blob: bd4d9d80cc76539a0e38ee250464e5c5643f77e6 [file] [log] [blame]
// 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 darwin
package fsnotify
import (
"errors"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"sync"
"syscall"
)
const (
// Flags (from <sys/event.h>)
sys_NOTE_DELETE = 0x0001 /* vnode was removed */
sys_NOTE_WRITE = 0x0002 /* data contents changed */
sys_NOTE_EXTEND = 0x0004 /* size increased */
sys_NOTE_ATTRIB = 0x0008 /* attributes changed */
sys_NOTE_LINK = 0x0010 /* link count changed */
sys_NOTE_RENAME = 0x0020 /* vnode was renamed */
sys_NOTE_REVOKE = 0x0040 /* vnode access was revoked */
// Watch all events
sys_NOTE_ALLEVENTS = sys_NOTE_DELETE | sys_NOTE_WRITE | sys_NOTE_ATTRIB | sys_NOTE_RENAME
// Block for 100 ms on each call to kevent
keventWaitTime = 100e6
)
type FileEvent struct {
mask uint32 // Mask of events
Name string // File name (optional)
create bool // set by fsnotify package if found new file
}
// IsCreate reports whether the FileEvent was triggerd by a creation
func (e *FileEvent) IsCreate() bool { return e.create }
// IsDelete reports whether the FileEvent was triggerd by a delete
func (e *FileEvent) IsDelete() bool { return (e.mask & sys_NOTE_DELETE) == sys_NOTE_DELETE }
// IsModify reports whether the FileEvent was triggerd by a file modification
func (e *FileEvent) IsModify() bool {
return ((e.mask&sys_NOTE_WRITE) == sys_NOTE_WRITE || (e.mask&sys_NOTE_ATTRIB) == sys_NOTE_ATTRIB)
}
// IsRename reports whether the FileEvent was triggerd by a change name
func (e *FileEvent) IsRename() bool { return (e.mask & sys_NOTE_RENAME) == sys_NOTE_RENAME }
type Watcher struct {
mu sync.Mutex // Mutex for the Watcher itself.
kq int // File descriptor (as returned by the kqueue() syscall)
watches map[string]int // Map of watched file diescriptors (key: path)
wmut sync.Mutex // Protects access to watches.
fsnFlags map[string]uint32 // Map of watched files to flags used for filter
fsnmut sync.Mutex // Protects access to fsnFlags.
enFlags map[string]uint32 // Map of watched files to evfilt note flags used in kqueue
enmut sync.Mutex // Protects access to enFlags.
paths map[int]string // Map of watched paths (key: watch descriptor)
finfo map[int]os.FileInfo // Map of file information (isDir, isReg; key: watch descriptor)
pmut sync.Mutex // Protects access to paths and finfo.
fileExists map[string]bool // Keep track of if we know this file exists (to stop duplicate create events)
femut sync.Mutex // Proctects access to fileExists.
Error chan error // Errors are sent on this channel
internalEvent chan *FileEvent // Events are queued on this channel
Event chan *FileEvent // Events are returned on this channel
done chan bool // Channel for sending a "quit message" to the reader goroutine
isClosed bool // Set to true when Close() is first called
kbuf [1]syscall.Kevent_t // An event buffer for Add/Remove watch
bufmut sync.Mutex // Protects access to kbuf.
}
// NewWatcher creates and returns a new kevent instance using kqueue(2)
func NewWatcher() (*Watcher, error) {
fd, errno := syscall.Kqueue()
if fd == -1 {
return nil, os.NewSyscallError("kqueue", errno)
}
w := &Watcher{
kq: fd,
watches: make(map[string]int),
fsnFlags: make(map[string]uint32),
enFlags: make(map[string]uint32),
paths: make(map[int]string),
finfo: make(map[int]os.FileInfo),
fileExists: make(map[string]bool),
internalEvent: make(chan *FileEvent),
Event: make(chan *FileEvent),
Error: make(chan error),
done: make(chan bool, 1),
}
go w.readEvents()
go w.purgeEvents()
return w, nil
}
// Close closes a kevent watcher instance
// It sends a message to the reader goroutine to quit and removes all watches
// associated with the kevent instance
func (w *Watcher) Close() error {
w.mu.Lock()
if w.isClosed {
w.mu.Unlock()
return nil
}
w.isClosed = true
w.mu.Unlock()
// Send "quit" message to the reader goroutine
w.done <- true
w.pmut.Lock()
ws := w.watches
w.pmut.Unlock()
for path := range ws {
w.removeWatch(path)
}
return nil
}
// AddWatch adds path to the watched file set.
