// +// # Watching files +// +// Watching individual files (rather than directories) is generally not +// recommended as many tools update files atomically. Instead of "just" writing +// to the file a temporary file will be written to first, and if successful the +// temporary file is moved to to destination removing the original, or some +// variant thereof. The watcher on the original file is now lost, as it no +// longer exists. +// +// Instead, watch the parent directory and use Event.Name to filter out files +// you're not interested in. There is an example of this in [cmd/fsnotify/file.go]. +func (w *Watcher) Add(name string) error { + w.mu.Lock() + w.userWatches[name] = struct{}{} + w.mu.Unlock() + _, err := w.addWatch(name, noteAllEvents) + return err +} + +// Remove stops monitoring the path for changes. +// +// Directories are always removed non-recursively. For example, if you added +// /tmp/dir and /tmp/dir/subdir then you will need to remove both. +// +// Removing a path that has not yet been added returns [ErrNonExistentWatch]. +func (w *Watcher) Remove(name string) error { + name = filepath.Clean(name) + w.mu.Lock() + watchfd, ok := w.watches[name] + w.mu.Unlock() + if !ok { + return fmt.Errorf("%w: %s", ErrNonExistentWatch, name) + } + + err := w.register([]int{watchfd}, unix.EV_DELETE, 0) + if err != nil { + return err + } + + unix.Close(watchfd) + + w.mu.Lock() + isDir := w.paths[watchfd].isDir + delete(w.watches, name) + delete(w.userWatches, name) + + parentName := filepath.Dir(name) + delete(w.watchesByDir[parentName], watchfd) + + if len(w.watchesByDir[parentName]) == 0 { + delete(w.watchesByDir, parentName) + } + + delete(w.paths, watchfd) + delete(w.dirFlags, name) + delete(w.fileExists, name) + w.mu.Unlock() + + // Find all watched paths that are in this directory that are not external. + if isDir { + var pathsToRemove []string + w.mu.Lock() + for fd := range w.watchesByDir[name] { + path := w.paths[fd] + if _, ok := w.userWatches[path.name]; !ok { + pathsToRemove = append(pathsToRemove, path.name) + } + } + w.mu.Unlock() + for _, name := range pathsToRemove { + // Since these are internal, not much sense in propagating error + // to the user, as that will just confuse them with an error about + // a path they did not explicitly watch themselves. + w.Remove(name) + } + } + + return nil +} + +// WatchList returns all paths added with [Add] (and are not yet removed). +func (w *Watcher) WatchList() []string { + w.mu.Lock() + defer w.mu.Unlock() + + entries := make([]string, 0, len(w.userWatches)) + for pathname := range w.userWatches { + entries = append(entries, pathname) + } + + return entries +} + +// Watch all events (except NOTE_EXTEND, NOTE_LINK, NOTE_REVOKE) +const noteAllEvents = unix.NOTE_DELETE | unix.NOTE_WRITE | unix.NOTE_ATTRIB | unix.NOTE_RENAME + +// addWatch adds name to the watched file set. +// The flags are interpreted as described in kevent(2). +// Returns the real path to the file which was added, if any, which may be different from the one passed in the case of symlinks. +func (w *Watcher) addWatch(name string, flags uint32) (string, error) { + var isDir bool + // Make ./name and name equivalent + name = filepath.Clean(name) + + w.mu.Lock() + if w.isClosed { + w.mu.Unlock() + return "", errors.New("kevent instance already closed") + } + watchfd, alreadyWatching := w.watches[name] + // We already have a watch, but we can still override flags. + if alreadyWatching { + isDir = w.paths[watchfd].isDir + } + w.mu.Unlock() + + if !alreadyWatching { + fi, err := os.Lstat(name) + if err != nil { + return "", err + } + + // Don't watch sockets or named pipes + if (fi.Mode()&os.ModeSocket == os.ModeSocket) || (fi.Mode()&os.ModeNamedPipe == os.ModeNamedPipe) { + return "", nil + } + + // Follow Symlinks + // + // Linux can add unresolvable symlinks to the watch list without issue, + // and Windows can't do symlinks period. To maintain consistency, we + // will act like everything is fine if the link can't be resolved. + // There will simply be no file