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Inotify file system watching for linux.

This commit is contained in:
Alexander Andreev 2022-02-08 00:23:40 +04:00
parent 6a8da44ee5
commit 04dedc5f5c
Signed by: Arav
GPG Key ID: 1327FE8A374CC86F

79
pkg/watcher/linux.go Normal file
View File

@ -0,0 +1,79 @@
package watcher
import (
"syscall"
"unsafe"
"github.com/pkg/errors"
)
const CrDelMask uint32 = syscall.IN_CREATE | syscall.IN_DELETE
type FSWatcher struct {
fd int
wds []int
closed bool
}
func NewFSWatcher() (fsw *FSWatcher, err error) {
fsw = &FSWatcher{closed: false}
fsw.fd, err = syscall.InotifyInit()
if err != nil {
return nil, errors.Wrap(err, "failed to initialise inotify watcher")
}
fsw.wds = make([]int, 0)
return nil, nil
}
func (fsw *FSWatcher) AddWatch(path string, mask uint32) error {
wd, err := syscall.InotifyAddWatch(fsw.fd, path, mask)
if err != nil {
return errors.Wrapf(err, "failed to set %s on watch", path)
}
fsw.wds = append(fsw.wds, wd)
syscall.Read(fsw.fd, nil)
return nil
}
// WatchForMask checking for events from mask and returns inotify mask to channel.
func (fsw *FSWatcher) WatchForMask(fired chan uint32, mask uint32) {
buffer := make([]byte, syscall.SizeofInotifyEvent)
go func() {
for !fsw.closed {
n, err := syscall.Read(fsw.fd, buffer)
if err != nil {
break
}
if n < syscall.SizeofInotifyEvent {
continue
}
event := (*syscall.InotifyEvent)(unsafe.Pointer(&buffer[0]))
if event.Mask&mask > 0 {
fired <- event.Mask
}
}
}()
}
func (fsw *FSWatcher) Close() error {
for _, wd := range fsw.wds {
if _, err := syscall.InotifyRmWatch(fsw.fd, uint32(wd)); err != nil {
return err
}
}
if err := syscall.Close(fsw.fd); err != nil {
return err
}
fsw.closed = true
return nil
}