// The flags are interpreted as described in kevent(2).
func (w *Watcher) addWatch(path string, flags uint32) error {
w.mu.Lock()
if w.isClosed {
w.mu.Unlock()
return errors.New("kevent instance already closed")
}
w.mu.Unlock()
watchDir := false
w.wmut.Lock()
watchfd, found := w.watches[path]
w.wmut.Unlock()
if !found {
fi, errstat := os.Lstat(path)
if errstat != nil {
return errstat
}
// don't watch socket
if fi.Mode()&os.ModeSocket == os.ModeSocket {
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 {
path, err := filepath.EvalSymlinks(path)
if err != nil {
return nil
}
fi, errstat = os.Lstat(path)
if errstat != nil {
return nil
}
}
fd, errno := syscall.Open(path, open_FLAGS, 0700)
if fd == -1 {
return errno
}
watchfd = fd
w.wmut.Lock()
w.watches[path] = watchfd
w.wmut.Unlock()
w.pmut.Lock()
w.paths[watchfd] = path
w.finfo[watchfd] = fi
w.pmut.Unlock()
}
// Watch the directory if it has not been watched before.
w.pmut.Lock()
w.enmut.Lock()
if w.finfo[watchfd].IsDir() &&
(flags&sys_NOTE_WRITE) == sys_NOTE_WRITE &&
(!found || (w.enFlags[path]&sys_NOTE_WRITE) != sys_NOTE_WRITE) {
watchDir = true
}
w.enmut.Unlock()
w.pmut.Unlock()
w.enmut.Lock()
w.enFlags[path] = flags
w.enmut.Unlock()
w.bufmut.Lock()
watchEntry := &w.kbuf[0]
watchEntry.Fflags = flags
syscall.SetKevent(watchEntry, watchfd, syscall.EVFILT_VNODE, syscall.EV_ADD|syscall.EV_CLEAR)
entryFlags := watchEntry.Flags
w.bufmut.Unlock()
wd, errno := syscall.Kevent(w.kq, w.kbuf[:], nil, nil)
if wd == -1 {
return errno
} else if (entryFlags & syscall.EV_ERROR) == syscall.EV_ERROR {
return errors.New("kevent add error")
}
if watchDir {
errdir := w.watchDirectoryFiles(path)
if errdir != nil {
return errdir
}
}
return nil
}
// Watch adds path to the watched file set, watching all events.
func (w *Watcher) watch(path string) error {
return w.addWatch(path, sys_NOTE_ALLEVENTS)
}
// RemoveWatch removes path from the watched file set.
func (w *Watcher) removeWatch(path string) error {
w.wmut.Lock()
watchfd, ok := w.watches[path]
w.wmut.Unlock()
if !ok {
return errors.New(fmt.Sprintf("can't remove non-existent kevent watch for: %s", path))
}
w.bufmut.Lock()
defer w.bufmut.Unlock()
watchEntry := &w.kbuf[0]
syscall.SetKevent(watchEntry, watchfd, syscall.EVFILT_VNODE, syscall.EV_DELETE)
success, errno := syscall.Kevent(w.kq, w.kbuf[:], nil, nil)
if success == -1 {
return os.NewSyscallError("kevent_rm_watch", errno)
} else if (watchEntry.Flags & syscall.EV_ERROR) == syscall.EV_ERROR {
return errors.New("kevent rm error")
}
syscall.Close(watchfd)
w.wmut.Lock()
delete(w.watches, path)
w.wmut.Unlock()
w.enmut.Lock()
delete(w.enFlags, path)
w.enmut.Unlock()
w.pmut.Lock()
delete(w.paths, watchfd)
delete(w.finfo, watchfd)
w.pmut.Unlock()
return nil
}
// readEvents reads from the kqueue file descriptor, converts the
// received events into Event objects and sends them via the Event channel
func (w *Watcher) readEvents() {
var (
eventbuf [10]syscall.Kevent_t // Event buffer
events []syscall.Kevent_t // Received events
twait *syscall.Timespec // Time to block waiting for events
n int // Number of events returned from kevent
errno error // Syscall errno
)
events = eventbuf[0:0]
twait = new(syscall.Timespec)
*twait = syscall.NsecToTimespec(keventWaitTime)
for {
// See if there is a message on the "done" channel
var done bool
select {
case done = <-w.done:
default:
}
// If "done" message is received
if done {
errno := syscall.Close(w.kq)
if errno != nil {
w.Error <- os.NewSyscallError("close", errno)
}
close(w.internalEvent)
close(w.Error)
return
}
// Get new events
if len(events) == 0 {
n, errno = syscall.Kevent(w.kq, nil, eventbuf[:], twait)
// EINTR is okay, basically the syscall was interrupted before
// timeout expired.