events for broken symlinks. Hence the + // returns of nil on errors. + if fi.Mode()&os.ModeSymlink == os.ModeSymlink { + name, err = filepath.EvalSymlinks(name) + if err != nil { + return "", nil + } + + w.mu.Lock() + _, alreadyWatching = w.watches[name] + w.mu.Unlock() + + if alreadyWatching { + return name, nil + } + + fi, err = os.Lstat(name) + if err != nil { + return "", nil + } + } + + // Retry on EINTR; open() can return EINTR in practice on macOS. + // See #354, and go issues 11180 and 39237. + for { + watchfd, err = unix.Open(name, openMode, 0) + if err == nil { + break + } + if errors.Is(err, unix.EINTR) { + continue + } + + return "", err + } + + isDir = fi.IsDir() + } + + err := w.register([]int{watchfd}, unix.EV_ADD|unix.EV_CLEAR|unix.EV_ENABLE, flags) + if err != nil { + unix.Close(watchfd) + return "", err + } + + if !alreadyWatching { + w.mu.Lock() + parentName := filepath.Dir(name) + w.watches[name] = watchfd + + watchesByDir, ok := w.watchesByDir[parentName] + if !ok { + watchesByDir = make(map[int]struct{}, 1) + w.watchesByDir[parentName] = watchesByDir + } + watchesByDir[watchfd] = struct{}{} + + w.paths[watchfd] = pathInfo{name: name, isDir: isDir} + w.mu.Unlock() + } + + if isDir { + // Watch the directory if it has not been watched before, + // or if it was watched before, but perhaps only a NOTE_DELETE (watchDirectoryFiles) + w.mu.Lock() + + watchDir := (flags&unix.NOTE_WRITE) == unix.NOTE_WRITE && + (!alreadyWatching || (w.dirFlags[name]&unix.NOTE_WRITE) != unix.NOTE_WRITE) + // Store flags so this watch can be updated later + w.dirFlags[name] = flags + w.mu.Unlock() + + if watchDir { + if err := w.watchDirectoryFiles(name); err != nil { + return "", err + } + } + } + return name, nil +} + +// readEvents reads from kqueue and converts the received kevents into +// Event values that it sends down the Events channel. +func (w *Watcher) readEvents() { + defer func() { + err := unix.Close(w.kq) + if err != nil { + w.Errors <- err + } + unix.Close(w.closepipe[0]) + close(w.Events) + close(w.Errors) + }() + + eventBuffer := make([]unix.Kevent_t, 10) + for closed := false; !closed; { + kevents, err := w.read(eventBuffer) + // EINTR is okay, the syscall was interrupted before timeout expired. + if err != nil && err != unix.EINTR { + if !w.sendError(fmt.Errorf("fsnotify.readEvents: %w", err)) { + closed = true + } + continue + } + + // Flush the events we received to the Events channel + for _, kevent := range kevents { + var ( + watchfd = int(kevent.Ident) + mask = uint32(kevent.Fflags) + ) + + // Shut down the loop when the pipe is closed, but only after all + // other events have been processed. + if watchfd == w.closepipe[0] { + closed = true + continue + } + + w.mu.Lock() + path := w.paths[watchfd] + w.mu.Unlock() + + event := w.newEvent(path.name, mask) + + if path.isDir && !event.Has(Remove) { + // Double check to make sure the directory exists. This can + // happen when we do a rm -fr on a recursively watched folders + // and we receive a modification event first but the folder has + // been deleted and later receive the delete event. + if _, err := os.Lstat(event.Name); os.IsNotExist(err) { + event.Op |= Remove + } + } + + if event.Has(Rename) || event.Has(Remove) { + w.Remove(event.Name) + w.mu.Lock() + delete(w.fileExists, event.Name) + w.mu.Unlock() + } + + if path.isDir && event.Has(Write) && !event.Has(Remove) { + w.sendDirectoryChangeEvents(event.Name) + } else { + if !w.sendEvent(event) { + closed = true + continue + } + } + + if event.Has(Remove) { + // Look for a file that may have overwritten this. + // For example, mv f1 f2 will delete f2, then create f2. + if path.isDir { + fileDir := filepath.Clean(event.Name) + w.mu.Lock() + _, found := w.watches[fileDir] + w.mu.Unlock() + if found { + // make sure the directory exists before we watch for changes. When we + // do a recursive watch and perform rm -fr, the parent directory might + // have gone missing, ignore the missing directory and let the + // upcoming delete event remove the watch from the parent