504 lines
13 KiB
Go
504 lines
13 KiB
Go
|
// Copyright 2010 The Go Authors. All rights reserved.
|
||
|
|
// Use of this source code is governed by a BSD-style
|
||
|
|
// license that can be found in the LICENSE file.
|
||
|
|
|
||
|
|
// +build freebsd openbsd netbsd dragonfly darwin
|
||
|
|
|
||
|
|
package fsnotify
|
||
|
|
|
||
|
|
import (
|
||
|
|
"errors"
|
||
|
|
"fmt"
|
||
|
|
"io/ioutil"
|
||
|
|
"os"
|
||
|
|
"path/filepath"
|
||
|
|
"sync"
|
||
|
|
"time"
|
||
|
|
|
||
|
|
"golang.org/x/sys/unix"
|
||
|
|
)
|
||
|
|
|
||
|
|
// Watcher watches a set of files, delivering events to a channel.
|
||
|
|
type Watcher struct {
|
||
|
|
Events chan Event
|
||
|
|
Errors chan error
|
||
|
|
done chan bool // Channel for sending a "quit message" to the reader goroutine
|
||
|
|
|
||
|
|
kq int // File descriptor (as returned by the kqueue() syscall).
|
||
|
|
|
||
|
|
mu sync.Mutex // Protects access to watcher data
|
||
|
|
watches map[string]int // Map of watched file descriptors (key: path).
|
||
|
|
externalWatches map[string]bool // Map of watches added by user of the library.
|
||
|
|
dirFlags map[string]uint32 // Map of watched directories to fflags used in kqueue.
|
||
|
|
paths map[int]pathInfo // Map file descriptors to path names for processing kqueue events.
|
||
|
|
fileExists map[string]bool // 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 establishes a new watcher with the underlying OS and begins waiting for events.
|
||
|
|
func NewWatcher() (*Watcher, error) {
|
||
|
|
kq, err := kqueue()
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
|
||
|
|
w := &Watcher{
|
||
|
|
kq: kq,
|
||
|
|
watches: make(map[string]int),
|
||
|
|
dirFlags: make(map[string]uint32),
|
||
|
|
paths: make(map[int]pathInfo),
|
||
|
|
fileExists: make(map[string]bool),
|
||
|
|
externalWatches: make(map[string]bool),
|
||
|
|
Events: make(chan Event),
|
||
|
|
Errors: make(chan error),
|
||
|
|
done: make(chan bool),
|
||
|
|
}
|
||
|
|
|
||
|
|
go w.readEvents()
|
||
|
|
return w, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// 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
|
||
|
|
w.mu.Unlock()
|
||
|
|
|
||
|
|
// copy paths to remove while locked
|
||
|
|
w.mu.Lock()
|
||
|
|
var 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
|
||
|
|
|
||
|
|
var err error
|
||
|
|
for _, name := range pathsToRemove {
|
||
|
|
if e := w.Remove(name); e != nil && err == nil {
|
||
|
|
err = e
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Send "quit" message to the reader goroutine:
|
||
|
|
w.done <- true
|
||
|
|
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// Add starts watching the named file or directory (non-recursively).
|
||
|
|
func (w *Watcher) Add(name string) error {
|
||
|
|
w.mu.Lock()
|
||
|
|
w.externalWatches[name] = true
|
||
|
|
w.mu.Unlock()
|
||
|
|
_, err := w.addWatch(name, noteAllEvents)
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
|
||
|
|
// Remove stops watching the the named file or directory (non-recursively).