if errno != nil && errno != syscall.EINTR {
w.Error <- os.NewSyscallError("kevent", errno)
continue
}
// Received some events
if n > 0 {
events = eventbuf[0:n]
}
}
// Flush the events we recieved to the events channel
for len(events) > 0 {
fileEvent := new(FileEvent)
watchEvent := &events[0]
fileEvent.mask = uint32(watchEvent.Fflags)
w.pmut.Lock()
fileEvent.Name = w.paths[int(watchEvent.Ident)]
fileInfo := w.finfo[int(watchEvent.Ident)]
w.pmut.Unlock()
if fileInfo.IsDir() && !fileEvent.IsDelete() {
// Double check to make sure the directory exist. 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(fileEvent.Name); os.IsNotExist(err) {
// mark is as delete event
fileEvent.mask |= sys_NOTE_DELETE
}
}
if fileInfo.IsDir() && fileEvent.IsModify() && !fileEvent.IsDelete() {
w.sendDirectoryChangeEvents(fileEvent.Name)
} else {
// Send the event on the events channel
w.internalEvent <- fileEvent
}
// Move to next event
events = events[1:]
if fileEvent.IsRename() {
w.removeWatch(fileEvent.Name)
w.femut.Lock()
delete(w.fileExists, fileEvent.Name)
w.femut.Unlock()
}
if fileEvent.IsDelete() {
w.removeWatch(fileEvent.Name)
w.femut.Lock()
delete(w.fileExists, fileEvent.Name)
w.femut.Unlock()
// Look for a file that may have overwritten this
// (ie mv f1 f2 will delete f2 then create f2)
fileDir, _ := filepath.Split(fileEvent.Name)
fileDir = filepath.Clean(fileDir)
w.wmut.Lock()
_, found := w.watches[fileDir]
w.wmut.Unlock()
if found {
// make sure the directory exist 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 form the parent folder
if _, err := os.Lstat(fileDir); !os.IsNotExist(err) {
w.sendDirectoryChangeEvents(fileDir)
}
}
}
}
}
}
func (w *Watcher) watchDirectoryFiles(dirPath string) error {
// Get all files
files, err := ioutil.ReadDir(dirPath)
if err != nil {
return err
}
// Search for new files
for _, fileInfo := range files {
filePath := filepath.Join(dirPath, fileInfo.Name())
// Inherit fsnFlags from parent directory
w.fsnmut.Lock()
if flags, found := w.fsnFlags[dirPath]; found {
w.fsnFlags[filePath] = flags
} else {
w.fsnFlags[filePath] = FSN_ALL
}
w.fsnmut.Unlock()
if fileInfo.IsDir() == false {
// Watch file to mimic linux fsnotify
e := w.addWatch(filePath, sys_NOTE_ALLEVENTS)
if e != nil {
return e
}
} else {
// If the user is currently waching directory
// we want to preserve the flags used
w.enmut.Lock()
currFlags, found := w.enFlags[filePath]
w.enmut.Unlock()
var newFlags uint32 = sys_NOTE_DELETE
if found {
newFlags |= currFlags
}
// Linux gives deletes if not explicitly watching
e := w.addWatch(filePath, newFlags)
if e != nil {
return e
}
}
w.femut.Lock()
w.fileExists[filePath] = true
w.femut.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 mach linux fsnotify 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.Error <- err
}
// Search for new files
for _, fileInfo := range files {
filePath := filepath.Join(dirPath, fileInfo.Name())
w.femut.Lock()
_, doesExist := w.fileExists[filePath]
w.femut.Unlock()
if !doesExist {
// Inherit fsnFlags from parent directory
w.fsnmut.Lock()
if flags, found := w.fsnFlags[dirPath]; found {
w.fsnFlags[filePath] = flags
} else {
w.fsnFlags[filePath] = FSN_ALL
}
w.fsnmut.Unlock()
// Send create event
fileEvent := new(FileEvent)
fileEvent.Name = filePath
fileEvent.create = true
w.internalEvent <- fileEvent
}
w.femut.Lock()
w.fileExists[filePath] = true
w.femut.Unlock()
}
w.watchDirectoryFiles(dirPath)
}