forked from howeyc/fsnotify
-
Notifications
You must be signed in to change notification settings - Fork 0
/
fsnotify_bsd.go
387 lines (338 loc) · 11.3 KB
/
fsnotify_bsd.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
// 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 implements filesystem notification.
package fsnotify
import (
"errors"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"syscall"
)
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 & NOTE_DELETE) == NOTE_DELETE }
// IsModify reports whether the FileEvent was triggerd by a file modification
func (e *FileEvent) IsModify() bool {
return ((e.mask&NOTE_WRITE) == NOTE_WRITE || (e.mask&NOTE_ATTRIB) == NOTE_ATTRIB)
}
// IsRename reports whether the FileEvent was triggerd by a change name
func (e *FileEvent) IsRename() bool { return (e.mask & NOTE_RENAME) == NOTE_RENAME }
type Watcher struct {
kq int // File descriptor (as returned by the kqueue() syscall)
watches map[string]int // Map of watched file diescriptors (key: path)
fsnFlags map[string]uint32 // Map of watched files to flags used for filter
enFlags map[string]uint32 // Map of watched files to evfilt note flags used in kqueue
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)
fileExists map[string]bool // Keep track of if we know this file exists (to stop duplicate create events)
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
}
// 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 {
if w.isClosed {
return nil
}
w.isClosed = true
// Send "quit" message to the reader goroutine
w.done <- true
for path := range w.watches {
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 {
if w.isClosed {
return errors.New("kevent instance already closed")
}
watchDir := false
watchfd, found := w.watches[path]
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, syscall.O_NONBLOCK|syscall.O_RDONLY, 0700)
if fd == -1 {
return errno
}
watchfd = fd
w.watches[path] = watchfd
w.paths[watchfd] = path
w.finfo[watchfd] = fi
}
// Watch the directory if it has not been watched before.
if w.finfo[watchfd].IsDir() &&
(flags&NOTE_WRITE) == NOTE_WRITE &&
(!found || (w.enFlags[path]&NOTE_WRITE) != NOTE_WRITE) {
watchDir = true
}
w.enFlags[path] = flags
watchEntry := &w.kbuf[0]
watchEntry.Fflags = flags
syscall.SetKevent(watchEntry, watchfd, syscall.EVFILT_VNODE, syscall.EV_ADD|syscall.EV_CLEAR)
wd, errno := syscall.Kevent(w.kq, w.kbuf[:], nil, nil)
if wd == -1 {
return errno
} else if (watchEntry.Flags & 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, NOTE_ALLEVENTS)
}
// RemoveWatch removes path from the watched file set.
func (w *Watcher) removeWatch(path string) error {
watchfd, ok := w.watches[path]
if !ok {
return errors.New(fmt.Sprintf("can't remove non-existent kevent watch for: %s", path))
}
watchEntry := &w.kbuf[0]
syscall.SetKevent(watchEntry, w.watches[path], 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)
delete(w.watches, path)
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)
fileEvent.Name = w.paths[int(watchEvent.Ident)]
fileInfo := w.finfo[int(watchEvent.Ident)]
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 |= 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)
delete(w.fileExists, fileEvent.Name)
}
if fileEvent.IsDelete() {
w.removeWatch(fileEvent.Name)
delete(w.fileExists, fileEvent.Name)
// 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)
if _, found := w.watches[fileDir]; 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())
if fileInfo.IsDir() == false {
// Watch file to mimic linux fsnotify
e := w.addWatch(filePath, NOTE_DELETE|NOTE_WRITE|NOTE_RENAME)
w.fsnFlags[filePath] = FSN_ALL
if e != nil {
return e
}
} else {
// If the user is currently waching directory
// we want to preserve the flags used
currFlags, found := w.enFlags[filePath]
var newFlags uint32 = NOTE_DELETE
if found {
newFlags |= currFlags
}
// Linux gives deletes if not explicitly watching
e := w.addWatch(filePath, newFlags)
w.fsnFlags[filePath] = FSN_ALL
if e != nil {
return e
}
}
w.fileExists[filePath] = true
}
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())
_, doesExist := w.fileExists[filePath]
if doesExist == false {
w.fsnFlags[filePath] = FSN_ALL
// Send create event
fileEvent := new(FileEvent)
fileEvent.Name = filePath
fileEvent.create = true
w.internalEvent <- fileEvent
}
w.fileExists[filePath] = true
}
w.watchDirectoryFiles(dirPath)
}
const (
// Flags (from <sys/event.h>)
NOTE_DELETE = 0x0001 /* vnode was removed */
NOTE_WRITE = 0x0002 /* data contents changed */
NOTE_EXTEND = 0x0004 /* size increased */
NOTE_ATTRIB = 0x0008 /* attributes changed */
NOTE_LINK = 0x0010 /* link count changed */
NOTE_RENAME = 0x0020 /* vnode was renamed */
NOTE_REVOKE = 0x0040 /* vnode access was revoked */
// Watch all events
NOTE_ALLEVENTS = NOTE_DELETE | NOTE_WRITE | NOTE_ATTRIB | NOTE_RENAME
// Block for 100 ms on each call to kevent
keventWaitTime = 100e6
)