|
||
|
|
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("can't remove non-existent kevent watch for: %s", name)
|
||
|
|
}
|
||
|
|
|
||
|
|
const registerRemove = unix.EV_DELETE
|
||
|
|
if err := register(w.kq, []int{watchfd}, registerRemove, 0); err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
|
||
|
|
unix.Close(watchfd)
|
||
|
|
|
||
|
|
w.mu.Lock()
|
||
|
|
isDir := w.paths[watchfd].isDir
|
||
|
|
delete(w.watches, name)
|
||
|
|
delete(w.paths, watchfd)
|
||
|
|
delete(w.dirFlags, 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 _, path := range w.paths {
|
||
|
|
wdir, _ := filepath.Split(path.name)
|
||
|
|
if filepath.Clean(wdir) == name {
|
||
|
|
if !w.externalWatches[path.name] {
|
||
|
|
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
|
||
|
|
}
|
||
|
|
|
||
|
|
// Watch all events (except NOTE_EXTEND, NOTE_LINK, NOTE_REVOKE)
|
||
|
|
const noteAllEvents = unix.NOTE_DELETE | unix.NOTE_WRITE | unix.NOTE_ATTRIB | unix.NOTE_RENAME
|
||
|
|
|
||
|
|
// keventWaitTime to block on each read from kevent
|
||
|
|
var keventWaitTime = durationToTimespec(100 * time.Millisecond)
|
||
|
|
|
||
|
|
// 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.
|
||
|
|
if fi.Mode()&os.ModeSocket == os.ModeSocket {
|
||
|
|
return "", nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// Don't watch named pipes.
|
||
|
|
if fi.Mode()&os.ModeNamedPipe == os.ModeNamedPipe {
|
||
|
|
return "", nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// Follow Symlinks
|
||
|
|
// Unfortunately, Linux can add bogus symlinks to watch list without
|
||
|
|
// issue, and Windows can't do symlinks period (AFAIK). To maintain
|
||
|
|
// consistency, we will act like everything is fine. 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
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
watchfd, err = unix.Open(name, openMode, 0700)
|
||
|
|
if watchfd == -1 {
|
||
|
|
return "", err
|
||
|
|
}
|
||
|
|
|
||
|
|
isDir = fi.IsDir()
|
||
|
|
}
|
||
|
|
|
||
|
|
const registerAdd = unix.EV_ADD | unix.EV_CLEAR | unix.EV_ENABLE
|
||
|
|
if err := register(w.kq, []int{watchfd}, registerAdd, flags); err != nil {
|
||
|
|
unix.Close(watchfd)
|
||
|
|
return "", err
|
||
|
|
}
|
||
|
|
|
||
|
|
if !alreadyWatching {
|
||
|
|
w.mu.Lock()
|
||
|
|
w.watches[name] = watchfd
|
||
|
|
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() {
|
||
|
|
eventBuffer := make([]unix.Kevent_t, 10)
|
||
|
|
|
||
|
|
for {
|
||
|
|
// See if there is a message on the "done" channel
|
||
|
|
select {
|
||
|
|
case <-w.done:
|
||
|
|
err := unix.Close(w.kq)
|
||
|
|
if err != nil {
|
||
|
|
w.Errors <- err
|
||
|
|
}
|
||
|
|
close(w.Events)
|
||
|
|
close(w.Errors)
|
||
|
|
return
|
||
|
|
default:
|
||
|
|
}
|
||
|
|
|
||
|
|
// Get new events
|
||
|
|
kevents, err := read(w.kq, eventBuffer, &keventWaitTime)
|
||
|
|
// EINTR is okay, the syscall was interrupted before timeout expired.
|
||
|
|
if err != nil && err != unix.EINTR {
|
||
|
|
w.Errors <- err
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
|
||
|
|
// Flush the events we received to the Events channel
|
||
|
|
for len(kevents) > 0 {
|
||
|
|
kevent := &kevents[0]
|
||
|
|
watchfd := int(kevent.Ident)
|
||
|
|
mask := uint32(kevent.Fflags)
|
||
|
|
w.mu.Lock()
|
||
|
|
path := w.paths[watchfd]
|
||
|
|
w.mu.Unlock()
|
||
|
|
event := newEvent(path.name, mask)
|
||
|
|
|
||
|
|
if path.isDir && !(event.Op&Remove == 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) {
|
||
|
|
// mark is as delete event
|
||
|
|
event.Op |= Remove
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if event.Op&Rename == Rename || event.Op&Remove == Remove {
|
||
|
|
w.Remove(event.Name)
|
||
|
|
w.mu.Lock()
|
||
|
|
delete(w.fileExists, event.Name)
|
||
|
|
w.mu.Unlock()
|
||
|
|
}
|
||
|
|
|
||
|
|
if path.isDir && event.Op&Write == Write && !(event.Op&Remove == Remove) {
|
||
|
|
w.sendDirectoryChangeEvents(event.Name)
|
||
|
|
} else {
|
||
|
|
// Send the event on the Events channel
|
||
|
|
w.Events <- event
|
||
|
|
}
|
||
|
|
|
||
|
|
if event.Op&Remove == 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)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Move to next event
|
||
|
|
kevents = kevents[1:]
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// newEvent returns an platform-independent Event based on kqueue Fflags.