directory. + if _, err := os.Lstat(fileDir); err == nil { + w.sendDirectoryChangeEvents(fileDir) + } + } + } else { + filePath := filepath.Clean(event.Name) + if fileInfo, err := os.Lstat(filePath); err == nil { + w.sendFileCreatedEventIfNew(filePath, fileInfo) + } + } + } + } + } +} + +// newEvent returns an platform-independent Event based on kqueue Fflags. +func (w *Watcher) newEvent(name string, mask uint32) Event { + e := Event{Name: name} + if mask&unix.NOTE_DELETE == unix.NOTE_DELETE { + e.Op |= Remove + } + if mask&unix.NOTE_WRITE == unix.NOTE_WRITE { + e.Op |= Write + } + if mask&unix.NOTE_RENAME == unix.NOTE_RENAME { + e.Op |= Rename + } + if mask&unix.NOTE_ATTRIB == unix.NOTE_ATTRIB { + e.Op |= Chmod + } + return e +} + +// watchDirectoryFiles to mimic inotify when adding a watch on a directory +func (w *Watcher) watchDirectoryFiles(dirPath string) error { + // Get all files + files, err := ioutil.ReadDir(dirPath) + if err != nil { + return err + } + + for _, fileInfo := range files { + path := filepath.Join(dirPath, fileInfo.Name()) + + cleanPath, err := w.internalWatch(path, fileInfo) + if err != nil { + // No permission to read the file; that's not a problem: just skip. + // But do add it to w.fileExists to prevent it from being picked up + // as a "new" file later (it still shows up in the directory + // listing). + switch { + case errors.Is(err, unix.EACCES) || errors.Is(err, unix.EPERM): + cleanPath = filepath.Clean(path) + default: + return fmt.Errorf("%q: %w", filepath.Join(dirPath, fileInfo.Name()), err) + } + } + + w.mu.Lock() + w.fileExists[cleanPath] = struct{}{} + w.mu.Unlock() + } + + return nil +} + +// Search the directory for new files and send an event for them. +// +// This functionality is to have the BSD watcher match the inotify, which sends +// a create event for files created in a watched directory. +func (w *Watcher) sendDirectoryChangeEvents(dir string) { + // Get all files + files, err := ioutil.ReadDir(dir) + if err != nil { + if !w.sendError(fmt.Errorf("fsnotify.sendDirectoryChangeEvents: %w", err)) { + return + } + } + + // Search for new files + for _, fi := range files { + err := w.sendFileCreatedEventIfNew(filepath.Join(dir, fi.Name()), fi) + if err != nil { + return + } + } +} + +// sendFileCreatedEvent sends a create event if the file isn't already being tracked. +func (w *Watcher) sendFileCreatedEventIfNew(filePath string, fileInfo os.FileInfo) (err error) { + w.mu.Lock() + _, doesExist := w.fileExists[filePath] + w.mu.Unlock() + if !doesExist { + if !w.sendEvent(Event{Name: filePath, Op: Create}) { + return + } + } + + // like watchDirectoryFiles (but without doing another ReadDir) + filePath, err = w.internalWatch(filePath, fileInfo) + if err != nil { + return err + } + + w.mu.Lock() + w.fileExists[filePath] = struct{}{} + w.mu.Unlock() + + return nil +} + +func (w *Watcher) internalWatch(name string, fileInfo os.FileInfo) (string, error) { + if fileInfo.IsDir() { + // mimic Linux providing delete events for subdirectories + // but preserve the flags used if currently watching subdirectory + w.mu.Lock() + flags := w.dirFlags[name] + w.mu.Unlock() + + flags |= unix.NOTE_DELETE | unix.NOTE_RENAME + return w.addWatch(name, flags) + } + + // watch file to mimic Linux inotify + return w.addWatch(name, noteAllEvents) +} + +// Register events with the queue. +func (w *Watcher) register(fds []int, flags int, fflags uint32) error { + changes := make([]unix.Kevent_t, len(fds)) + for i, fd := range fds { + // SetKevent converts int to the platform-specific types. + unix.SetKevent(&changes[i], fd, unix.EVFILT_VNODE, flags) + changes[i].Fflags = fflags + } + + // Register the events. + success, err := unix.Kevent(w.kq, changes, nil, nil) + if success == -1 { + return err + } + return nil +} + +// read retrieves pending events, or waits until an event occurs. +func (w *Watcher) read(events []unix.Kevent_t) ([]unix.Kevent_t, error) { + n, err := unix.Kevent(w.kq, nil, events, nil) + if err != nil { + return nil, err + } + return events[0:n], nil +}