|
||
|
|
func 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
|
||
|
|
}
|
||
|
|
|
||
|
|
func newCreateEvent(name string) Event {
|
||
|
|
return Event{Name: name, Op: Create}
|
||
|
|
}
|
||
|
|
|
||
|
|
// 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 {
|
||
|
|
filePath := filepath.Join(dirPath, fileInfo.Name())
|
||
|
|
filePath, err = w.internalWatch(filePath, fileInfo)
|
||
|
|
if err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
|
||
|
|
w.mu.Lock()
|
||
|
|
w.fileExists[filePath] = true
|
||
|
|
w.mu.Unlock()
|
||
|
|
}
|
||
|
|
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// sendDirectoryEvents searches the directory for newly created files
|
||
|
|
// and sends them over the event channel. This functionality is to have
|
||
|
|
// the BSD version of fsnotify match Linux inotify which provides a
|
||
|
|
// create event for files created in a watched directory.
|
||
|
|
func (w *Watcher) sendDirectoryChangeEvents(dirPath string) {
|
||
|
|
// Get all files
|
||
|
|
files, err := ioutil.ReadDir(dirPath)
|
||
|
|
if err != nil {
|
||
|
|
w.Errors <- err
|
||
|
|
}
|
||
|
|
|
||
|
|
// Search for new files
|
||
|
|
for _, fileInfo := range files {
|
||
|
|
filePath := filepath.Join(dirPath, fileInfo.Name())
|
||
|
|
err := w.sendFileCreatedEventIfNew(filePath, fileInfo)
|
||
|
|
|
||
|
|
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 {
|
||
|
|
// Send create event
|
||
|
|
w.Events <- newCreateEvent(filePath)
|
||
|
|
}
|
||
|
|
|
||
|
|
// like watchDirectoryFiles (but without doing another ReadDir)
|
||
|
|
filePath, err = w.internalWatch(filePath, fileInfo)
|
||
|
|
if err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
|
||
|
|
w.mu.Lock()
|
||
|
|
w.fileExists[filePath] = true
|
||
|
|
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)
|
||
|
|
}
|
||
|
|
|
||
|
|
// kqueue creates a new kernel event queue and returns a descriptor.
|
||
|
|
func kqueue() (kq int, err error) {
|
||
|
|
kq, err = unix.Kqueue()
|
||
|
|
if kq == -1 {
|
||
|
|
return kq, err
|
||
|
|
}
|
||
|
|
return kq, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// register events with the queue
|
||
|
|
func register(kq int, 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(kq, changes, nil, nil)
|
||
|
|
if success == -1 {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// read retrieves pending events, or waits until an event occurs.
|
||
|
|
// A timeout of nil blocks indefinitely, while 0 polls the queue.
|
||
|
|
func read(kq int, events []unix.Kevent_t, timeout *unix.Timespec) ([]unix.Kevent_t, error) {
|
||
|
|
n, err := unix.Kevent(kq, nil, events, timeout)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
return events[0:n], nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// durationToTimespec prepares a timeout value
|
||
|
|
func durationToTimespec(d time.Duration) unix.Timespec {
|
||
|
|
return unix.NsecToTimespec(d.Nanoseconds())
|
||
|
|
}
|